U.S. patent application number 13/881295 was filed with the patent office on 2013-10-31 for capsule for non-ferrous metal collection and method of collecting non-ferrous metal.
This patent application is currently assigned to MORISHITA JINTAN CO., LTD.. The applicant listed for this patent is Taku Hashimoto, Ryosei Kamaguchi, Yasuhiro Konishi, Masaaki Nakatsuji, Daisuke Tagawa, Koshiro Tamaoki. Invention is credited to Taku Hashimoto, Ryosei Kamaguchi, Yasuhiro Konishi, Masaaki Nakatsuji, Daisuke Tagawa, Koshiro Tamaoki.
Application Number | 20130288330 13/881295 |
Document ID | / |
Family ID | 46024530 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130288330 |
Kind Code |
A1 |
Konishi; Yasuhiro ; et
al. |
October 31, 2013 |
CAPSULE FOR NON-FERROUS METAL COLLECTION AND METHOD OF COLLECTING
NON-FERROUS METAL
Abstract
Provided are: a capsule for non-ferrous metal collection that
can collect a non-ferrous metal; and a method for collecting a
non-ferrous metal using same. The capsule for non-ferrous metal
collection comprises capsule contents and a covering section
covering the capsule contents, and collects a non-ferrous metal
within the capsule for non-ferrous metal collection by means of the
capsule for non-ferrous metal collection being immersed in a
solution containing a non-ferrous metal.
Inventors: |
Konishi; Yasuhiro;
(Sakai-shi, JP) ; Tamaoki; Koshiro; (Sakai-shi,
JP) ; Kamaguchi; Ryosei; (Hirakata-shi, JP) ;
Tagawa; Daisuke; (Hirakata-shi, JP) ; Hashimoto;
Taku; (Hirakata-shi, JP) ; Nakatsuji; Masaaki;
(Hirakata-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Konishi; Yasuhiro
Tamaoki; Koshiro
Kamaguchi; Ryosei
Tagawa; Daisuke
Hashimoto; Taku
Nakatsuji; Masaaki |
Sakai-shi
Sakai-shi
Hirakata-shi
Hirakata-shi
Hirakata-shi
Hirakata-shi |
|
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
MORISHITA JINTAN CO., LTD.
Osaka-shi, Osaka
JP
KONISHI; Yasuhiro
Sakai-shi, Osaka
JP
|
Family ID: |
46024530 |
Appl. No.: |
13/881295 |
Filed: |
November 2, 2011 |
PCT Filed: |
November 2, 2011 |
PCT NO: |
PCT/JP2011/075311 |
371 Date: |
July 3, 2013 |
Current U.S.
Class: |
435/182 ;
435/174; 435/262 |
Current CPC
Class: |
C22B 7/006 20130101;
A61K 2035/128 20130101; Y02P 10/234 20151101; B01J 13/14 20130101;
B29K 2101/12 20130101; C22B 3/24 20130101; B01J 13/206 20130101;
Y02P 10/20 20151101; C22B 3/18 20130101; B29C 35/0805 20130101;
B29C 48/21 20190201; Y02P 10/238 20151101; C12N 1/20 20130101; B29C
2035/0827 20130101 |
Class at
Publication: |
435/182 ;
435/174; 435/262 |
International
Class: |
C22B 3/18 20060101
C22B003/18 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2010 |
JP |
2010-246200 |
Claims
1. A capsule for collecting a non-ferrous metal comprising a
capsule content and a shell covering the capsule content, wherein
the capsule is immersed in a solution containing the non-ferrous
metal to collect the non-ferrous metal in the capsule.
2. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule content comprises one or more bacteria
selected from the group consisting of Geobacter bacteria,
Desulfomonas bacteria, Desulfuromusa bacteria, Pelobacter bacteria,
Shewanella bacteria, Ferrimonas bacteria, Aeromonas bacteria,
Sulfurospirillum bacteria, Wolinella bacteria, Desulfovibrio
bacteria, Geothrix bacteria, Deferribacter bacteria, Geovibrio
bacteria, Pyrobaculum bacteria, Thermotogae bacteria, Archaeoglobus
bacteria, Pyrococcus bacteria and Pyrodictium bacteria.
3. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule content comprises Shewanella
bacteria.
4. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule content comprises Shewanella
oneidensis or Shewanella algae.
5. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the non-ferrous metal to be collected is one or
more selected from the group consisting of a rare metal and a rare
noble metal.
6. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the non-ferrous metal to be collected is
palladium, platinum, rhodium, gold, silver, indium, gallium or a
rare earth element.
7. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule content further comprises at least one
selected from the group consisting of an electron donating
component, an electron accepting component and a liquid culture
medium.
8. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule for collecting a non-ferrous metal is
a seamless capsule.
9. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the shell is obtained by curing a shell formation
composition comprising a photocurable component and a shell
permeation aid.
10. The capsule for collecting a non-ferrous metal according to
claim 9, wherein the photocurable component is one or more selected
from the group consisting of an acrylate-based oligomer, an
unsaturated polyester-based oligomer, an polyene thiol-based
oligomer, a cinnamic acid-based oligomer, an epoxy-based oligomer,
a vinyl ether-based oligomer and an unsaturated polyamide-based
oligomer, and the shell permeation aid is one or more selected from
the group consisting of alginic acid, polyvinyl alcohol, agar,
carrageenan, gellan gum, pectin, starch, a starch derivative,
dextrin, cellulose and protein.
11. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule content comprises an oil containing
Shewanella bacteria.
12. The capsule for collecting a non-ferrous metal according to
claim 1, wherein the capsule content comprises an intermediate
layer portion containing an oily substance, and a hydrophilic
portion containing Shewanella bacteria, wherein the intermediate
layer portion is in layer structure at the time of preparing a
capsule.
13. The capsule for collecting a non-ferrous metal according to
claim 11, obtained by: extruding an oily composition comprising
Shewanella bacteria from a first nozzle, and extruding a shell
formation composition from a second nozzle simultaneously into a
carrier fluid, wherein the first nozzle and the second nozzle are
concentrically arranged with sequentially increased radiuses in
which the first nozzle is present innermost and the second nozzle
is present outermost, and then, curing the shell formation
composition with light irradiation.
14. The capsule for collecting a non-ferrous metal according to
claim 12, obtained by: extruding a hydrophilic composition
comprising Shewanella bacteria from a first nozzle, extruding an
oily composition from a second nozzle and extruding a shell
formation composition from a third nozzle simultaneously into a
carrier fluid, wherein the first nozzle, the second nozzle and the
third nozzle are concentrically arranged with sequentially
increased radiuses in which the first nozzle is present innermost
and the third nozzle is present outermost, and then curing the
shell formation composition with light irradiation.
15. A method of collecting a non-ferrous metal, comprising: an
immersion step of immersing the capsule for collecting a
non-ferrous metal according to claim 1 in a solution containing a
non-ferrous metal, and a separation step of separating the capsule
for collecting a non-ferrous metal immersed in the immersing
step.
16. The method of collecting a non-ferrous metal according to claim
15, wherein the non-ferrous metal to be collected is one or more
selected from the group consisting of a rare metal and a rare noble
metal.
17. The method of collecting a non-ferrous metal according to claim
15, wherein the non-ferrous metal to be collected is palladium,
platinum, rhodium, gold, silver, indium, gallium or a rare earth
element.
Description
TECHNICAL FIELD
[0001] The present invention relates to a capsule which can collect
a non-ferrous metal, and a method of collecting a non-ferrous metal
using the same.
BACKGROUND ART
[0002] Non-ferrous metals other than steel material (iron and alloy
containing mainly iron) are becoming highly useful in industry, and
an amount of a non-ferrous metal to be used is increasing. In order
to avoid resource depletion of the non-ferrous metals, recycle
technique which effectively utilizes non-ferrous metals contained
in wastes such as home electric appliances is becoming highly
important. For example, rare metal or rare noble metal is recovered
from parts of wasted mobile phones, personal computers, automobiles
and the like, which is sometimes called urban mines and intensely
studied.
[0003] For recovering rare metal or rare noble metal, a recovery
method using a chemical reaction, a recovery method using solvent
extraction, and the like have been conventionally proposed. For
example, JP-A 2010-150569 discloses a method for producing a
platinum group element metal powder, comprising chlorinating waste
material containing a platinum group element in a molten salt bath
to form a metal chloride, and then subjecting the resulting metal
chloride to reduction treatment to obtain metal powder having high
purity. In the method, chlorine gas is blown into the molten salt
bath and reacted at a temperature of 300 to 1000.degree. C.,
whereby a chloride of a metal to be recovered is formed.
Accordingly, a recovery method using a chemical reaction has a
problem that consumption of a large amount of energy is
accompanied. Further, there is also a problem that the cost of
constructing a recovery system is necessary.
[0004] As the recovery method using solvent extraction, JP-A
2007-270250 discloses, as a method of selectively recovering a
platinum group metal from an aqueous solution, a procedure of
back-extracting palladium with an aqueous ammonia solution, and
crystallizing palladium from the palladium-containing aqueous
ammonia solution. The solvent extraction method has an advantage
that, even when a concentration of a metal component is low, the
metal component can be recovered. On the other hand, it is
necessary to use a large amount of various solvents such as an
organic solvent. For this reason, there is a problem that a large
amount of waste solvent is generated and an environmental load is
great.
[0005] JP-A 2008-127604 describes use of a biological membrane,
such as an egg shell membrane, in a method of recovering a noble
metal. The recovery method, however, needs an electric reduction
recovery method, such as a gold electrolysis method, and has a
different configuration from that of the method of the present
invention.
OBJECT OF THE INVENTION
[0006] As a method of recovering a useful rare metal or rare noble
metal, various methods have been studied as described above.
