(10) Patent No.: US 6458183 B1

USOO6458183B1 (12) United States Patent (10) Patent No.: US 6,458,183 B1 Phillips et al. (45) Date of Patent: Oct. 1, 2002 (54) METHOD FOR PURIFYING RUTHENIUM FOREIGN PATENT DOCUMENTS AND RELATED PROCESSES JP 5-177137 * 7/1993 (75) Inventors: James E. Phillips, Somerville, NJ JP 10-273327 * 10/1999 (US); Len D. Spaulding, Newark, DE OTHER PUBLICATIONS (US) Translation of Japan 5-177137, Jul. 20, 1993.* Z. Naturforsch, A Method for the Preparation of Anhydrous (73) Assignee: Colonial Metals, Inc., Elkton, MD Ruthenium (VIII) Oxide, Journal of Science, 36b, 395 (US) (1981), no month. (*) Notice: Subject to any disclaimer, the term of this * cited by examiner patent is extended or adjusted under 35 Primary Examiner Steven Bos U.S.C. 154(b) by 0 days. (74) Attorney, Agent, or Firm- Pillsbury Winthrop, LLP (57) ABSTRACT (21) Appl. No.: 09/655,307 The present invention provides a method for purifying (22) Filed: Sep. 5, 2000 ruthenium Sources to obtain high purity ruthenium metal without the need for high temperature processing, expensive Related U.S. Application Data reagents, complex Series of wet processes, or expensive (60) Provisional application No. 60/152,342, filed on Sep. 7, equipment. According to the present invention, a gas Stream 1999. including OZone (O) is brought into contact with a ruthe (51) Int. Cl. ................................................ C01G 55/00 nium Source, Such as a commercial ruthenium metal Sponge, (52) U.S. Cl. ............................................ 75/631; 75/710 in one or more reaction vessels. The OZone reacts with the (58) Field of Search .......................... 75/363, 369, 631, ruthenium present in the ruthenium Source to form ruthe 75/710 nium tetraoxide (RuO), a compound that is a gas at the reaction conditions. The ruthenium tetraoxide, along with (56) References Cited unreacted OZone and the remainder of the gas Stream is then U.S. PATENT DOCUMENTS fed into a collection vessel where a major portion of the gaseous ruthenium tetraoxide is thermally reduced to form 4,132,569 A 1/1979 DePablo et al. ruthenium dioxide (RuO) deposits within the collection 4,642,134 A 2/1987 Van Antwerp et al. vessel. The deposited ruthenium dioxide is then reduced, 4,752,412 A 6/1988 Van Antwerp et al. preferably with hydrogen, to produce highly pure ruthenium 5.248,496 A 9/1993 Schuster et al. metal that is, in turn removed from the collection vessel. 6,036,741 A 3/2000 Shindo et al. 6.284,013 B1 * 9/2001 Shindo et al. 18 Claims, 3 Drawing Sheets U.S. Patent Oct. 1, 2002 Sheet 1 of 3 US 6,458,183 B1 Ozone Heated Collection Vessel GeneratOr 4 1 First Second Reaction Reaction Fig. 1 Vessel Vessel 2 3 Nitrogen Hydrogen Exhaust Source Source 6 5 Ozone Heated Collection Vessel Generator 4. 1 First Second Reaction Reaction Vessel Vessel Fig. 2 2 3 U.S. Patent Oct. 1, 2002 Sheet 2 of 3 US 6,458,183 B1 Nitrogen Hydrogen Exhaust Source Source 6 5 Ozone Heated Collection Vessel Generator 4 1. First Reaction Vessel Fig. 3 2 151 O 171 8 OO Fig. 4a t Fig. 4-b U.S. Patent Oct. 1, 2002 Sheet 3 of 3 US 6,458,183 B1 Form Ru Elayer on Wafer 101 102 103 105 Fig. 5 US 6,458,183 B1 1 2 METHOD FOR PURIFYING RUTHENIUM dium. The ruthenium and osmium were then normally AND RELATED PROCESSES purified by a collective chlorine distillation, followed by a nitric acid distillation for osmium. The rhodium is treated for This applin claims benefit of provisional application the removal of impurities Such as palladium, tellurium and 60/152,342 filed Sep. 7, 1999. other base metals that are also rendered soluble by the KHSO fusion. The iridium has to be separated from large BACKGROUND OF THE INVENTION quantities of lead and other impurities present in the con 1. Field of the Invention centrate which have been rendered soluble by the Sodium The present invention relates to a method and apparatus peroxide (NaO) fusion. AS can be appreciated, this method for the production of highly pure ruthenium and ruthenium used both large quantities of concentrates and correspond dioxide. ingly large quantities of costly reagents. Further, the impurities, in particular tellurium were Sometimes difficult 2. Description of the Related Art and General Background to remove. A member of the platinum group, ruthenium occurs The improvement outlined in the 337 patent was naturally with other members of the platinum group in ores 15 found in Russia's Ural mountains, North and South intended to provide a process for the treatment of a by-metal America, and particularly, South Africa. It is also found concentrate for 1) to remove troublesome impurities Such as along with other platinum metals in Small but commercial Te, AS, Bi, Ag, and Pb; 2) the removal of osmium; and 3) to quantities in both the pentlandite of the