In January 1957, Nippon Mining Co., Ltd. jointly established Toyo Zirconium Co., Ltd. with the Ishizuka ResearchI nstitute Ltd.Toyo produced reactor grade zirconium sponge and exported it to U.S.AEC and Europe until 1961. This sponge was evaluated at Metallurgical Center of Bureau of Mines in Albany and at Westinghouse Electric Corp. The results of evaluation showed that the sponge was of good quality. Especially, contents of nitrogen, oxygen, magnesium and chlorine were lower than that of U.S. sponge. Quantity of zirconium sponge produced by Toyo amounted approximately to 260 tons.In 1964, Nippon Mining took over engineers and equipments of Toyo in order to keep production technology for future business, and resumed the production and the marketing of reactor grade zirconium sponge in order to meet the domestic demand. At the same time the company also started research on new process for hafnium separation by the tertiary amine solvent extraction method.In Nov. 1978, the company was successful in producing hafnium-free zirconium oxide by the amine solvent extraction method, and started the commercial production by this new process from the middle of 1979. As compared with the conventional solvent extraction method, it has many advantages as follows;(1) very high separation factor of zirconium from hafnium, (2) very low hafnium content in refined zirconium oxide and (3) waste water is free from pollution.