US20080190779A1 - Method for Recovering Indium - Google Patents
Method for Recovering Indium Download PDFInfo
- Publication number
- US20080190779A1 US20080190779A1 US11/883,138 US88313806A US2008190779A1 US 20080190779 A1 US20080190779 A1 US 20080190779A1 US 88313806 A US88313806 A US 88313806A US 2008190779 A1 US2008190779 A1 US 2008190779A1
- Authority
- US
- United States
- Prior art keywords
- indium
- solution
- predetermined
- particle size
- recovering
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/02—Hydrogen or oxygen
- C25B1/04—Hydrogen or oxygen by electrolysis of water
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B58/00—Obtaining gallium or indium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
- C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
- C22B3/10—Hydrochloric acid, other halogenated acids or salts thereof
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
- C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
- C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/006—Wet processes
- C22B7/007—Wet processes by acid leaching
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C28/00—Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
- C25C3/34—Electrolytic production, recovery or refining of metals by electrolysis of melts of metals not provided for in groups C25C3/02 - C25C3/32
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- the present invention relates generally to a method for recovering indium. More specifically, the invention relates to a method for recovering indium metal from indium containing substances, such as indium-tin-oxide (ITO) target scraps.
- ITO indium-tin-oxide
- a method comprising the steps of: dissolving an indium containing substance in hydrochloric acid; adding an alkali to the solution after dissolution, to neutralize the solution so that the pH of the solution is 0.5 to 4; depositing and removing hydroxides of predetermined metal ions in the solution; blowing hydrogen sulfide gas into the solution to deposit and remove sulfides of metal ions which are harmful to electrolysis; and then, electrowinning indium metal using the solution as an initial electrolytic solution (see, e.g., Japanese Patent Laid-Open No. 2000-169991).
- This method is very useful as a method for recycling ITO target scraps and so forth since it is possible to recover indium having a high purity of not less than 99.999% at simple and inexpensive steps.
- the content of indium in indium containing substances, such as ITO target scraps, and the shape and size of the substances are not constant, so that such indium containing substances can not suitably used as recycled materials in the method disclosed in Japanese Patent Laid-Open No. 2000-169991, as they are.
- the variation in sharp and size of raw materials causes the increase of the treating time and/or the decrease of the leaching rate, so that the treating time and leaching rate at the dissolving step are changed.
- the leaching rate is decreased, so that it is required to additionally provide a circulating or reprocessing line for improving the leaching rate.
- the improvement of the leaching rate (recovery) takes precedence over the decrease of the treating time at the dissolving step, it takes a lot of time to obtain a desired leaching rate. Therefore, in order to industrially utilize the method disclosed in Japanese Patent Laid-Open No. 2000-169991, it is required to achieve both of the shortening of the treating time and the improvement of the leaching rate at the dissolving step so that indium can be recovered in a short time and with a high recovery.
- the amount of tin in indium metal obtained by electrowinning is about 1 ppm, so that it is desired to further decrease the amount of tin.
- the inventors have diligently studied and found that it is possible to achieve both of the shortening of a treating time and the improvement of a leaching rate at a dissolving step and it is possible to stabilize a neutralized precipitate to decrease the amount of tin in electrowon indium metal, so that it is possible to provide a method for recovering indium, the method being capable of recovering indium having a high purity at simple and inexpensive steps in a short time and with a high recovery, if an indium containing substance is dissolved in an acid after being ground until the percentage of coarse particles having a larger particle size than a predetermined particle size is not larger than a predetermined percentage and if aging is carried out at a predetermined temperature for a predetermined period of time after neutralization.
- the inventors have made the present invention.
- a method for recovering indium comprises: a grinding step of grinding an indium containing substance until the percentage of coarse particles of the indium containing substance is not larger than a predetermined percentage, the coarse particles having a larger particle size than a predetermined particle size; a dissolving step of dissolving fine particles, which are obtained at the grinding step, in an acid, such as hydrochloric acid, sulfuric acid or nitric acid; a neutralizing step of adding an alkali to a solution after dissolution, which is obtained at the dissolving step, to neutralize the solution after dissolution so that the solution after dissolution has a pH of 0.5 to 4, to deposit and remove hydroxides of predetermined metal ions in the solution after dissolution; an aging step of aging a solution after neutralization, which is obtained at the neutralizing step, at a predetermined temperature for a predetermined period of time; a sulfurizing step of blowing hydrogen sulfide gas into a solution after aging, which is obtained at the aging step, to deposit
- the predetermined particle size is preferably 150 ⁇ m.
- the predetermined percentage is preferably 10%, more preferably 5% and most preferably substantially 0%.
- the predetermined temperature is preferably in the range of from a room temperature to 80° C., more preferably in the range of from 40° C. to 70° C., and most preferably in the range of from 60° C. to 70° C.
- the predetermined period of time is preferably 2 hours or longer, and more preferably 3 hours or longer.
- the method for recovering indium may further comprise a classification step of removing coarse particles having a larger particle size than the predetermined particle size by classification before the dissolving step after the grinding step.
- the indium containing substance is preferably an ITO target scrap.
- indium has a purity of not less than 99.999% and contains tin, the content of which is not larger than 0.5 ppm and preferably not larger than 0.1 ppm.
- indium is obtained by electrowinning which uses indium-tin-oxide as a raw material, and contains tin, the content of which is not larger than 0.5 ppm and preferably not larger than 0.1 ppm.
- Such indium can be obtained by the above described method for recovering indium according to the present invention.
