U.S. patent application number 12/397818 was filed with the patent office on 2010-09-09 for indium recovery by supported liquid membrane with strip dispersion.
This patent application is currently assigned to CHUNG YUAN CHRISTIAN UNIVERSITY. Invention is credited to W.S. Winston Ho, Juin-Yih Lai, Chih-Hsieh Lee, Chung-Ching Lee, Ying-Ling Liu, Da-Ming Wang.
Application Number | 20100224030 12/397818 |
Document ID | / |
Family ID | 42677072 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100224030 |
Kind Code |
A1 |
Liu; Ying-Ling ; et
al. |
September 9, 2010 |
INDIUM RECOVERY BY SUPPORTED LIQUID MEMBRANE WITH STRIP
DISPERSION
Abstract
The present invention provides a process for the removal and
recovery of indium from waste waters and process streams. The
process of the present invention utilizes a combination of a
supported liquid membrane (SLM) and a strip dispersion to improve
extraction of indium while increasing membrane stability and
decreasing processing costs. This novel process selectively removes
indium from the feed stream, provides the increased flexibility of
aqueous strip/organic volume ratio, and produces a concentrated
strip solution of indium.
Inventors: |
Liu; Ying-Ling; (Taoyuan,
TW) ; Wang; Da-Ming; (Taipei City, TW) ; Lai;
Juin-Yih; (Taoyuan County, TW) ; Ho; W.S.
Winston; (Columbus, OH) ; Lee; Chung-Ching;
(Tainan County, TW) ; Lee; Chih-Hsieh; (Taichung
City, TW) |
Correspondence
Address: |
WPAT, PC;INTELLECTUAL PROPERTY ATTORNEYS
7225 BEVERLY ST.
ANNANDALE
VA
22003
US
|
Assignee: |
CHUNG YUAN CHRISTIAN
UNIVERSITY
Taoyuan
TW
SOLAR APPLIED MATERIALS TECHNOLOGY CORP.
Tainan County
TW
|
Family ID: |
42677072 |
Appl. No.: |
12/397818 |
Filed: |
March 4, 2009 |
Current U.S.
Class: |
75/711 |
Current CPC
Class: |
C22B 3/22 20130101; Y02P
10/234 20151101; C22B 3/0068 20130101; C22B 58/00 20130101; C22B
7/007 20130101; B01D 61/38 20130101; C22B 3/0005 20130101; Y02P
10/20 20151101 |
Class at
Publication: |
75/711 |
International
Class: |
C22B 58/00 20060101
C22B058/00 |
Claims
1. A combined supported liquid membrane (SLM)/strip dispersion
process for the removal and recovery of indium from a feed solution
containing the indium comprising (1) treating a feed solution
containing indium on one side of the SLM embedded in a microporous
support material to remove the indium by the use of a strip
dispersion on the other side of the SLM, the strip dispersion being
formed by dispersing an aqueous strip solution in an organic liquid
comprising an extractant using a mixer; and (2) allowing the strip
dispersion or a part of the strip dispersion to separate into two
phases, the organic liquid phase and the aqueous strip solution
phase containing a concentrated indium solution.
2. The process of claim 1, wherein the feed solution is treated to
remove indium to a concentration of 5 parts per million (ppm) or
lower.
3. The process of claim 1, wherein the aqueous strip solution of
the strip dispersion comprises an acid.
4. The process of claim 3, wherein the acid is selected from the
group consisting of hydrochloric acid, sulfuric acid, nitric acid,
acetic acid, and mixtures thereof.
5. The process of claim 1, wherein the organic liquid of the strip
dispersion further comprises a modifier in a hydrocarbon solvent or
mixture.
6. The process of claim 1, wherein the organic liquid of the strip
dispersion comprises about 2 volume % to about 100 volume %
extractant and about 0 volume % to about 20 volume % modifier in a
hydrocarbon solvent or mixture.
7. The process of claim 6, wherein the organic liquid of the strip
dispersion comprises about 5 volume % to about 40 volume %
extractant and about 1 volume % to about 10 volume % modifier in a
hydrocarbon solvent or mixture.
8. The process of claim 5, wherein the modifier is selected from
the group consisting of alcohols, nitrophenyl alkyl ethers,
trialkyl phosphates, and mixtures thereof.
9. The process of claim 8 wherein the alcohol is selected from the
group consisting of hexanol, heptanol, octanol, nonanol, decanol,
undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol,
hexadecanol, heptadacanol, octadecanol, and mixtures thereof.
10. The process of claim 8 wherein the nitrophenyl alkyl ether is
selected from the group consisting of o-nitrophenyl octyl ether
(o-NPOE), o-nitrophenyl heptyl ether, o-nitrophenyl hexyl ether,
o-nitrophenyl pentyl ether (o-NPPE), o-nitrophenyl butyl ether,
o-nitrophenyl propyl ether, and mixtures thereof.
11. The process of claim 8, wherein the trialkyl phosphate is
selected from the group consisting of tributyl phosphate,
tris(2-ethylhexyl)phosphate, and mixtures thereof.
12. The process of claim 5, wherein the hydrocarbon solvent is
selected from a group consisting of n-decane; n-undecane;
n-dodecane; n-tridecane; n-tetradecane; isodecane; isoundecane;
isododecane; isotridecane; isotetradecane; isoparaffinic
hydrocarbon solvent having a flash point of 92.degree. C., a
boiling point of 254.degree. C., a viscosity of 3 cp at 25.degree.
C., and a density of 0.791 g/ml at 15.6.degree. C.; and mixtures
thereof.
13. The process of claim 1, wherein the microporous support
material is selected from the group consisting of polypropylene,
polytetrafluoroethylene, polyethylene, polysulfone,
polyethersulfone, polyetheretherketone, polyimide, polyamide,
polyaramide, and mixtures thereof.
14. The process of claim 1, wherein the microporous support
material is polypropylene.
15. The process of claim 1, wherein the extractant comprises a
dialkyl phosphoric acid.
16. The process of claim 15, wherein the dialkyl group of the
dialkyl phosphoric acid is paraffinic (saturated) and has from 6 to
26 carbon atoms.
17. The process of claim 15, wherein the dialkyl phosphoric acid is
selected from the group consisting of di(2-ethyl-hexyl)phosphoric
acid (D2EHPA), di(2-butyl-octyl)phosphoric acid,
di(2-hexyl-decyl)phosphoric acid,
di(2-octyl-decyl/2-hexyl-dodecyl)phosphoric acid,
di(2-octyl-dodecyl)phosphoric acid, di(hexyl)phosphoric acid,
di(heptyl)phosphoric acid, di(octyl)phosphoric acid,
di(nonyl)phosphoric acid, di(decyl)phosphoric acid,
di(undecyl)phosphoric acid, di(dodecyl)phosphoric acid,
di(tridecyl)phosphoric acid, di(tetradecyl)phosphoric acid,
di(pentadecyl)phosphoric acid, di(hexadecyl)phosphoric acid,
di(heptadecyl)phosphoric acid, di(octadecyl)phosphoric acid,
di(nonadecyl)phosphoric acid, di(decadecyl)phosphoric acid,
di(undecadecyl)phosphoric acid, di(dodecadecyl)phosphoric acid,
di(tridecadecyl)phosphoric acid, di(tetrdecadecyl)phosphoric acid,
di(pentadadecyl)phosphoric acid, di(hexadecadecyl)phosphoric acid,
and mixtures thereof.
18. The process of claim 15 wherein the dialkyl phosphoric acid is
di(2-ethyl-hexyl)phosphoric acid (D2EHPA).
