The hydrogen reduction technique of purple tungsten oxide(WO2.72), the formation mechanism of tungsten powder particles and its hydrogen reduction process conditions are analyzed, it is found that WO2.72 is the most suitable raw material for the preparation of nano tungsten powder.
The nano tungsten powder is the fine tungsten powder with nanometer particle size, which is prepared by nanotechnology, test shows that the WO2.72 is most suitable raw material to prepare the tungsten powder.
Domestic nanotechnology is far less mature than oversea,currently tungsten producers are trying to overcome the difficulties that how to produce nanometer ultra-fine tungsten powder by optimizing the production process based on available equipment and technology. This article introduces that how to use APT material to calcine and prepare high quality purple tungsten oxide, optimize reduction technique parameters, determine the technology and technique of preparing tungsten powder, and analyze the technique parameters affecting the tungsten reduction.
The research shows that WO2.72 is the most suitable material for preparing fine and uniform tungsten powder. The ultrafine tungsten powder prepared is fine and uniform, and has good dispersibility, which is suitable for making ultrafine cemented carbide.
Some researchers have done the preparation test of WO2.72, analyze its hydrogen reduction process, the formation mechanism of tungsten powder particles and its hydrogen reduction technique conditions. It is concluded after complete analysis that it is necessary to reduce the reduction temperature, slow down the boat pushing speed, reduce the boat loading amount, increase the hydrogen flow rate, and dry hydrogen reduction so as to prepare the purple tungsten powder.
The tungsten nano-powder prepared by WO2.72 will unavoidably agglomerate. Once agglomerated, it will be difficult to make full use of the advantage and the property is easy to get worse. Therefore in practical application effective measures should be taken to remove the agglomerations such as adding surfactant or using air flow crushing classification to eliminate the agglomerations of tungsten nano-powder. In this experiment, the method of air crushing classification is used.
The advantages of the preparation from the test are as follows:
1.0 WO2.72 is the most suitable raw material for preparing nanometer tungsten powder for its large specific surface area, high activity, low oxygen index and good air permeability.
2.0 WO2.72 uses traditional hydrogen reduction technique, and high quality tungsten powder can be prepared by optimizing the reduction process parameters. This method has the advantages of short process, high stability and CO2 gas no emission from the atmosphere. It is an environmental protection production method.
