WO2015010667A1 - Method of bulk iridium dissolution in hydrochloric acid media - Google Patents
Method of bulk iridium dissolution in hydrochloric acid media Download PDFInfo
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- WO2015010667A1 WO2015010667A1 PCT/CZ2013/000087 CZ2013000087W WO2015010667A1 WO 2015010667 A1 WO2015010667 A1 WO 2015010667A1 CZ 2013000087 W CZ2013000087 W CZ 2013000087W WO 2015010667 A1 WO2015010667 A1 WO 2015010667A1
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- Prior art keywords
- iridium
- anode
- plasma
- hydrochloric acid
- cathode
- Prior art date
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- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 title claims abstract description 66
- 229910052741 iridium Inorganic materials 0.000 title claims abstract description 63
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000004090 dissolution Methods 0.000 title description 32
- 239000000126 substance Substances 0.000 claims abstract description 16
- 239000002184 metal Substances 0.000 claims abstract description 14
- 239000000203 mixture Substances 0.000 claims abstract description 11
- 229910000575 Ir alloy Inorganic materials 0.000 claims abstract description 6
- 229910001092 metal group alloy Inorganic materials 0.000 claims abstract description 5
- 239000000919 ceramic Substances 0.000 claims abstract description 4
- 239000003014 ion exchange membrane Substances 0.000 claims abstract description 4
- 150000003839 salts Chemical class 0.000 claims abstract description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 9
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 229910017604 nitric acid Inorganic materials 0.000 claims description 9
- 150000002739 metals Chemical class 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 5
- 239000000956 alloy Substances 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- 239000010936 titanium Substances 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- DANYXEHCMQHDNX-UHFFFAOYSA-K trichloroiridium Chemical compound Cl[Ir](Cl)Cl DANYXEHCMQHDNX-UHFFFAOYSA-K 0.000 claims description 3
- 239000000463 material Substances 0.000 claims 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 13
- 229910052697 platinum Inorganic materials 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000005275 alloying Methods 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000010970 precious metal Substances 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- 239000010948 rhodium Substances 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 239000011669 selenium Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- YJZATOSJMRIRIW-UHFFFAOYSA-N [Ir]=O Chemical class [Ir]=O YJZATOSJMRIRIW-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011978 dissolution method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 150000002484 inorganic compounds Chemical class 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 229910000457 iridium oxide Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 150000003385 sodium Chemical class 0.000 description 1
- 239000001117 sulphuric acid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 210000002268 wool Anatomy 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G55/00—Compounds of ruthenium, rhodium, palladium, osmium, iridium, or platinum
- C01G55/005—Halides
-
- 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
- C22B11/00—Obtaining noble metals
- C22B11/04—Obtaining noble metals by wet 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
- 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
-
- 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 invention relates to a plasma-chemical process, generally known as Contact Glow Discharge Electrolysis (CGDE) or also as Asymmetric Plasma Electrolysis (APE) for dissolution of bulk iridium electrodes and/or metallic Ir scrap and/or its alloys with other metals in aqueous hydrochloric acid media.
- CGDE Contact Glow Discharge Electrolysis
- APE Asymmetric Plasma Electrolysis
- Iridium is known as most corrosive resistant metal out of all metals towards aqueous inorganic acids like for example hydrochloric acid, nitric acid and their mixtures. It is virtually insoluble in these acids and this property makes dissolution of Iridium for its further refining or chemical salts production very complicated.
- Today methods to dissolve Iridium comprise mostly in alloying Ir metal or scrap with other precious metal, namely Platinum, to reach concentration of Iridium lesser than 12% by weight in such alloys.
- This alloy can be dissolved by conventional techniques in either Aqua Regia or HC1/C12 systems.
- the use of Platinum as an alloying element with Iridium is generally known to precious metals industry.
- To dissolve one (1) kilogram of Iridium one needs to add and keep in the refining circle more than 8kg of Platinum and this is very costly.
- Tanaka Precious Metals Industries has filed the patent No. : JPS 6483527, 1989.
- bulk Iridium is first alloyed with Manganese metal to the content lower than 30% by weight of Iridium, resulted alloy is digested in e.g. sulphuric acid to leach out Manganese and to obtain Ir black powder.
- This powder is washed dried and homogenized with mixture of sodium chloride and active carbon. This mixture is than sparged with gaseous Chlorine at temperatures above 350°C and finally digested with water to get solution of sodium chloroiridate.
- this sodium chloroiridate has to be hydrolyzed to produce hydrated Iridium oxides, these are filtered out and converted to Chloroiridic acid. This is required Ir salt that can be used for further refining of production of chemicals. As explained this process is very lengthy, laborious and expensive.
