Synergetic Decomposition of Tungsten Molybdenum Ore by Parathion Mixed Acid System

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.

In order to clean and efficiently deal with complex mineral resources of complex tungsten and molybdenum, Central South University developed a "synergetic decomposition technology of  parathion mixed acid system". This technology is used to form heteropoly acid with phosphorus in acid environment. High efficiency decomposition.

No matter what the grade of tungsten and molybdenum in the mineral, the tungsten and molybdenum can be leached efficiently after the decomposition of the mixed acid system of phosphorus. The content of tungsten and molybdenum in the decomposed slag can be reduced to less than 0.5%. The decomposition technology uses a cheaper sulfuric acid and phosphoric acid as the leaching agent. It can completely replace the traditional sodium alkali decomposition process, and the decomposition efficiency is high. At the same time, it can eliminate the environmental problems caused by the discharge of soluble sodium salt. The synergistic decomposition technology of sulphuric acid mixed acid system includes the following steps:

In accordance with the molar ratio of tungsten and molybdenum in phosphotungstic acid / phosphotungstate solution from 1 to 2:1, adding 5 to 30% of hydrogen peroxide to phosphotungstic acid / phosphotungstate solution and stirring to make tungsten form peroxy tungstate acid.

The mixture was heated to 40~90°C until tungsten was precipitated in tungstate form. Tungsten tungstate was calcined further to produce tungsten trioxide or ammonium tungstate solution was dissolved with ammonia solution. Finally, ammonium para tungstate (APT) was prepared by evaporation crystallization.

The extractant was used to extract molybdenum from filtrate, and then the extract was returned to phosphotungstic acid / phosphotungstate solution.

Ammonium molybdate solution was obtained by stripping ammonia with an ammonia solution, four ammonium molybdate was obtained by acid precipitation.

Phosphotungstic acid / phosphotungstate solution can avoid the influence of the acidity and other impurities in the solution of tungsten in the cooling crystallization process. At the same time, a certain amount of calcium sulfate crystal is mixed in the crystalline phosphotungstic acid crystal, the acid loss of the extraction process of industrial extraction, the complex phosphorus removal process and the low analytical rate can be avoided. It is an effective method for extracting tungsten from sulphuric acid mixed acid system.

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