However, the methods have some problems in respect of energy
consumption or environmental load. As other methods, recovery
methods using, for example, an adsorbent or a microorganism are
studied, but the methods also have a problem that a recovery rate
is low. An object of the present invention is to solve such
conventional problems.
SUMMARY OF THE INVENTION
[0007] That is, the present invention provides a capsule which can
collect a non-ferrous metal easily and well, and a method of
collecting a non-ferrous metal using the same.
[0008] The present invention provides a capsule for collecting a
non-ferrous metal comprising a capsule content and a shell covering
the capsule content, wherein the capsule is immersed in a solution
containing the non-ferrous metal to collect the non-ferrous metal
in the capsule, and the aforementioned problems are thus
solved.
[0009] It is more preferable that the capsule content comprises one
or more bacteria selected from the group consisting of Geobacter
bacteria, Desulfomonas bacteria, Desulfuromusa bacteria, Pelobacter
bacteria, Shewanella bacteria, Ferrimonas bacteria, Aeromonas
bacteria, Sulfurospirillum bacteria, Wolinella bacteria,
Desulfovibrio bacteria, Geothrix bacteria, Deferribacter bacteria,
Geovibrio bacteria, Pyrobaculum bacteria, Thermotogae bacteria,
Archaeoglobus bacteria, Pyrococcus bacteria and Pyrodictium
bacteria.
[0010] In addition, it is more preferable that the capsule content
comprises Shewanella bacteria.
[0011] In addition, it is more preferable that the capsule content
comprises Shewanella oneidensis or Shewanella algae.
[0012] In addition, it is more preferable that the non-ferrous
metal to be collected is one or more selected from the group
consisting of a rare metal and a rare noble metal.
[0013] In addition, it is more preferable that the non-ferrous
metal to be collected is palladium, platinum, rhodium, gold,
silver, indium, gallium or a rare earth element.
[0014] It is more preferable that the capsule content further
comprises at least one selected from the group consisting of an
electron donating component, an electron accepting component and a
liquid culture medium.
[0015] In addition, it is more preferable that the capsule for
collecting a non-ferrous metal is a seamless capsule.
[0016] It is more preferable that the shell is obtained by curing a
shell formation composition comprising a photocurable component and
a shell permeation aid.
[0017] It is more preferable that the photocurable component is one
or more selected from the group consisting of an acrylate-based
oligomer, an unsaturated polyester-based oligomer, a polyene
thiol-based oligomer, a cinnamic acid-based oligomer, an
epoxy-based oligomer, a vinyl ether-based oligomer and an
unsaturated polyamide-based oligomer, and the shell permeation aid
is one or more selected from the group consisting of alginic acid,
polyvinyl alcohol, agar, carrageenan, gellan gum, pectin, starch, a
starch derivative, dextrin, cellulose and protein.
[0018] Examples of one aspect of the capsule for collecting a
non-ferrous metal include an aspect in which the capsule content
comprises an oily portion containing Shewanella bacteria. It is
more preferable that this capsule for collecting a non-ferrous
metal is obtained by extruding an oily composition comprising
Shewanella bacteria from a first nozzle, and extruding a shell
formation composition from a second nozzle simultaneously into a
carrier fluid, wherein the first nozzle and the second nozzle are
concentrically arranged with sequentially increased radiuses in
which the first nozzle is present innermost and the second nozzle
is present outermost, and then curing the shell formation
composition with light irradiation.
[0019] Examples of another aspect of the capsule for collecting a
non-ferrous metal include an aspect in which the capsule comprises
an intermediate layer portion containing an oily substance, and a
hydrophilic portion containing Shewanella bacteria, wherein the
intermediate layer portion is in layer structure at the time of
preparing a capsule. It is more preferable that the capsule for
collecting a non-ferrous metal is obtained by extruding a
hydrophilic composition comprising Shewanella bacteria from a first
nozzle, extruding an oily composition from a second nozzle and
extruding a shell formation composition from a third nozzle
simultaneously into a carrier fluid, wherein the first nozzle, the
third nozzle and the third nozzle are concentrically arranged with
sequentially increased radiuses in which the first nozzle is
present innermost and the second nozzle is present outermost, and
then curing the shell formation composition with light
irradiation.
[0020] Further, the present invention also provides a method of
collecting a non-ferrous metal, including:
[0021] an immersion step of immersing the capsule for collecting a
non-ferrous metal in a solution containing a non-ferrous metal,
and
[0022] a separation step of separating the capsule for collecting a
non-ferrous metal immersed in the immersing step.
[0023] Herein, it is preferable that the non-ferrous metal to be
collected is one or more selected from the group consisting of a
rare metal and a rare noble metal. It is more preferable that the
non-ferrous metal to be collected is palladium, platinum, rhodium,
gold, silver, indium, gallium or a rare earth element.
ADVANTAGES OF THE INVENTION
[0024] The capsule for collecting a non-ferrous metal of the
present invention has an advantage that a non-ferrous metal can be
easily collected by a simple operation of immersion in a solution
containing a non-ferrous metal for a given time. In the collection
of a non-ferrous metal, a non-ferrous metal can be effectively
concentrated and collected, even in the case where an amount of a
non-ferrous metal contained is very small.
[0025] In collection of a non-ferrous metal using the capsule for
collecting a non-ferrous metal of the present invention, a
non-ferrous metal can be collected without accompanying consumption
of a large amount of energy like a method using chemical reaction.
There is also an advantage that a large amount of waste solvent is
not accompanied like a solvent extraction method, and the load on
the environment is small. Further, in the present invention, since
a non-ferrous metal can be collected by a simple operation of
immersing the capsule for collecting a non-ferrous metal in a
solution for a given period, and, thereafter, taking out the
capsule by a means such as filtration, there is an advantage that
the collection can be simply implemented without accompanying the
large cost of facility investment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic view showing one example of a
preferable embodiment of the capsule for collecting a non-ferrous
metal of the present invention, and is a schematic view showing a
capsule for collecting a non-ferrous metal having a two-layered
structure immediately after manufacturing.
[0027] FIG. 2 is a schematic view showing another example of a
preferable embodiment of the capsule for collecting a non-ferrous
metal of the present invention, and is a schematic view showing a
capsule for collecting a non-ferrous metal having a three-layered
structure immediately after manufacturing.
[0028] FIG. 3 is an outline view showing a method for manufacturing
the capsule for collecting a non-ferrous metal of the present
invention, having a two-layered structure, shown in FIG. 1.
[0029] FIG. 4 is a graph chart showing changes in Pd (II) ion
concentration in an aqueous solution in Example 3 and Reference
Comparative Example.
[0030] FIG. 5 shows photographs of the capsules for collecting a
non-ferrous metal before a solution immersion operation (after
culturing operation, before solution immersion) and the capsules
for collecting a non-ferrous metal taken out after 24 hours from
solution immersion, used in Example 4.
[0031] FIG. 6 is a graph chart showing changes in indium
concentration in an aqueous solution in Example 5 and Comparative
Test.
[0032] FIG. 7 is a graph chart showing changes in gold
concentration in an IC chip percolate in Example 6 and Comparative
Test.
[0033] FIG. 8 is a graph chart showing changes in platinum (IV)
concentration in an aqueous solution in Example 7 and Comparative
Test.
[0034] FIG. 9 is a graph chart showing changes in gallium (III)
concentration in an aqueous solution in Example 8 and Comparative
Test.
[0035] FIG. 10 is a graph chart showing changes in rhodium (III)
concentration in an aqueous solution in Example 9 and Comparative
Test.
[0036] FIG. 11 is a graph chart showing changes in dysprosium (III)
concentration in an aqueous solution in Example 10 and Comparative
Test.
DETAILED DESCRIPTION OF THE INVENTION
Capsule for Collecting Non-Ferrous Metal and Method for
Manufacturing the Same
[0037] The capsule for collecting a non-ferrous metal of the
present invention is composed of a capsule content, and a shell
covering the capsule content. The capsule for collecting a
non-ferrous metal is characterized in that a non-ferrous metal can
be collected into the capsule by a simple operation of immersing
the capsule in a solution containing a non-ferrous metal. In the
present description, it is intended that the term "collection" also
includes the meaning "recovery", and the term "collecting a
non-ferrous metal" also includes "recovering a non-ferrous
metal".
[0038] In the present description, the "non-ferrous metal" means a
metal except for iron and an alloy containing mainly iron. Examples
of the non-ferrous metal to be collected in the present invention
include a rare metal and a rare noble metal.
[0039] Herein, the rare metal means a metal other than a base metal
(also called common metal or major metal) such as iron, copper,
zinc, and aluminum, which is a metal not belonging to a noble metal
such as gold and silver being a non-ferrous metal utilized in
industry. Specific examples of the rare metal include lithium,
beryllium, titanium, vanadium, chromium, manganese, cobalt, nickel,
gallium, germanium, selenium, rubidium, strontium, zirconium,
niobium, molybdenum, indium, antimony, tellurium, cesium, barium,
hafnium, tantalum, tungsten, rhenium, thallium, bismuth and a rare
earth element. Examples of the rare earth element include scandium,
yttrium, lanthanum, cerium, praseodymium, neodymium, promethium,
samarium, europium, gadolinium, terbium, dysprosium, holmium,
erbium, thulium, ytterbium and lutetium. In addition, the rare
metal includes palladium, platinum and the like, and, in the
present description, it is intended that palladium and platinum are
included in the rare noble metal.
[0040] The rare noble metal means a metal, particularly, having a
small amount of deposit, and excellent in corrosion resistance,
among metals of Group 8 to Group 11 in the periodic table of
chemical elements. Examples of the rare noble metal include gold,
silver, platinum, palladium, rhodium, iridium, ruthenium and
osmium.
[0041] More preferable examples of the metal to be collected by the
capsule for collecting a non-ferrous metal of the present invention
include palladium, platinum, rhodium, gold, silver, indium, gallium
or a rare earth element.