19. The process of claim 1 wherein the extractant comprises an
alkyl phenylphosphonic acid.
20. The process of claim 19 wherein the alkyl group of the alkyl
phenylphosphonic acid is paraffinic (saturated) and has from 6 to
26 carbon atoms.
21. The process of claim 19 wherein the alkyl phenylphosphonic acid
is selected from the group consisting of 2-butyl-1-octyl
phenylphosphonic acid (BOPPA), 2-hexyl-1-decyl phenylphosphonic
acid, 2-octyl-1-decyl/2-hexyl-1-dodecyl phenylphosphonic acid,
2-octyl-1-dodecyl phenylphosphonic acid, hexyl phenylphosphonic
acid, heptyl phenylphosphonic acid, octyl phenylphosphonic acid,
nonyl phenylphosphonic acid, decyl phenylphosphonic acid, undecyl
phenylphosphonic acid, dodecyl phenylphosphonic acid, tridecyl
phenylphosphonic acid, tetradecyl phenylphosphonic acid, pentadecyl
phenylphosphonic acid, hexadecyl phenylphosphonic acid, heptadecyl
phenylphosphonic acid, octadecyl phenylphosphonic acid, nonadecyl
phenylphosphonic acid, decadecyl phenylphosphonic acid, undecadecyl
phenylphosphonic acid, dodecadecyl phenylphosphonic acid,
tridecadecyl phenylphosphonic acid, tetrdecadecyl phenylphosphonic
acid, pentadadecyl phenylphosphonic acid, hexadecadecyl
phenylphosphonic acid, and mixtures thereof.
22. The process of claim 19 wherein the alkyl phenylphosphonic acid
is 2-butyl-1-octyl phenylphosphonic acid (BOPPA).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the removal and recovery of
indium from feed solutions, such as process streams and waste
waters, using supported liquid membrane technology.
[0003] 2. Description of the Prior Art
[0004] Liquid membranes combine extraction and stripping, which are
normally carried out in two separate steps in conventional
processes such as solvent extractions, into one step. A one-step
liquid membrane process provides the maximum driving force for the
separation of a targeted species, leading to the best clean-up and
recovery of the species (W. S. Winston Ho and Kamalesh K. Sirkar,
eds., Membrane Handbook, Chapman & Hall, New York, 1992).
[0005] There are two types of liquid membranes: (1) supported
liquid membranes (SLMs) and (2) emulsion liquid membranes (ELMs).
In SLMs, the liquid membrane phase is the organic liquid imbedded
in pores of a microporous support, e.g., microporous polypropylene
hollow fibers (W. S. Winston Ho and Kamalesh K. Sirkar, eds.,
Membrane Handbook, Chapman & Hall, New York, 1992). When the
organic liquid contacts the microporous support, it readily wets
the pores of the support, and the SLM is formed.
[0006] For the extraction of a target species from a feed solution,
the organic-based SLM is placed between two aqueous solutions--the
feed solution and the strip solution where the SLM acts as a
selective membrane for the transport of the target species from the
feed solution to the strip solution. The organic liquid in the SLM
contains an extractant, a diluent which is generally an inert
organic solvent, and sometimes a modifier, and it is immiscible in
the aqueous feed and strip streams.
[0007] SLMs have been investigated to remove metals, radionuclides,
and rare earth metals from aqueous feed solutions in the scientific
and industrial community. The removal of metals, including copper,
zinc, cadmium, and palladium, with SLMs has been described (N.
Aouad, G. Miquel-Mercier, E. Bienvenue, E. Tronel-Peyroz, G.
Jerninet, J. Juillard, and P. Seta, "Lasalocid (X537A) as a
Selective Carrier for Cd(II) in Supported Liquid Membranes," J.
Membrane Sci., 139, 167-174 (1998); J. A. Daoud, S. A. El-Reefy,
and H. F. Aly, "Permeation of Cd(II) Ions through a Supported
Liquid Membrane Containing Cyanex-302 in Kerosene," Sep. Sci.
Technol., 33, 537-549 (1998); J. Vander Linden and R. F. De
Ketelaere, "Selective Recuperation of Copper by Supported Liquid
Membrane (SLM) Extraction," J. Membrane Sci., 139, 125-135 (1998);
M. E. Campderros, A. Acosta, and J. Marchese, "Selective Separation
of Copper with LIX 864 in a Hollow Fiber Module," Talanta, 47,
19-24 (1998); M. Rovira and A. M. Sastre, "Modelling of Mass
Transfer in Facilitated Supported Liquid-Membrane Transport of
Palladium(II) Using Di-(2-ethylhexyl)Thiophosphoric Acid," J.
Membrane Sci., 149, 241-250 (1998); J. C. Lee, J. Jeong, J. T.
Park, I. J. Youn, and H. S. Chung, "Selective and Simultaneous
Extractions of Zn and Cu Ions by Hollow Fiber SLM Modules
Containing HEH(EHP) and LIX84," Sep. Sci. Technol., 34, 1689-1701
(1999); F. Valenzuela, C. Basualto, C. Tapia, and J. Sapag,
"Application of Hollow-Fiber Supported Liquid Membranes Technique
to the Selective Recovery of a Low Content of Copper from a Chilean
Mine Water," J. Membrane Sci., 155, 163-168 (1999)).
[0008] On the removal of radionuclides, Dozol et al. (J. F. Dozol,
N. Simon, V. Lamaare, H. Rouquette, S. Eymard, B. Tournois, D. De
Marc, and R. M. Macias, "A Solution for Cesium Removal from
High-Salinity Acidic or Alkaline Liquid Waste: the Crown
Calix[4]arenes", Sep. Sci. Technol., 34, 877-909 (1999)) have
described the use of the extractant, Calix[4]arenes monocrown or
biscrown, blocked in 1,3 alternative cone conformation, in SLMs for
the removal of cesium from high-salinity acidic or alkaline liquid
waste. Kedari et al. (C. S. Kedari, S. S. Pandit, and A. Ramanujam,
"Selective Permeation of Plutonium (IV) through Supported Liquid
Membrane Containing 2-Ethylhexyl 2-Ethylhexyl Phosphonic Acid as
Ion Carrier", J. Membrane Sci., 156, 187-196 (1999)) have studied
the selective permeation of plutonium (IV) through a SLM containing
2-ethylhexyl 2-ethylhexyl phosphonic acid as the ion carrier.
[0009] On the extraction of rare earth metals, Yaftian et al. (M.
R. Yaftian, M. Burgard, C. B. Dieleman and D. Matt, "Rare-earth
Metal-ion Separation Using a Supported Liquid Membrane Mediated by
a Narrow Rim Phosphorylated Calix[4]arene," J. Membrane Sci., 144,
57-64 (1998)) has reported the use of SLMs for europium, lanthanum,
neodymium, praseodymium, and gadolinium.
[0010] One disadvantage of SLMs is their instability due mainly to
loss of the membrane liquid (organic solvent, extractant, and/or
modifier) into the aqueous phases on each side of the membrane (A.
J. B. Kemperman, D. Bargeman, Th. Van Den Boomgaard, H. Strathmann,
"Stability of Supported Liquid Membranes: State of the Art", Sep.
Sci. Technol., 31, 2733 (1996); T. M. Dreher and G. W Stevens,
"Instability Mechanisms of Supported Liquid Membranes", Sep. Sci.
