Thermal expansion and cold shrinkage of materials is a common phenomenon in nature, but some materials are contrary to this. The coefficient of thermal expansion is negative, that is, the volume decreases with the increase of temperature, which is called negative thermal expansion material (NTE) or thermal shrinkage material. ZrW₂O₈ is a recently discovered material with large isotropic negative thermal expansion in a wide temperature range (0.3k to 1050k). The simple cubic ZrW₂O₈ was first synthesized in 1959 and found to have NTE effect. At that time, it was known that its crystal was cubic structure, but the atomic position was not determined, and its unique NTE performance did not attract attention. Until 1996, the a w sight research group of Oregon State University reported the crystal structure type of the material in science, and the research on ZrW₂O₈ started. It's the beginning of attention.

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.

Zirconium tungstate has a formula of Zr(WO₄)₂ and a molecular weight of 586.9. It is a negative thermal expansion material with excellent performance. It has negative thermal expansion performance in the temperature range of 0.3-1050.0k.

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.