- FIG. 1 is a process drawing showing a method for recovering indium according to the present invention
- FIG. 2 is a graph showing a variation in leaching rate with respect to time in Examples 1 and 2 and Comparative Example 1;
- FIG. 3 is a graph showing a variation in leaching rate with respect to time in Example 3 and Comparative Example 2;
- FIG. 4 is a graph showing a variation in leaching rate with respect to time in Example 4 and Comparative Example 3.
- the crushed substance is ground until the percentage of coarse particles having a larger particle size than a predetermined particle size is not larger than a predetermined percentage. Thereafter, the ground substance is dissolved in hydrochloric acid, and an alkali, such as sodium hydroxide or sodium carbonate, is added to the solution to neutralize the solution so that the pH of the solution is 0.5 to 4. Then, the solution after dissolution is aged at a predetermined temperature for a predetermined period of time to deposit and remove hydroxides of predetermined metal ions in the solution.
- an alkali such as sodium hydroxide or sodium carbonate
- the indium containing substances serving as raw materials are preferably ITO target scraps.
- various indium containing substances may be used as the raw materials.
- the crushing and grinding of the raw materials may be carried out by a crusher and a grinder, respectively.
- the percentage of coarse particles having a larger particle size than 15 ⁇ m in fine particles obtained by grinding is preferably 10% or less, more preferably 5% or less, and most preferably substantially 0%. If the percentage of coarse particles is thus decreased by grinding, the contact of the raw materials with a hydrochloric acid solution can be improved for obtaining a desired leaching rate in a short time.
- classification such as sieving or screening, may be carried out in order to thus remove coarse particles.
- the amount of the solution after dissolving the indium containing fine particles in hydrochloric acid is preferably adjusted so that the concentration of indium is in the range of from 20 g/L to 200 g/L, and the amount of hydrochloric acid used in dissolution is preferably 1.1 to 1.5 times as large as the theoretical equivalent thereof.
- the solution after dissolution is preferably heated in order to promote dissolution.
- the reasons why the alkali is added so that the pH is 0.5 to 4 are that the pH is adjusted to be 4 or lower to prevent the deposition of hydroxides of indium and that the pH is adjusted to be 0.5 or higher to hydrolyze impurity ions to deposit hydroxides of the ions.
- the alkali it is possible to efficiently remove most of tin which is a main impurity in ITO target scraps.
- the reason why aging is carried out after neutralization is that the neutralized precipitate is stabilized.
- the aging temperature is preferably in the range of from a room temperature to 80° C., more preferably in the range of from 40° C. to 70° C., and most preferably in the range of from 60° C. to 70° C.
- the aging time is preferably 2 hours or longer, and more preferably 3 hours or longer.
- the indium-dissolved solution thus purified is fed to the electrowinning step at which indium is recovered as a metal by electrowinning on appropriate electrolytic conditions.
- the indium metal thus recovered contains alkali metals, such as sodium, which are components of the electrolytic solution, as impurities.
- the indium metal together with solid sodium hydroxide, is heated to be mixed and melted, so that the alkali metals are dissolved in the melted sodium hydroxide to be removed, and then, the metal part obtained by gravity separation is cast in a mold to be cooled to recover indium having a high purity.
- the solution after electrowinning is mixed with hydrochloric acid to be reused for the dissolution of indium containing fine particles.
- hydrochloric acid to be reused for the dissolution of indium containing fine particles.
- base metal ions such as aluminum and iron ions, which are baser than indium
- part or all of the solution after electrowinning is preferably extracted to the outside of the system.
- the solution after sulfurization thus purified was used as an initial electrolytic solution for electrowinning indium metal on electrolytic conditions (at a liquid temperature of 30° C. and a current density of 150 A/m 2 ).
- the amount of tin in the electrowon indium metal was 0.4 ppm.
- the electrowon metal, together with solid sodium hydroxide, was heated to be mixed and melted, and a metal part obtained by gravity separation was cast in a mold to be cooled to recover cast indium.
- the grade of the cast indium thus obtained was not less than 99.999%, so that indium having a high purity was obtained.
- compositions of the solution after dissolution, solution after neutralization and solution after sulfurization, and the grades of the electrowon metal and cast indium, which were obtained in this example, are shown in Table 1, and the relationship between the leaching rate and time is shown in Table 2 and FIG. 2 .
- Example 1 Example 1 Example 2 150 ⁇ m ⁇ : 86% 150 ⁇ m ⁇ : 4% 150 ⁇ m ⁇ : 0% Time In Leaching In Leaching In Leaching (min.) (g/l) Rate (%) (g/l) Rate (%) (g/l) Rate (%) 0 0 0 0 0 0 30 70 35 133 66 159 79 60 120 60 179 89 192 96 90 140 70 191 95 197 98 120 146 73 195 97 201 100 180 148 74 198 99 201 100 240 151 75 200 100 201 100 360 155 77 200 100 201 100 480 160 79 201 100 201 100 600 163 81 200 100 201 100 720 164 81 200 100 201 100
- the amount of indium in the ITO target scraps was determined by measurement using an inductively coupled plasma mass spectrometer (ICP-Mass) after the fine particles obtained by grinding the ITO target scraps were dissolved in hydrochloric acid and tartaric acid.
- the percentage of coarse particles (larger particles than 150 ⁇ m) in the fine particles was determined by calculating the percentage of the coarse particle part on the basis of the results that a particle size distribution was measured by a laser diffraction type particle size distribution measuring device (Model LA500 produced by HORIBA, Ltd.) after a small number of the fine particles were ultrasonically dispersed in a dispersion medium (200 mL of a sodium hexametaphosphate solution).