Technol., 33, 835-853 (1998); J. F. Dozol, J. Casas, and A. Sastre,
"Stability of Flat Sheet Supported Liquid Membranes in the
Transport of Radionuclides from Reprocessing Concentrate
Solutions", J. Membrane Sci., 82, 237-246 (1993)). The prior art
has attempted to solve this problem through the combined use of SLM
with a module containing two set of hollow fibers, i.e., the
hollow-fiber contained liquid membrane (W. S. Winston Ho and
Kamalesh K. Sirkar, eds., Membrane Handbook, Chapman & Hall,
New York, 1992). In this configuration with two sets of microporous
hollow-fiber membranes, one carries the aqueous feed solution, and
the other carries the aqueous strip solution. The organic phase is
contained between the two sets of hollow fibers by maintaining the
aqueous phases at a higher pressure than the organic phase. The use
of the hollow-fiber contained liquid membrane increases membrane
stability, because the liquid membrane may be continuously
replenished. However, this configuration is not advantageous
because it requires mixing two sets of fibers to achieve a low
contained liquid membrane thickness.
[0011] In ELMs, an emulsion acts as a liquid membrane for the
separation of the target species from a feed solution. An ELM is
created by forming a stable emulsion, such as a water-in-oil
emulsion, between two immiscible phases, followed by dispersion of
the emulsion into a third, continuous phase by agitation for
extraction. The membrane phase is the oil phase that separates the
encapsulated, internal aqueous droplets in the emulsion from the
external, continuous phase (W. S. Winston Ho and Kamalesh K.
Sirkar, eds., Membrane Handbook, Chapman & Hall, New York,
1992). The species-extracting agent is contained in the membrane
phase, and the stripping agent is contained in the internal aqueous
droplets. Emulsions formed from these two phases are generally
stabilized by use of a surfactant. The external, continuous phase
is the feed solution containing the target species. The target
species is extracted from the aqueous feed solution into the
membrane phase and then stripped into the aqueous droplets in the
emulsion. The target species can then be recovered from the
internal aqueous phase by breaking the emulsion, typically via
electrostatic coalescence, followed by electroplating or
precipitation.
[0012] The use of ELMs to remove metals, rare earth metals, and
radionuclides from aqueous feed solutions has also been pursued in
the scientific and industrial community. The ELMs for the removal
of metals, including cobalt, copper, zinc, nickel, mercury, lead,
cadmium, and silver, and for the removal of rare earth metals,
including europium, lanthanum, and neodymium, have been described
in detail (W. S. Winston Ho and Kamalesh K. Sirkar, eds., Membrane
Handbook, Chapman & Hall, New York, 1992). The removal of
metals including cobalt, nickel, cadmium, mercury, and lead with
ELMs has been reported quite a lot in the literature (B.
Raghuraman, N. Tirmizi, and J. M. Wiencek, "Emulsion Liquid
Membranes for Wastewater Treatment. Equilibrium Models for Some
Typical Metal-Extractant Systems," Environ. Sci. Technol., 28,
1090-1098 (1994); T. Kakkoi, M. Goto, K. Sugimoto, K. Ohto, and F.
Nakashio, "Separation of Cobalt and Nickel with Phenylphosphonic
Acid Mono-4-tert-octylphenyl Ester by Liquid Surfactant Membranes,"
Sep. Sci. Technol., 30, 637-657 (1995); R. S. Juang and J. D.
Jiang, "Recovery of Nickel from a Simulated Electroplating Rinse
Solution by Solvent Extraction and Liquid Surfactant Membrane," J.
Membrane Sci., 100, 163-170 (1995); H. Kasaini, F. Nakashio, and M.
Goto, "Application of Emulsion Liquid Membranes to Recover Cobalt
Ions from a Dual-component Sulphate Solution Containing Nickel
Ions," J. Membrane Sci., 146, 159-168 (1998); S. Y. B. Hu and J. M.
Wiencek, "Emulsion-Liquid-Membrane Extraction of Copper Using a
Hollow-Fiber Contactor," AIChE J., 570-581 (1998)).
[0013] On radionuclides, the removal of strontium, cesium,
technetium, and uranium has also been described in detail by Ho and
Sirkar (W. S. Winston Ho and Kamalesh K. Sirkar, eds., Membrane
Handbook, Chapman & Hall, New York, 1992). The extraction of
strontium with the ELM technique has been investigated (I. Eroglu,
R. Kalpakci, and G. Gunduz, "Extraction of Strontium Ions with
Emulsion Liquid Membrane Technique", J. Membrane Sci., 80, 319-325
(1993)).
[0014] One disadvantage of ELMs is that the emulsion swells upon
prolonged contact with the feed stream. This swelling causes a
reduction in the stripping reagent concentration in the aqueous
droplets which reduces stripping efficiency. It also results in
dilution of the target species that has been concentrated in the
aqueous droplets, resulting in lower separation efficiency of the
membrane. The swelling further results in a reduction in membrane
stability by making the membrane thinner. Finally, swelling of the
emulsion increases the viscosity of the spent emulsion, making it
more difficult to demulsify. A second disadvantage of ELMs is
membrane rupture, resulting in leakage of the contents of the
aqueous droplets into the feed stream and a concomitant reduction
of separation efficiency. Raghuraman and Wiencek (B. Raghuraman and
J. Wiencek, "Extraction with Emulsion Liquid Membranes in a
Hollow-Fiber Contactor", AIChE J., 39, 1885-1889 (1993)) have
described the use of microporous hollow-fiber contactors as an
alternative contacting method to direct dispersion of ELMs to
minimize the membrane swelling and leakage. This is due to the fact
that the hollow-fiber contactors do not have the high shear rates
typically encountered with the agitators used in the direct
dispersion. Additional disadvantages include the necessary process
steps for making and breaking the emulsion.
[0015] Thus, there has been a need in the art for an extraction
process which maximizes the stability of the SLM membrane,
resulting in efficient removal and recovery of metals,
radionuclides, penicillin, and organic acids from the aqueous feed
solutions. Ho recognized the need and invented the combined
supported liquid membrane/strip dispersion process for the removal
of chromium (W. S. Winston Ho, "Supported Liquid Membrane Process
for Chromium Removal and Recovery", U.S. Pat. No. 6,171,563
(2001)), metals (W. S. Winston Ho, "Combined Supported Liquid
Membrane/Strip Dispersion Process for the Removal and Recovery of
Radionuclides and Metals", U.S. Pat. No. 6,328,782 (2001); W. S.
Winston Ho, "Combined Supported Liquid Membrane/Strip Dispersion
Process for the Removal and Recovery of Metals", U.S. Pat. No.
6,350,419 (2002)), radionuclides (W. S. Winston Ho, "Combined
Supported Liquid Membrane/Strip Dispersion Process for the Removal
and Recovery of Radionuclides and Metals", U.S. Pat. No. 6,328,782
(2001); W. S. Winston Ho, "Combined Supported Liquid Membrane/Strip
Dispersion Process for the Removal and Recovery of Radionuclides",
U.S. Pat. No. 6,696,589 (2004)), and penicillin and organic acids
(W. S. Winston Ho, "Combined Supported Liquid Membrane/Strip
Dispersion Process for the Removal and Recovery of Penicillin and
Organic Acids", U.S. Pat. No. 6,433,163 (2002)). The synthesis of
dialkyl monothiophosphoric acid extractants for the combined
supported liquid membrane/strip dispersion process for the removal
of metals has been reported (W. S. Winston Ho and Bing Wang,
"Combined Supported Liquid Membrane/Strip Dispersion Process for
the Removal and Recovery of Metals: Dialkyl Monothiophosphoric
Acids and Their Use as Extractants", U.S. Pat. No. 6,291,705
(2001)). But, none of these patents by Ho disclose the use of the
combined supported liquid membrane/strip dispersion process for the
removal and recovery of indium.
