U.S. patent application number 12/065354 was filed with the patent office on 2009-09-03 for method for separating impurities out of feed stock in copper melts.
This patent application is currently assigned to Montanunversitaet Leoben. Invention is credited to Bernd Hollauf, Werner Leopold Kepplinger, Wolfgang Franz Mayer.
Application Number | 20090217785 12/065354 |
Document ID | / |
Family ID | 37101870 |
Filed Date | 2009-09-03 |
United States Patent
Application |
20090217785 |
Kind Code |
A1 |
Kepplinger; Werner Leopold ;
et al. |
September 3, 2009 |
METHOD FOR SEPARATING IMPURITIES OUT OF FEED STOCK IN COPPER
MELTS
Abstract
The invention relates to a method for separating impurities out
of slags, dusts, minerals, preparation residues of minerals or of
recyclings or remaining substances, subsequently called feed stock.
In order to save energy and reduce costs, the inventive method is
characterized by the combination of the following features: melting
the feed stock containing the impurities; forming a copper melt;
bring the feed stock into contact with the copper melt while adding
reducing agents, preferably coke and/or coal; vaporizing, if
required, existing volatile compounds such as metal chlorides;
reducing metals of the feed stock more noble than copper in the
copper melt, and; forming a slag with constituents of the feed
stock to be purified that is less noble than copper.
Inventors: |
Kepplinger; Werner Leopold;
(Leonding, AT) ; Hollauf; Bernd; (Graz, AT)
; Mayer; Wolfgang Franz; (Proleb, AT) |
Correspondence
Address: |
SMITH FROHWEIN TEMPEL GREENLEE BLAHA, LLC
Two Ravinia Drive, Suite 700
ATLANTA
GA
30346
US
|
Assignee: |
Montanunversitaet Leoben
Leoben
AT
|
Family ID: |
37101870 |
Appl. No.: |
12/065354 |
Filed: |
August 17, 2006 |
PCT Filed: |
August 17, 2006 |
PCT NO: |
PCT/AT06/00343 |
371 Date: |
August 6, 2008 |
Current U.S.
Class: |
75/585 |
Current CPC
Class: |
C22B 15/0054 20130101;
C22B 5/16 20130101; C22B 15/006 20130101; C22B 5/10 20130101; Y02P
10/214 20151101; Y02P 10/22 20151101; Y02P 10/20 20151101 |
Class at
Publication: |
75/585 |
International
Class: |
C22B 9/00 20060101
C22B009/00; C22B 11/00 20060101 C22B011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 1, 2005 |
AT |
A 1433/2005 |
Claims
1. A method for separating impurities from slag, dust, minerals,
preparation residues of minerals or of recyclings or remaining
substances, subsequently called feed stock, the method comprising
the following features: melting the feed stock containing the
impurities; forming a copper melt, bringing the feed stock in
contact with the copper melt whilst adding reducing agents,
preferably coke or coal, vaporising if required existing volatile
compounds such as metal chlorides, reducing metals of the feed
stock more noble than copper in the copper melt and forming a slag
with constituents of the feed stock to be purified that are less
noble than copper.
2. The method according to claim 1, wherein a copper melt is formed
with at least 50% copper.
3. The method according to claim 1, wherein after reduction and
taking up metals more noble than copper originating from the feed
stock, the copper melt is subjected to a copper recycling
process.
4. The method according to claim 3, wherein the copper melt is
recycled by blowing in oxygen.
5. The method according to claim 1, wherein the copper melt is
formed by melting scrap copper and/or by melting old or new scrap
of copper and/or copper alloys and/or a part of the copper melt is
formed by adding slag produced by blowing in oxygen into the copper
melt.
6. The method according to claim 1, wherein the slag formed from
the feed stock to be purified is processed using adjuvants and/or
waste materials to form clinker substitute and/or sand blasting
abrasives.
7. The method according to any one of claims 1 to 6, characterised
in that dust from waste incineration is used as feed stock to be
purified.
8. The method according to claim 1, wherein dust from the iron and
steel industry is used as feed stock to be purified.
9. The method according to claim 1, wherein anodic sludge
accumulating during electrolytic refining in the course of copper
recycling is used as feed stock to be purified.
10. The method according to claim 1, wherein substances less noble
than copper are used as reducing agents.
11. The method according to claim 1, wherein metallic waste
materials such as aluminium-containing waste materials and/or
iron-containing waste material are used as reducing agents.
12. The method according to claim 1, wherein a reducing or
oxidising atmosphere is adjusted above the copper melt.
13. The method according to claim 1, wherein the feed stock to be
purified together with the reducing agents are injected into the
copper melt.
