How to Effectively Remove Sodium and Chlorine from Ammonium Paratungstate

With the development of the subsequent product process of tungsten, tungsten wire, tungsten powder, tungsten bars and other high-end hard alloy material of ammonium paratungstate rising, ammonium paratungstate zero grade existing national standard has been unable to meet the requirements of high-end hard alloy, not only the impurity and physical of ammonium paratungstate can put forward certain requirements, and part of the production of high-end products enterprises to individual impurity elements proposed particularly stringent requirements.

How to reduce the content of sodium and chloride in tungsten powder, it needs to do it from the upstream products of ammonium paratungstate, recent scholars have published a story about a high pure ammonium paratungstate preparation method of academic papers, in the paper mentioned how to effectively remove the sodium and chloride in ammonium paratungstate, the steps are as follows:

1.The ore blending and ball milling

After milling tungsten concentrate and adding quantitative water at the same time, the -325 mesh of grinding size is controlled more than 95%.

2.The alkali decomposition

Add a quantity of caustic soda, sodium nitrate and water slurry in grinding pulp, followed by alkali decomposition to obtain the crude sodium tungstate slurry; coarse sodium tungstate slurry by plate filter, get the sodium tungstate filtrate clarifying, and adding water to dilute sodium tungstate solution 16-22g/l;

3.The ion exchange

The prepared sodium dilute tungstate solution was pumped into the ion exchange column containing strong alkali anion exchange resin for adsorption operation, and then stopped after being adsorbed to saturation.

4.The removal of Mo

The peak pump sent to the analytical steps of removing molybdenum barrel, adding quantitative ammonium sulfide after adding copper sulfate, followed by CuMoS₄ precipitation; after removing the molybdenum, the peak fluid was filtered through the filter tank with filter cloth, and then entered the ion exchange column equipped with strong alkali anion exchange resin to remove impurities, and the high-purity ammonium tungstate solution was obtained.

5.Crystallization and drying

The step 4 high purity ammonium tungstate solution was concentrated and crystallized until the concentration of WO₃ concentration of 24g / l, to stop the concentration of crystallization; concentrated filtrate obtained by filtration and then washed with deionized water 2-3 times, high purity ammonium paratungstate is obtained by the drying treatment.

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