[0016] Thus, there is a need in the art for an extraction process
which maximizes the stability and effectiveness of the SLM membrane
for the efficient removal and recovery of indium from the aqueous
feed solutions.
SUMMARY OF THE INVENTION
[0017] The present invention relates to a process for the removal
and recovery of indium from a feed solution using a combined
SLM/strip dispersion.
[0018] In one embodiment, the present invention relates to a
process for the removal and recovery of indium from a feed solution
which comprises the following steps. First, a feed solution
containing indium is passed on one side of the SLM embedded in a
microporous support material and treated to remove the indium by
the use of a strip dispersion on the other side of the SLM. The
strip dispersion can be formed by dispersing an aqueous strip
solution in an organic liquid, for example, using a mixer. Second,
the strip dispersion, or a part of the strip dispersion, is allowed
to stand, resulting in separation of the dispersion into two
phases: the organic liquid phase and the aqueous strip solution
phase containing a concentrated indium solution.
[0019] The continuous organic phase of the strip dispersion readily
wets the pores of a microporous support to form a stable SLM. The
process of the present invention provides a number of operational
and economic advantages over the use of conventional SLMs or
solvent extraction.
[0020] Thus, it is an object of the present invention to provide an
SLM process for the removal and recovery of indium which provides
increased membrane stability.
[0021] It is another object of the invention to provide an SLM
process having high indium removal and recovery.
[0022] It is yet another object of the present invention to provide
an SLM process having improved recovery of indium to provide a
concentrated strip solution of indium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a schematic representation of the combined
supported liquid membrane/strip dispersion of the present invention
for the recovery of indium.
[0024] FIG. 2 is an enlarged view of the schematic representation
of the combined supported liquid membrane/strip dispersion of the
present invention for the recovery of indium.
[0025] FIG. 3 shows the indium concentrations in the feed and strip
solutions as a function of time for the feed solution containing
200 ppm In.sup.3+ in pH 1 H.sub.2SO.sub.4 of 15.5 L. The strip
dispersion was prepared by mixing together 0.12 L (120 ml) of the
strip solution of 5M HCl and 0.9 L (900 ml) of the organic solution
containing 0.6M di(2-ethyl-hexyl)phosphoric acid (D2EHPA) and 2 vol
% dodecanol in Isopar-L.
[0026] FIG. 4 shows the indium concentrations in the feed and strip
solutions as a function of time for the feed solution containing
about 180 ppm In.sup.3+ in pH 1 HNO.sub.3 of 1 L. The strip
dispersion was prepared by mixing together 0.12 L (120 ml) of the
strip solution of 5M HCl and 0.9 L (900 ml) of the organic solution
containing 0.6M D2EHPA and 2 vol % dodecanol in Isopar-L. Also
shown are the indium concentrations in the feed solutions for the
original feed solutions containing about 190 ppm In.sup.3+ in pH 1
H.sub.2SO.sub.4 and 160 ppm In.sup.3+ in pH 1 HCl, all with the
same feed volume of 1 L and the same strip dispersion.
[0027] FIG. 5 depicts the indium concentrations in the feed
solutions originally containing about 200 ppm In.sup.3+ in pH 1, 2
wt % H.sub.2C.sub.2O.sub.4 as a function of time for 0.2M, 0.6M and
1M D2EHPA concentrations. Each of the strip dispersions was
prepared by mixing together 0.1 L (100 ml) of the strip solution of
5M HCl and 0.9 L (900 ml) of the organic solution containing the
specified D2EHPA concentration and 2 vol % dodecanol in
Isopar-L.
[0028] FIG. 6 depicts the indium concentrations in the feed and
strip solutions as a function of time for the feed solution
containing 200 ppm In.sup.3+ in pH 1, 2 wt % H.sub.2C.sub.2O.sub.4
of 15.5 L. The strip dispersion was prepared by mixing together
0.12 L (120 ml) of the strip solution of 5M HCl and 0.9 L (900 ml)
of the organic solution containing 0.6M D2EHPA and 2 vol %
dodecanol in Isopar-L.
[0029] FIG. 7 shows the indium concentrations in the feed and strip
solutions as a function of time for the ITO feed solution of 15.5 L
containing about 140 ppm In.sup.3+ at pH 0.9. The strip dispersion
was prepared by mixing together 0.12 L (120 ml) of the strip
solution of 5M HCl and 0.9 L (900 ml) of the organic solution
containing 0.6M D2EHPA and 2 vol % dodecanol in Isopar-L. Also
shown is the tin concentration in the feed solution as a function
of time.
[0030] FIG. 8 depicts the indium concentrations in the feed and
strip solutions as a function of time for the residual electrolyte
feed solution of 0.5 L containing about 11000 ppm In.sup.3+ at pH
1. The strip dispersion was prepared by mixing together 0. 1 L (100
ml) of the strip solution of 5M HCl and 0.9 L (900 ml) of the
organic solution containing 0.6M D2EHPA and 2 vol % dodecanol in
Isopar-L. In this figure, both the indium concentration in the
strip solution obtained experimentally, i.e., strip-exp, and that
calculated from the feed concentration based on the material
balance, i.e., strip-ideal (the ideal case), are included.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] The present invention relates to a process for the removal
and recovery of indium from a feed solution, such as waste waters
or process streams. This new process employs a combination of a
supported liquid membrane (SLM) and a strip dispersion.
[0032] In one embodiment, the present invention relates to a
process for the removal and recovery of indium from a feed solution
which comprises the following steps. First, a feed solution
containing indium is passed on one side of the SLM embedded in a
microporous support material and treated to remove the indium by
the use of a strip dispersion on the other side of the SLM. The
strip dispersion can be formed by dispersing an aqueous strip
solution in an organic liquid, for example, using a mixer. Second,
the strip dispersion, or a part of the strip dispersion, is allowed
to stand, resulting in separation of the dispersion into two
phases: the organic liquid phase and the aqueous strip solution
phase containing a concentrated indium solution.
[0033] While any SLM configuration may be employed in the process
of the invention, the preferred configuration employs a hollow
fiber module as the liquid membrane microporous support. Such
hollow fiber modules consist of microporous hollow fibers arranged
in a shell-and-tube configuration. In the present invention, the
strip dispersion is passed through either the shell side of the
module or the tube side of the module, and the aqueous feed
solution containing indium for extraction is passed through the
opposing side of the module. The use of the hollow fiber system in
the combined SLM/strip dispersion process allows constant supply of
the strip dispersion as shown in FIG. 1, ensuring a stable and
continuous operation.
[0034] For the purposes of the invention, strip dispersion is
defined as a mixture of an aqueous phase and an organic phase. The
aqueous phase of the dispersion comprises an aqueous strip
solution, while the organic phase comprises an extractant or
extractants in an organic liquid. The dispersion is formed by the
mixing of the aqueous and organic phases as shown in FIG. 1. This
combination results in droplets of the aqueous strip solution in a
continuous organic phase. The dispersion is maintained during the
extraction process due to the flow of the dispersion through a
membrane module, e.g., a hollow-fiber module. The continuous
organic phase of the strip dispersion readily wets the hydrophobic
pores of the microporous hollow fibers in the module, forming a
stable liquid membrane.
[0035] FIG. 2 shows an enlarged view of a schematic representation
of the SLM with strip dispersion of the present invention. A low
pressure, Pa, which is typically less than approximately 2 psi, is
applied on the feed solution side of the SLM. The pressure Pa is
greater than the pressure, Po, on the strip dispersion side of the
SLM. This difference in pressure prevents the organic solution of
the strip dispersion from passing through the pores to come into
the feed solution side. The dispersed droplets of the aqueous strip
solution in a typical size of about 80 to about 800 micrometers and
are orders of magnitude larger than the pore size of the
microporous support employed for the SLM, which is in the order of
approximately 0.03 micrometer. Thus, these droplets are retained on
the strip dispersion side of the SLM and cannot pass through the
pores to go to the feed solution side.