14. The method according to claim 1, wherein the feed stock to be
purified is applied to a hot copper block which has not yet melted
and any metal chlorides that may be present are thereby
vaporised.
15. The method according to claim 14, wherein a halogenating
atmosphere is adjusted, preferably using a chlorine-containing
flushing gas.
16. The method according to claim 14, wherein the copper block
together with the feed stock to be purified is melted and reducing
agents are introduced into the melt, preferably are injected via
lances.
Description
[0001] The present application claims the benefit of the filing
date of Austrian Patent Application A1433/2005--filed Sep. 1, 2005,
the disclosure of which is hereby incorporated herein by
reference.
[0002] This invention relates to a method for separating impurities
out of slag, dust, minerals, preparation residues of minerals or
out of recyclings or remaining substances. All these substances to
be purified are subsequently called feed stock.
[0003] Fusion metallurgy treatment methods in which iron melts are
used to take up impurities are known for the purpose of separating
impurities. A method of this type is described, for example, in AT
412 283 B. The aim of the method is to form environmentally
compatible slag from iron-containing blast-furnace residue and to
recover the iron fraction contained therein. For this purpose the
residue is reduced in or over an iron melt by the carbon dissolved
in the iron melt. Iron oxide and other metal oxides are reduced and
recovered from the iron metal. After dephosphorization, the
resulting metal can be used as a replacement for pig iron produced
in a blast furnace or if the Cr/Ni contents are high, it can be
used as a working resource for stainless steel production. The slag
produced can be used as a clinker replacement in the cement
industry.
[0004] According to WO 97/29214 A, residue or slag from rubbish
incineration or pyrolysis is heated together with chlorine or
chlorine-containing substances under reducing conditions to
temperatures above 650.degree. C. whereupon volatile metal
chlorides such as heavy metal chlorides (PbCl.sub.2, ZnCl.sub.2,
CuCl.sub.2) are removed in the gas phase. The remaining solid
residue is mixed with steel slag or lime marl. The mixed slag is
reduced over a turbulent iron bath. In this case a synthetic blast
furnace slag with hydraulic properties and a carbon-saturated iron
alloy can be produced. The iron alloy obtained forms a feed stock
for the steel industry. Alternatively a carbon-free, highly
enriched ferro-chromium alloy can be obtained by fractional
reduction.
[0005] JP 11207288 likewise describes a smelting method for the
treatment of residue from rubbish incineration. In this case, the
incineration residue is charged in an electric arc furnace into a
metal bath which substantially consists of iron. A slag layer is
thereby formed. Slag and metal are jointly extracted continuously
and supplied to a water bath. Separation takes place by means of a
magnetic separator. The metal contains a relatively large amount of
copper and can be used as copper raw material.
[0006] In said methods which specify utilisation in the steel
industry for contaminated iron melts, the enrichment by metals
nobler than iron, for example, copper or tin is disadvantageous.
These metals can no longer be removed economically and above
certain limiting contents, present problems for further use of the
iron melt. According to AT 412 283 B, for example, a high-quality
pig iron bath system is used and this is contaminated with nobler
metals after treatment of the residue. This deterioration in
quality can have the result that use in the steel industry is no
longer possible.
[0007] When using a pig iron bath system, an oxidising procedure
has a disadvantageous effect. The carbon dissolved in the pig iron
would thereby escape in the form of CO/CO.sub.2 and thus the
melting temperature would increase above 1500.degree.. In order to
prevent solidification of the melt when adding the residue, the
required processing temperature must be significantly higher. At
such high temperatures, the stressing of the refractory furnace
lining and the increased energy requirement has a disadvantageous
effect.
[0008] The purpose of the invention is to avoid these disadvantages
and its object is to provide a method for separating impurities
from slag, dust, minerals, preparation residues of minerals or from
recyclings or remaining substances, subsequently called feed stock,
in which deterioration in quality is avoided in a process extending
over a fairly long time or in a plurality of successive process
cycles. In addition, the method should allow energy savings
compared with known methods and furthermore allow costs savings in
that refractory linings of reactor vessels in which the process is
carried out have a long life.
[0009] This object is achieved by the following combination of
features: [0010] melting the feed stock containing the impurities;
[0011] forming a copper melt, [0012] bringing the feed stock in
contact with the copper melt while adding reducing agents,
preferably coke or coal, [0013] vaporising if required existing
volatile compounds such as metal chlorides, [0014] reducing metals
of the feed stock more noble than copper in the copper melt and
[0015] forming a slag with constituents of the feed stock to be
purified that is less noble than copper.
[0016] The copper melt preferably has a minimum content of 50%
copper.
