Production of Tungsten at Japan New Metals Co., Ltd.

Abstract

Japan New Metals (JNM) was established in 1963, as a joint venture between Mitsubishi Materials and Awamura Mining, and has consistently produced tungsten, tungsten carbide and molybdenum powder from raw materials. Based on the nonferrous manufacturing technologies, we have produced high purity tungsten powder, heteropolyacids and several non-oxide ceramics powders. These are used for electronics devises, hard components and chemicals. In order to avoid the risk related to the supply of tungsten raw materials greatly dependent on China, JNM started a recycling business since 2002. Tungsten is recovered from cemented carbide scraps by the chemical process in the Akita plant.

Recovery and Recycling of Tungsten by Alkaline Leaching of Scrap and Charged Amino Group Assisted Precipitation

“…Alkaline leaching is then performed by dissolving this powder in an aqueous sodium hydroxide solution with heating to obtain a sodium tungstate (Na 2 WO 4 ) solution. An aqueous solution of ammonium tungstate is then obtained by precipitation using calcium chloride − or with an IE resin. , Finally, crystallization is used to obtain the intermediate ammonium paratungstate (APT, (NH 4 ) 10 (H 2 W 12 O 42 )·4H 2 O), which is transformed into tungsten carbide (WC) by thermal decomposition, reduction, and carburization. However, several problems remain with the precipitation and IE methods.…”