Classifications

• • 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
  • C22B11/042—Recovery of noble metals from waste materials
• • 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
  • C22B11/02—Obtaining noble metals by dry processes
  • C22B11/021—Recovery of noble metals from waste materials
  • C22B11/025—Recovery of noble metals from waste materials from manufactured products, e.g. from printed circuit boards, from photographic films, paper, or baths
• • 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
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
• • 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 to a recovery method of high purity platinum for recovering high purity platinum, at a high yield, from a platinum alloy containing platinum and ruthenium as components, and in particular from scraps of a magnetic material target or the like.
• an alloy sputtering target containing platinum is also used for forming a specific thin film for use as a magnetic thin film for a recording medium or as a semiconductor material.
• This kind of platinum alloy target often also contains ruthenium as an alloy element.
• These thin films are formed by sputtering an alloy target containing platinum or the like in an inert atmosphere of argon gas or the like.
• the foregoing impurities may cause the deterioration of performance of recording mediums, hard disks and semiconductor device elements, as well as cause the deterioration of performance of thin films as a result of generating splashes, abnormal discharges, particles and the like during the sputtering process.
• platinum is recovered by dissolving platinum-containing scraps in acid such as aqua regia to eliminate residue, thereafter causing the acid with platinum dissolved therein and an ammonium chloride solution to react so as to precipitate/recover the product as ammonium hexachloroplatinate, and additionally roasting the ammonium hexachloroplatinate.
• a magnetic thin film containing platinum as its main component of the constituent elements or as a part of the constituent elements often contains ruthenium also as a part of the constituent elements. Since ruthenium is a platinum group element, in addition to the properties being similar, there is also the problem of platinum and ruthenium being difficult to separate.
• Patent Document 1 discloses, upon precipitating platinum as an ammonium chloride salt and extracting platinum, technology of adjusting the pH of a chloride-containing aqueous solution which contains gold and platinum group metals and performing two-stage neutralization and filtering to separate tellurium.
• Patent Document 2 discloses technology of eliminating ruthenium as an impurity by heating ammonium hexachloroplatinate or platinum to a high temperature in an oxygen gas airflow.
• Patent Document 3 discloses, upon separating ruthenium from a solution containing a platinum group via oxidation/distillation, technology of adjusting the pH of the solution, and thereafter using sodium bromate to transform ruthenium into ruthenium tetroxide and performing oxidation/distillation thereto so as to separate/recover ruthenium.
• Patent Document 4 discloses, upon forming ammonium hexachloroplatinate, a method of producing a platinum powder by using a dispersion stabilization agent in an ammonium chloride solution to obtain fine ammonium hexachloroplatinate, and burning the ammonium hexachloroplatinate at a low temperature.
• Patent Document 5 discloses a high purity platinum recovery method including the steps of dissolving platinum-containing scraps in acid, thereafter causing the product to react with an ammonium chloride solution, precipitating/recovering the product as ammonium hexachloroplatinate, and roasting the ammonium hexachloroplatinate to obtain a platinum sponge.
• Patent Document 6 describes technology of dissolving platinum-containing scraps in acid, thereafter causing the product to react with an ammonium chloride solution, precipitating/recovering the product as ammonium hexachloroplatinate, and thereafter recovering the platinum remaining in the liquid by using ion-exchange resin and activated carbon.
• the present invention provides a method of enabling recovery of high purity platinum as a result of efficiently eliminating cobalt, chromium, copper, iron, nickel, silicon and the like which become included in a platinum alloy used for sputtering particularly in a target scrap (spent target) containing platinum used for forming a magnetic thin film or in scraps such as mill ends, sawdust, and surface grinding scraps generated in the production process of such a target.
• a target scrap spent target
• recovery of high purity platinum which can be reused in platinum and a platinum-containing target can be achieved at a high yield and at a low cost.
• the present invention provides:
• a high purity platinum recovery method including the steps of dissolving a platinum alloy containing ruthenium in aqua regia and eliminating residue, thereafter causing acid with platinum dissolved therein and an ammonium chloride solution to react so as to deposit chloroplatinic ammonium salt, and reducing the chloroplatinic ammonium salt to obtain a platinum sponge, wherein the acid with platinum dissolved therein and the ammonium chloride solution are caused to react at a temperature of 40° C.
• the present invention additionally provides:
• the present invention yields a superior effect of being able to eliminate, with a relatively simple process, cobalt, chromium, copper, iron, nickel, silicon and the like which become included in a platinum-containing target scrap (spent target) for use in sputtering or in scraps such as mill ends, sawdust, and surface grinding scraps generated during the production process of such a target, and efficiently separate, from platinum, ruthenium as a platinum group element contained in the magnetic material target.
