A clean non-toxic method for leaching of barium tungstate

Abstract

• A new method for leaching BaWO 4 with Na 2 SO 4 is proposed. • Thermodynamics proves that Na 2 SO 4 is an effective decompose agent. • The leaching rate of BaWO 4 can reach more than 99%. • The product is stable, eco-friendly and non-toxic BaSO 4 . • BaSO 4 can be used as a barium meal, which realizing zero waste. Barium tungstate is one of the important components of complex tungsten minerals and is also an intermediate product of hydrometallurgy. Since it is thermodynamically a very stable mineral, most of the current tungsten ore leaching methods are ineffective for its processing. In addition, due to the high toxicity of barium ions, special attention must be paid during the leaching process. In order to solve these problems, a new method of using sodium sulfate to decompose barium tungstate is proposed in this article. A thermodynamic analysis of the Ba 2+ -SO 4 2– -WO 4 2– -H 2 O system is carried out, in which the changes of various ions and precipitations at different pH values and different amounts of sodium sulfate were explored. Moreover, this method is theoretically proved to be feasible. Also, the leaching of barium tungstate experiment was carried out. Under optimum conditions with liquid/solid ratio 10:1 mL/g, reaction temperature 75 °C, and Na 2 SO 4 dosage 2.5–3.0 M times to BaWO 4 , the leaching rate of barium tungstate was >99%. This method has the advantages of simplicity, and high leaching rate, and it is cost effective with no barium toxicity.