[0036] In this SLM/strip dispersion system, there is a constant
supply of the organic membrane solution, i.e., the organic phase of
the strip dispersion, into the pores. This constant supply of the
organic phase ensures a stable and continuous operation of the SLM.
In addition, the direct contact between the organic and strip
phases provides efficient mass transfer for stripping. The organic
and strip phases can be mixed, for example, with high-shear mixing,
to increase the contact area between the two phases.
[0037] Once removal of indium is complete, the mixer for the strip
dispersion is stopped, and the dispersion is allowed to stand until
it separates into two phases, the organic membrane solution and the
concentrated strip solution. The concentrated strip solution
containing indium is the product of this process.
[0038] The feed solution includes, but is not limited to, waste
waters or process streams containing indium.
[0039] The microporous support employed in the invention is
comprised of, for example, microporous polypropylene,
polytetrafluoroethylene, polyethylene, polysulfone,
polyethersulfone, polyetheretherketone, polyimide, polyamide,
polyaramide, or mixtures thereof. The preferred microporous
supports are microporous polypropylene and polytetrafluoroethylene
hollow fibers.
[0040] The aqueous portion of the strip dispersion comprises an
aqueous acid solution, such as a mineral acid. Examples of mineral
acids useful in the present invention include, but are not limited
to, hydrochloric acid (HCl), sulfuric acid (H.sub.2SO.sub.4),
nitric acid (HNO.sub.3), and acetic acid (CH.sub.3COOH). The acid
is present in a concentration between about 0.1 M and about 18 M.
The preferred concentration for the acid solution is between about
1 M and about 6 M.
[0041] The continuous organic liquid phase into which the aqueous
strip solution is dispersed contains an extractant or extractants.
The extractant is capable of extracting indium contained in the
feed solution. Typical extractants which are known in the art for
extraction of indium from waste waters or process streams may be
employed in the present strip dispersion.
[0042] The extractants include dialkyl phosphoric acids and alkyl
phenylphosphonic acids. The dialkyl group of the dialkyl phosphoric
acid is paraffinic (saturated) and has from 6 to 26 carbon atoms.
The dialkyl phosphoric acids are selected from the group consisting
of di(2-ethyl-hexyl)phosphoric acid (D2EHPA),
di(2-butyl-octyl)phosphoric acid, di(2-hexyl-decyl)phosphoric acid,
di(2-octyl-decyl/2-hexyl-dodecyl)phosphoric acid,
di(2-octyl-dodecyl)phosphoric acid, di(hexyl)phosphoric acid,
di(heptyl)phosphoric acid, di(octyl)phosphoric acid,
di(nonyl)phosphoric acid, di(decyl)phosphoric acid,
di(undecyl)phosphoric acid, di(dodecyl)phosphoric acid,
di(tridecyl)phosphoric acid, di(tetradecyl)phosphoric acid,
di(pentadecyl)phosphoric acid, di(hexadecyl)phosphoric acid,
di(heptadecyl)phosphoric acid, di(octadecyl)phosphoric acid,
di(nonadecyl)phosphoric acid, di(decadecyl)phosphoric acid,
di(undecadecyl)phosphoric acid, di(dodecadecyl)phosphoric acid,
di(tridecadecyl)phosphoric acid, di(tetrdecadecyl)phosphoric acid,
di(pentadadecyl)phosphoric acid, di(hexadecadecyl)phosphoric acid,
and mixtures thereof. The preferred dialkyl phosphoric acid is
di(2-ethyl-hexyl)phosphoric acid (D2EHPA).
[0043] The alkyl group of the alkyl phenylphosphonic acid is
paraffinic (saturated) and has from 6 to 26 carbon atoms. The alkyl
phenylphosphonic acids are selected from the group consisting of
2-butyl-1-octyl phenylphosphonic acid (BOPPA), 2-hexy-1-decyl
phenylphosphonic acid, 2-octyl-1-decyl/2-hexyl-1-dodecyl
phenylphosphonic acid, 2-octyl-1-dodecyl phenylphosphonic acid,
hexyl phenylphosphonic acid, heptyl phenylphosphonic acid, octyl
phenylphosphonic acid, nonyl phenylphosphonic acid, decyl
phenylphosphonic acid, undecyl phenylphosphonic acid, dodecyl
phenylphosphonic acid, tridecyl phenylphosphonic acid, tetradecyl
phenylphosphonic acid, pentadecyl phenylphosphonic acid, hexadecyl
phenylphosphonic acid, heptadecyl phenylphosphonic acid, octadecyl
phenylphosphonic acid, nonadecyl phenylphosphonic acid, decadecyl
phenylphosphonic acid, undecadecyl phenylphosphonic acid,
dodecadecyl phenylphosphonic acid, tridecadecyl phenylphosphonic
acid, tetrdecadecyl phenylphosphonic acid, pentadadecyl
phenylphosphonic acid, hexadecadecyl phenylphosphonic acid, and
mixtures thereof. The preferred alkyl phenylphosphonic acid is
2-butyl-1-octyl phenylphosphonic acid (BOPPA).
[0044] The organic liquid of the present strip dispersion
optionally comprises a hydrocarbon solvent or mixture. The
hydrocarbon solvent or mixture has a number of carbon atoms per
solvent molecule ranging from 6 to 18, preferably from 10 to 14.
The hydrocarbon solvent includes, for example, n-decane,
n-undecane, n-dodecane, n-tridecane, n-tetradecane, isodecane,
isoundecane, isododecane, isotridecane, isotetradecane,
isoparaffinic hydrocarbon solvent (with a flash point of 92.degree.
C., a boiling point of 254.degree. C., a viscosity of 3 cp (at
25.degree. C.), and a density of 0.791 g/ml (at 15.6.degree. C.))
or mixtures thereof.
[0045] The organic liquid of the present strip dispersion
optionally contains a modifier to enhance the complexation and/or
stripping of the target species. The modifier can be, for example,
an alcohol, a nitrophenyl alkyl ether, a trialkyl phosphate or
mixtures thereof. The alcohol can be, for example, hexanol,
heptanol, octanol, nonanol, decanol, undecanol, dodecanol,
tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol,
octadecanol or mixtures thereof. The nitrophenyl ether can be, for
example, o-nitrophenyl octyl ether (o-NPOE), o-nitrophenyl heptyl
ether, o-nitrophenyl hexyl ether, o-nitrophenyl pentyl ether
(o-NPPE), o-nitrophenyl butyl ether, o-nitrophenyl propyl ether or
a mixture thereof. The trialkyl phosphate can be, for example,
tributyl phosphate, tris(2-ethylhexyl)phosphate or mixtures
thereof.
[0046] The organic liquid of the present strip dispersion comprises
about 2 volume % to about 100 volume % (approximately 0.05M to 3M)
extractant and about 0 volume % to about 20 volume % modifier in a
hydrocarbon solvent or mixture. More preferably, the organic liquid
of the present strip dispersion comprises about 5 volume % to about
40 volume % extractant and about 1 volume % to about 10 volume %
modifier in a hydrocarbon solvent or mixture. Even more preferably,
the organic liquid comprises 5 volume % to about 40 volume %
extractant and about 1 volume % to about 10 volume % dodecanol in
an isoparaffinic hydrocarbon solvent or in n-dodecane. All
percentages are by volume unless specified otherwise.
