Tungsten Extraction Process from Wolframite in Mixed Symbiotic Ore

At present, the main method to decompose tungsten minerals in industry is the NaOH decomposition process. Obviously, the traditional method can not cope with the decomposition of wolframite and scheelite mixed symbiotic ore. Therefore, a set of effective combination scheme is also very important.

Some scholars have proposed to transform wolframite into scheelite, and then use scheelite decomposition process. In practice, it is found that the general method of transformation operation has high energy consumption, high production cost, high grain size and low production efficiency, especially when the raw material containing a small amount of wolframite is treated.

A method of extracting tungsten from wolframite is proposed by some scholars. This method has realized the high efficient decomposition of wolframite at normal temperature and atmospheric pressure. The process is as follow.

The wolframite concentrate with a particle size of less than 250μm (containing WO₃ 71.3%) and apatite (including P₂O₅ 35.81%) are added into the ball milling tank and react 2H by ball milling after the liquid and solid ratio 0.5:1mL/g is added to the water. After the reaction is terminated, the wolframite is filtered to dry 24h, and the wolframite has been partially converted to scheelite.

At 80°C, the mixed acid solution with H2SO4 concentration of 250g/L and H₃PO₄ concentration of 300g/L is used to extract 4h, the ratio of liquid to solid is 10:1mL/g, and the leaching rate of tungsten is 99.2%. After extraction of tungsten by tertiary amine extractant, mother liquor is added to the spent sulfuric acid to return to the new round of leaching. Under the same decomposition conditions, the leaching rate of tungsten is 99.1%.

The decomposition rate of this method is more than 98% for wolframite, which is more than 97% for the wolframite ore. The calcium containing material is used to produce phosphoric acid at the time of decomposition. It can be used to make up the phosphoric acid consumed in the decomposition process. The whole process is easy to operate and easy to achieve industrialization.

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