[0042] The capsule for collecting a non-ferrous metal of the
present invention is constructed of a capsule content and a shell
covering the capsule content. Each constituent will be described
below.
Capsule Content
[0043] It is preferable that the capsule content constituting the
capsule for collecting a non-ferrous metal of the present invention
contains bacteria selected from the following group:
[0044] Geobacter bacteria (representative species: Geobacter
metallireducens: ATCC (American Type Culture Collection) 53774
strain),
[0045] Desulfuromonas bacterial (representative species:
Desulfuromonas palmitatis: ATCC 51701 strain),
[0046] Desulfuromusa bacteria (representative species:
Desulfuromusa kysingii: Desulfuromusa kysingii DSM (Deutsche
Sammlung von Mikroorganismen and Zellkulturen) 7343 strain),
[0047] Pelobacter bacteria (representative species: Pelobacter
venetianus: ATCC 2394 strain),
[0048] Shewanella bacteria (Shewanella algae: ATCC 51181 strain,
Shewanella oneidensis: etc.),
[0049] Ferrimonas bacteria (Ferrimonas balearica: DSM 9799
strain),
[0050] Aeromonas bacteria (Aeromonas hydrophila: ATCC 15467
strain),
[0051] Sulfurospirillum bacteria (representative species:
Sulfurospirillum barnesii: ATCC 700032 strain),
[0052] Wolinella bacteria (representative species: Wolinella
succinogenes: ATCC 29543 strain),
[0053] Desulfovibrio bacteria (representative species:
Desulfovibrio desulfuricans: ATCC 29577 strain),
[0054] Geothrix bacteria (representative species: Geothrix
fermentans: ATCC 700665 strain),
[0055] Deferribacter bacteria (representative species:
Deferribacter thermophilus: DSM 14813 strain),
[0056] Geovibrio bacteria (representative species: Geovibrio
ferrireducens: ATCC 51996 strain),
[0057] Pyrobaculum bacteria (representative species: Pyrobaculum
islandicum: DSM 4184 strain),
[0058] Thermotogae bacteria (representative species: Thermotogae
maritima: DSM3109 strain),
[0059] Archaeoglobus bacteria (representative species:
Archaeoglobus fulgidus: ATCC49558 strain),
[0060] Pyrococcus bacteria (representative species: Pyrococcus
furiosus ATCC 43587 strain), and
[0061] Pyrodictium bacteria (representative species: Pyrodictium
abyssi: DSM6158 strain).
[0062] Since the bacteria are contained in the capsule content of
the capsule for collecting a non-ferrous metal, a non-ferrous metal
can be collected in the capsule well.
[0063] In the present invention, it is preferable that the capsule
content contains Shewanella bacteria. Examples of Shewanella
bacteria include Shewanella algae, Shewanella oneidensis,
Shewanella algidipiscicola, Shewanella amazonensis, Shewanella
baltica, Shewanella benthica, Shewanella colwelliana, Shewanella
denitrificans, Shewanella fidelis, Shewanella frigidimarina,
Shewanella gelidimarina, Shewanella glacialipiscicola, Shewanella
hafniensis, Shewanella hanedai, Shewanella japonica, Shewanella
loihica, Shewanella marinintestina, Shewanella morhuae, Shewanella
pealeana, Shewanella putrefaciens, Shewanella sp. (KMM 3587) and
Shewanella woodyi. It is more preferable that, among them,
Shewanella algae or Shewanella oneidensis is contained in the
capsule.
[0064] The bacteria may preferably be contained in the capsule for
collecting a non-ferrous metal in the live state, or may be
contained in the capsule for collecting a non-ferrous metal in the
state of dead bacterial cells. For example, Shewanella algae and
Shewanella oneidensis are characterized in that, even in the state
of dead bacterial cells, a non-ferrous metal can be collected
well.
[0065] In the present invention, the capsule content preferably
contains the bacteria in an amount of 0.01 to 30 parts by mass,
more preferably in an amount of 0.1 to 20 parts by mass, based on
100 parts by mass of the capsule content. For example, the bacteria
is preferably contained at a ratio of 1 cell/capsule to
5.times.10.sup.11 cells/capsule, more preferably at a ratio of
1.times.10.sup.3 cells/capsule to 1.times.10.sup.11 cells/capsule,
based on the capsule content (based on one capsule).
[0066] In the capsule for collecting a non-ferrous metal of the
present invention, the bacterium may be contained in the capsule
content in the state of being dispersed in a hydrophilic
composition such as an aqueous solution, or may be contained in the
capsule content in the state of being dispersed in an oily
composition.
[0067] Examples of the hydrophilic composition which can be used
for preparing the capsule content include various aqueous
solutions. Examples of the oily composition which can be used for
preparing the capsule content include olive oil, jojoba oil, corn
oil, rapeseed oil, lard, beef tallow, whale oil, castor oil,
soybean oil, rice oil, rice germ oil, coconut oil, palm oil, cacao
oil, avocado oil, macadamia nut oil, squalane, mink oil, turtle
oil, corn oil, hydrocarbons having 8 to 30 carbon atoms, beeswax,
carnauba wax, rice wax, lanolin, liquid paraffin, vaseline, fatty
acids having 4 to 30 carbon atoms, esters of fatty acids having 4
to 30 carbon atoms and sucrose, esters of fatty acids having 4 to
30 carbon atoms and glycerol, aliphatic alcohols having 4 to 30
carbon atoms, esters of fatty acids having 4 to 30 carbon atoms and
aliphatic alcohols having 4 to 30 carbon atoms, and silicone oil.
These are employed solely or can be used in combination thereof.
Among the oily compositions, liquid fat or oil having a viscosity
of 200 mPAs or lower in a temperature range of -30.degree. C. to
60.degree. C. is preferred.
[0068] The capsule content may further contain an additional
component which can keep bacteria good, as necessary. Examples of
the additional component are an electron donating component, an
electron accepting component and various liquid media. When the
bacteria are contained in the capsule content in the state of being
dispersed in a hydrophilic composition, the following electron
donating component or the like may preferably be contained in the
capsule content.
[0069] The electron donating component in the present description
means a component having a nature of donating an electron to the
bacteria. The bacteria can grow well when the capsule content
comprises both the electron donating component and the electron
accepting component, because the two components are led to an
oxidation-reduction reaction and the bacteria can get growth energy
therefrom.
[0070] Examples of the electron donating component include:
[0071] a carboxylic acid having 1 to 7 carbon atoms and a
derivative thereof, for example, formic acid, acetic acid,
propionic acid, butyric acid, valeric acid, lactic acid, citric
acid, malic acid, tartaric acid, oxalic acid, malonic acid,
succinic acid, glutaric acid, adipic acid, fumaric acid, maleic
acid, and a salt thereof;
[0072] an aromatic carboxylic acid having 5 to 10 carbon atoms and
a derivative thereof, for example, benzoic acid, phthalic acid,
isophthalic acid, terephthalic acid, salicylic acid, gallic acid,
mellitic acid, cinnamic acid, and a salt thereof;
[0073] an alcohol having 1 to 10 carbon atoms, for example,
methanol and ethanol;
[0074] an unsaturated aromatic compound, for example,
toluenephenol; and
[0075] hydrogen gas.
[0076] Examples of the electron accepting component include a metal
ion such as Fe (III) ion.
[0077] According to the present invention, the electron donating
component can be suitably selected based on the type of bacteria to
be used. For example, when Shewanella algae is used, a carboxylic
acid having 1 to 7 carbon atoms or a derivative thereof, such as
formic acid and lactic acid or a salt thereof can be preferably
used as the electron donating component. If necessary, as the
electron accepting component, Fe (III) ion may also be used. By
using the electron accepting component, growth energy derived from
an oxidation-reduction reaction in cells can be obtained well.
[0078] When Shewanella oneidensis is employed, the electron
donating component can preferably be a carboxylic acid having 1 to
7 carbon atoms or a derivative thereof (such as formic acid or a
salt thereof).
[0079] In case where the bacteria are dispersed in an aqueous
composition, it is necessary that oily substance may intervene as
an intermediate layer portion between an aqueous composition
containing the bacteria and a shell formation composition, when
producing the capsule. The oily substance can be the same with
those explained for the oily composition above. Preferable examples
of the oily substance which can intervene as the intermediate layer
portion include those having a melting point of 60.degree. C. or
lower (e.g., olive oil, jojoba oil, corn oil, rapeseed oil, lard,
beef tallow, whale oil, castor oil, soybean oil, rice oil, rice
germ oil, coconut oil, palm oil, cacao oil, avocado oil, macadamia
nut oil, squalane, mink oil, turtle oil, and corn oil), and sucrose
acetate isobutyrate (SAIB) and the like.
[0080] When the oily substance intervenes as the intermediate layer
portion, the intermediate layer is preferably formed at a weight
ratio of 5 to 40 parts by mass, and is more preferably formed at a
weight ratio of 10 to 30 parts by mass, based on 100 parts by mass
of the capsule for collecting a non-ferrous metal.
Shell
[0081] In the shell constituting the capsule for collecting a
non-ferrous metal of the present invention, a component which can
cover the capsule content well can be used without particular
limitation. In the present invention, it is more preferable that
the shell is formed from a shell formation composition containing a
photocurable component. By forming the shell using the shell
formation composition containing a photocurable component, there is
an advantage that a capsule, particularly, a seamless capsule can
be manufactured better and more simply.
[0082] The photocurable component which can be used in the present
invention is not limited as far as it is cured by light
irradiation. In the present invention, it is more preferable to use
an aqueous (hydrophilic) photocurable component as the photocurable
component. By forming the shell using the aqueous (hydrophilic)
photocurable component, the resulting capsule is excellent in water
hydrophilicity of a capsule surface and shows excellent non-ferrous
metal collecting property when it is immersed in an aqueous
solution containing a non-ferrous metal. Examples of the
photocurable component include a photopolymerizable oligomer and an
addition polymerization product thereof. These may be used alone,
or two or more of them may be used in combination.