- Electrolytic dissolution of Iridium anodes in molten mixture of KCl/LiCl is described in the Metals Review 1978,22,(3), 98-99 at temperatures above 450°C In the same article electrolytic dissolution of Iridium anode in molten cyanide salts is described.
- This invention provides fast, efficient and cheap process for direct dissolution of bulk Iridium in hydrochloric acid and/or its mixtures with nitric acid. It takes place in simple equipment at temperatures up to 100°C. The method of dissolution is driven by plasma-chemical effect.
- the dissolution method of bulk Iridium metal and/or Iridium alloys, in particular with Pt, Pd, Rh, Ru and Au, in aqueous hydrochloric acid and/or its mixtures with nitric acid is characterized in that the dissolution process takes place in plasma-chemical cell subdivided into two compartments by porous ceramic or ion exchange membranes under temperatures between 5-100°C and controlled direct current voltage of 60- 350Vd.c. and current density of 10 to 180A/dm 2 . Furthermore, the dissolution occurs only under the condition when plasma glow discharge is developed by suitable electrodes arrangement on the submerged Iridium electrode.
- the Iridium dissolution takes place when Iridium is used as either anode, cathode or even under alternating current conditions. However, best results have been achieved when Iridium has been used as anode or cathode. As Iridium dissolves, it is obvious that dissolution takes place also in the mixture of hydrochloric acid and/or its mixture with nitric acid and with dissolved Iridium chloride formed.
- the surface of Iridium electrode is at least 10 times smaller than the surface of opposite electrode.
- the dissolution mechanism is plasma-chemical and hence Iridium electrode is used as either anode or cathode as the process is not dependent on the Iridium electrode polarity.
- Both cell compartments are filled with pure 5-13M (concentrated) hydrochloric acid or its mixture with nitric acid where content of nitric acid is 5-75% by volume.
- a process according to this invention operates preferably at 130-230Vd.c. and current densities of 80-120A/dm 2 at temperatures 70-90°C.
- the solutions in both compartments are heated by Joule heat developed during the dissolution process.
- Te electrode opposite to the Iridium is preferably made out of the porous carbon or titanium gauze and best results has been achieved when opposite electrode surface was 105 times bigger that the surface of the Iridium electrode.
- the cell is equipped with condenser that returns condensate back into the cell.
- Beside alloying metals like Pt (Platinum), Pd (Palladium), Rh (Rhodium), Ir (Iridium), Ru (Ruthenium) and Au (Gold) also other impurities can be contained in the Iridium electrode.
- impurities are represented mainly but not limited to: Cu (Copper), Fe (Iron), Ni (Nickel), Si (Silicon), Sb (Antimony), As (Arsenic), Se (Selenium), Te (Tellurium), Cd (Cadmium), Zn (Zinc), Sn (Tin), Zr (Zirconium), Ti (Titanium), W (Tungsten), Mo (Molybdenum) and Mn (Manganese).
- the present invention is characterized by following advantages: It is the only method to dissolve directly bulk Iridium metal in hydrochloric acid media, it uses simple and cheap equipment, it is fast, non-laborious and can be easily automated. Therefore also represents safe and
- Iridium wire as a fine metal 1,5 mm in diameter is used as anode and submerged into the concentrated hydrochloric acid in anode compartment.
- Cathode compartment is filled with concentrated hydrochloric acid too.
- Iridium starts immediately to dissolve due to the plasma chemic reaction as indicated by dark brownish color of Iridic acid. Dissolution process has taken 60 minutes and dissolution speed of Iridium of 1812g/h.m 2 has been achieved. Dissolution speed has been calculated by measuring weight at the beginning and at the end of the reaction. The system sets its own temperature during the dissolution due to developed head.
- Example 4 Dissolution of bulk Iridium according to the Example 1 while iridium anode of diameter 5mm has been used and as anolyte hydrochloric acid with 10% by volume of nitric acid has been used. Cathode compartment has been filled with 5M NaCl solution acidified by 1M hydrochloric acid. Voltage applied was 198V. Dissolution speed achieved was 5318g/hm 2 .
