Tungsten and molybdenum have the same atomic radius and similar electronic structure, showing very similar chemical properties. Therefore, tungsten and molybdenum are often found in scheelite in nature. Tungsten and molybdenum separation is a technical problem in tungsten smelting process.

China is the world's largest tungsten producing country and the main producer of tin, millions of tons of tungsten tin symbiotic minerals are separated and enriched by the methods of general gravity separation and flotation or magnetic separation.

Tungsten and molybdenum are often co born in scheelite in nature. At present, China's high molybdenum resources account for about 50% of the total industrial reserves of tungsten, and the tungsten resources of molybdenum resources account for about 1/3. This kind of ore is difficult to choose. It is a major problem that troubles the tungsten smelting industry.

Tungsten slag is a waste residue produced by tungsten smelting enterprises in the process of pressure leaching. The pressure leaching process is based on a standard tungsten ore with a content of 65% of tungsten ore after ore dressing and adding additives. Under high temperature and high pressure alkaline conditions, after wet decomposition or fire decomposition, tungsten primary products such as sodium tungstate, calcium tungstate and ammonium para tungstate are obtained and the fineness is more than 100 orders of tungsten residue, each of which is produced. The output of a ton of WO₃ primary products and the discharge of about 0.8 tons of tungsten slag at the same time, with the exhaustion of resources, the recovery of tungsten slag is of great significance.