• the present invention foremost dissolves, in acid, scraps containing platinum and ruthenium and additionally containing cobalt, chromium, copper, iron, nickel, silicon and the like as impurity elements.
• Aqua regia is used as the acid for dissolving the scraps. While other acids can also be used for dissolving the scraps, for instance, if hydrochloric acid is used for dissolving the scraps, the dissolution will be incomplete. In addition, hydrogen will be generated; which is a possibility of hydrogen explosion.
• caustic alkali such as sodium hydroxide (NaOH) is added to the solution containing platinum, the pH is adjusted to be 3 to 6 to achieve neutralization, cobalt, copper and the like are precipitated as hydroxide, and these are filtered and eliminated.
• NaOH sodium hydroxide
• the solution contains palladium
• hydroxides of cobalt, copper and the like are precipitated and eliminated, and palladium is extracted via solvent extraction.
• the extracted palladium is subject to back extraction with ammonia, and the palladium-containing fluid is reduced with a reducing agent such as hydrazine so as to recover a high purity palladium sponge.
• the acid with platinum dissolved therein and an ammonium chloride solution are caused to react so as to precipitate ammonium hexachloroplatinate ((NH 4 ) 2 PtCl 6 ) crystals.
• ammonium hexachloroplatinate (NH 4 ) 2 PtCl 6 ) crystals.
• aqua regia that dissolved the platinum is added to the ammonium chloride solution.
• ruthenium is a platinum group element as described above, it cannot be separated from platinum easily.
• the present invention provides technology for easily and efficiently separating ruthenium from platinum.
• the high purity platinum recovery method of the present invention includes the steps of dissolving a platinum alloy containing ruthenium in aqua regia and eliminating residue, thereafter causing acid with platinum dissolved therein and an ammonium chloride solution to react so as to deposit chloroplatinic ammonium salt, and reducing the chloroplatinic ammonium salt to obtain a platinum sponge, wherein the acid with platinum dissolved therein and the ammonium chloride solution are caused to react at a temperature of 40° C. or higher.
• the temperature is preferably 100° C. or less where the solution does not evaporate.
• the platinum concentration of the liquid resulting from dissolving the platinum alloy containing ruthenium in the aqua regia is 15 g/L or more. This is because the solubility of the platinum salt will increase and the platinum recovery rate from scraps will deteriorate (to less than 99%), if the platinum concentration is reduced to less than 15 g/L.
• the platinum content rate in the scraps is usually 30 wt % or higher, and, when the scraps are dissolved in aqua regia under normal conditions, the platinum concentration in the solution becomes a concentration that becomes considerably greater than 15 g/L; the concentration will not fall below 15 g/L unless the product is diluted in a large volume of water.
• the ruthenium concentration of the liquid resulting from dissolving the platinum alloy containing ruthenium in the aqua regia is 6 g/L or less.
• the high purity platinum recovery method of the present invention can cause the ruthenium content as an impurity in the platinum sponge, which is obtained by roasting the chloroplatinic ammonium salt, to be 2% or less, and even 1% or less.
• the present invention can achieve a platinum recovery rate of 99% or higher from scraps of a magnetic material target containing a platinum alloy containing ruthenium. The present invention provides this kind of high purity platinum recovery method.
• Example 1 scraps of a magnetic material target containing platinum, cobalt, chromium, and ruthenium were dissolved in aqua regia and residue was eliminated, and the resulting product was diluted in water to obtain an aqua regia solution having a platinum concentration of 30 g/L and a ruthenium concentration of 5 g/L.
• the aqua regia solution and ammonium chloride were caused to react at 45° C. to obtain chloroplatinic ammonium salt ((NH 4 ) 2 PtCl 6 ) crystals. Subsequently, the crystals were roasted at 800° C. to obtain a platinum sponge, and the platinum recovery rate from the aqua regia solution and the ruthenium content rate as an impurity were measured. The results are shown in Table 1.
• the platinum recovery rate reached 99.5%, and the ruthenium content rate in the platinum salt decreased to 0.5 wt %.
• This ruthenium content was sufficiently decreased to use the recycled platinum as a target.
• similar platinum purity and ruthenium reduction could be achieved as long as the reaction temperature of the aqua regia solution and ammonium chloride was 40° C. or higher. Note that there is no particular limitation to the roast temperature and may be adjusted as needed, and the temperature capable of normally obtaining a platinum sponge may be arbitrarily selected; hereinafter the same.