[0017] The use of a copper melt has the advantage that the
impurities which cannot be removed from an iron melt can easily be
removed from a copper melt in a normal copper recycling process. In
this way, the contaminated copper melt can be processed to
high-quality copper again. A particular advantage of using a copper
melt is its low melting point compared to an iron melt. As a
result, the processing temperature of the feed stock is primarily
determined by the melting point of the slag. It is thereby possible
to maintain low processing temperatures when carrying out the
method, which is reflected in lower energy costs and in
conservation of refractory linings of the metallurgical vessel in
which the method is carried out.
[0018] The copper melt can optionally be purified by blowing oxygen
directly into the metallurgical vessel in which the method is
carried out. In this case, the impurities less noble than copper
form a slag. As a result of its high copper content, the slag thus
formed can be used for separating impurities from feed stock at the
beginning of a following process.
[0019] It is particularly advantageous for the method according to
the invention to use scrap copper for producing the copper melt
since scrap copper is fed to the copper recycling process
anyway.
[0020] The copper melt can be formed by melting copper-containing
waste material. For this purpose new scrap (fabrication waste)
and/or old scrap of copper and/or copper alloys can be formed. Part
of the copper melt can be formed by adding slag produced by blowing
oxygen into the copper melt, as has been mentioned above.
[0021] The slag formed from the feed stock to be purified is
preferably processed using adjuvants and/or waste materials to form
clinker substitute and/or sand blasting abrasives.
[0022] Dust from waste incineration and from the iron and steel
industry can be used as feed stock to be purified.
[0023] Anodic sludge accumulating during electrolytic refining in
the course of copper recycling is advantageously used as feed stock
to be purified.
[0024] As has already been mentioned, preferably coke and/or coal
are used as reducing agents for the feed stock but substances less
noble that copper such as metallic waste materials e.g.
aluminium-containing waste materials and/or iron-containing waste
material can be used as reducing agents.
[0025] When using a copper melt, it is advantageously possible to
adjust various atmospheres above said melt; both reducing and
oxidising conditions can be adjusted. The atmosphere can also be
varied over the duration of the process, whereby undesirable
contents of the impurities can be specifically separated.
[0026] The feed stock to be purified together with the reducing
agents are preferably injected into the copper melt.
[0027] The formation of a copper melt and the melting of the feed
stock and the addition of the reducing agents can take place
simultaneously or successively. For example, it is also possible
that the feed stock to be purified is applied to a hot copper block
which has not yet melted, preferably in layers, and any metal
chlorides that may be present are thereby vaporised, whereby a
halogenating atmosphere is preferably adjusted, preferably using a
chlorine-containing flushing gas.
[0028] The copper block together with the feed stock to be purified
is then melted and reducing agents are introduced into the melt,
preferably are injected via lances.
[0029] The method according to the invention is explained in detail
with reference to the description of two variants. The two variants
show ways which are feasible in principle for using a copper
melt.
Variant 1
[0030] The feed stock to be treated is injected into a copper melt
located in a metallurgical vessel together with a reducing agent.
Coal or coke, for example, can be used as reducing agents.
TABLE-US-00001 TABLE 1 Reducing agents Coke Coal Component [%] [%]
C 91.15 87.10 SiO.sub.2 2.88 2.20 Al.sub.2O.sub.3 1.91 1.25 CaO
0.36 0.39 MgO 0.12 0.09
[0031] Metals in the feed stocks which are less noble than copper
are also used as reducing agents. In addition, metallic reducing
agents in the form of metallic waste materials, for example,
aluminium or iron filings can be added, where the fraction of
aluminium or iron is preferably at least 80%.
[0032] The copper melt is produced by melting copper-containing
waste material. Predominantly considered for this purpose is new
waste (fabrication waste) or old waste of copper and copper alloys
(for example, brass, bronzes, red brass, nickel silver) including
chippings and dust. The preferred copper content in the feed stock
is at least 50%. Table 2 gives the composition of a brass and a
bronze waste as examples.
TABLE-US-00002 TABLE 2 Copper-containing waste material Brass waste
Bronze waste Element [%] [%] Cu 60.19 94.49 Zn 37.62 Pb 0.63 Sn
0.42 4.77 Fe 0.2 Al 0.21 0.039 Ni 0.13 Si 0.023 0.016 Sb 0.006 Mn
0.038 0.0023 P 0.007 0.18 As 0.015 S 0.21 Pb 0.008
[0033] The method according to the invention can be used to process
contaminated dust, slag and minerals of different origin, in
particular dust from rubbish incineration and slag or dust from the
iron and steel industry. Lead or coloured glass waste, scrap
catalysts and processing residue of minerals such as, for example,
roasting residues (e.g. pyrite combustion) can also be used.
