Carborundum Metals Corporation

In the United States, practically all zirconium metal is now being made by the Kroll process. This process was an adaptation to zirconium of a similar process for titanium developed by W. J. Kroll. The work of Kroll and metallurgists of the Albany, Oregon, station of the Bureau of Mines culminated in a plant to produce 135,000 kg zirconium/year at the station. A similar plant was operated by the Carborundum Metals Corporation, at Akron, New York. These have been superseded by the plant of the Teledyne Wah Chang Albany Company, at Albany, Oregon, with a capacity in 1978 of 3.4 million kg/year. 

A similar hexone-thiocyanate process has been operated in the U.S.A., firstly by the Northwest Electrodevelopment Laboratories at Albany since 1952 and the Carborundum Metals Corporation plant near Akron, New York, since 1953. They use packed and unpacked columns and the difficulties associated with polymerization of thiocyanic acid were alleviated by using a solvent consisting of 80 per cent hexone and 20 per cent butyl acetate instead of solely hexone. > The zirconium product is precipitated as the acid sulphate, phthalate or salicylate, and a certain additional degree of purification is obtained at this stage. A typical analysis of pure zirconium oxide after hexone-thiocyanate extraction and salicylate precipitation is as follows ... 

In the initial thiocyanate-complex liquid—liquid extraction process (42,43), the thiocyanate complexes of hafnium and zirconium were extracted with ether from a dilute sulfuric acid solution of zirconium and hafnium to obtain hafnium. This process was modified in 1949—1950 by an Oak Ridge team and is still used in the United States. A solution of thiocyanic acid in methji isobutji ketone (MIBK) is used to extract hafnium preferentially from a concentrated zirconium—hafnium oxide chloride solution which also contains thiocyanic acid. The separated metals are recovered by precipitation as basic zirconium sulfate and hydrous hafnium oxide, respectively, and calcined to the oxide (44,45). This process is used by Teledyne Wah Chang Albany Corporation and Western Zirconium Division of Westinghouse, and was used by Carborundum Metals Company, Reactive Metals Inc., AMAX Specialty Metals, Toyo Zirconium in Japan, and Pechiney Ugine Kuhlmann in France. 

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