Removal of Chromium from Tungsten Waste

Recovering tungsten from tungsten waste has become an important measure to alleviate the shortage of raw materials. At present, the main ways to treat tungsten waste at home and abroad include mechanical crushing, electrolysis, alkali leaching, sodium roasting and zinc melting. Among them, sodium roasting technology is more mature and has wide applicability to waste tungsten materials. Therefore, this method is generally used to recycle tungsten carbide and various kinds of tungsten.

However, when the waste tungsten materials are calcined by sodium, the chromium will be oxidized, and it will enter the sodium tungstate solution when it is immersed in water. If it does not remove, it will lead to excessive chromium in tungsten products. Therefore, in order to obtain high quality tungsten products, the chromium in sodium tungstate solution must be removed.

At present, there are two main methods to remove chromium in sodium tungstate solution, each of which is deficient. Therefore, some scholars have proposed an improved method of recovering chromium from tungsten waste. The method is simple and effective, and the following steps are as follows:

1)Adding sodium sulfide precipitant to the crude sodium tungstate solution at 60~100 degrees centigrade, mixed treatment and filtration, and filtrate.

2)The filtrate is diluted and the anion exchange resin is used for adsorption.

3)The analytical agent was used to analyze the treated ion exchange column, and the ammonium tungstate solution was obtained.

4)Adding vulcanizing agent into ammonium tungstate solution for vulcanization and filtration treatment.

This method can achieve deep chromium removal, and the chromium removal rate is as high as 99% and above. At the same time, the removal process of chromium is combined with the removal process of subsequent molybdenum and other impurities, which greatly reduces the processing cost.

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