Interaction of Tungsten-Containing Mineral Raw Materials with a Mixture of Ammonium Bifluoride and Sulfate

Abstract

The interaction of tungsten mineral raw materials with a mixture of NH₄HF₂ and (NH₄)₂SO₄ upon heating was studied. It was determined that, first, at temperatures up to 200°C, the incoming components are fluorinated to form complex and simple fluorides. A further increase in temperature is accompanied by the decomposition of ammonium sulfate to form NH₄HSO₄, which leads to the conversion of fluorides into sulfates and of the tungsten ammonium fluoride complex into tungstic acid H₂WO₄. It was shown that water leaching of the product of the decomposition of tungsten-containing mineral raw materials with a mixture of NH₄HF₂ and (NH₄)₂SO₄ makes it possible to extract tungsten from mineral raw materials in the form of the commercial product WO₃.