- compositions of the solution after dissolution, solution after neutralization and solution after sulfurization were determined by measurement using an ICP-Mass after these solutions were sampled.
- the grades of the electrowon metal and cast indium were determined by measurement using an ICP-Mass after each of the electrowon metal and the case indium was dissolved in nitric acid.
- the variation in leaching rate with respect to time was determined by analyzing the residue and liquid, which were obtained by the solid-liquid separation of a slurry sampled every a predetermined time, by means of an ICP-Mass.
- the liquid after solid-liquid separation was diluted with nitric acid to be used as a sample to be analyzed.
- the residue after solid-liquid separation was dried to be dissolved in nitric acid and sulfuric acid, and then, dissolved in perchloric acid to be used as a sample to be analyzed.
- Cast indium was recovered by the same method as that in Example 1, except that fine particles containing no coarse particles having a larger particle size than 153 ⁇ m were obtained by grinding.
- the leaching rate was 100% after 120 minutes at the dissolving step using hydrochloric acid.
- the amount of tin in the electrowon metal was 0.1 ppm.
- the compositions of the solution after dissolution, solution after neutralization and solution after sulfurization, and the grades of the electrowon metal and cast indium, which were obtained in this example, are shown in Table 3, and the relationship between the leaching rate and time in this example is shown in Table 2 and FIG. 2 .
- Cast indium was recovered by the same method as that in Example 1, except that grinding and aging were not carried out.
- the percentage of coarse particles having a larger particle size than 150 ⁇ m was about 86% before dissolution in hydrochloric acid, and the leaching rate was only 81% after 720 minutes at the dissolving step using hydrochloric acid.
- the amount of tin in the electrowon metal was 0.9 ppm which was larger than that in Examples 1 and 2.
- the compositions of the solution after dissolution, solution after neutralization and solution after sulfurization, and the grades of the electrowon metal and cast indium, which were obtained in this comparative example are shown in Table 4, and the relationship between the leaching rate and time in this comparative example is shown in Table 2 and FIG. 2 .
- a dissolving step was carried out by the same method as that in each of Example 1 and Comparative Example 1, except that sulfuric acid was substituted for hydrochloric acid.
- the leaching rate was 99% after 240 minutes in Example 3 in which there were used fine particles wherein the percentage of coarse particles having a larger particle size than 150 ⁇ m was about 4%, whereas the leaching rate was only 81% after 720 minutes in Comparative Example 2 wherein grinding was not carried out.
- Example 3 150 ⁇ m ⁇ : 86% 150 ⁇ m ⁇ : 4% Time Leaching Leaching (min.) In(g/l) Rate(%) In(g/l) Rate(%) 0 0 0 0 0 30 69 34 132 65 60 119 59 177 88 90 139 69 189 94 120 144 72 193 96 180 147 73 196 98 240 149 74 198 99 360 153 76 198 99 480 158 79 198 99 600 161 80 198 99 720 162 81 198 99
- a dissolving step was carried out by the same method as that in each of Example 1 and Comparative Example 1, except that nitric acid was substituted for hydrochloric acid.
- the leaching rate was 97% after 360 minutes in Example 4 in which there were used fine particles wherein the percentage of coarse particles having a larger particle size than 150 ⁇ m was about 4%, whereas the leaching rate was only 79% after 720 minutes in Comparative Example 3 wherein grinding was not carried out.
- Example 4 150 ⁇ m ⁇ : 86% 150 ⁇ m ⁇ : 4% Time Leaching Leaching (min.) In(g/l) Rate(%) In(g/l) Rate(%) 0 0 0 0 0 30 68 34 129 64 60 117 58 173 86 90 136 67 185 92 120 141 70 189 94 180 143 71 192 95 240 146 73 194 96 360 150 74 194 97 480 154 77 194 97 600 157 78 194 97 720 158 79 194 97
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- Electrochemistry (AREA)
- Geochemistry & Mineralogy (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
Description
- The present invention relates generally to a method for recovering indium. More specifically, the invention relates to a method for recovering indium metal from indium containing substances, such as indium-tin-oxide (ITO) target scraps.
- With the rapid development of liquid crystal techniques in recent years, a demand for ITO films used as transparent conductive films for liquid crystals is remarkably increased, and the quantity of ITO target materials consumed as the raw materials of ITO films is also remarkably increased.
- As a conventional method for recovering indium from indium containing substances, such as ITO target scraps, a method utilizing solvent extraction is proposed (see, e.g., Japanese Patent Laid-Open No. 8-91838). However, this method has complicated steps due to the repetition of extraction and back extraction, and costs a lot due to the use of expensive solvents. There is also proposed a method comprising the steps of: dissolving an indium containing substance in hydrochloric acid or a mixed acid of hydrochloric acid and sulfuric acid; putting an indium metal plate in the solution after dissolution, to replace impurity ions in the solution to deposit and remove substitution products; and electrowinning indium metal using the solution after dissolution as an electrolytic solution (see, e.g., Japanese Patent Laid-Open No. 10-204673). This method has simple steps, but there is a limit to the concentration of impurity ions capable of being removed by substitution and deposition, so that the purity of obtainable indium metal is only about 99.99%.