[0047] The present invention has several advantages over
conventional SLM technology for removal and recovery of indium from
aqueous feed solution. These advantages include increased membrane
stability, reduced costs, increased simplicity of operation,
improved flux, and improved recovery for indium.
[0048] The present invention provides a constant supply of the
organic membrane solution into the pores of the hollow fiber
support for removal and recovery of indium from aqueous feed
solution. This constant supply results in an SLM which is more
stable than conventional SLMs, ensuring stable and continuous
operation. This constant supply also eliminates the need for
recharging membrane modules, which is required with conventional
SLMs. Further, it eliminates the need for a second set of membrane
modules for use during recharging of the first set of membrane
modules. Thus, the present invention decreases not only operational
costs but also the initial capital investment in the system. The
present invention also increases simplicity of the removal
operation.
[0049] The present invention provides direct contact between the
organic/extraction phase and aqueous strip phase. Mixing of these
phases provides an extra mass transfer surface area in addition to
the area given by the hollow fibers, leading to extremely efficient
stripping of the target species from the organic phase. This
efficient stripping enhances the flux for the extraction of
indium.
[0050] The present invention comprises a new type of SLM for
removal and recovery of indium, and it provides increased
flexibility of aqueous strip/organic volume ratio. This flexibility
allows the use of a smaller volume of aqueous strip solution to
obtain a higher concentration of the recovered indium in the
aqueous strip solution. The concentrated strip solution is a
valuable product for resale or reuse.
[0051] This invention is further illustrated by the following
examples, which are not to be construed in any way as imposing
limitations upon the scope thereof. To the contrary, it is to be
clearly understood that reading the description herein may suggest
various other embodiments, modifications, and equivalents to those
skilled in the art without departing from the spirit of the present
invention and/or the scope of the appended claims.
EXAMPLES
General Procedure
[0052] In all of the following examples, the supported liquid
membranes (SLMs) with trip dispersion were used to extract indium
from an aqueous feed solution to an organic solution, in which an
aqueous strip solution was dispersed to continually strip the
extracted indium. The SLM system consisted of a hollow-fiber
membrane module (Liquid-Cel.RTM., extra-flow 2.5.times.8,
Membrana-Charlotte, USA), a feed solution tank, a feed pump (model
7592-50, Cole-Parmer, USA) to drive the feed solution into the
polypropylene hollow fibers in the module, a strip dispersion tank
with a mixer (SS-NZ-1000, Eyela, Japan) to well disperse the
aqueous strip solution in the organic solution, and another pump
(model 7553-70, Cole-Parmer, USA) to drive the water-in-oil
dispersion into the shell side of the module. The hollow-fiber
module was 6.35 cm (2.5 inches) in diameter and 20.3 cm (8 inches)
in length, and it had a membrane surface area of 1.4 m.sup.2.
[0053] All of the following examples were run in the countercurrent
mode with the feed solution passing through the tube side of the
microporous polypropylene hollow fiber module whereas the strip
dispersion passing through the shell side of the module. Indium in
the feed solution was extracted to the organic solution in the
membrane module, and the extracted indium was stripped into the
dispersed strip solution both in the module and in the dispersion
tank.
[0054] The aqueous feed solution, containing indium, was placed in
the feed tank that was agitated by a magnetic stirring bar at a
rate of 300 rpm. The strip solution, 5M HCl aqueous solution, was
dispersed with a 2-bladed paddle (8.5 cm in diameter) at a rate of
300 rpm in the organic solution containing D2EHPA (Merck) as the
extractant for indium in Isopar-L (ExxonMobil). The concentration
of D2EHPA in Isopar-L was 0.6 M (20.5 vol %) for most of the
experiments we performed unless specified otherwise. The organic
solution also contained 2 vol % of 1-dodecanol (Merck), unless
specified otherwise, as the modifier for the extractant. The total
volume of the organic solution was 0.90 L (900 ml), and that of the
strip solution was 0.12 L (120 ml) unless specified otherwise. Both
of the feed and dispersion tanks were thermo-stated at 25.degree.
C.
[0055] The process was first started by passing the feed solution
through the tube side of the hollow fiber module. After the hollow
fibers were filled with the feed solution, the water-in-oil
dispersion was pumped into the shell side of the module. To prevent
the organic phase form passing through the pores of the hollow
fibers into the feed solution, the pressure in the tube side was
maintained at a positive pressure, i.e., 4 to 5 psi higher than
that in the shell side unless specified otherwise. Both the feed
and dispersion solutions were pumped from the tanks to the module
and then recycled back to the tanks. The pumping rate for both
streams was kept at 1 L/min.
[0056] During each experiment, samples from the feed and strip
solutions were taken at certain timed intervals. The strip
dispersion samples were allowed to stand until phase separation
occurred. The aqueous phase from the strip dispersion sample was
then collected. The aqueous phase samples from the strip dispersion
samples and the feed solution samples were then analyzed to
determine the indium concentrations by using an atomic absorption
spectrophotometer (GBC 906, GBC, Australia) unless specified
otherwise (for example, using an inductively coupled plasma (ICP)
spectrometer).
[0057] Experiments with different feed compositions and volumes
were carried out to investigate the performance of the process of
SLM with strip dispersion. The performance maybe expressed in terms
of indium recovery and concentrations in both the treated feed and
strip solutions.
Example 1
[0058] Feed Solution with 200 ppm In.sup.3+ in pH 1 H.sub.2SO.sub.4
of 15.5 L. [0059] Condition: Organic Solution=0.6M D2EHPA, 2 vol %
dodecanol in Isopar-L, 0.9 L. [0060] Strip=5M HCl, 0.12 L The feed
solution contained 200 ppm In.sup.3+ in pH 1 H.sub.2SO.sub.4, and
it had a volume of 15.5 L. The organic solution was 0.6M
di(2-ethyl-hexyl)phosphoric acid (D2EHPA) and 2 vol % dodecanol in
Isopar-L, and it had a volume of 0.9 L. The strip solution was 5M
HCl with a volume of 0.12 L. A strip dispersion was prepared by
mixing together 0.12 L (120 ml) of the strip solution and 0.9 L
(900 ml) of the organic solution as described in the general
procedure above. The feed solution containing about 200 ppm
In.sup.3+ was pumped into the tube side of the polypropylene hollow
fiber module. The strip dispersion was fed into the shell side of
the hollow fiber module. Samples of the feed and strip solutions
were collected at certain timed intervals as described in the
general procedure above and analyzed by atomic absorption
spectrophotometry. The indium concentrations in the feed and strip
solution samples as a function of time are listed in Table 1. The
results are shown in FIG. 3. Both the table and figure show that
the SLM process with strip dispersion can produce the strip
solution with a very high indium concentration of greater than
20000 ppm.
TABLE-US-00001 [0060] TABLE 1 Time Feed Time Strip (min) (ppm)
(min) (ppm) 0 200.2 0 0 5 172.0 10 4459 10 141.5 20 8996 15 125.9
30 12191 20 105.9 40 15037 25 90.07 50 17364 30 79.76 60 18851 35
65.73 70 20580 40 49.63 80 21386 45 48.40 90 21100 50 41.26 100
22337 55 34.82 110 22641 60 29 120 23528 70 21.71 140 22808 80
14.62 160 22203 90 9.48 180 22758 100 5.09 200 21742 110 2.94 120
0.32 130 0 140 0 150 0 160 0 170 0 180 0 195 0 200 0
Example 2
[0061] Feed Solution with about 180 ppm In3+ in pH 1 HNO.sub.3 of 1
L. [0062] Condition: Organic Solution=0.6M D2EHPA, 2 vol %
dodecanol in Isopar-L, 0.9 L. [0063] Strip=5M HCl, 0.12 L. The
experimental procedure for this example was the same as that
described in Example 1 except the feed solution with about 180 ppm
In.sup.3+ in pH 1 HNO.sub.3 of 1 L was used instead of the feed
solution with 200 ppm In.sup.3+ in pH 1 M H.sub.2SO.sub.4 of 15.5
L. The indium concentrations in the feed and strip solution samples
as a function of time are listed in Table 2. The results are also
shown in FIG. 4.
