At present, in the production of tungsten powder, most of the tungstate thermal decomposition of blue tungsten oxide, blue tungsten oxide hydrogen reduction process to tungsten powder. The conventional process generally uses ammonium paratungstate as the initial raw material, but it is difficult to obtain ultrafine tungsten powder with average particle size of less than 1 micron by hydrogen reduction.

China has abundant tungsten resources, and reserves and concentrate output rank first in the world. However, the tungsten concentrates produced in several important tungsten mines belong to high calcium wolframite concentrates. At the same time, a considerable amount of refractory tungsten slime containing calcium is produced in each tungsten concentrator. There is no suitable treatment method at present.

Carboxylic esters are a kind of basic organic chemical raw materials. They are widely used in perfumes, flavors, plasticizers, solvents, resins, coatings, cosmetics, pharmaceuticals, surfactants and organic synthetic intermediates. They have broad market demand at home and abroad.

Hydrogen is a kind of clean energy with high calorific value, friendly environment and convenient transportation. The combustion product is water, which does not cause any harm to the environment. The earth is rich in water, easy to get and cheap. Sunlight is an ideal way to convert solar energy into chemical energy.

Tungstate nanomaterials have been widely used in many fields, such as optics, electricity, magnetism, conductor/superconductor, catalysis, biology and so on. The synthesis methods of transition metal tungstate materials mainly include sol-gel method, copolymer-assisted synthesis method, inverted micelle soft template method, wet chemical method and solution synthesis method.

Through some domestic studies about the damage mode of tungsten carbide mining button, the analyses of mining button and shock resistance experiments, there are some reasons for the invalidation which are listed as below: