In tungsten smelting, ammonium chloride is recycled by evaporation crystallization, and ammonia nitrogen is recycled. The existing technology has low ammonia nitrogen recovery rate and high energy consumption of evaporation crystallization. Low recycling rate will cause poor working environment and waste water difficult to reach standard discharge. At the same time, the cost of evaporation recycling will also be higher and higher. Therefore, it is of great significance to develop a low energy recovery process to replace the current evaporation crystallization process.

In the mineral processing of tungsten minerals, single scheelite or wolframite recovery of tungsten concentrate is easy, but it is relatively difficult for tungsten ores in scheelite and wolframite ore bodies, mainly because the heavy magnetic separation is difficult to have good indicators in the recycling of fine-grained scheelite and wolframite, and therefore, Flotation is usually used in ore mixing.

Although tungsten is mainly derived from scheelite, there is a considerable proportion of wolframite. The largest tungsten ore reserves in China are 747 thousand T, and the ratio of wolframite and scheelite is 3:7. For such minerals, the sulphuric acid phosphoric acid mixed acid process is used directly, and the wolframite does not react completely, and all of them enter the leaching residue. In fact, it is difficult to decompose wolframite without sulphuric acid phosphoric acid mixed system. Even if other acids are used, the leaching reaction of wolframite is very slow.

In view of the shortage of raw tungsten resources, it is of great significance to reuse the waste hard alloy products and reuse it after recycling, and it is very important to make full use of the protection resources. In the United States, 35% of tungsten products are derived from recycled tungsten.