[0083] Examples of the photopolymerizable oligomers are an
acrylate-based oligomer, an unsaturated polyester-based oligomer, a
polyene thiol-based oligomer, a cinnamic acid-based oligomer, an
epoxy-based oligomer, a vinyl ether-based oligomer, and an
unsaturated polyamide-based oligomer. More specifically, an
acrylate-based oligomer having at least two ethylenic unsaturated
bonds and a hydrophilic group in one molecule, a high acid value
unsaturated polyester-based oligomer, a high acid value unsaturated
epoxy-based oligomer, an anionic unsaturated acrylic oligomer, an
unsaturated polyamide-based oligomer, and the like are suitably
used. Among them, an acrylate-based oligomer having at least two
ethylenic unsaturated bonds and a hydrophilic group in one molecule
is preferably used.
[0084] Examples of the acrylate-based oligomer having at least two
ethylenic unsaturated bonds and a hydrophilic group in one molecule
include an oligomer having a photopolymerizable ethylenic
unsaturated group on both terminals of polyalkylene glycol.
Examples of the acrylate-based oligomer include:
[0085] (1) polyethylene glycol di(meth)acrylates in which both
terminal hydroxy groups of polyethylene glycol having a molecular
weight of 400 to 6,000 are esterified with 2 moles of (meth)acrylic
acid;
[0086] (2) polypropylene glycol di(meth)acrylates in which both
terminal hydroxy groups of polypropylene glycol having a molecular
weight of 200 to 4,000 are esterified with 2 moles of (meth)acrylic
acid;
[0087] (3) an unsaturated polyethylene glycol urethanated product
in which both terminal hydroxy groups of 1 mole of polyethylene
glycol having a molecular weight of 400 to 6,000 are urethanated
with 2 moles of a diisocyanate compound (tolylene diisocyanate,
xylylene diisocyanate, isophorone diisocyanate, or the like) and,
further, 2 moles of an unsaturated monohydroxy compound
(2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,
3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate,
trimethylolpropane di(meth)acrylate, pentaerythritol
tri(meth)acrylate, or the like) is added; and
[0088] (4) an unsaturated polypropylene glycol urethanated product
in which both terminal hydroxy groups of 1 mole of polypropylene
glycol having a molecular weight of 200 to 40,000 are urethanated
with 2 moles of a diisocyanate compound and, further, 2 moles of an
unsaturated monohydroxy compound is added.
[0089] Examples of the high acid value unsaturated polyester-based
oligomer include salts of an unsaturated polyester having an acid
value of 40 to 200, obtained by esterifying polyvalent carboxylic
acid having an unsaturated bond, and a polyhydric alcohol.
[0090] Examples of the high acid value unsaturated epoxy-based
oligomer include an unsaturated epoxy oligomer having an acid value
of 40 to 200. The oligomer is obtained, for examples, by preparing
an addition reaction product of an epoxy compound and an
unsaturated carboxyl compound ((meth)acrylic acid or the like), and
adding an acid anhydride to a hydroxyl group remaining in the
addition reaction product.
[0091] Examples of the anionic unsaturated acryl oligomer include
an oligomer which is derived from at least two (meth)acryl-based
monomers of (meth)acrylic acid and (meth)acrylic acid esters, and
in which a photopolymerizable ethylenic unsaturated group is
introduced into a copolymer having a carboxyl group, a phosphoric
acid group and/or a sulfonic acid group.
[0092] The unsaturated polyamide-based oligomer is obtained, for
example, by adding an addition product of diisocyanate (tolylene
diisocyanate, xylylene diisocyanate, or the like) and an ethylenic
unsaturated hydroxy compound (2-hydroxyethyl acrylate or the like)
to a water-soluble polyamide such as gelatin.
[0093] A number average molecular weight of the photopolymerizable
oligomers is preferably 300 to 30,000, and more preferably 500 to
20,000. Herein, the number average molecule weight can be measured
by a GPC (Gel Permeation Chromatography) method.
[0094] Among the photocurable components, an acrylate-based
oligomer having a polymerizable ethylenic unsaturated group on both
terminals of polyalkylene glycol can be particularly preferably
used.
[0095] As the acrylate-based oligomer, commercially available
products may be used. Examples of the acrylate-based oligomer which
can be used in the present invention include an acrylate-based
oligomer which is sold from Sanyu Rec Co., Ltd. under a trade name
such as RM-6572, RM-6560, RM-6550, RM-6551, and RL-6527; an
acrylate-based oligomer which is sold from Kansai Paint Co., Ltd.
under a trade name such as ENT-1000, ENT-2000, ENT-3400, ENT-4000,
ENTG-2000, and ENTG-3800; and an acrylate-based oligomer which is
sold from Shin Nakamura Chemical Co., Ltd. under a trade name such
as UA-7100, UA-7000, and UA-W2A.
[0096] The photocurable component is preferably contained as a
solid content in the shell formation composition in an amount of 10
to 99% by mass, more preferably 20 to 90% by mass, and further
preferably 40 to 90% by mass.
[0097] In the present invention, the shell is preferably formed
from a composition containing the photocurable component, that is,
a shell formation composition. The shell formation composition may
further contain an additive such as a polymerization initiator, a
photosensitizer, a coloring agent, a polymerizable monomer, a shell
permeation aid, and an electric charge adjusting agent, as
necessary. An amount of the additive is preferably 30% by mass or
less, and more preferably 20% by mass or less, based on the mass of
the shell formation composition, as a solid content.
[0098] As the polymerization initiator, a conventionally known
polymerization initiator suitable for the photocurable component to
be used can be used without particular limitation. As the
polymerization initiator, a photopolymerization initiator is
suitably used. The photopolymerization initiator means a compound
which can generate a polymerization initiation species by light
irradiation and promote a polymerization reaction or a crosslinking
reaction. Examples of the photopolymerization initiator include
benzoin, acetoin, benzoin methyl ether, benzoin ethyl ether,
benzoin isopropyl ether, benzoin isobutyl ether, benzophenone,
benzyl Michler's ketone, xanthone, chlorothioxanthone,
isopropylthioxanthone, benzyl dimethyl ketal, naphthol,
anthraquinone, hydroxyanthracene, acetophenone diethyl ketal,
.alpha.-hydroxycyclohexyl phenyl ketone,
2-hydroxy-2-methylphenylpropane, an aromatic iodonium salt, an
aromatic sulfonium salt, an iodonium salt, a sulfonium salt, a
triarylsulfonium salt, a trifluorocarbon sulfonium salt and the
like. The polymerization initiator may be used alone, or may be
used by combining two or more kinds. The polymerization initiator
is preferably contained in an amount of 0.001 to 20% by mass, more
preferably 0.1 to 10% by mass, based on the mass of the shell
formation composition, as a solid content. When an amount of the
polymerization initiator is less than 0.001% by mass, there is a
possibility of a problem that a polymerization reaction does not
completely progress, a film strength cannot be provided, or the
like and, when an amount exceeds 20% by mass, an initiation
reaction excessively progresses, there is a possibility of a
problem that a polymerization reaction does not progress, leading
to decrease in a film strength, or the like. In the present
invention, it is preferable that the photocurable component and the
polymerization initiator, particularly the photopolymerization
initiator are used by appropriately combining them.
[0099] When the shell is formed by curing the photocurable
component with a visible light region, it is desirable that a
photosensitizer is blended with the shell formation composition.
Examples of the photosensitizer include a ruthenium complex and a
porphyrin-based compound. The use amount of the photosensitizer is
preferably 0.001 to 5% by mass, and more preferably 0.01 to 1% by
mass, based on the mass of the shell formation composition, as a
solid content.
[0100] If necessary, to the shell formation composition may be
added a water-soluble monomer which is dissolved in an aqueous
solvent at 80.degree. C. or lower and has an unsaturated bond
(e.g., itaconic acid, N,N'-methylenebisacrylate, hydroxyethyl
methacrylate, hydroxypropyl methacrylate,
N,N'-methylenebisacrylamide, N-isopropylacrylamide,
N-vinylpyrrolidone, acryloylmorpholine, N,N'-dimethylacrylamide,
and N-vinylformamide) alone or by combining two or more kinds. By
using the water-soluble monomer, a reaction adversely influencing
on a polymerization reaction can be suppressed, and strength of the
shell can be further enhanced. An amount of the water-soluble
monomer is preferably 0.01 to 30% by mass, and more preferably 0.1
to 25% by mass, based on the mass of the shell formation
composition, as a solid content.
[0101] It is more preferable that the shell formation composition
contains a shell permeation aid. A shell obtained by curing the
shell formation composition containing a photocurable component and
a shell permeation aid has an advantage that permeability of a
non-ferrous metal ion is high and, therefore a non-ferrous metal
can be collected better. Examples of the shell permeation aid
include alginic acid, polyvinyl alcohol, agar, carrageenan, gellan
gum, pectin, starch, a starch derivative (alkylated starch,
etherized starch, and the like), dextrin, cellulose, and protein.
The shell permeation aid is preferably contained at a solid content
ratio of 1 to 0.1 to 30% by mass, and more preferably 0.5 to 30% by
mass, based on the shell formation composition.
[0102] When the shell permeation aid is contained in the shell
formation composition, the shell formation composition is cured and
then subjected to a treatment, such as enzyme treatment, alkali
treatment or acid treatment for enhancing permeability of the
shell. The treatments cut, degrade or dissolve a part of a polymer
forming the shell, thereby making it possible to improve
permeability of the shell.
