The low-grade tungsten concentrate produced by some tungsten concentrators can not meet the quality standard, the grade of WO3 is 5-30%, and the content of other impurities is also relatively high. It is mainly low-grade tungsten slime concentrate, tungsten tin medium ore, tungsten bearing iron sand and other refractory tungsten containing intermediate products. These products are sold in the form of sodium tungstate or scheelite, ammonium paratungstate, tungstic acid or tungsten trioxide through chemical beneficiation, and other useful components are comprehensively recovered from the leaching slag. The principle process of chemical beneficiation of low-grade tungsten mineral raw materials can be divided into material preparation, etc.

Ammonium paratungstate is the main raw material of tungsten industry. In a sense, it is a kind of purified tungsten concentrate, that is to say, the tungsten concentrate containing 60% bustard is purified to the intermediate products containing more than 88.5% tungsten oxide. In the final application products of tungsten, more than 70% are made of apt as the main raw material, while the rest are made of ferrotungsten, metatungsten, tungstic acid and waste tungsten.

With the rapid development of petroleum processing industry, the research and development of tungsten catalysts have been paid more and more attention. The active component of the catalyst, tungsten trioxide, is used as catalyst carrier, such as spherical silicon and aluminum oxide, which are made by leaching and pyrolysis of ammonium metatungstate. This is the direct driving force to promote the development of AMT in recent years. There are many processes for AMT production. Nanofiltration technology is a membrane separation technology separated from reverse osmosis technology, which is the continuation and development branch of ultra-low pressure reverse osmosis technology.

Tungsten trioxide is an important intermediate product in the process of tungsten extraction and gold treatment. It is the main raw material for the production of tungsten powder and tungsten related products. It is usually obtained by calcining ammonium paratungstate. The traditional production process of tungsten trioxide is to place the powdered ammonium paratungstate in a fixed furnace or a rotary furnace for calcination.