TABLE-US-00002 [0063] TABLE 2 Time Feed Time Strip (min) (ppm)
(min) (ppm) 0 181.9 0 0 1 89.5 5 1034 3 16.8 10 1246 5 0 15 1315 20
1305 25 1337 30 1282 40 1280 50 1325 60 1315
Example 3
[0064] Feed Solution with about 190 ppm In3+ in pH 1
H.sub.2SO.sub.4 of 1 L [0065] Condition: Organic Solution=0.6M
D2EHPA, 2 vol % dodecanol in Isopar-L, 0.9 L [0066] Strip=5M HCl,
0.12 L The experimental procedure for this example was the same as
that described in Example 1 except the feed solution with about 190
ppm In.sup.3+ in pH 1 H.sub.2SO.sub.4 of 1 L was used instead of
the feed solution with 200 ppm In.sup.3+ in pH 1 M H.sub.2SO.sub.4
of 15.5 L. The indium concentrations in the feed solution samples
as a function of time are listed in Table 3. The results are also
shown in FIG. 4 for comparison. Both the table and figure show that
the results for this example using the feed solution with pH 1
H.sub.2SO.sub.4 were very similar to those for Example 2 using the
feed solution with pH 1 HNO.sub.3 while the other conditions were
essentially the same.
TABLE-US-00003 [0066] TABLE 3 Time Feed (min) (ppm) 0 191.6 1 99.01
2 53.77 3 25.17 5 0
Example 4
[0067] Feed Solution with about 160 ppm In.sup.3+ in pH 1 HCl of 1
L [0068] Condition: Organic Solution=0.6M D2EHPA, 2 vol % dodecanol
in Isopar-L, 0.9 L [0069] Strip=5M HCl, 0.12 L The experimental
procedure for this example was the same as that described in
Example 1 except the feed solution with about 160 ppm In.sup.3+ in
pH 1 HCl of 1 L was used instead of the feed solution with 200 ppm
In.sup.3+ in pH 1 M H.sub.2SO.sub.4 of 15.5 L. The indium
concentrations in the feed solution samples as a function of time
are listed in Table 4. The results are also shown in FIG. 4 for
comparison. Both the table and figure show that the results for
this example using the feed solution with pH 1 HCl were very
similar to those for Example 2 using the feed solution with pH 1
HNO.sub.3 and Example 3 using the feed solution with pH 1
H.sub.2SO.sub.4 while the other conditions were essentially the
same.
TABLE-US-00004 [0069] TABLE 4 Time Feed (min) (ppm) 0 156.6 1 87.98
3 29.48 5 8.27 7 0.72 10 0
Example 5
[0070] Feed Solution with about 200 ppm In.sup.3+ in pH 1, 2 wt %
H.sub.2C.sub.2O.sub.4 of 1 L [0071] Condition: Organic
Solution=0.2M D2EHPA, 2 vol % dodecanol in Isopar-L, 0.9 L [0072]
Strip=5M HCl, 0.1 L The experimental procedure for this example was
the same as that described in Example 1 except (1) the feed
solution with about 200 ppm In.sup.3+ in pH 1, 2 wt %
H.sub.2CO.sub.4 (oxalic acid) of 1 L was used instead of the feed
solution with 200 ppm In.sup.3+ in pH 1 M H.sub.2SO.sub.4 of 15.5
L, and (2) 0.2M D2EHPA was used instead of 0.6M, and (3) the volume
of the strip solution used was 0.1 L (100 ml) instead of 0.12 L
(120 ml). The indium concentrations in the feed solution samples as
a function of time are listed in Table 5. The results are also
shown in FIG. 5.
TABLE-US-00005 [0072] TABLE 5 Time Feed (min) (ppm) 0 208.0 1 194.9
3 189.7 5 183.8 7 176.5 10 167.2 15 150.0 20 128.7 25 124.2 30
111.7 40 87.16 50 69.80 60 55.66 72 40.14 80 30.03 90 21.90 100 16
110 13.48 120 10.98 130 9.58 140 8.35 155 7.05 160 6.11 170 4.67
190 2.89
Example 6
[0073] Feed Solution with about 200 ppm In.sup.3+ in pH 1, 2 wt %
H.sub.2C.sub.2O.sub.4 of 1 L [0074] Condition: Organic
Solution=0.6M D2EHPA, 2 vol % dodecanol in Isopar-L, 0.9 L [0075]
Strip=5M HCl, 0.1 L The experimental procedure for this example was
identical to that described in Example 5 except 0.6M D2EHPA was
used instead of 0.2M, i.e., the experimental procedure was similar
to that for Example 1. The indium concentrations in the feed
solution samples as a function of time are listed in Table 6. The
results are also shown in FIG. 5 for comparison. Both the table and
figure show that the results for this example using the 0.6M D2EHPA
were much better than those for Example 5 using 0.2M D2EHPA.
TABLE-US-00006 [0075] TABLE 6 Time Feed (min) (ppm) 0 205.7 1 169.3
3 137.1 5 107.2 7 86.34 10 60.57 15 31.99 20 13.82 25 3.99 30 0
Example 7
[0076] Feed Solution with about 200 ppm In.sup.3+ in pH 1, 2 wt %
H.sub.2C.sub.2O.sub.4 of 1 L [0077] Condition: Organic Solution=1M
D2EHPA, 2 vol % dodecanol in Isopar-L, 0.9 L [0078] Strip=5M HCl,
0.1 L The experimental procedure for this example was identical to
that described in Example 5 except 1M D2EHPA was used instead of
0.2M, i.e., the experimental procedure was similar to that for
Example 1. The indium concentrations in the feed solution samples
as a function of time are listed in Table 7. The results are also
shown in FIG. 5 for comparison. Both the table and figure show that
the results for this example using the 0.6M D2EHPA were better than
those for Example 6 using 0.6M D2EHPA and much better than those
for Example 5 using 0.2M D2EHPA. These results indicated that 0.6M
D2EHPA was suitable and effective for the extraction of indium from
the feed solution containing the oxalic acid.
TABLE-US-00007 [0078] TABLE 7 Time Feed (min) (ppm) 0 194.2 1 141.5
3 109.6 5 81.82 7 59.68 10 34.33 12.5 18.34 15 10.85 17.5 6.28 20
0
Example 8
[0079] Feed Solution with 200 ppm In.sup.3+ in pH 1, 2 wt %
H.sub.2C.sub.2O.sub.4 of 15.5 L [0080] Condition: Organic
Solution=0.6M D2EHPA, 2 vol % dodecanol in Isopar-L, 0.9 L [0081]
Strip=5M HCl, 0. 12 L The experimental procedure for this example
was identical to that described in Example 1 except the feed
solution with 200 ppm In.sup.3+ in pH 1, 2 wt % H.sub.2C.sub.2l
O.sub.4 was used instead of that in pH 1 H.sub.2SO.sub.4. The
indium concentrations in the feed and strip solution samples as a
function of time are listed in Table 8. The results are also shown
in FIG. 6. Both the table and figure show that the SLM with strip
dispersion can recover and concentrate indium in the strip solution
with 18000 ppm or higher from the feed solution containing the
oxalic acid.