[0103] As another aspect, the shell constituting the capsule for
collecting a non-ferrous metal of the present invention can also be
formed using the shell formation composition containing a
thermosetting component. The thermosetting component can generally
be used by a person skilled in the art. Examples of the
thermosetting component include an acrylate-based oligomer, an
unsaturated polyester-based oligomer, a polyene thiol-based
oligomer, a cinnamic acid-based oligomer, an epoxy-based oligomer,
a vinyl ether-based oligomer, and an unsaturated polyamide-based
oligomer, exemplified as the photopolymerizable oligomer.
[0104] When the shell is formed from the shell formation
composition containing the thermosetting component, it is
preferable that a thermal polymerization initiator is used
together. The thermal polymerization initiator is generally used by
a person skilled in the art. Specific examples of the thermal
polymerization initiator include an azo compound such as
4,4'-azobis(4-cyanovaleric acid),
2,2'-azobis(2,4-dimethylvaleronitrile),
2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile),
and dimethyl 2,2'-azobis(2-methylpropionate), and a peroxide
compound such as dibenzoyl peroxide, tert-butyl hydroperoxide,
cumene hydroperoxide, di-tert-butyl peroxide and the like. The
thermal polymerization initiator is preferably contained in an
amount of 0.001 to 20% by mass, and more preferably 0.1 to 10% by
mass, based on the mass of the shell formation composition, as a
solid content.
[0105] Also in the case where the shell is formed from the shell
formation composition containing the thermosetting component, the
aforementioned shell permeation aid can be used as described
above.
[0106] In the capsule for collecting a non-ferrous metal in the
present invention, the shell can also be formed from the shell
formation composition containing a thermoplastic resin. Examples of
the thermoplastic resin which can be used in formation of the shell
include a thermoplastic resin which is generally used by a person
skilled in the art, such as a polyolefin resin, for example, a
polyethylene resin or a polypropylene resin, a polystyrene resin,
an AS resin, an ABS resin, a vinyl chloride resin, an acrylic
resin, a methacrylic resin, a methyl (meth)acrylate resin, a
fluorine resin, a polycarbonate resin, or a polyester resin such as
a polyethylene terephthalate resin or a polybutylene terephthalate
resin. Also in the case where the shell is formed from the shell
formation composition containing the thermoplastic resin, the
aforementioned shell permeation aid can be used as described
above.
[0107] The capsule for collecting a non-ferrous metal of the
present invention encloses bacteria or the like therein. By
immersing the capsule for collecting a non-ferrous metal in a
solution containing a non-ferrous metal for a given time, the
solution permeates through the shell, and enters the capsule. The
bacteria are activated in the capsule, and non-ferrous metal
collection activity is initiated. Thus, a non-ferrous metal is
collected in the capsule. In the capsule for collecting a
non-ferrous metal of the present invention, the bacteria are first
activated by immersion in a solution containing a non-ferrous
metal. For this reason, there is an advantage from the viewpoint of
handling that a bacterium can be retained in the better state until
immediately before immersion. There is also an advantage that
damage of a bacterium at preservation of the capsule for collecting
a non-ferrous metal can be reduced. In the case where the capsule
for collecting a non-ferrous metal is a seamless capsule, there is
an advantage that since the capsule has a spherical structure, an
area of contact with a solution containing a non-ferrous metal is
increased and, therefore, a non-ferrous metal can be collected
better.
[0108] In collection of a non-ferrous metal using the capsule for
collecting a non-ferrous metal of the present invention, a
non-ferrous metal can be collected without accompanying consumption
of a large amount of energy like a method using a chemical reaction
which is one kind of conventional methods. In addition, there is an
advantage that a large amount of waste solvent is not accompanied
and the load on environment is also small, in comparison with the
conventional solvent extraction method which necessitates a large
amount of solvent and gives heavy load on environment. In the
present invention, there is another advantage that collection of
the non-ferrous metal can be easily conducted without accompanying
large cost of facility investment, because a non-ferrous metal can
be collected by a simple operation of immersing the capsules for
collecting a non-ferrous metal in a solution for a given period and
the capsules are easily collected by a means such as
filtration.
Method of Manufacturing Capsule for Collecting Non-Ferrous
Metal
[0109] The capsule for collecting a non-ferrous metal of the
present invention can be manufactured by extruding the shell
formation composition and the capsule content into a carrier fluid,
using a concentric double nozzle or a concentric triple nozzle, and
then curing the shell formation composition with light
irradiation.
[0110] In this manufacturing method, it is necessary that
components which contact each other at preparation preferably have
a different polarity from each other. For example, in a first
embodiment shown in FIG. 1, it is preferred that the shell
formation composition is hydrophilic and the capsule content is an
oily composition containing Shewanella bacteria or the like.
[0111] FIGS. 1 and 2 show preferable embodiments of the capsule for
collecting a non-ferrous metal of the present invention (first and
second embodiments, respectively). With reference to the respective
embodiment, the method of manufacturing the capsule for collecting
a non-ferrous metal of the present invention will be described in
detail.
Method of Manufacturing Capsule for Collecting Non-Ferrous Metal
Having Two-Layered Structure (First Embodiment)
[0112] A left drawing of FIG. 1 is a schematic view showing the
capsule for collecting a non-ferrous metal having a two-layered
structure immediately after manufacturing. The capsule for
collecting a non-ferrous metal of the present invention having a
two-layered structure shown in FIG. 1 (first embodiment) can be
manufactured by an in-liquid dropwise addition method, for example,
using a conventionally known capsule manufacturing apparatus
provided with a concentric double nozzle (10) shown in FIG. 3.
Specifically, as shown in FIG. 3, the capsule for collecting a
non-ferrous metal having a two-layered structure can be
manufactured by using a capsule manufacturing apparatus provided
with a concentric double nozzle (10) having a first nozzle
(internal side) and a second nozzle (external side) to extrude an
oily composition containing bacteria (11) being the capsule content
through the internal first nozzle, and a shell formation
composition (12) through the external second nozzle into a carrier
fluid (16) simultaneously, and then curing the shell formation
composition with light irradiation.
[0113] In the method of manufacturing the capsule for collecting a
non-ferrous metal of the first embodiment, the oily composition
containing bacteria (11) being the capsule content is injected
through the internal first nozzle, and the shell formation
composition (12) is injected through the external second nozzle,
via the concentric double nozzle (10). Then, upon contact between
the capsule content and the shell formation composition in the
carrier fluid (16), a seamless capsule of a two-layered structure
is constructed due to a difference between polarity of the capsule
content and polarity of the shell formation composition. More
particularly, upon extrusion from the concentric double nozzle (1),
a jet stream of a two-layered structure is formed due to interface
tension present between the carrier fluid (16) and the shell
formation composition (12). Then, the jet stream forms spherical
liquid droplets having a two-layered structure by action of
gravity. When forming liquid droplets, it is preferred that
vibration is added to the jet stream to make a particle size of the
liquid droplet to be uniform. The carrier fluid (16) is circulated
in the apparatus desirably at a constant rate, by a driving means
(17) such as a pump.
[0114] In addition, it is desirable that the carrier fluid (16) has
different polarity from polarity of the shell formation
composition. If the shell formation composition is hydrophilic
(which is preferred), then the carrier fluid (16) would preferably
be hydrophobic, i.e. oily substance. Examples of the carrier fluid
include olive oil, jojoba oil, corn oil, rapeseed oil, lard, beef
tallow, whale oil, castor oil, soybean oil, rice oil, rice germ
oil, coconut oil, palm oil, cacao oil, avocado oil, macadamia nut
oil, squalane, mink oil, turtle oil, corn oil, hydrocarbons having
8 to 30 carbon atoms, beeswax, carnauba wax, rice wax, lanolin,
liquid paraffin, vaseline, fatty acids having 4 to 30 carbon atoms,
esters of fatty acids having 4 to 30 carbon atoms and sucrose,
esters of fatty acids having 4 to 30 carbon atoms and glycerol,
aliphatic alcohols having 4 to 30 carbon atoms, esters of fatty
acids having 4 to 30 carbon atoms and aliphatic alcohols having 4
to 30 carbon atoms, silicone oil and the like. The carrier fluid
may be used solely or in combination thereof. It is more preferred
that the carrier fluid has a viscosity of 10 to 300 mPas, and more
preferably 30 to 200 mPas in the temperature range of 0.degree. C.
to 30.degree. C.
[0115] The spherical liquid droplets having a two-layered structure
are then irradiated with light using a light source (14). The light
irradiation may be performed at any stage and, for example, the
light irradiation may be performed in the carrier fluid (16), or
may be performed after separation of liquid droplets and the
carrier fluid (16) via a separation means (15) such as a net. Thus,
the capsule for collecting a non-ferrous metal having a two-layered
structure shown in a left drawing of FIG. 1 can be obtained.
[0116] The light source (14) is not particularly limited as far as
it can radiate light having a wavelength of about 200 nm to about
800 nm and includes, for example, a mercury lamp, a fluorescent
lamp, a xenon lamp, a carbon arc lamp, and a metal halide lamp. The
light source can be appropriately selected depending on a
photocurable component used. When a photosensitizer is blended with
the shell formation composition, the photocurable component can be
cured by visible light. An irradiation time can be set depending on
an intensity of the light source or a distance from the light
source. The irradiation time can generally be 0.05 seconds to 10
minutes, preferably 0.1 seconds to 2 minutes.
[0117] The shell formation composition is cured by light
irradiation to form a shell, thus obtaining capsules for collecting
a non-ferrous metal. The resulting capsules may be dried by a
normal pressure drying method or a reduced pressure drying method
as necessary.
[0118] In the first embodiment (FIG. 1), since polarity of the
capsule content (2) and polarity of the shell formation composition
forming the shell (1) are different from each other, a capsule for
collecting a non-ferrous metal can be simply produced. There is
also an advantage that a particle size distribution can be set
narrow.
