Leaching of Scheelite Concentrate for Tungsten Extraction

As a critical raw material, tungsten plays a broad role in machining, electronics, aerospace, and other high-tech industries. The extraction of tungsten from tungsten concentrates is a prerequisite for the production of high-purity products. Approximately 70% of China’s tungsten resources are in the form of scheelite. The extraction method of low-quality scheelite is crucial for the production application of the tungsten process as resources of high-quality wolframite are gradually being depleted. This article systematically reviews the processes and challenges faced in the hydrometallurgical process of scheelite concentrates and provides useful insights. Typical leaching processes for scheelite concentrate have shown excellent leaching efficiencies, with tungsten trioxide (WO₃) recoveries exceeding 90%. Alkaline leaching processes are promising, but temperature and pressure are crucial for this method. The sintering–leaching process is energy-consuming and costly. Meanwhile, leaching with hydrochloric acid (HCl) or sulfuric acid (H₂SO₄) often results in the formation of tungstic acid (H₂WO₄) on the mineral surface, which inhibits further leaching and leads to a low extraction rate. In contrast, the mixed-acid leaching method is more promising, with recovery close to 100%, a short process, and low-cost, and the acid leaching solution is recyclable.