- Example 6 Dissolution according to Example 6 while Iridium anode was prepared by pressing Iridium powder into the mold with cross-section of 10 10mm and sintered at 1200°C for one hour.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Metallurgy (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Geochemistry & Mineralogy (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The solution according to invention consists in a plasma-chemical method for dissolving bulk Iridium metal and/or Iridium alloy in hydrochloric acid, comprising following steps a) providing an electrolytic cell divided into the compartments by either porous ceramic diaphragm or by ion exchange membrane, b) providing an anode in said anode compartment is made of Iridium metal and/or Iridium alloy containing body to be dissolved, c) placing a portion of 8-13M hydrochloric acid in said anode compartment, d) filling the said cathode compartment with 8-13M hydrochloric acid or its mixture with salts thereof, e) placing into said cathode compartment cathode that has at least 10 times larger surface than said Iridium anode, f) applying potential from 60 to 350 Vd.c. between anode and cathode, g) developing glowing plasma discharge on the submerged surface of said Iridium anode.
Description
METHOD OF BULK IRIDIUM DISSOLUTION IN HYDROCHLORIC ACID MEDIA
Field of the Invention
The invention relates to a plasma-chemical process, generally known as Contact Glow Discharge Electrolysis (CGDE) or also as Asymmetric Plasma Electrolysis (APE) for dissolution of bulk iridium electrodes and/or metallic Ir scrap and/or its alloys with other metals in aqueous hydrochloric acid media.
Background Art
Iridium is known as most corrosive resistant metal out of all metals towards aqueous inorganic acids like for example hydrochloric acid, nitric acid and their mixtures. It is virtually insoluble in these acids and this property makes dissolution of Iridium for its further refining or chemical salts production very complicated.
Today methods to dissolve Iridium comprise mostly in alloying Ir metal or scrap with other precious metal, namely Platinum, to reach concentration of Iridium lesser than 12% by weight in such alloys. This alloy can be dissolved by conventional techniques in either Aqua Regia or HC1/C12 systems. The use of Platinum as an alloying element with Iridium is generally known to precious metals industry. However, to dissolve one (1) kilogram of Iridium one needs to add and keep in the refining circle more than 8kg of Platinum and this is very costly.
Tanaka Precious Metals Industries has filed the patent No. : JPS 6483527, 1989. According to this patent bulk Iridium is first alloyed with Manganese metal to the content lower than 30% by weight of Iridium, resulted alloy is digested in e.g. sulphuric acid to leach out Manganese and to obtain Ir black powder. This powder is washed dried and homogenized with mixture of sodium chloride and active carbon. This mixture is than sparged with gaseous Chlorine at temperatures above 350°C and finally digested with water to get solution of sodium chloroiridate. In further steps this sodium chloroiridate has to be hydrolyzed to produce hydrated Iridium oxides, these are filtered out and converted to Chloroiridic acid. This is required Ir salt that can be used for further
refining of production of chemicals. As explained this process is very lengthy, laborious and expensive.
Russian scientist A.D. Styrkas has published a process for dissolution of PGM including Iridium powders in hydrochloric acid using alternating current applied in glass "U" tube (Electrochemical dissolution of metals of the platinum group by alternating current, Physical Chemistry
Laboratory, South Parks Road, Oxford, GB in Journal of Applied Electrochemistry 25(1995) 490-494). Though it is claimed the Iridium dissolves at the speed of 6mg/cm2.min, this method does not work with bulk Iridium at all. Thus Iridium has to be converted to the powder first and high currents exceeding 500A/dm2 must be applied.
Electrolytic dissolution of Iridium anodes in molten mixture of KCl/LiCl is described in the Metals Review 1978,22,(3), 98-99 at temperatures above 450°C In the same article electrolytic dissolution of Iridium anode in molten cyanide salts is described.
Perry L.D. in his Handbook of Inorganic Compounds, 1995 mentions possibility to attack the Iridium by fluorine at elevated temperatures. In our experience also dry Chlorine attacks Iridium at temperatures exceeding 600°C and under the strong light. However, Iridium chloride made by this way is not soluble in either water or hydrochloric acid.
All described prior art processes are represented by substantial disadvantages: high cost, low Iridium recovery, laborious process, necessity to work with Iridium powder and long Iridium lock up in the process. In addition these processes are mostly not so much friendly to the environment.
Summary of the Invention
This invention provides fast, efficient and cheap process for direct dissolution of bulk Iridium in hydrochloric acid and/or its mixtures with nitric acid. It takes place in simple equipment at temperatures up to 100°C. The method of dissolution is driven by plasma-chemical effect.
