Preparing Tungsten Powder from Violet Tungsten Oxide

Violet tungsten powder with unique needle structure and high chemical activity is an important raw material for the preparation of ultrafine tungsten powder. The preparation process with violet tungsten oxide is usually fast.

Tungsten powder is a significant material to make hard alloy, pure tungsten alloy and tungsten alloy products. Generally, it can be successfully prepared by hydrogen reduction method, using oxides of tungsten as raw materials. Before 1950s, tungsten powder was mainly prepared from tungstic acid and yellow tungsten oxide (WO₃) at home and abroad. From 1960s to 1970s, blue tungsten oxide (WO_2.90) was widely used to prepare tungsten powder in the United States, France, Netherlands and many other countries. At the end of 1980s and the beginning of 1990s, blue tungsten has completely replaced yellow tungsten oxide (WO₃) as the raw material for the preparation of tungsten powder. The quality of hard alloy products and economic benefits are two factors affecting the selection of raw materials for the preparation of tungsten powder.

Violet tungsten oxide is a product developed by Zhuzhou Cemented Carbide Group Co., Ltd. in 1990s. As it has good performance and low cost, it has become an ideal ram material for the production of ultrafine tungsten powder, together with blue tungsten oxide (WO_2.90).

Violet tungsten oxide is composed of strongly deformed octahedron. This kind of deformation make it has high chemical activity. The grains with need structure distribute randomly, which leads to the large gap of violet tungsten oxide, accelerating the permeation of hydrogen and the release of water vapor. The hydrogen reduction happens not only from the active center on the surface of violet tungsten oxide, but also inside violet tungsten oxide. Therefore, the preparation process of tungsten powder from violet tungsten oxide is fast. Usually, the obtained tungsten powder is even and ultrafine. Violet tungsten oxide is suitable for the production of tungsten powder and has broad application prospects in the processing of hard alloy products.

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