Preparation method of high-billet-strength tungsten powder

Abstract

The invention relates to a preparation method of high-pressure blank strength tungsten powder, and aims to further improve the dependence of a preparation method of tungsten powder in the prior art on specific raw materials and further improve the blank strength of the tungsten powder. According to the method, the specific reduction technology in the tungsten powder preparation process is improved, the hydrogen flow and the gas inlet and outlet flow ratio of the first reduction process, the second reduction process and the third reduction process in the hydrogen reduction process are controlled, the reduction temperature and time are further controlled, and therefore the tungsten powder with the higher pressure blank strength is prepared. The preparation method of the tungsten powder with the high compact strength can be suitable for various wide tungsten oxide raw materials such as yellow tungsten, blue tungsten and purple tungsten, the tungsten powder with the compact strength larger than or equal to 4.7 MPa can be stably prepared without adopting special tungsten oxide raw materials, and the application market prospect is very wide.

Description

technical field [0001] The invention belongs to the field of powder metallurgy, and in particular relates to a method for preparing tungsten powder with high compact strength. Background technique [0002] Tungsten is a non-ferrous metal and also an important strategic metal. Tungsten ore was called "heavy stone" in ancient times. The content of tungsten in the earth's crust is 0.001%. There are 20 kinds of tungsten-containing minerals that have been discovered. China is the largest tungsten reserve in the world. country. Tungsten has a high melting point, low vapor pressure, and low evaporation rate. The chemical properties of tungsten are very stable. It does not react with air and water at room temperature. When it is not heated, any concentration of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and aqua regia has no effect on tungsten. Tungsten has the advantages of high density, high melting point and boiling point, good high-temperature mechanical ...

AI Technical Summary

Problems solved by technology

Due to the closed calcination, the water vapor generated by the reaction is difficult to get rid of, which will lead to the agglomeration of the material, thus affecting the product quality

Therefore, the production of high-phase blue tungsten has disadvantages such as the material is easy to agglomerate and block the furnace, the production cost is high, and the composition control is unstable.

[0005] In order to improve the defects of high-phase blue tungsten raw materials, patent CN112846210A invented the use of transition-state violet tungsten as raw material, because the transition-state violet tungsten consists of most of the violet tungsten and a small part of WO 2 Composition, reducing gas is introduced in the production process, the water vapor produced by the reaction can be discharged in time, and the oxygen content is reduced. Although tungsten powder with high compact strength can be obtained after reduction in hydrogen atmosphere, it can be seen from the examples that the prepared tungsten powder The compact strength of tungsten powder can reach 4.6MPa at the maximum, the compact strength of tungsten powder needs to be further improved, and the quality of the product needs to be further improved

Moreover, this method is still limited by the special selection of raw materials, and the cost is relatively high.

In addition, although the patent CN112846211A uses tungsten oxide to be supplied to a tube furnace and reduced in a hydrogen atmosphere to prepare a high compact strength tungsten powder, it can be seen from the examples that the compact strength of the prepared tungsten powder can reach the maximum. 4.5MPa, the compact strength of tungsten powder needs to be further improved, and the quality of the product needs to be further improved

And it adopts the method of arranging the inlet pipe plug near the air inlet and the outlet pipe plug near the gas outlet in the tube furnace, which increases the production cost, and the existence of the air pipe plug will also affect the production efficiency and the quality of the product. quality

[0006] It can be seen that most of the current production processes or research on high-pressure tungsten powder are carried out around the selection of raw materials or the addition of other devices, which puts forward higher standards for the preparation process and equipment of tungsten powder, and at the same time The production of tungsten powder is limited, the production efficiency and production cost need to be further improved, the compact strength of tungsten powder needs to be further improved, and the quality of the product needs to be further improved

Moreover, judging from the currently published research, there is no systematic research on the improvement of the reduction process in the tungsten powder preparation process.