- In order to solve such problems in conventional methods for recovering indium, there is proposed a method comprising the steps of: dissolving an indium containing substance in hydrochloric acid; adding an alkali to the solution after dissolution, to neutralize the solution so that the pH of the solution is 0.5 to 4; depositing and removing hydroxides of predetermined metal ions in the solution; blowing hydrogen sulfide gas into the solution to deposit and remove sulfides of metal ions which are harmful to electrolysis; and then, electrowinning indium metal using the solution as an initial electrolytic solution (see, e.g., Japanese Patent Laid-Open No. 2000-169991). This method is very useful as a method for recycling ITO target scraps and so forth since it is possible to recover indium having a high purity of not less than 99.999% at simple and inexpensive steps.
- However, the content of indium in indium containing substances, such as ITO target scraps, and the shape and size of the substances are not constant, so that such indium containing substances can not suitably used as recycled materials in the method disclosed in Japanese Patent Laid-Open No. 2000-169991, as they are. In particular, at the step of dissolving indium containing substances in hydrochloric acid, the variation in sharp and size of raw materials causes the increase of the treating time and/or the decrease of the leaching rate, so that the treating time and leaching rate at the dissolving step are changed. If the decrease of the treating time takes precedence over the improvement of the leaching rate at the dissolving step, the leaching rate is decreased, so that it is required to additionally provide a circulating or reprocessing line for improving the leaching rate. On the other hand, if the improvement of the leaching rate (recovery) takes precedence over the decrease of the treating time at the dissolving step, it takes a lot of time to obtain a desired leaching rate. Therefore, in order to industrially utilize the method disclosed in Japanese Patent Laid-Open No. 2000-169991, it is required to achieve both of the shortening of the treating time and the improvement of the leaching rate at the dissolving step so that indium can be recovered in a short time and with a high recovery. In addition, in the method disclosed in Japanese Patent Laid-Open No. 169991, the amount of tin in indium metal obtained by electrowinning is about 1 ppm, so that it is desired to further decrease the amount of tin.
- It is therefore an object of the present invention to eliminate the aforementioned problems and to provide a method for recovering indium, the method being capable of recovering indium having a high purity at simple and inexpensive steps in a short time and with a high recovery.
- In order to accomplish the aforementioned object, the inventors have diligently studied and found that it is possible to achieve both of the shortening of a treating time and the improvement of a leaching rate at a dissolving step and it is possible to stabilize a neutralized precipitate to decrease the amount of tin in electrowon indium metal, so that it is possible to provide a method for recovering indium, the method being capable of recovering indium having a high purity at simple and inexpensive steps in a short time and with a high recovery, if an indium containing substance is dissolved in an acid after being ground until the percentage of coarse particles having a larger particle size than a predetermined particle size is not larger than a predetermined percentage and if aging is carried out at a predetermined temperature for a predetermined period of time after neutralization. Thus, the inventors have made the present invention.
- According to the present invention, a method for recovering indium comprises: a grinding step of grinding an indium containing substance until the percentage of coarse particles of the indium containing substance is not larger than a predetermined percentage, the coarse particles having a larger particle size than a predetermined particle size; a dissolving step of dissolving fine particles, which are obtained at the grinding step, in an acid, such as hydrochloric acid, sulfuric acid or nitric acid; a neutralizing step of adding an alkali to a solution after dissolution, which is obtained at the dissolving step, to neutralize the solution after dissolution so that the solution after dissolution has a pH of 0.5 to 4, to deposit and remove hydroxides of predetermined metal ions in the solution after dissolution; an aging step of aging a solution after neutralization, which is obtained at the neutralizing step, at a predetermined temperature for a predetermined period of time; a sulfurizing step of blowing hydrogen sulfide gas into a solution after aging, which is obtained at the aging step, to deposit and remove sulfides of metal ions; and an electrowinning step of using a solution after sulfurization, which is obtained at the sulfurizing step, as an initial electrolytic solution to electrowin indium metal. At the grinding step in this method for recovering indium, the predetermined particle size is preferably 150 μm. The predetermined percentage is preferably 10%, more preferably 5% and most preferably substantially 0%. At the aging step, the predetermined temperature is preferably in the range of from a room temperature to 80° C., more preferably in the range of from 40° C. to 70° C., and most preferably in the range of from 60° C. to 70° C. The predetermined period of time is preferably 2 hours or longer, and more preferably 3 hours or longer. Furthermore, the method for recovering indium may further comprise a classification step of removing coarse particles having a larger particle size than the predetermined particle size by classification before the dissolving step after the grinding step. The indium containing substance is preferably an ITO target scrap.
- According to the present invention, indium has a purity of not less than 99.999% and contains tin, the content of which is not larger than 0.5 ppm and preferably not larger than 0.1 ppm. Alternatively, indium is obtained by electrowinning which uses indium-tin-oxide as a raw material, and contains tin, the content of which is not larger than 0.5 ppm and preferably not larger than 0.1 ppm. Such indium can be obtained by the above described method for recovering indium according to the present invention.
- According to the present invention, it is possible to recover indium having a high purity at simple and inexpensive steps in a short time and with a high recovery.