[0119] The obtained capsules of the present invention are immersed
in a solution containing a non-ferrous metal, in which the solution
containing a non-ferrous metal permeates the shell and enters into
the capsules. A right drawing of FIG. 1 is a view showing the state
where, after immersion, a solution containing a non-ferrous metal
(5) permeates a capsule, and the solution is present in the
interior of the capsule. The bacteria and the solution in the
capsule are brought into contact with each other, and the bacteria
are activated. Then, non-ferrous metal collection activity by the
bacteria is initiated, and a non-ferrous metal is collected in the
capsule.
[0120] The capsule for collecting a non-ferrous metal may be
immersed in a liquid culture medium before immersion in a solution
containing a non-ferrous metal, as necessary, to culture bacteria
in the capsule. For example, the capsules of the present invention
are immersed in a liquid culture medium such as TSB (Trypticase Soy
Broth) at a pH of about 7 and 30.degree. C. for 6 to 72 hours, and
number of bacterial in the capsules can be increased by
culturing.
Method of Manufacturing Capsule for Collecting Non-Ferrous Metal
Having Three-Layered Structure (Second Embodiment)
[0121] A left drawing of FIG. 2 is a schematic view showing a
capsule for collecting a non-ferrous metal having a three-layered
structure immediately after manufacturing. The capsule for
collecting a non-ferrous metal of the present invention having a
three-layered structure (second embodiment) shown in this FIG. 2
can be manufactured, for example, by an in-liquid dropwise addition
method, using a conventionally known capsule manufacturing
apparatus, in which the concentric double nozzle is changed to a
concentric triple nozzle, shown in FIG. 3. Specifically, the
capsule for collecting a non-ferrous metal having a three-layered
structure can be manufactured by using a capsule manufacturing
apparatus provided with a concentric triple nozzle having a first
nozzle (innermost portion), a second nozzle (intermediate portion)
and a third nozzle (outermost portion) to extrude a hydrophilic
composition containing Shewanella bacteria or the like through the
first nozzle, an oily composition through the second nozzle, and a
shell formation composition through the third nozzle into a carrier
fluid (16) simultaneously, and then curing the shell formation
composition with light irradiation. A specific procedure and the
like in this method are the same as those described above, with the
exception that a concentric triple nozzle is used in place of the
concentric double nozzle.
[0122] In the capsule for collecting a non-ferrous metal obtained
by the manufacturing method, an intermediate layer consisting of an
oily substance (4) is present in the state of covering a
hydrophilic composition (6) containing a bacterium of Shewanella
bacteria or the like, immediately after manufacturing. The presence
of the intermediate layer portion (4) makes it possible that the
capsule content and the shell forming composition both have same
polarity, for example, when the capsule content is hydrophilic
composition (6) containing Shewanella bacteria or the like, and a
shell formation composition (1) can be same polarity
(hydrophilicity).
[0123] The obtained capsule having a three-layered structure may be
brought into the state where the oily substance (4) is localized,
as shown in a right drawing of FIG. 2, over time, by performing the
aforementioned bacterium culturing treatment, or immersion in a
solution containing a non-ferrous metal. Thereby, the bacteria and
the solution in the capsule are brought into contact with each
other well, and the bacteria can be activated well. Then,
non-ferrous metal collection activity by the bacteria is initiated,
and a non-ferrous metal is collected into the capsule.
[0124] In the capsules having a three-layered structure, a
composition obtained by concentrating bacteria in a hydrophilic
substance can be used as the capsule content, as it is.
Accordingly, the hydrophilic composition containing bacteria can be
prepared more easily. In addition, since a hydrophilic composition
can be used as the capsule content, there is also an advantage that
an electron donating component and/or an electron accepting
component can be contained in the capsule content well.
[0125] The capsule of the present invention has a particle size of
preferably 0.1 to 10 mm, and more preferably 0.1 to 5 mm. The
particle size of the capsule of the present invention can be
appropriately selected depending on a kind and/or a concentration
of a non-ferrous metal contained in a solution, a concentration of
bacteria contained in the capsule, and the like.
[0126] When the shell is formed using the shell formation
composition containing a thermosetting component, the capsule for
collecting a non-ferrous metal can be manufactured by using a
heated carrier fluid in place of using the light source which
radiates light, in the aforementioned manufacturing method.
[0127] In the case where the shell is formed from the shell
formation composition containing a thermoplastic resin, the capsule
for collecting a non-ferrous metal can be manufactured by using a
cooled carrier fluid in place of using the light source which
radiates light, in the aforementioned manufacturing method. In the
case where the shell formation composition containing a
thermoplastic resin is used, it is preferable that a heating means
is provided in a nozzle portion in a capsule manufacturing
apparatus.
Method of Collecting Non-Ferrous Metal
[0128] According to the present invention, a non-ferrous metal can
be collected using the capsule of the present invention. The method
of collecting a non-ferrous metal in the present invention includes
the following steps:
[0129] an immersion step of immersing the capsule for collecting a
non-ferrous metal in a solution containing a non-ferrous metal,
and
[0130] a separation step of separating the capsule for collecting a
non-ferrous metal immersed in the immersion step.
[0131] The solution containing a non-ferrous metal, which can be
used in the method of the present invention, is not limited as far
as it contains one or more of non-ferrous metals selected from the
group consisting of a rare metal and a rare noble metal. Examples
of the solution include a non-ferrous metal-containing aqueous
solution (percolate) prepared from:
[0132] a sea bottom mineral resource, such as cobalt-rich crust,
manganese crust, manganese nodule, and sea bottom hot water mineral
deposit,
[0133] a marine mineral resource, such as sea water,
[0134] a land mineral resource, such as metal-containing oxidized
mineral (e.g., laterite and monazite),
[0135] a waste component-containing recycle resource, such as
metal-containing incineration residue obtained upon incineration of
waste, and urban mine, and the like.
[0136] It is preferable that the mineral component, such as a
non-ferrous metal contained in the solutions is crushed or ground
in advance. When the particle size of the mineral component is
large, a specific surface area is small and thus a solid-liquid
contact area is decreased, leading to deterioration in non-ferrous
metal collection efficiency. In addition, when the particle size of
the mineral component is larger as mentioned above, the mineral
component is easily precipitated, and thus there is a possibility
that trouble is generated in an operation of collecting a
non-ferrous metal.
[0137] According to the method of the present invention, the
capsule for collecting a non-ferrous metal is immersed in the
solution containing a non-ferrous metal and a non-ferrous metal
contained in the solution permeates the shell constituting the
capsule. Thereby, a non-ferrous metal is collected in the
capsule.
[0138] If necessary, an electron donating component and/or electron
accepting component may be added to a solution containing a
non-ferrous metal. By adding these components, an efficiency of
collecting a non-ferrous metal may be enhanced. For example, the
electron donating component can preferably be added to the solution
containing a non-ferrous metal in a concentration of 1 to 500
mM.
[0139] If necessary, the pH of the solution containing a
non-ferrous metal may be adjusted. It is more preferable that the
solution containing a non-ferrous metal has a pH in the range of 6
to 9.
[0140] An immersion time for immersing the capsule for collecting a
non-ferrous metal in the solution containing a non-ferrous metal
can be appropriately selected depending on a concentration of a
non-ferrous metal in the solution, and the like. The immersion time
can generally be 6 to 240 hours.
[0141] The capsules in which non-ferrous metal is collected by the
immersion are separated from the solution. The separation operation
herein has an advantage that the capsule for collecting a
non-ferrous metal can be separated by a very simple operation, for
example, filtration or sieving. The collected metal can be easily
taken out by performing treatment of destructing a capsule
structure, or incineration treatment of a capsule component under a
temperature in such a range that does not adversely influence on
the collected metal.
[0142] The capsule for collecting a non-ferrous metal of the
present invention has an advantage that a non-ferrous metal can be
easily collected by a simple operation of immersion in the solution
containing a non-ferrous metal for a given time. In this collection
of a non-ferrous metal, there is an advantage that, even in the
case where an amount of a non-ferrous metal contained is small, a
non-ferrous metal can be concentrated and collected
effectively.
EXAMPLES
[0143] The present invention will be described in more detail by
way of the following Examples, but the present invention is not
limited to them. In Examples, unless otherwise indicated, "part"
and "%" are on a mass basis.
Example 1
[0144] Example 1 is a capsule for collecting a non-ferrous metal
having a two-layered structure immediately after manufacturing, in
which a capsule content is an oily portion containing Shewanella
bacteria, and a shell covering the capsule content is obtained by
curing a shell formation composition containing a hydrophilic
photocurable component.
[0145] The shell formation composition was prepared by mixing 60
parts by mass of a 40% aqueous solution of ENTG-3800 (manufactured
by Kansai Paint Co., Ltd.), 0.6 parts by mass of acetoin, and 20
parts by mass of a 0.5% aqueous poval solution.
[0146] The capsule content was prepared by dispersing and
suspending Shewanella oneidensis being reducing bacteria cultured
at a high concentration in coconut oil being an oily substance, to
prepare a suspension composition in which a concentration was
adjusted to 1.2.times.10.sup.8 cells/capsule per one capsule.
[0147] Then, the capsules were obtained using an apparatus having a
concentric double nozzle (a seamless capsule manufacturing
apparatus, manufactured by Morishita Jintan Co., Ltd.), shown in
FIG. 3, in which the suspension composition was injected through an
internal nozzle of a double nozzle, and the shell formation
composition was injected through an external nozzle simultaneously
into a carrier fluid flowing down to form capsule particles in the
carrier fluid. Ultraviolet ray was radiated using a high pressure
mercury lamp of a wavelength of 320 to 400 nm immediately after
formation of the capsule particles to polymerize the photocurable
component (ENTG-3800) of the shell formation composition, to obtain
seamless capsules of a two-layered structure having a particle size
of 4 mm. Liquid paraffin was used as the carrier fluid.