Therefore, according to the present invention, the dissolution method of bulk Iridium metal and/or Iridium alloys, in particular with Pt, Pd, Rh, Ru and Au, in aqueous hydrochloric acid and/or its mixtures with nitric acid, is characterized in that the dissolution process takes place in
plasma-chemical cell subdivided into two compartments by porous ceramic or ion exchange membranes under temperatures between 5-100°C and controlled direct current voltage of 60- 350Vd.c. and current density of 10 to 180A/dm2. Furthermore, the dissolution occurs only under the condition when plasma glow discharge is developed by suitable electrodes arrangement on the submerged Iridium electrode. The Iridium dissolution takes place when Iridium is used as either anode, cathode or even under alternating current conditions. However, best results have been achieved when Iridium has been used as anode or cathode. As Iridium dissolves, it is obvious that dissolution takes place also in the mixture of hydrochloric acid and/or its mixture with nitric acid and with dissolved Iridium chloride formed.
In the plasma-chemical cell, the surface of Iridium electrode is at least 10 times smaller than the surface of opposite electrode. Although the process takes place in electrolytic like cell, the dissolution mechanism is plasma-chemical and hence Iridium electrode is used as either anode or cathode as the process is not dependent on the Iridium electrode polarity. Both cell compartments are filled with pure 5-13M (concentrated) hydrochloric acid or its mixture with nitric acid where content of nitric acid is 5-75% by volume.
A process according to this invention operates preferably at 130-230Vd.c. and current densities of 80-120A/dm2 at temperatures 70-90°C. The solutions in both compartments are heated by Joule heat developed during the dissolution process. Te electrode opposite to the Iridium is preferably made out of the porous carbon or titanium gauze and best results has been achieved when opposite electrode surface was 105 times bigger that the surface of the Iridium electrode.
To prevent losses of hydrochloric acid through evaporation the cell is equipped with condenser that returns condensate back into the cell.
Beside alloying metals like Pt (Platinum), Pd (Palladium), Rh (Rhodium), Ir (Iridium), Ru (Ruthenium) and Au (Gold) also other impurities can be contained in the Iridium electrode. These impurities are represented mainly but not limited to: Cu (Copper), Fe (Iron), Ni (Nickel), Si (Silicon), Sb (Antimony), As (Arsenic), Se (Selenium), Te (Tellurium), Cd (Cadmium), Zn (Zinc), Sn (Tin), Zr (Zirconium), Ti (Titanium), W (Tungsten), Mo (Molybdenum) and Mn (Manganese).
The present invention is characterized by following advantages: It is the only method to dissolve directly bulk Iridium metal in hydrochloric acid media, it uses simple and cheap equipment, it is fast, non-laborious and can be easily automated. Therefore also represents safe and
environmentally sound process especially on the side of waste waters disposed in technologies described above. Comparing to other processes it locks up Iridium for short time and reaches extraordinary high recovery rates.
Examples Example 1
Bulk Iridium wire as a fine metal 1,5 mm in diameter is used as anode and submerged into the concentrated hydrochloric acid in anode compartment. Cathode compartment is filled with concentrated hydrochloric acid too. As cathode Titanium mesh having surface 10 times greater than submerged part of Iridium anode is used. Voltage of 140V is applied to develop glowing plasma discharge on the submerged Iridium electrode. Both compartments are separated with ceramic micro porous diaphragm. Iridium starts immediately to dissolve due to the plasma chemic reaction as indicated by dark brownish color of Iridic acid. Dissolution process has taken 60 minutes and dissolution speed of Iridium of 1812g/h.m2 has been achieved. Dissolution speed has been calculated by measuring weight at the beginning and at the end of the reaction. The system sets its own temperature during the dissolution due to developed head.
Example 2
Dissolution of bulk Iridium according to the Example 1 while Iridium has been used as cathode. The voltage of 80V has been applied and dissolution speed achieved was 1 181g/hm2.
Example 3
Dissolution of bulk Iridium according to Example 1 while alternating voltage of 120 V has been applied. Dissolution speed achieved was 1342g/hm2.
Example 4
Dissolution of bulk Iridium according to the Example 1 while iridium anode of diameter 5mm has been used and as anolyte hydrochloric acid with 10% by volume of nitric acid has been used. Cathode compartment has been filled with 5M NaCl solution acidified by 1M hydrochloric acid. Voltage applied was 198V. Dissolution speed achieved was 5318g/hm2.
Example 5
Dissolution of bulk Iridium according to Example 4 while Teflon ion exchange membrane has been used as separator of anode and cathode compartments. As cathode porous graphite wool has been used. Voltage applied was 233V. Dissolution speed has been 4598g/hm2.
Example 6
Dissolution of bulk Iridium according to Example 1 while Iridium alloy containing 52% by weight of Iridium, 47% by weight of Platinum and 1% by weight of Gold has been used. Ir anode has been made by pressing Ir scrap into the mold having cross-section 10x10 mm. As the anolyte hydrochloric acid with 5% by volume of nitric acid has been used. Applied voltage was 195 V and dissolution speed achieved was 7328g/hm2.