TABLE-US-00008 [0081] TABLE 8 Time (min) Feed (ppm) Time (min)
Strip (ppm) 0 200.1 0 0 5 196.6 10 1057 10 190.7 20 2209 15 185.5
30 3253 20 180.1 40 4399 25 179.0 50 5560 30 172.9 60 6399 35 169.3
70 7181 40 163.2 80 7965 45 158.6 90 8078 50 153.4 100 10162 55
148.9 110 10953 60 144.4 120 11491 70 137.6 140 12445 80 129.5 160
13741 90 124.9 180 14744 100 116.5 200 15453 110 112.0 220 16166
120 105.0 240 16762 130 99.03 270 17308 140 93.15 330 18200 150
88.31 360 17725 160 83.72 390 18258 170 80.51 420 18320 180 75.44
450 18342 195 70.85 480 18274 200 67.99 510 18272 210 66.24 540
18662 220 62.07 570 17853 240 55.45 600 17168 255 51.75 630 17127
270 47.97 660 17305 285 43.52 300 39.39 315 36.43 330 34.09 345
31.97 360 29.08 375 26.32 390 24.23 405 21.68 420 20.54 435 17.99
450 17.01 465 15.19 480 14.16 500 11.97 510 12.21 540 9.74 560 8.23
570 7.57 600 6.16 630 5.98 660 4.48
Example 9
[0082] ITO Feed Solution with about 140 ppm In.sup.3+ and pH 0.9 of
15.5 L [0083] Condition: Organic Solution=0.6M D2EHPA, 2 vol %
dodecanol in Isopar-L, 0.9 L [0084] Strip=5M HCl, 0. 12 L The
experimental procedure for this example was identical to that
described in Example 1 except the ITO (indium tin oxide) feed
solution with about 140 ppm In.sup.3+ and pH 0.9 was used instead
of that with 200 ppm In.sup.3+ in pH 1 H.sub.2SO.sub.4. The indium
concentrations in the feed and strip solution samples as a function
of time are given in Table 9. The results are also shown in FIG. 7.
Both the table and figure show that the SLM with strip dispersion
can recover and concentrate indium in the strip solution with 11000
ppm or higher from the ITO feed solution. Also given in this table
are the tin concentrations in the feed solution samples as a
function of time and those in the strip solution samples at the
beginning and end of the experiment. Also shown in the figure are
the tin concentrations in the feed solution samples as a function
of time. These results indicate that the tin was hardly extracted
from the feed solution and nor concentrated in the strip solution.
Thus, the SLM with strip dispersion was effective for the removal
and recovery of indium form the ITO feed solution.
TABLE-US-00009 [0084] TABLE 9 Feed Strip Time In Sn Time In Sn
(min) (ppm) (ppm) (min) (ppm) (ppm) 0 143.5 14.52 0 0 0 10 136.6
14.67 20 1240 -- 20 131.7 17.15 40 2538 -- 30 124.8 16.11 60 3485
-- 40 123.4 19.97 80 4564 -- 50 113.4 15.79 120 6222 -- 60 109.5
17.28 180 8692 -- 80 101.4 17.13 240 10532 -- 100 92.53 19.39 300
11177 -- 120 84.62 12.99 420 11631 -- 140 75.69 18.2 480 11695 --
160 75.94 22.28 540 11606 -- 180 59.28 18.81 600 11581 -- 210 54.21
19.60 660 10932 -- 240 45.84 16.17 720 11018 20 270 35.88 14.71 300
34.15 14.42 330 29.21 14.83 360 23.93 17.00 390 20.03 10.33 420
17.43 9.97 450 13.81 10.30 480 12.71 12.51 510 8.71 13.50 540 6.76
16.48 570 6.19 15.20 600 5.72 13.31 630 4.12 13.29 660 3.32 13.45
690 2.64 14.23 720 2.26 12.34
Example 10
[0085] Residual Electrolyte Feed Solution with about 11000 ppm
In.sup.3+ and pH 0.9 of 0.5 L [0086] Condition: Organic
Solution=0.6M D2EHPA, 2 vol % dodecanol in Isopar-L, 0.9 L [0087]
Strip=5M HCl, 0.1 L The experimental procedure for this example was
identical to that described in Example 1 except the residual
electrolyte feed solution with about 11000 ppm In.sup.3+ and pH 1
was used instead of that with 200 ppm In.sup.3+ in pH 1
H.sub.2SO.sub.4. The indium concentrations in the feed and strip
solution samples as a function of time are given in Table 10. In
this table, both the indium concentration in the strip solution
obtained experimentally, i.e., strip-exp, and that calculated from
the feed concentration based on the material balance, i.e.,
strip-ideal (the ideal case), are included. The results are also
shown in FIG. 8. Both the table and figure show that the SLM with
strip dispersion can recover and concentrate indium in the strip
solution with 25000 ppm or higher (strip-exp) from the feed
solution of residual electrolyte.
TABLE-US-00010 [0087] TABLE 10 Time Feed Strip-ideal Time
Strip-exp. (min) (ppm) (ppm) (min) (ppm) 0 11018 0 0 0 0.5 10798
1103 6 4738 1 10309 3545 10 7412 1.5 9966 5261 20 11440 2 9723 6476
30 12791 2.5 9690 6641 45 15170 3 9335 8414 60 18783 3.5 9154 9321
150 25206 4 9154 9321 5 8605 12068 6 8422 12981 7 8403 13076 8 8329
13448 10 8121 14488 12 7775 16214 15 7687 16658 20 7460 17789 25
7269 18745 30 7437 17908 40 7337 18404 50 7019 19998 60 6897 20606
100 6022 24980 150 5262 28779
[0088] Examples 1 to 10 have demonstrated that D2EHPA is an
effective extractant in the supported liquid membranes (SLMs) with
strip dispersion for the removal and recovery of indium from
various aqueous feed solutions. These results of the SLMs with
strip dispersion for indium are very much different from those for
the metals and radionuclides disclosed in Ho's patents mentioned
earlier (U.S. Pat. Nos. 6,291,705, 6,328,782, 6,350,419, 6,696,589)
where D2EHPA was ineffective. Thus, these results disclosed in this
present invention are unexpected in view of the prior art disclosed
in the Ho's patents.
Example 11
2-Butyl-1-Octyl Phenylphosphonic Acid (BOPPA) Extractant
[0089] Feed Solution with 200 ppm In.sup.3+ in pH 1 H.sub.2SO.sub.4
of 1 L [0090] Condition: Organic Solution=0.6M BOPPA, 2 vol %
dodecanol in Isopar-L, 0.8 L [0091] Strip=5M HCl, 0. 12 L The
experimental procedure for this example was similar to that
described in Example 1 except the extractant of 0.6M
2-butyl-1-octyl phenylphosphonic acid (BOPPA; C12 alkyl group) was
used instead of that of 0.6M D2EHPA. The indium concentrations in
the feed and strip solution samples as a function of time are given
in Table 11. The results are also shown in FIG. 9. Both the table
and figure show that the SLM with strip dispersion can effectively
recover and concentrate indium in the strip solution with 20000 ppm
or higher from the feed solution.
TABLE-US-00011 [0091] TABLE 11 Time Feed Time Strip (min) (ppm)
(min) (ppm) 0 173.6 0 0 5 137.5 5 1044 10 98.2 10 1584 15 69.2 15
2207 20 48.5 20 2567 25 32.1 25 2849 30 20.4 30 3010 40 9.7 40 2940
50 3.0 50 3125 60 1.4 60 3021 120 0.1 120 3130
* * * * *