Tungsten Oxide

The thermal degradation method is a process for the preparation of ammonium metatungstate based on ammonium paratungstate (APT).  This method is also the mainstream process of preparing ammonium metatungstate (AMT). At present, the pyrolysis equipment used in China is mainly rotary calciner. At the same time, there are many kinds of patented pyrolysis equipment used in AMT abroad, and the plate type multiple hearth furnace is one of them. The plate type multiple furnace is composed of a multi-layer drying plate separated from each other, and the material is in continuous contact with the pyrolysis plate. It is characterized by the fact that the solid can be conveyed by low-speed air or low-speed steam to avoid excessive dust. The furnace has a wide range of particle size control, and even includes a very fine particle size, the machine's feed is completed by the bucket wheel, feeding position is in the top of the plate drye...

Violet Tungsten Oxide , abbreviated as VTO, is a kind of tungsten oxide, violet fine crystalline powder.  Violet tungsten is a kind of tungsten oxide product developed in China recent years. Its phase composition is WO 2.72  or W 18 O 49 . Because of its unique properties, it has more advantages than blue tungsten in the production of ultrafine tungsten powder. Violet Tungsten Oxide (VTO) powder has the largest pore volume, micropore volume minimum, narrow pore size distribution, the smallest fraction dimension and maximum average diameter, which is conducive to hydrogen production of ultrafine tungsten powder is the main raw material, producing ultrafine tungsten powder and nano tungsten powder. Chinese scholars proved that the key to the production of ultrafine tungsten powder is kind of raw material of oxide, compared with yellow tungsten and blue tungsten, violet tungsten has the following characteristics: 1. Strong chemical activity, reducin...

Purple tungsten oxide is a kind of tungsten oxide product developed in China in recent years. Its phase composition is WO 2.72  or W 18 O 49 . Because of its unique properties, purple tungsten oxide is the main raw material of ultrafine tungsten powder and nanometer tungsten powder.  The production of purple tungsten oxide is mainly made up of APT hydrogen reduction process. It is carried out in a multi tube furnace. There are two ways of flow direction of hydrogen in the furnace tube, one is that the direction of hydrogen flow is opposite to the direction in which the boat (material) is pushed in the furnace tube. This is the traditional method of hydrogen production by the medium and fine particle tungsten powder, which is called the reverse hydrogen reduction process. But later research found, such as changing the direction of hydrogen, the hydrogen flow direction and the boat forward in the same direction, can prevent spontaneous combustion of tung...

Electrical selection method is an important auxiliary way of ore processing, when tungsten ores  are under electrical selection, tungsten ores and cassiterite need to be separated.  With high voltage electrical selection machine, wolframite and scheelite can successfully separated,  sulfide ores and wolframite can successfully separated as well. Because wolframite and sulfide ores are with conductivity, scheelite and tin ores are not with conductivity.  The effect of electrical selection method is not only determined by the conductivity of tungsten, also by three major factors: temperature, structure, and surface states.  1. Temperature: For conductors, the conductivity decreases when temperature increases. For semiconductors like tungsten ores, as the temperature goes high, the bound charge is released by the heat energy, the free electron increases and the conductivity incr...