Ammonium paratungstate (APT), is a prevalent starting material in the production of tungsten oxides, catalysts, tungsten alloys, electrochromic materials and so on. It is produced by crystallization from purified ammonium tungstate solutions in batch and continuous processes. Commonly, repeated crystallization is used as a method of improving the quality of the product.

Thermal decomposition of ammonium paratungstate (APT) in air has been investigated previously. The thermal decomposition of ammonium paratungstate (APT) in hydrogen (H2) now has been studied to investigate the decomposition process.

Chitosan (Chit) is a non-toxic derivative of chitin, namely the β-(1,4)- linked polysaccharide of D-glucosamine. Application of chitosan coatings on substrates by the dip coating technique was proved to be highly effective in corrosion prevention by producing thin layers with controlled characteristics. The transparency of chitosan coatings also constitutes an advantage as it does not change the appearance of the underlying substrate.

Low grade tungsten concentrate has such characteristics as a high content of calcium and impurities, and a low content of WO3. But it has a lower price than standard tungsten concentrate.