-
FIG. 1 is a process drawing showing a method for recovering indium according to the present invention; -
FIG. 2 is a graph showing a variation in leaching rate with respect to time in Examples 1 and 2 and Comparative Example 1; -
FIG. 3 is a graph showing a variation in leaching rate with respect to time in Example 3 and Comparative Example 2; and -
FIG. 4 is a graph showing a variation in leaching rate with respect to time in Example 4 and Comparative Example 3. - Referring to the process drawing of
FIG. 1 , the preferred embodiment of a method for recovering indium according to the present invention will be described below. - As shown in
FIG. 1 , in the preferred embodiment of a method for recovering indium according to the present invention, after an indium containing substance, such as an ITO target scrap, is crushed, the crushed substance is ground until the percentage of coarse particles having a larger particle size than a predetermined particle size is not larger than a predetermined percentage. Thereafter, the ground substance is dissolved in hydrochloric acid, and an alkali, such as sodium hydroxide or sodium carbonate, is added to the solution to neutralize the solution so that the pH of the solution is 0.5 to 4. Then, the solution after dissolution is aged at a predetermined temperature for a predetermined period of time to deposit and remove hydroxides of predetermined metal ions in the solution. Then, hydrogen sulfide gas is blown into the solution to deposit and remove sulfides of metal ions which are harmful to electrolysis at the subsequent step. Thereafter, the solution thus obtained is used as an electrolytic solution for electrowinning indium metal to recover indium having a high purity. - The indium containing substances serving as raw materials are preferably ITO target scraps. In the preferred embodiment of a method for recovering indium according to the present invention, various indium containing substances may be used as the raw materials. The crushing and grinding of the raw materials may be carried out by a crusher and a grinder, respectively. The percentage of coarse particles having a larger particle size than 15 μm in fine particles obtained by grinding is preferably 10% or less, more preferably 5% or less, and most preferably substantially 0%. If the percentage of coarse particles is thus decreased by grinding, the contact of the raw materials with a hydrochloric acid solution can be improved for obtaining a desired leaching rate in a short time. Furthermore, classification, such as sieving or screening, may be carried out in order to thus remove coarse particles.
- The amount of the solution after dissolving the indium containing fine particles in hydrochloric acid is preferably adjusted so that the concentration of indium is in the range of from 20 g/L to 200 g/L, and the amount of hydrochloric acid used in dissolution is preferably 1.1 to 1.5 times as large as the theoretical equivalent thereof. In addition, the solution after dissolution is preferably heated in order to promote dissolution.
- The reasons why the alkali is added so that the pH is 0.5 to 4 are that the pH is adjusted to be 4 or lower to prevent the deposition of hydroxides of indium and that the pH is adjusted to be 0.5 or higher to hydrolyze impurity ions to deposit hydroxides of the ions. By thus adding the alkali, it is possible to efficiently remove most of tin which is a main impurity in ITO target scraps.
- The reason why aging is carried out after neutralization is that the neutralized precipitate is stabilized. The aging temperature is preferably in the range of from a room temperature to 80° C., more preferably in the range of from 40° C. to 70° C., and most preferably in the range of from 60° C. to 70° C. The aging time is preferably 2 hours or longer, and more preferably 3 hours or longer.
- After deposited hydroxides of tin and so forth are removed by filtration, hydrogen sulfide gas is blown into the filtrate to deposit and remove sulfides of copper, lead and so forth, which are harmful to electrolysis at the subsequent step, and sulfides of a very small amount of tin. The indium-dissolved solution thus purified is fed to the electrowinning step at which indium is recovered as a metal by electrowinning on appropriate electrolytic conditions. The indium metal thus recovered contains alkali metals, such as sodium, which are components of the electrolytic solution, as impurities. Therefore, the indium metal, together with solid sodium hydroxide, is heated to be mixed and melted, so that the alkali metals are dissolved in the melted sodium hydroxide to be removed, and then, the metal part obtained by gravity separation is cast in a mold to be cooled to recover indium having a high purity.
- The solution after electrowinning is mixed with hydrochloric acid to be reused for the dissolution of indium containing fine particles. In order to prevent the accumulation of base metal ions, such as aluminum and iron ions, which are baser than indium, part or all of the solution after electrowinning is preferably extracted to the outside of the system.
- Examples of a method for recovering indium according to the present invention will be described below in detail.
- After ITO target scraps containing about 400 g of indium were crushed, the crushed scraps were ground to obtain fine particles wherein the percentage of coarse particles having a larger particle size than 150 μm was about 4%. The fine particles thus obtained were dissolved in 5 moles of hydrochloric acid to obtain 2L of an indium-dissolved solution. At the dissolving step using hydrochloric acid, the leaching rate was 100% after 240 minutes. After sodium hydroxide was added to the indium-dissolved solution to neutralize the solution so that the pH of the solution was 1.7, the deposited hydroxides were removed by filtration to obtain a solution after neutralization. The solution after neutralization was aged at 60° C. for 3 hours, and thereafter, hydrogen sulfide gas was brown into the solution at a flow rate of 50 cc/min for 2 minutes Then, the deposited sulfides were removed by filtration to obtain a solution after sulfurization. The solution after sulfurization thus purified was used as an initial electrolytic solution for electrowinning indium metal on electrolytic conditions (at a liquid temperature of 30° C. and a current density of 150 A/m2). The amount of tin in the electrowon indium metal was 0.4 ppm. The electrowon metal, together with solid sodium hydroxide, was heated to be mixed and melted, and a metal part obtained by gravity separation was cast in a mold to be cooled to recover cast indium. The grade of the cast indium thus obtained was not less than 99.999%, so that indium having a high purity was obtained.
