Sodium doped ammonium paratungstate may be used to prepare coarse grain size tungsten trioxide (WO3), and the content of sodium (Na) may affect the particle size of tungsten (W) powder prepared by WO3.
APT with high sodium content may be calcined to produce high sodium content of WO3 powder - an upstream raw material for preparing coarse grain size tungsten powder, which is a raw material for tungsten carbide with coarse grain size. And tungsten carbide with coarse grain size is widely applied in mining tools, stamping dies, oil drilling and other fields.
Preparation of Sodium Doped Ammonium Paratungstate
At present, the common producing method of sodium doped APT is mechanical blending method, in which a certain amount of sodium salt is added in APT or WO3, and then mechanical mixing is performed with mixing equipment.
In addition, there is invention that indicates a new method for preparing APT containing with high sodium, the steps are as below:
1. Adopt ammonium tungstate solution as raw material. Ammonium tungstate solution is prepared by decomposing tungsten concentrate with alkali solution and then going on with ion exchange, molybdenum removal and other process.
2. Add a certain amount of sodium salt according to the requirement of the subsequent product before evaporation crystallization to obtain sodium doped ammonium tungstate solution;
3. Carry out evaporation crystallization until the end point of crystallization, stopping heating and cooling the solution to 20~50°C, filtering and draining the feed liquid to generate wet APT, then dry them to get dried high sodium doped ammonium paratungstate.
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