Material cleared from furnaces which has been infiltrated with
noble metals (e.g. Pt, Au, Ag) can also be processed with the
method according to the invention.
[0034] In the course of copper recycling, the noble metals (Pt, Ag,
Au) are deposited in the anodic sludge during electrolytic
refining. The noble metals can be recovered from the anodic sludge
by means of the method according to the invention and reused.
Noble-metal-containing feed stock such as, for example, the
aforementioned material cleared from furnaces thus make a decision
contribution to improving the economic efficiency of a copper
refinery.
[0035] Example compositions are given in the following tables:
TABLE-US-00003 TABLE 3 Dust from rubbish incineration Fly ash from
Fly ash from incineration rubbish incineration of special rubbish
Element [mg/kg] [mg/kg] Ca 107000 47985 Cl 74000 33370 Si 160000
54804 Mg 15000 8041 Fe 25000 43763 Al 71000 17302 K 36000 47485 Na
31000 154364 Zn 28000 68165 S 26000 81929 Pb 11000 19527 Ti 8700
18332 Mn 1300 1992 Ba 1700 124 Sn 1400 2741 Cu 1200 6340
TABLE-US-00004 TABLE 4 Slag and dust from the iron and steel
industry LD EAF Blast furnace Converter Slag dust dust dust
Component [%] [%] [%] [%] CaO 50 5-12 6.3 3-5 SiO2 15 6.3 Al2O3
<2 2 MgO <3 Fe 16 20-30 34.4 50-70 MnO <4 P2O5 <2
Cr.sub.tot <1 0.1-0.4 C 28.9 20-50 Pb 1-8 0.07 0.2-0.5 Zn 15-35
0.2 1-3
TABLE-US-00005 TABLE 5 Residue from other branches of industry
Catalytic Pyrite converter combustion Lead glass (car indus-
(sulphuric acid waste (glass try) production) [%] industry) [%] [%]
Fe 55 SiO.sub.2 56 Pt 0.14 Zn 2.8 PbO* 32 Pd 0.07 Cu 1.3 K.sub.2O
11.4 Rh 0.015 S 2.6 Al.sub.2O.sub.3 0.1 Carrier Residue material Pb
0.5 As.sub.2O.sub.5 0.5 Waste 10.00 rock Co 0.12 Ag 0.004 Au 0.0001
Cd 0.005 Tl 0.003 P 0.11 *The PbO content can be 3-32% depending on
the type of glass
[0036] The components of the feed stock are divided by the
treatment process into copper bath, slag or waste gas according to
their composition.
[0037] Metals in the feed stock which are nobler than copper are
reduced and remain in the copper melt. Less noble components are
transferred into the slag located above the melt. Volatile
compounds in the feed stock such as, for example, metal chlorides,
in particular zinc chloride and lead chloride, vaporise.
[0038] At the end of the treatment process the slag is adjusted
with adjuvants or waste materials so that it can be used as clinker
substitute or as sand blasting abrasive. The slag is then tapped
and charged into a dry granulator. The granulation can take place
by separating the slag stream on a rotary plate into fine droplets,
which then solidify in a glass-like manner in the air stream. The
copper melt is also tapped and fed to the copper recycling process
whereby copper and the noble metals contained therein can be
recovered from the melt.
[0039] The copper bath can optionally be purified by blowing oxygen
directly into the melt system. The impurities which are less noble
than copper thereby form slag. As a result of the high copper
content, the slag thereby formed can be fed together with the scrap
copper at the beginning of the process.
Variant 2
[0040] A block of scrap copper is heated in the melting system.
Advantageously solidified residual copper melt from the previous
treatment can be used for this. As in variant 1, the copper melt is
produced by melting copper-containing waste material. The feed
stock to be treated is applied in layers to the copper block. When
using residual copper melt, charging can begin immediately after
the surface of the copper bath has solidified. The heat of the
cooling copper bath can be used to vaporise metal chlorides present
in the feed stock. A halogenating atmosphere can be used for
assistance, for example, using a chlorine-containing flushing gas.
The flushing gas is blown onto the residue from above.
Alternatively the residue can be roasted with chlorine or
chlorine-containing substances under reducing conditions.
[0041] In this case, metal chlorides can be vaporised from the feed
stock. The gas phase can be purified in the usual manner whereby
the metal chlorides are retained in filters. The heavy metals can
be recovered in a known manner (electrolysis, extraction).
[0042] The remaining metal compounds in the feed stocks can be
removed by subsequent purification under reducing conditions. For
this purpose the feed stock and the solidified copper melts are
melted. Reducing agent is fed into the copper bath by means of
lances (see Variant 1).
[0043] The copper melt and the slag can undergo further treatment
as in variant 1.
* * * * *