- The compositions of the solution after dissolution, solution after neutralization and solution after sulfurization, and the grades of the electrowon metal and cast indium, which were obtained in this example, are shown in Table 1, and the relationship between the leaching rate and time is shown in Table 2 and
FIG. 2 . -
TABLE 1 In Sn Cu Pb Na Zn Cr Ni Fe Solution after 200 0.99 0.0025 0.0010 — — 0.0010 <0.001 0.1980 Dissolution (g/l) Solution after 198 <0.001 0.0024 0.0010 — — 0.0010 <0.001 0.0018 Neutralization (g/l) Solution after 198 <0.001 <0.001 <0.001 — — 0.0010 <0.001 <0.001 Sulfurization (g/l) Electrowon Metal — 0.4 <0.1 <0.1 31 <0.1 <0.1 0.5 <0.1 (ppm) Cast Indium >99.999 0.5 <0.1 <0.1 <0.1 <0.1 <0.1 0.3 <0.1 (ppm) (%) -
TABLE 2 Comp. Example 1 Example 1 Example 2 150 μm<: 86% 150 μm<: 4% 150 μm<: 0% Time In Leaching In Leaching In Leaching (min.) (g/l) Rate (%) (g/l) Rate (%) (g/l) Rate (%) 0 0 0 0 0 0 0 30 70 35 133 66 159 79 60 120 60 179 89 192 96 90 140 70 191 95 197 98 120 146 73 195 97 201 100 180 148 74 198 99 201 100 240 151 75 200 100 201 100 360 155 77 200 100 201 100 480 160 79 201 100 201 100 600 163 81 200 100 201 100 720 164 81 200 100 201 100 - Furthermore, the amount of indium in the ITO target scraps was determined by measurement using an inductively coupled plasma mass spectrometer (ICP-Mass) after the fine particles obtained by grinding the ITO target scraps were dissolved in hydrochloric acid and tartaric acid. The percentage of coarse particles (larger particles than 150 μm) in the fine particles was determined by calculating the percentage of the coarse particle part on the basis of the results that a particle size distribution was measured by a laser diffraction type particle size distribution measuring device (Model LA500 produced by HORIBA, Ltd.) after a small number of the fine particles were ultrasonically dispersed in a dispersion medium (200 mL of a sodium hexametaphosphate solution).
- The compositions of the solution after dissolution, solution after neutralization and solution after sulfurization were determined by measurement using an ICP-Mass after these solutions were sampled. The grades of the electrowon metal and cast indium were determined by measurement using an ICP-Mass after each of the electrowon metal and the case indium was dissolved in nitric acid.
- The variation in leaching rate with respect to time was determined by analyzing the residue and liquid, which were obtained by the solid-liquid separation of a slurry sampled every a predetermined time, by means of an ICP-Mass. The liquid after solid-liquid separation was diluted with nitric acid to be used as a sample to be analyzed. The residue after solid-liquid separation was dried to be dissolved in nitric acid and sulfuric acid, and then, dissolved in perchloric acid to be used as a sample to be analyzed.
- Cast indium was recovered by the same method as that in Example 1, except that fine particles containing no coarse particles having a larger particle size than 153 μm were obtained by grinding. In this example, the leaching rate was 100% after 120 minutes at the dissolving step using hydrochloric acid. The amount of tin in the electrowon metal was 0.1 ppm. Furthermore, the compositions of the solution after dissolution, solution after neutralization and solution after sulfurization, and the grades of the electrowon metal and cast indium, which were obtained in this example, are shown in Table 3, and the relationship between the leaching rate and time in this example is shown in Table 2 and
FIG. 2 . -
TABLE 3 In Sn Cu Pb Na Zn Cr Ni Fe Solution after 201 1.01 0.0026 0.0012 — — 0.0013 <0.001 0.2000 Dissolution (g/l) Solution after 197 <0.001 0.0026 0.0012 — — 0.0013 <0.001 0.0013 Neutralization (g/l) Solution after 198 <0.001 <0.001 <0.001 — — 0.0013 <0.001 <0.001 Sulfurization (g/l) Electrowon Metal — <0.1 <0.1 <0.1 36 <0.1 <0.1 0.6 <0.1 (ppm) Cast Indium >99.999 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 0.2 <0.1 (ppm) (%) - Cast indium was recovered by the same method as that in Example 1, except that grinding and aging were not carried out. In this comparative example, the percentage of coarse particles having a larger particle size than 150 μm was about 86% before dissolution in hydrochloric acid, and the leaching rate was only 81% after 720 minutes at the dissolving step using hydrochloric acid. The amount of tin in the electrowon metal was 0.9 ppm which was larger than that in Examples 1 and 2. Furthermore, the compositions of the solution after dissolution, solution after neutralization and solution after sulfurization, and the grades of the electrowon metal and cast indium, which were obtained in this comparative example, are shown in Table 4, and the relationship between the leaching rate and time in this comparative example is shown in Table 2 and
FIG. 2 . -
TABLE 4 In Sn Cu Pb Na Zn Cr Ni Fe Solution after 164 1.08 0.0025 0.0012 — — 0.0012 0.0010 0.2010 Dissolution (g/l) Solution after 160 <0.001 0.0025 0.0012 — — 0.0012 0.0010 0.0024 Neutralization (g/l) Solution after 160 <0.001 <0.001 <0.001 — — 0.0012 0.0010 <0.001 Sulfurization (g/l) Electrowon Metal — 0.9 <0.1 <0.1 40 <0.1 <0.1 0.7 <0.1 (ppm) Cast Indium >99.999 0.9 <0.1 <0.1 <0.1 <0.1 <0.1 0.5 <0.1 (ppm) (%) - A dissolving step was carried out by the same method as that in each of Example 1 and Comparative Example 1, except that sulfuric acid was substituted for hydrochloric acid. As a result, the leaching rate was 99% after 240 minutes in Example 3 in which there were used fine particles wherein the percentage of coarse particles having a larger particle size than 150 μm was about 4%, whereas the leaching rate was only 81% after 720 minutes in Comparative Example 2 wherein grinding was not carried out. These results are shown in Table 5.
