Direct Reduction of Ammonium Metatungstate and Ammonium Paratungstate Producing Tungsten Powder 1/2

In modern tungsten industry, tungsten products are generated from tungsten powder, and tungsten powder with high purity and good quality will help in improving tungsten products’ properties. So, it supposed to be very important that how to make the tungsten powder with excellent properties, such as particle well developed, good uniformity and fluidity, and concentration of the particle size distribution. With the development and application of new products and materials in tungsten industry, the quality of tungsten powder supposed to be higher and higher. Tungsten powder with higher quality is required in preparing tube with large diameter and thin wall and large tungsten crucible ect. Usually strength higher than 2.5MPa will meet the requirement of pressing, transport and machining and improve the survival rate of products. However, at present, strength of tungsten powder is generally 1.0MPa, which is far less than the requirement. Therefore, the preparation of tungsten powder with good formability and high strength is the basis for preparing huge tungsten products with high properties.

In the process of production, the morphology and size distribution between tungsten powder and ammonium paratungstate (APT) are hereditary, that is, they are strong related. During the formation of tungsten powder, both morphology and particle distribution are important factors that affect strength.

A new method that directs reduction of ammonium paratungstate and ammonium metatungstate for production of tungsten powder was proposed. A certain proportion of ammonium tungstate (AMT) and ammonium paratungstate (APT) are mixed, direct reduction in reducing furnace, then get tungsten powder with high purity and strength; or deducted ammonium tungstate and ammonium metatungstate in different reducing furnace to obtain tungsten powder, then mixed according to a certain proportion. Tungsten powder strength reached 2.8~4.0Mpa in two ways above, and they can be widely used for preparing excellent properties of tungsten or tungsten carbide products.

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