Example 2
[0148] Example 2 is a capsule for collecting a non-ferrous metal
having a three-layered structure immediately after manufacturing,
in which a capsule content is a hydrophilic portion containing
Shewanella bacteria, a shell covering the capsule content is
obtained by curing a shell formation composition containing a
hydrophilic photocurable component, and an intermediate layer is
made of an oily substance.
[0149] The shell formation composition was prepared by mixing 60
parts by mass of a 40% aqueous solution of ENTG-3800 (manufactured
by Kansai Paint Co., Ltd.), 0.6 parts by mass of acetoin, and 20
parts by mass of a 0.5% aqueous poval solution.
[0150] The capsule content was prepared from a hydrophilic internal
layer composition in which a concentration of Shewanella oneidensis
being a reducing bacterium cultured at a high concentration was
adjusted so that the bacterium was contained in a hydrophilic
solution culture medium at 1.2.times.10.sup.8 cells/capsule per one
capsule.
[0151] The intermediate layer was prepared from an oily composition
obtained by mixing sucrose acetate isobutyrate (SAIB) and coconut
oil at a mass ratio of 50:50.
[0152] Then, the capsules were obtained using an apparatus in which
a concentric double nozzle was replaced with a concentric triple
nozzle (a seamless capsule manufacturing apparatus, manufactured by
Morishita Jintan Co., Ltd.) instead of the apparatus having the
concentric double nozzle shown in FIG. 3, in which the capsule
content was injected through an innermost nozzle of a triple
nozzle, the intermediate layer composition was injected through an
middle nozzle, and the shell formation composition was injected
through an outermost nozzle simultaneously into an oily fluid
flowing down to form capsule particles in the oily fluid.
Ultraviolet ray was radiated using a high pressure mercury lamp of
a wavelength of 320 to 400 nm immediately after formation of
capsule particles to polymerize a photocurable component
(ENTG-3800) of the shell formation composition, to obtain seamless
capsules for collecting a non-ferrous metal of a three-layered
structure having a particle size of 4 mm. Silicone oil was used as
a carrier fluid.
Example 3
[0153] The seamless capsules for collecting a non-ferrous metal of
a two-layered structure obtained in Example 1 were immersed in a
TSB liquid culture medium at a pH of 7.2 and 30.degree. C. for 48
hours, and Shewanella oneidensis contained in the capsules was
cultured.
[0154] The cultured capsules were washed using a buffer solution
(KH.sub.2PO.sub.4/NaOH). Then, the capsules were immersed in an
aqueous solution (25.degree. C., pH 7.0) containing 1 mM Pd (II)
ion and 50 mM formic acid. Number of the capsules immersed in the
aqueous solution is 1.2.times.10.sup.7 capsules/m.sup.3.
[0155] Pd(II) ion concentrations were measured by an ICP
(Inductively Coupled Plasma) light emission analyzing device at
times of 3 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours and
24 hours passing after immersion of the capsules.
[0156] After 24 hours from the capsule immersion, the aqueous
solution containing the capsule was filtered, and the immersed
capsules were taken out.
[0157] In this experiment, the capsules were milky white after the
culturing operation and before immersion operation. On the other
hand, the capsules taken out after 24 hours from capsule immersion
were gray to black.
[0158] As comparative tests without using capsules, the aqueous
solution containing Pd (II) ion and formic acid obtained above was
employed without adding anything (Comparative Example 1: control).
The aqueous solution containing Pd (II) ion and formic acid was
mixed with Shewanella oneidensis which was not encapsulated at a
bacteria concentration of 6.7.times.10.sup.15 cells/m.sup.3 to
suspend the cells (Comparative Example 2). The aqueous solution
containing Pd (II) ion and formic acid was mixed with Shewanella
oneidensis not encapsulated at a bacteria concentration of
6.7.times.10.sup.15 cells/m.sup.3 to suspend the cells and the
concentration of formic acid was adjusted to 200 mM (Comparative
Example 3). Pd (II) ion concentrations were measured at times of 3
minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours and 24 hours
passing after the bacteria were put in, using an ICP light emission
analyzing device.
[0159] A graph showing changes in Pd (II) ion concentration in the
aqueous solution in Example 3 and these comparative tests is shown
in FIG. 4.
[0160] In two comparative tests in which Shewanella oneidensis was
added as it is to suspend the cells, measurement was stopped
because Pd (II) ion concentration after 2 hours was considerably
decreased.
Example 4
[0161] The seamless capsules for collecting a non-ferrous metal of
a two-layered structure obtained in Example 1 were immersed in a
TSB liquid culture medium at a pH of 7.2 and 30.degree. C. for 48
hours, and S. oneidensis contained in the capsule was cultured.
[0162] The cultured capsules were washed with a buffer solution
(KH.sub.2PO.sub.4/NaOH). Then, the capsules were immersed in an
aqueous solution (25.degree. C., pH 7.0) containing 5 mM Pd(II) ion
and 200 mM formic acid. Number of capsules immersed in the aqueous
solution was 1.2.times.10.sup.7 capsules/m.sup.3.
[0163] After 24 hours from the capsule immersion, the aqueous
solution containing the capsules was filtered, and the immersed
capsules were taken out.
[0164] In this experiment, the capsules after the culturing
operation and before immersion operation were milky white. On the
other hand, the capsules taken out after 24 hours from capsule
immersion were black.
[0165] Photographs of the capsules before immersion operation
(after culturing operation, before immersion experimental
operation, left), and the capsules taken out after 24 hours from
capsule immersion (right) are shown in FIG. 5.
[0166] As shown in Example 3, the concentration of a palladium ion
in the aqueous solution could be significantly reduced by immersing
the capsules for collecting a non-ferrous metal of the present
invention in the aqueous solution containing a palladium ion for 24
hours. The capsules after immersion were gray to black, and the
capsules could be easily taken out by filtration.
[0167] In the comparative test in which Shewanella oneidensis was
added as it is to the aqueous solution containing a palladium ion
at a concentration of 6.7.times.10.sup.15 cells/m.sup.3 to suspend
the cells, palladium ion in the aqueous solution was significantly
reduced at time of 2 hours. However, in this experimental example,
it was difficult to take out the bacteria by filtration or the
like, because Shewanella oneidensis was dispersed in the suspended
state.
Example 5
[0168] The capsules for collecting a non-ferrous metal having a
three-layered structure immediately after manufacturing obtained in
Example 2 were immersed in a TSB liquid culture medium at a pH of
7.2 and 30 degrees for 48 hours as in Examples 3 and 4, and
bacteria contained in the capsule were cultured.
[0169] The cultured capsules were washed using a buffer solution
(KH.sub.2PO.sub.4/NaOH). Then, the resulting capsules were immersed
in an aqueous solution (pH 3.5, 20 mL) having an indium chloride
concentration of 1 mM. Number of the capsules which were immersed
in the aqueous solution was 100. Number of bacteria present in the
capsules immersed in the aqueous solution was 1.0.times.10.sup.10
cells/ml.
[0170] The concentrations of an indium ion contained in the aqueous
solution were measured using an ICP light emission analyzing device
at a time before capsule immersion, and at times of 5 minutes, 30
minutes, 1 hour, 2 hours, 3 hours and 6 hours after capsule
immersion. The collection rate of indium at the time after 6 hours
from capsule immersion was 98.5%.
[0171] In addition, as a comparative test, also regarding the
aqueous solution in which the capsule was not immersed, the indium
ion concentration was measured at each of the aforementioned
times.
[0172] A graph showing changes in indium ion concentration in the
aqueous solution in Example 5 and the comparative test is shown in
FIG. 6.
Example 6
[0173] Example 6 shows that gold was recovered from wastes of IC
chips. Capsules having a three-layered structure immediately after
manufacturing were prepared as follow.
[0174] A shell formation composition was prepared by mixing 60
parts by mass of a 40% aqueous solution of RM-6572 (manufactured by
Sanyu Rec Co., Ltd.), 0.6 parts by mass of acetoin, and 20 parts by
mass of a 0.5% aqueous poval solution.
[0175] A hydrophilic internal layer composition was prepared as a
capsule content by mixing Shewanella algae being a reducing
bacterium cultured at a high concentration in a hydrophilic
solution culture medium so that the bacteria was contained at
1.2.times.10.sup.8 cells/capsule per one capsule.
[0176] An oily composition was prepared as an intermediate layer
composition by mixing sucrose acetate isobutyrate (SAIB) and
coconut oil at a mass ratio of 50:50.
[0177] Then, capsules were obtained using an apparatus in which a
concentric double nozzle was replaced with a concentric triple
nozzle (seamless capsule manufacturing apparatus, manufactured by
Morishita Jintan Co., Ltd.) instead of the apparatus having a
concentric double nozzle shown in FIG. 3, wherein the capsule
content was injected through an innermost nozzle of a triple
nozzle, the intermediate layer composition was injected through an
intermediate nozzle, and the shell formation composition was
injected through an outermost nozzle simultaneously into an oily
fluid flowing down to form capsule particles in the oily fluid.
Ultraviolet ray was radiated on the capsule particles using a high
pressure mercury lamp of a wavelength of 320 to 400 nm immediately
after formation of capsule particles to polymerize a photocurable
component (RM-6572) of the shell formation composition, to obtain
seamless capsules for collecting a non-ferrous metal of a
three-layered structure having a particle size of 4 mm. Silicone
oil was used as a carrier fluid.
[0178] The capsules for collecting a non-ferrous metal having a
three-layered structure, thus obtained, were immersed in a TSB
liquid culture medium at a pH of 7.2 and 30 degrees for 48 hours as
in Examples 3 and 4, and the bacteria contained in the capsule were
cultured.
[0179] The cultured capsules was washed using a buffer solution
(KH.sub.2PO.sub.4/NaOH).