-
TABLE 5 Comp. Example 2 Example 3 150 μm<: 86% 150 μm<: 4% Time Leaching Leaching (min.) In(g/l) Rate(%) In(g/l) Rate(%) 0 0 0 0 0 30 69 34 132 65 60 119 59 177 88 90 139 69 189 94 120 144 72 193 96 180 147 73 196 98 240 149 74 198 99 360 153 76 198 99 480 158 79 198 99 600 161 80 198 99 720 162 81 198 99 - A dissolving step was carried out by the same method as that in each of Example 1 and Comparative Example 1, except that nitric acid was substituted for hydrochloric acid. As a result, the leaching rate was 97% after 360 minutes in Example 4 in which there were used fine particles wherein the percentage of coarse particles having a larger particle size than 150 μm was about 4%, whereas the leaching rate was only 79% after 720 minutes in Comparative Example 3 wherein grinding was not carried out. These results are shown in Table 6.
-
TABLE 6 Comp. Example 3 Example 4 150 μm<: 86% 150 μm<: 4% Time Leaching Leaching (min.) In(g/l) Rate(%) In(g/l) Rate(%) 0 0 0 0 0 30 68 34 129 64 60 117 58 173 86 90 136 67 185 92 120 141 70 189 94 180 143 71 192 95 240 146 73 194 96 360 150 74 194 97 480 154 77 194 97 600 157 78 194 97 720 158 79 194 97
Claims (10)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2005-022836 | 2005-01-31 | ||
JP2005022836A JP5071700B2 (en) | 2005-01-31 | 2005-01-31 | Indium recovery method |
PCT/JP2006/301819 WO2006080565A1 (en) | 2005-01-31 | 2006-01-27 | Method for recovering indium |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080190779A1 true US20080190779A1 (en) | 2008-08-14 |
Family
ID=36740573
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/883,138 Abandoned US20080190779A1 (en) | 2005-01-31 | 2006-01-27 | Method for Recovering Indium |
Country Status (6)
Country | Link |
---|---|
US (1) | US20080190779A1 (en) |
EP (1) | EP1845169B1 (en) |
JP (1) | JP5071700B2 (en) |
KR (1) | KR101199661B1 (en) |
CN (1) | CN100507033C (en) |
WO (1) | WO2006080565A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080299035A1 (en) * | 2007-05-30 | 2008-12-04 | Cheng Loong Corporation | Method for recycling used sputtering target |
US10202703B2 (en) | 2017-01-05 | 2019-02-12 | Boe Technology Group Co., Ltd. | Method for treating waste liquid from process of etching indium tin oxide |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5065732B2 (en) * | 2007-03-29 | 2012-11-07 | Jx日鉱日石金属株式会社 | Method for recovering indium from display panel |
WO2009101864A1 (en) * | 2008-02-12 | 2009-08-20 | Nippon Mining & Metals Co., Ltd. | Method of recovering valuable metals from izo scrap |
KR101232745B1 (en) * | 2009-07-03 | 2013-02-13 | 주식회사 지엠에스 21 | Method for recycling indium |
KR100932706B1 (en) * | 2009-08-31 | 2009-12-21 | (주)티에스엠 | Method for recycling indium from indium containing waste solution |
EP3141621A1 (en) * | 2011-05-04 | 2017-03-15 | Orbite Aluminae Inc. | Processes for recovering rare earth elements from various ores |
RU2463388C2 (en) * | 2011-08-01 | 2012-10-10 | Виталий Евгеньевич Дьяков | Electrolytic cell to extract indium from melt of indium-containing alloys |
RU2471893C2 (en) * | 2011-10-07 | 2013-01-10 | Виталий Евгеньевич Дьяков | Method for electrolytic production of bismuth from alloy containing lead, tin and bismuth, and electrolysis cell for realising said method |
RU2490375C2 (en) * | 2012-07-09 | 2013-08-20 | Борис Николаевич Дьяков | Electrolysis unit for extraction of indium from indium-containing molten metal in form of condensate from vacuum furnace |
CN103103356B (en) * | 2012-11-09 | 2014-12-10 | 柳州百韧特先进材料有限公司 | Process for recovering crude indium and tin from ITO (indium tin oxide) waste target |
RU2507283C1 (en) * | 2012-12-25 | 2014-02-20 | Открытое акционерное общество "Государственный научно-исследовательский и проектный институт редкометаллической промышленности ОАО "Гиредмет" | Method for obtaining high-purity indium |
KR101495213B1 (en) * | 2014-10-10 | 2015-03-23 | 비케이리메탈(주) | Method for refining indium |
JP6373772B2 (en) * | 2015-02-25 | 2018-08-15 | Jx金属株式会社 | Method for recovering indium and gallium |
KR101725919B1 (en) * | 2016-04-18 | 2017-04-12 | (주)한청알에프 | Method for withdrawing high purity indium from spent ITO |
TWI638896B (en) | 2017-04-24 | 2018-10-21 | 國立中山大學 | Treating method for recycling indium |
CN108642522A (en) * | 2018-05-17 | 2018-10-12 | 汉能新材料科技有限公司 | A kind of recovery method of the waste material containing indium |
CN108823405B (en) * | 2018-07-09 | 2020-12-29 | 刘罗平 | Rare-leaching solution method for indium hydrometallurgy |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4198231A (en) * | 1978-02-17 | 1980-04-15 | Swiss Aluminium Ltd. | Recovery and separation of gadolinium and gallium |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2738192B2 (en) * | 1991-12-02 | 1998-04-08 | 住友金属鉱山株式会社 | Recovery method of crude indium for electrolysis |