• Example 2 scraps of a magnetic material target containing platinum, cobalt, chromium, and ruthenium were dissolved in aqua regia and residue was eliminated, and the resulting product was diluted in water to obtain an aqua regia solution having a platinum concentration of 18 g/L and a ruthenium concentration of 3 g/L.
• the aqua regia solution and ammonium chloride were caused to react at 90° C. to deposit chloroplatinic ammonium salt, and the deposited chloroplatinic ammonium salt was roasted at 800° C. to obtain a platinum sponge, and the platinum recovery rate from the aqua regia solution and the ruthenium content rate as an impurity were measured.
• the results are shown in Table 1.
• the platinum recovery rate reached 99.3%, and the ruthenium content rate in the platinum salt decreased to 0.3 wt %. This ruthenium content was sufficiently decreased to use the recycled platinum as a target.
• Example 3 scraps of a magnetic material target containing platinum, cobalt, chromium, and ruthenium were dissolved in aqua regia and residue was eliminated, and the resulting product was diluted in water to obtain an aqua regia solution having a platinum concentration of 16 g/L and a ruthenium concentration of 5 g/L.
• the aqua regia solution and ammonium chloride were caused to react at 50° C. to deposit chloroplatinic ammonium salt, and the deposited chloroplatinic ammonium salt was roasted at 800° C. to obtain a platinum sponge, and the platinum recovery rate from the aqua regia solution and the ruthenium content rate as an impurity were measured.
• the results are shown in Table 1.
• the platinum recovery rate reached 99.2%, and the ruthenium content rate in the platinum salt decreased to 1.7 wt %.
• This ruthenium content was sufficiently decreased to use the recycled platinum as a target.
• similar platinum purity and ruthenium reduction could be achieved so as long as the reaction temperature of the aqua regia solution and ammonium chloride was 40° C. or higher.
• Scraps of a magnetic material target containing platinum, cobalt, chromium, and ruthenium were dissolved in aqua regia and residue was eliminated, and the resulting product was diluted in water to obtain an aqua regia solution having a platinum concentration of 12 g/L and a ruthenium concentration of 2 g/L.
• the platinum concentration was low and lower than the 15 g/L of the present invention.
• the aqua regia solution and ammonium chloride were caused to react at 70° C. to deposit chloroplatinic ammonium salt, and the deposited chloroplatinic ammonium salt was roasted at 800° C. to obtain a platinum sponge, and the platinum recovery rate from the aqua regia solution and the ruthenium content rate as an impurity were measured.
• the aqua regia solution and ammonium chloride were caused to react at 70° C. to deposit chloroplatinic ammonium salt, and the deposited chloroplatinic ammonium salt was roasted at 800° C. to obtain a platinum sponge, and the platinum recovery rate from the aqua regia solution and the ruthenium content rate as an impurity were measured.
• Scraps of a magnetic material target containing platinum, cobalt, chromium, and ruthenium were dissolved in aqua regia and residue was eliminated, and the resulting product was diluted in water to obtain an aqua regia solution having a platinum concentration of 30 g/L and a ruthenium concentration of 5 g/L.
• the aqua regia solution and ammonium chloride were caused to react at 30° C. to deposit chloroplatinic ammonium salt, and the deposited chloroplatinic ammonium salt was roasted at 800° C. to obtain a platinum sponge, and the platinum recovery rate from the aqua regia solution and the ruthenium content rate as an impurity were measured.
• the temperature for causing the aqua regia solution and ammonium chloride to react did not satisfy 40° C. or higher, which is a condition of the present invention.
• the present invention yields a superior effect of being able to eliminate, with a relatively simple process, cobalt, chromium, copper, iron, nickel, silicon and the like which become included in scraps such as mill ends, sawdust, and surface grinding scraps generated during the production process of a platinum and platinum-containing target for use in sputtering, and recover, at a high yield, high purity platinum that can be reused as platinum or as a target containing platinum.
• the present invention also yields an effect of being able to reduce ruthenium, which is said to be difficult to separate from platinum, using a relatively simple method, the present invention can provide a method that is useful for recovering high purity platinum at a low cost and at a high yield.

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• 2011
  • 2011-06-21 MY MYPI2012005486A patent/MY160898A/en unknown
  • 2011-06-21 SG SG2012093555A patent/SG186401A1/en unknown
  • 2011-06-21 CN CN201180030294.7A patent/CN102959103B/zh not_active Expired - Fee Related
  • 2011-06-21 WO PCT/JP2011/064096 patent/WO2012029379A1/ja not_active Ceased
  • 2011-06-21 JP JP2011539574A patent/JP5399510B2/ja not_active Expired - Fee Related
  • 2011-06-21 US US13/813,354 patent/US20130139648A1/en not_active Abandoned

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