Example 7
Dissolution according to Example 6 while Iridium anode was prepared by pressing Iridium powder into the mold with cross-section of 10 10mm and sintered at 1200°C for one hour.
Voltage applied was 208V and dissolution speed achieved was 8521g/hm2.
While the invention has been illustrated and described in the text and examples above it is not intended to be limited to the details shown, while different modifications and structural changes may be made without departing away from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of present invention that others can readily adapt for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
What is claimed is set forth in following claims.
Claims
1. A plasma-chemical method for dissolving bulk Iridium metal and/or Iridium alloy in hydrochloric acid, comprising following steps: a) providing an electrolytic cell divided into the compartments by either porous ceramic diaphragm or by ion exchange membrane, b) providing an anode in said anode compartment is made of Iridium metal and/or Iridium alloy containing body to be dissolved, c) placing a portion of 8-13M hydrochloric acid in said anode compartment, d) filling the said cathode compartment with 8-13M hydrochloric acid or its mixture with salts thereof, e) placing into said cathode compartment cathode that has at least lOtimes larger surface than said Iridium anode, f) applying potential from 60 to 350Vd.c. between anode and cathode, g) developing glowing plasma discharge on the submerged surface of said Iridium anode.
2. The plasma-chemical method as defined in Claim 1, wherein the method operates at 130 to 230Vd.c. and current density of 80 to 120 A/dm2 at the temperatures from 70 to 90°C.
3. The plasma-chemical method as defined in Claim 1 or claim 2, wherein hydrochloric acid contains 5-75% by volume of nitric acid.
4. The plasma-chemical method as defined in any Claim 1 to 3, wherein hydrochloric acid contains dissolved Iridium chloride.
5. The plasma-chemical method as defined in Claim 1 or claim 2, wherein Iridium content in the alloy with other metals in said anode contains at least 15% by weight of Iridium.
6. The plasma-chemical method as defined in Claim 1 or claim 2, wherein cathode is selected from the group of materials consisting of Titanium, Carbon or Iridium.
7. The plasma-chemical method as defined in claim 1 or claim 2, wherein the polarity of the plasma-chemical cell is changed whereby said Iridium is used as a cathode and an original cathode is used as the anode.
8. The plasma-chemical method as defined in Claim 7, wherein instead of direct voltage alternating voltage is used to develop glowing plasma discharge on said Iridium electrode.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019061017A1 (en) * | 2017-09-26 | 2019-04-04 | 深圳先进技术研究院 | Method for utilizing room pressure plasma in preparing two-dimensional material |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6483527A (en) | 1987-09-26 | 1989-03-29 | Tanaka Precious Metal Ind | Method for dissolving iridium |
| JPH02116634A (en) * | 1988-10-26 | 1990-05-01 | Tanaka Kikinzoku Kogyo Kk | Method for producing chloroiridic acid |
-
2013
- 2013-07-26 WO PCT/CZ2013/000087 patent/WO2015010667A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6483527A (en) | 1987-09-26 | 1989-03-29 | Tanaka Precious Metal Ind | Method for dissolving iridium |
| JPH02116634A (en) * | 1988-10-26 | 1990-05-01 | Tanaka Kikinzoku Kogyo Kk | Method for producing chloroiridic acid |
Non-Patent Citations (5)
| Title |
|---|
| "Electrochemical dissolution of metals of the platinum group by alternating current, Physical Chemistry Laboratory, South Parks Road, Oxford, GB", JOURNAL OF APPLIED ELECTROCHEMISTRY, vol. 25, 1995, pages 490 - 494 |
| DATABASE WPI Week 199023, Derwent World Patents Index; AN 1990-175823, XP002716421 * |
| METALS REVIEW, vol. 22, no. 3, 1978, pages 98 - 99 |
| PERRY L.D.: "Handbook of Inorganic Compounds", 1995 |
| SCHREIER G ET AL: "Separation of Ir, Pd and Rh from secondary Pt scrap by precipitation and calcination", HYDROMETALLURGY, ELSEVIER SCIENTIFIC PUBLISHING CY. AMSTERDAM, NL, vol. 68, no. 1-3, 1 February 2003 (2003-02-01), pages 69 - 75, XP004409422, ISSN: 0304-386X, DOI: 10.1016/S0304-386X(02)00194-9 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019061017A1 (en) * | 2017-09-26 | 2019-04-04 | 深圳先进技术研究院 | Method for utilizing room pressure plasma in preparing two-dimensional material |
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