Sudbury, Ontario, reduce the bulk of the by-metals being refmed thereby nickel-mining region, and in the pyroximite deposits of providing Saving in both reagents and equipment. This was South Africa. Commercially, ruthenium may be isolated accomplished by treating a concentrate of by-metals by from the other platinum metals through Several complex heating to between about 1100° C. and 1500° C. in an chemical processes, the final Stage of which generally oxygen-containing gaseous Stream for a period of time includes the hydrogen reduction of ammonium ruthenium (examples include times of 20 hours) Sufficient to ensure chloride or nitroSylruthenium chloride, to produce ruthe both quantitative removal of one or more of lead, arsenic, 25 silver, bismuth and/or tellurium and the oxidation of nium metal powder. ruthenium, rhodium and iridium to their oxides. According Ruthenium, a hard, white metal, is one of the most to the patent, the oxygen-containing gaseous Stream could effective hardeners for platinum and palladium and is typi be air and the exhaust gas could be Scrubbed with a liquid cally alloyed with these metals to produce electrical contacts to recover osmium. The 337 patent also provided for the for Severe wear resistance. There have also been reports that Separation of ruthenium from the other platinum group a ruthenium alloy, Specifically a ruthenium-molybdenum metals by fusing the ignited by-metal concentrate with alloy, exhibits Superconductivity at 10.6 K. It has also been potassium hydroxide and leaching the melt with water to reported that the corrosion resistance of titanium can be dissolve ruthenium complexes formed during the fusion improved over 100 times by adding as little as 0.1% ruthe process. AS described in the 337 patent, a by-metal con nium. Ruthenium is also a versatile catalyst and is frequently 35 centrate was heated to about 1300 C. for 20 hours in a used in petrochemical and other industrial processes to Stream of air, a process by which osmium, together with remove HS. lead, arsenic, Silver, bismuth and tellurium, were quantita One method for extracting ruthenium is disclosed in U.S. tively removed from the concentrate while less than 10% of Pat. No. 3,997,337 (“the 337 patent”). The 337 patent the ruthenium and only traces of the other platinum group included a discussion of both earlgier methods for the 40 metals were volatilized. The vapors were scrubbed with a Separation and purification of precious metals, including 10% NaOH solution to precipitate all the metals, with the ruthenium, from a concentrate of by-metals and the exception of ruthenium and osmium, as hydrous oxides improved method taught by the patent. The improvement (which settle to the bottom of the receiving vessel). The disclosed in the 337 patent for the separation and purifica ruthenium and OSmium oxides which are converted to tion of precious metals, including ruthenium, from a con 45 Soluble Sodium Salts according to the following reactions: centrate of by-metals comprised heating the concentrate to a temperature between 1100° C. and 1500 C., preferably at (a) about 1300 C., in a gaseous stream which comprises oxygen. This heating Step is continued for a period Sufficient (b) to ensure quantitative removal of one or more of lead, 50 The ruthenium was then precipitated from the alkali arsenic, Silver, bismuth and/or tellurium and the oxidation of Solution by the addition of ethanol to reduce the OXO-anion ruthenium, rhodium and iridium. The referenced by-metal RuO and precipitate the insoluble hydrous oxide concentrate is obtained as a by-product of the Separation of (reported as RuOnH2O but the applicants believe platinum, palladium, and gold from an ore or other mixed RuOnH2O may be more accurate). This precipitate is SOCC. 55 filtered off together with the sludge in the receiver which In the previous process, the by-metal concentrate was contains the other metals which have been volatized and is fused with potassium bisulphate (KHSO) to convert the recycled to the lead alloying Stage of the metal proceSS or to rhodium to the water-soluble sulphate, Rh(SO), which Some other convenient point if lead alloying is not utilized. can be removed by Washing. The remaining residue was then The OSmium remaining in Solution is then precipitated at Subjected to a Sodium peroxide (NaO2) fusion to convert 60 room temperature as a hydrous oxide (reported as the ruthenium and OSmium to water Soluble Sodium Salts of OsOnHO, but the applicants believe OsOnHO may be their oxo-anions (e.g. RuO and OsO2 respectively) and more accurate) by acidifying the solution with HCl to a pH to convert the iridium to an acid soluble hydrous oxide of 4.0. (probably IrOnH2O). The ruthenium and osmium were U.S.

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