The Advantages of Sulfuric Acid Replace Hydrochloric Acid for The Wolframite Concentrate Decomposition

In industry, the main mineral containing tungsten for wolframite and scheelite. Although the wolframite reserves less, the total reserves of less than 30%, but the wolframite resources easy to mining, smelting difficulty is small, it has inherent advantages compared with scheelite. The processing of wolframite are mainly soda high pressure leaching method, NaOH decomposition method and hydrochloric acid decomposition method.

Hydrochloric acid decomposition process is wolframite WO₃ in the form of tungstic acid precipitation, iron, manganese soluble salt into the solution, so as to achieve separation. Hydrochloric acid decomposition process is short, the cost is low, but during the decomposition of hydrochloric acid serious evaporation, the operating environment deteriorated, Cl^- serious corrosion of equipment, while a large number of Cl^- containing wastewater discharge, resulting in environmental pollution.

Some scholars have proposed a sulfuric acid instead of hydrochloric acid treatment of wolframite to prepare tungstate solution, the main steps are as follows:

1) Conversion of wolframite, the preparation of a certain concentration of sulfuric acid solution, a certain size of wolframite added to the solution for reaction, liquid to solid ratio of 2: 1 ~ 10: 1, the temperature is> 70 ℃, the reaction time > 3h, the filtrate after the reaction was filtered and the transformation of the material;

2) The transition material is eluted to prepare a certain concentration of ammonium salt or sodium salt solution, the liquid to solid ratio is 2: 1 to 6: 1, the temperature is 10 to 50 ℃, and the reaction is performed for 0.5 to 5 hours. After the reaction is completed, the ammonium tungstate solution or sodium tungstate solution;

3)The filtrate is treated by adding a theoretical amount of the ammonium salt to the filtrate. The (NH₄) ₂SO₄ and FeSO₄ in the solution are reacted at a temperature of 60-70 ℃ to form a crystal film on the surface of the solution, and the mixture is allowed to stand to cool to complete ferrous ammonium sulfate crystals Precipitation, decompression excess ammonium ferrous sulfate crystals were obtained, the filtrate was added sulfuric acid and returned to the treatment of wolframite.

Compared with the prior art, the advantages of sulfuric acid to decompose black refined tungsten ore are to overcome the problems of serious chloride corrosion and Cl^- corrosion in traditional hydrochloric acid decomposition process, carry out at room temperature, be easier to produce, save energy and reduce consumption, and the decomposition rate can reach 98.5 % above; The equipment consumption is lower and the comprehensive utilization of materials is achieved. The ferrous sulfate produced in the transformation filtrate treatment can be used for the preparation of ammonium ferrous sulfate, without pollutant emission and environmental friendliness.

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