In the field of microwave electric vacuum device, the preparation of tungsten sponge with uniform pore size is the key to achieve uniform emission of tantalum tungsten cathode current. The tungsten sponge is the main carrier of the impregnated ruthenium tungsten cathode and is made by powder metallurgy. The pores in the sponge are used to store the emitting material and at the same time serve as a transport channel for the emitting material.

Currently, there are three industrial methods for purifying the Ammonium paratungstate (APT) solution from the sodium tungstate solution: chemical method, ion exchange method, and solvent extraction method. Wherein the classical chemical method consumes large energy and has low production, it has been less frequently used. Both ion exchange and solvent extraction have their own advantages and disadvantages.

Molybdenum is a strictly controlled impurity element in tungsten products. China's national standard GB10116-88 stipulates that molybdenum is not more than 20ppm in the 0 grade ammonium paratungstate. At the same time, tungsten is also a strictly controlled impurity element in molybdenum products. The national standard GB/T3480-2007 stipulates that MSA-0 grade molybdenum acid is not more than 150ppm in the product.

Scheelite is the main raw material for tungsten smelting. The general method of smelting scheelite is pure alkali smelting. This method has a large amount of alkali and needs to be decomposed under the conditions of high temperature and high pressure. The pollutant discharge is serious, which is not conducive to the economic development of our country.

The base reserves of wolframite account for 70.4% of the China's tungsten base reserves. In general, the quartz or silicate minerals are more easily selected in the vein rocks. The scheelite calcite and the scheelite fluorite (barite) ores are more difficult to separate because of the floatability of the minerals, there are still a large number of fine particles in the scheelite coarse concentrate. Gangue minerals such as calcite and fluorite are more similar to scheelite than those of collectors, they are difficult to separate.

The balance of aircraft load is the key link to ensure flight safety. Choosing and optimizing the balance device of aircraft's weight can make full use of the aircraft's payload and improve the efficiency of air transportation. High density tungsten alloy is small in size and easy to install and connect.

Heteropoly acid is a kind of acid, which has been acidified, condensed and dehydrated by two or more than two kinds of inorganic oxyacid ions. It is a new type of acid catalyst and oxidation-reduction catalyst, which has been widely studied and developed in recent years.

Tungsten oxide limonite is a multi metal component, containing tungsten oxide 0.3%-0.6%, iron 26%-31% and other elements such as silicon, aluminum and calcium. It is difficult to be separated and enriched by traditional ore dressing method, it can not be enriched in high grade like other tungsten ores. At present, the ore can only be used as the raw material for cement production. A large amount of precious metal tungsten is irreversibly disappearing in building materials.

Pressure leaching and water leaching are two mature methods for industrial leaching of tungsten from tungsten ore. The leachate obtained by the above two leaching methods is a mixed solution of sodium tungstate and sodium carbonate, which usually contains a small amount of impurities such as P, As, Si, etc. and this solution is a soda leaching solution containing a tungsten material.

Tungsten is a very important non-ferrous metal. It has a series of properties such as high density and high strength. It is commonly used in counterweight materials, shielding materials, military firing materials, semiconductor materials, etc.