[0180] Wasted IC (semiconductor integrated circuit) chips were
finely ground to obtain an IC chip ground product. The resulting IC
chip ground product was immersed for 1 day in an aqueous solution,
a pH of which had been adjusted to 0.7 using hydrochloric acid, to
prepare an IC chip percolate.
[0181] The capsules obtained above were immersed in the obtained IC
chip percolate (pH 0.7, 20 mL). Number of the capsules that were
immersed in the IC chip percolate was 100. Number of the bacteria
present in the capsule immersed in the IC chip percolate was
3.0.times.10.sup.10 cells/ml.
[0182] Concentrations of gold element contained in the IC chip
percolate were measured using an ICP light emission analyzing
device at a time before capsule immersion and at times of 10
minutes, 30 minutes, 1 hour, 2 hours, 3 hours and 6 hours after
capsule immersion. A collection rate of gold after 6 hours from
capsule immersion in Example 6 was 75.7%.
[0183] As comparative experiments without capsules, the IC chip
percolate was employed as it is without bacteria. Separately,
Shewanella algae was added to the IC chip percolate at a
concentration of 4.0.times.10.sup.10 cells/ml to suspend the cells.
Concentration of gold ion was measured at each of the
aforementioned times using an ICP light emission analyzing
device.
[0184] A graph showing changes in concentration of gold ion
([AuCl.sub.4].sup.-) in the IC chip percolate in Example 6 and the
comparative tests is shown in FIG. 7.
[0185] From the Examples 5 and 6, it was confirmed that indium and
gold could be collected using the capsules for collecting a
non-ferrous metal of the present invention.
[0186] Further, as shown in Example 6, it was also confirmed that
gold could be recovered from the wasted IC chips. The IC chip
percolate used in Example 6 is a strong acidic aqueous solution
having a pH of 0.7. It was confirmed that gold could be recovered
well from the strong acidic aqueous solution.
[0187] In addition, also in the comparative test of Example 6, in
which Shewanella algae was added as it is to the IC chip percolate
at a concentration of 4.0.times.10.sup.10 cells/ml to suspend the
cells, concentration of gold ion was significantly reduced.
However, in Example 6, it was difficult to take out the bacterial
by filtration or the like, because Shewanella algae was dispersed
as they were in the suspension state.
[0188] In addition, Example 6 shows that the capsules for
collecting a non-ferrous metal of the present invention can
selectively collect only gold, from an IC chip percolate although
the IC chip percolate contains a variety of metal other than gold
as collection subject metal. The IC chip percolate contains a
variety of metal components such as copper other than gold. It was
confirmed that the concentration of copper ion contained in the IC
chip percolate used in Example 6 is as high as the concentration of
gold ion. Nevertheless, a metal component collected in the capsules
for collecting a non-ferrous metal was only gold in Example 6.
Thus, it was confirmed that the capsules for collecting a
non-ferrous metal of the present invention had extremely excellent
performance that only gold could be selectively collected from the
IC chip percolate containing gold and copper.
Example 7
[0189] The capsules for collecting a non-ferrous metal having a
three-layered structure immediately after manufacturing,
manufactured in Example 6, were subjected to the culturing
operation as explained in Example 6.
[0190] The resulting capsules were immersed in an aqueous solution
(pH 7.0, 20 mL) containing 1 mM platinum (IV) ion and 50 mM sodium
lactate. Number of the capsules immersed in the aqueous solution
was 100. Number of the bacteria present in the capsule immersed in
the aqueous solution was 3.0.times.10.sup.10 cells/ml.
[0191] Concentrations of platinum contained in an aqueous solution
were measured using an ICP light emission spectral analysis device
at a time before capsule immersion, and at times of 10 minutes, 30
minutes, 1 hour, 3 hours, and 6 hours after capsule immersion. A
collection rate of platinum after 6 hours from capsule immersion in
Example 7 was 72.0%.
[0192] In addition, as a comparative test, the aqueous solution was
employed as it was without the capsules and a platinum
concentration was measured at each of the aforementioned times.
[0193] A graph showing changes in platinum (IV) concentration in
the aqueous solution in Example 7 and this comparative test is
shown in FIG. 8.
Example 8
[0194] According to the same manner as that of Example 6 except
that, as the shell formation composition forming a shell, a
composition in which 60 parts by mass of a 40% aqueous solution of
UA-7100 (manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.6
parts by mass of acetoin, and 20 parts by mass of a 0.5% aqueous
poval solution were mixed, was prepared and used, capsules for
collecting a non-ferrous metal having a three-layered structure
immediately after manufacturing was obtained. Then, the resulting
capsules were subjected to the culturing operation as explained in
Example 6.
[0195] The capsules thus obtained were immersed in an aqueous
solution (pH 3.6, 20 mL) containing 1 mM gallium (III) ion. Number
of the capsules immersed in the aqueous solution was 100. Number of
the bacteria present in the capsules immersed in the aqueous
solution was 3.0.times.10.sup.10 cells/ml.
[0196] Concentrations of gallium contained in the aqueous solution
were measured using an ICP light emission spectral analysis device
at a time before capsule immersion, and at time of 15 minutes, 30
minutes, 1 hour, 3 hours, and 6 hours after capsule immersion. A
collection rate of gallium after 6 hours from capsule immersion in
Example 8 was 79.2%.
[0197] In addition, as a comparative test, the aqueous solution
containing gallium ion was employed as it was without the capsules,
and a gallium concentration was measured at each of the
aforementioned times.
[0198] A graph showing changes in gallium (III) ion concentration
in the aqueous solution in Example 8 and this comparative test is
shown in FIG. 9.
Example 9
[0199] The capsules for collecting a non-ferrous metal having a
three-layered structure immediately after manufacturing,
manufactured in Example 6 were subjected to the culturing operation
as explained in Example 6.
[0200] The resulting capsules were immersed in an aqueous solution
(pH 7.0, 20 mL) containing 1 mM rhodium (III) ion and 50 mM sodium
formate. Number of the capsules immersed in the aqueous solution
was 100. Number of the bacteria present in the capsule immersed in
the aqueous solution was 3.0.times.10.sup.10 cells/ml.
[0201] Concentrations of rhodium contained in the aqueous solution
were measured using an ICP light emission spectral analysis device
a time before capsule immersion, and at times of 10 minutes, 30
minutes, 1 hour, 3 hours, and 6 hours after capsule immersion. A
collection rate of rhodium after 6 hours from capsule immersion in
Example 9 was 58.0%.
[0202] In addition, as a comparative test, the aqueous solution was
employed as it was without the capsules and a rhodium concentration
was measured at each of the aforementioned times.
[0203] A graph showing changes in rhodium (III) ion concentration
in the aqueous solution in Example 9 and this comparative test is
shown in FIG. 10.
Example 10
[0204] The capsules for collecting a non-ferrous metal having a
three-layered structure immediately after manufacturing,
manufactured in Example 6 were subjected to the culturing operation
as in Example 6.
[0205] The resulting capsules were immersed in an aqueous solution
(pH 5.5, 20 mL) containing 0.5 mM dysprosium (III) ion. Number of
the capsules immersed in the aqueous solution was 100. Number of
the bacteria present in the capsule immersed in the aqueous
solution was 3.0.times.10.sup.10 cells/ml.
[0206] Concentrations of dysprosium contained in the aqueous
solution were measured using an ICP light emission spectral
analysis device at a time before capsule immersion, and at times of
15 minutes, 30 minutes, 1 hour, 3 hours, and 6 hours after capsule
immersion. A collection rate of rhodium after 6 hours from capsule
immersion in Example 10 was 88.0%.
[0207] In addition, as a comparative test, the aqueous solution was
employed without the capsules, and a dysprosium concentration was
measured at each of the aforementioned times.
[0208] A graph showing changes in dysprosium (III) ion
concentration in the aqueous solution in Example 9 and this
comparative test is shown in FIG. 11.
[0209] As shown in Examples 7 to 10, it was confirmed that a
variety of non-ferrous metals such as platinum, gallium, rhodium
and a rare earth element could be collected using the capsules for
collecting a non-ferrous metal of the present invention.
[0210] In Examples, a collection rate and/or a collection speed of
a non-ferrous metal can be improved by a method, e.g. (1) an
increase of number of bacteria contained in the capsule for
collecting a non-ferrous metal, (2) an increase of number of
capsules for collecting a non-ferrous metal to be immersed in the
aqueous solution, and (3) a design change of a particle size of the
capsule for collecting a non-ferrous metal to a range of 0.1 to 2
mm.
INDUSTRIAL APPLICABILITY
[0211] The capsule for collecting a non-ferrous metal of the
present invention has an advantage that, by a simple operation of
immersion in a solution containing a non-ferrous metal for a given
time, a non-ferrous metal can be easily collected. In collection of
a non-ferrous metal using the capsule for collecting a non-ferrous
metal of the present invention, a non-ferrous metal can be
collected without accompanying consumption of a large amount of
energy like a method using a chemical reaction. There is an
advantage that a large amount of waste solvent like a solvent
extraction method is not accompanied, and the load on the
environment is also small. Further, in the present invention, since
a non-ferrous metal can be collected by a simple operation of
immersing a capsule for collecting a non-ferrous metal in a
solution for a given period and, thereafter, taking out the capsule
by a means such as filtration, there is an advantage that
implementation is simple without accompanying the large cost of
facility investment.
EXPLANATION OF NUMBERS IN DRAWINGS
[0212] 1: Shell, [0213] 2: Oily portion, [0214] 3: Capsule content,
[0215] 4: Intermediate layer portion (oily substance), [0216] 5:
Hydrophilic portion, [0217] 6: Hydrophilic portion, [0218] 10:
Double nozzle, [0219] 11: Capsule content, [0220] 12: Shell
formation composition, [0221] 13: Formation tube, [0222] 14: Light
source, [0223] 15: Separation means, [0224] 16: Carrier fluid,
[0225] 17: Driving means.
* * * * *