HISTORY OF MITSUBISHI

Akita Smelter & Refinery

Zinc products responding to the expectations of the region

Akita Smelter & Refinery was built in Akita City in 1953 by Mitsubishi Metal Mining Co., Ltd., the predecessor of Mitsubishi Materials Corporation. The company worked to meet the growing demand for zinc needed for pos-twar restoration. The high quality of its electrolytic zinc production led to the company’s rapid growth. However, the increasing cost of electricity and stagnant metal prices in the 1980s - 1990s forced the company to discontinue electrolytic zinc production in 1996. Currently, Mitsubishi Materials Group companies uses the vast site for a wide range of business activities. Japan New Metals Co., Ltd. recycles tungsten; a product used in the manufacture of cemented carbide tools, this means that the site plays an important role for Mitsubishi Materials.

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New smelter & refinery brings hope to post-war restoration

Zinc has been alloyed with copper to make brass since before the Common Era. Smelting was developed in the 15th century, but the technique was not common in Japan until the 20th century. Demand began to grow as Japanese manufacturers started producing zinc-coated steel and galvanized anti-corrosive materials. Mitsubishi Mining Co., Ltd. began smelting zinc at Naoshima Smelter & Refinery and Hosokura Mining Plant in 1934. Naoshima stopped production when the war ended, but Hosokura Plant continued producing some 600 tons per month. Along with post-war restoration, the Korean War (1950-1953) spurred demand for zinc and production at the Ikuno and Akenobe plants surged. Yokkaichi Plant Construction Headquarters was set up to lead the effort to establish a new zinc refinery. Its efforts to purchase land in Yokkaichi were unsuccessful, and the company turned its eyes to Akita. Approximately 35% of the electricity required for zinc refining could be procured at low cost from the Osarizawa Mine’s Komatagawa Power Station and the sulfuric acid produced as a byproduct of zinc refining could be used by Tohoku Hiryo Co., Ltd., the predecessor of Mitsubishi Materials Electronic Chemicals Co., Ltd. These advantages also made Akita a desirable site for the new refinery.
Riding on a wave of increasing demand during Japan’s period of rapid economic growth, and with the support of Michiyuki Hani, President of Mitsubishi Metal Mining Co., Ltd Akita Smelter & Refinery started operation in November 1953 with the most up-to-date fluidized roasters from the United States. The fluidized roasters were tested by Mining Research Institute engineer and former Mitsubishi Materials Chairman Ken Nagano. Applying this technique to cement production at the Higashiya Plant ten years later led to Japan’s first successful SP kiln operation. The start of operations was the result of the efforts exerted by the people who moved to Akita from Naoshima, Hosokura, and Osarizawa. They hoped that this new refinery would serve as a symbol of post-war restoration. Starting with the delivery of 560 tons of zinc, production steadily increased. In March 1973, electrolytic zinc production reached 8,000 tons per month, spurring the company to realize its vision to produce 10,000 tons per month as the world’s number one zinc refinery.

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Moving forward for Akita

The oil crisis in December 1973 caused the Japanese economy to languish at low levels; plus increasing electricity costs on top of stagnating metal prices forced the company into an economic slump. Despite employee efforts to save energy and streamline systems, together with cooperation between the work force and management to enhance business infrastructure, the prolonged slump and the sudden rise in the value of the Japanese yen around 1990 forced the company to discontinue zinc production in 1996. Following the cessation of operations, it demolished the plant and shifted to environmental operations. In response to a request from Akita City, the site was used by Mitsubishi Materials Group companies Mitsubishi Materials Electronic Chemicals Co., Ltd., Materials Eco-Refining Co., Ltd., Japan New Metals Co., Ltd., Diaplaza Co., Ltd., SUMCO Corporation and Japan Super Quartz (JSQ).

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Further expansion as a recycling plant for cemented carbide raw materials

One of the plants built at the site was the Japan New Metals Akita Plant. It manufactures tungsten carbide powder, a raw material used in Mitsubishi Materials cutting tools. The Akita Plant is engaged in the complete production of tungsten carbide powder. In order to provide a stable supply of high quality products, regardless of the changing availability of raw materials, scrap materials containing tungsten, such as cemented carbide tools, are collected for recycling. Approximately 99% of the tungsten contained in the scrap is successfully recycled, it is this contribution that goes significantly towards the ability of the achievement of goals, namely the realization of a recycling-based society. Utilizing know-how accumulated over a long period of time, water discharged from the plant at the existing Akita Smelter & Refinery building is also treated. The recycling facility will be expanded with the hope of further contributions in the vitalization of the region.

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