JP3173404B2 (en) | 1997-01-22 | 2001-06-04 | 三菱マテリアル株式会社 | How to recover indium |
JP3602329B2 (en) * | 1998-03-20 | 2004-12-15 | 同和鉱業株式会社 | Method for recovering indium from indium-containing material |
JP4304254B2 (en) * | 1998-12-04 | 2009-07-29 | Dowaメタルマイン株式会社 | Recovery method of high purity indium |
JP2001040436A (en) * | 1999-07-29 | 2001-02-13 | Sumitomo Chem Co Ltd | Method for recovering and refining indium |
JP3822409B2 (en) * | 2000-01-24 | 2006-09-20 | 同和鉱業株式会社 | Ga, Ge, In separation method |
JP4549501B2 (en) * | 2000-08-28 | 2010-09-22 | 日鉱金属株式会社 | Indium recovery method |
JP4519294B2 (en) * | 2000-08-28 | 2010-08-04 | 日鉱金属株式会社 | Indium recovery method |
RU2218244C1 (en) * | 2002-04-05 | 2003-12-10 | Акционерное общество открытого типа "Челябинский электролитный цинковый завод" | Method for producing high-purity indium powder |
JP2006083457A (en) * | 2004-09-17 | 2006-03-30 | Dowa Mining Co Ltd | Treatment method for zinc leach residue and the like |
JP2005146420A (en) * | 2004-12-28 | 2005-06-09 | Dowa Mining Co Ltd | High purity indium |
-
2005
- 2005-01-31 JP JP2005022836A patent/JP5071700B2/en not_active Expired - Fee Related
-
2006
- 2006-01-27 KR KR20077019797A patent/KR101199661B1/en active IP Right Grant
- 2006-01-27 WO PCT/JP2006/301819 patent/WO2006080565A1/en active Application Filing
- 2006-01-27 EP EP20060712962 patent/EP1845169B1/en not_active Not-in-force
- 2006-01-27 CN CNB2006800035042A patent/CN100507033C/en not_active Expired - Fee Related
- 2006-01-27 US US11/883,138 patent/US20080190779A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4198231A (en) * | 1978-02-17 | 1980-04-15 | Swiss Aluminium Ltd. | Recovery and separation of gadolinium and gallium |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20080299035A1 (en) * | 2007-05-30 | 2008-12-04 | Cheng Loong Corporation | Method for recycling used sputtering target |
US10202703B2 (en) | 2017-01-05 | 2019-02-12 | Boe Technology Group Co., Ltd. | Method for treating waste liquid from process of etching indium tin oxide |
Also Published As
Publication number | Publication date |
---|---|
EP1845169B1 (en) | 2014-10-08 |
CN100507033C (en) | 2009-07-01 |
JP5071700B2 (en) | 2012-11-14 |
JP2006206990A (en) | 2006-08-10 |
EP1845169A4 (en) | 2009-09-02 |
WO2006080565A1 (en) | 2006-08-03 |
KR20070101368A (en) | 2007-10-16 |
CN101115854A (en) | 2008-01-30 |
EP1845169A1 (en) | 2007-10-17 |
KR101199661B1 (en) | 2012-11-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20080190779A1 (en) | Method for Recovering Indium | |
JP4304254B2 (en) | Recovery method of high purity indium | |
US8734633B2 (en) | Method of recovering valuable metal from scrap containing conductive oxide | |
EP2078766B1 (en) | Method for collection of valuable metal from ito scrap | |
US8007652B2 (en) | Method for collection of valuable metal from ITO scrap | |
US8308934B2 (en) | Method of recovering valuable metals from IZO scrap | |
KR20090055651A (en) | Method for collection of valuable metal from ito scrap | |
US20100294082A1 (en) | Method for Collection of Valuable Metal from ITO Scrap | |
KR101567499B1 (en) | A selectively recovery method for valuable metal from the LED wastes | |
US7604786B2 (en) | Method for recovering indium from indium-containing material | |
JP4310388B2 (en) | Indium recovery method | |
JP6662230B2 (en) | Method for producing high-purity indium | |
KR101528598B1 (en) | A selectively recovery method for indium & gallium from the mixed indium, gallium and znic scraps | |
JP5283403B2 (en) | Indium recovery method | |
JP5339762B2 (en) | Method for producing indium metal | |
JP5219968B2 (en) | Method for electrolysis of scrap containing conductive metal oxide | |
KR101232745B1 (en) | Method for recycling indium | |
JP6373772B2 (en) | Method for recovering indium and gallium | |
JP2005146420A (en) | High purity indium | |
KR20240066642A (en) | Method for recovering indium | |
JP2006022407A (en) | Method for recovering indium | |
CN110938838A (en) | Method for treating anode carbon slag of aluminum electrolysis cell by using NaCl molten salt extraction method | |
US20050132844A1 (en) | Method for producing indium powder |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: DOWA METALS & MINING CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NAKAMURA, YUZURU;OGASAWARA, SHIGERU;KOMORI, ATSUSHI;AND OTHERS;REEL/FRAME:019673/0079;SIGNING DATES FROM 20070618 TO 20070619 Owner name: DOWA METALS & MINING CO., LTD., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NAKAMURA, YUZURU;OGASAWARA, SHIGERU;KOMORI, ATSUSHI;AND OTHERS;SIGNING DATES FROM 20070618 TO 20070619;REEL/FRAME:019673/0079 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |