Method for extracting tungsten and molybdenum in high molybdenum scheelite

Abstract

The invention relates to a method for extracting tungsten and molybdenum in high molybdenum scheelite. The method comprises the following steps: employing mixed acid of sulfuric acid and phosphoric acid for leaching the high molybdenum scheelite; separating a leachate by employing a cooling crystallization method to obtain the primary phospho-tungstic acid crystal and dissolving in an acid solution for secondary cooling crystallization, the processes of performing ammonia dissolution, removing phosphate by an ammonium magnesium salt method, removing molybdenum by a selective precipitation method as well as evaporating and crystallizing to obtain the APT which accords with a national zero-grade standard; a mother liquor after the primary cooling crystallization is performed with the processes of extracting molybdenum, performing back extraction by ammonium salt, removing the impurities and adjusting acidity to obtain ammonium molybdate; and a raffinade containing spent acid and the mother liquor after secondary cooling crystallization are directly returned for leaching to realize the circulation of acid. The invention realize the extraction with high efficiency under normal pressure of tungsten, the leaching rate of tungsten and molybdenum reach more than 98.5%; the complete separation of tungsten and molybdenum can be effectively realized by using a refrigeration crystallization and extraction technology, subsequent operation processing burden is reduced, the leaching process is simple, and the acid consumption is less, recycleleaching of most acid can be realized, and the production cost and waste water discharge can be greatly reduced.

Description

technical field [0001] The invention belongs to the field of nonferrous metallurgy and relates to a new method for extracting tungsten and molybdenum from high-molybdenum scheelite. technical background [0002] my country is a country with a large amount of tungsten resources. Among the reserves of tungsten resources, black tungsten accounts for about 20%, scheelite accounts for about 70%, and scheelite accounts for about 10%. However, since the 1970s, with the gradual depletion of wolframite in my country, the situation of tungsten metallurgical industry resources has undergone major changes, mainly reflected in: 1) The objects of tungsten smelting and processing have gradually changed from traditional wolframite The transformation is dominated by refractory scheelite; 2) High-quality and high-grade tungsten resources are becoming less and less. In my country's scheelite reserves, more than 80% of the ore grade is less than 0.4%; 3) Existing scheelite resources are getting ...

AI Technical Summary

Problems solved by technology

Chinese patent 101565778B provides a preliminary separation of Mo / WO 3 The method with a mass ratio of 0.3~3, but because this method is to decompose the WO into the solution by adding a manganese salt precipitant 4 2- Re-enter the precipitation, that is, the process of artificial black tungsten, and then carry out alkali decomposition of the artificial black tungsten to recover tungsten, the treatment process is circuitous and lengthy

For the hydrochloric acid decomposition process, tungsten forms tungstic acid precipitation during the leaching process, and molybdenum enters the solution. Although tungsten and molybdenum can be initially separated, due to HCl’s strong corrosion on equipment, and the process uses strong acid and strong alkali alternately, the operating environment is harsh. Basically eliminated; and for soda pressure cooking and caustic soda pressure cooking process, although its treatment effect on minerals is ideal, but the amount of leaching agent required is large (3~6 times the theoretical amount), especially in the process of tungsten and molybdenum The separation process is complicated, the free alkali in the leaching solution is difficult to recycle, and the production cost is high

[0005] In summary, there are certain limitations in the existing processes for processing high-molybdenum scheelite

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