Tungsten Recycling from Low Grade Scheelite Tailings

At present, the content of WO₃ in white tungsten flotation tailings in many mines has reached more than 0.2%, even as high as 0.4%. These tailings are very low in floatability due to strong inhibition of inhibitor water glass, and the size of the inlay is very fine. It is very difficult and difficult to recycle.

In order to achieve effective recycling, some scholars provide a process for extracting scheelite concentrate from low-grade scheelite tailings; for low-grain inlays and low-grade stellite flotation tailings containing a large amount of calcareous gangue minerals, The scheelite concentrate is extracted therefrom, and the beneficiation process of the scheelite resources in the tailings is comprehensively recovered, and the high-grade scheelite concentrate obtained by the process is obtained, and the recovery rate is high. The process steps are as follows:

(1) First leaching: adding sodium hydroxide to the slurry, and leaching scheelite under heating and stirring under alkaline conditions; wherein the amount of sodium hydroxide is 50-150 kg/t, and the liquid-solid ratio of the slurry is 2:1 -5:1, the leaching time is 30-120 min, and the leaching temperature is 50-80 °C.

(2) Circulating leaching: the slurry is filtered, the leaching slag is discharged, the leaching solution is supplemented with sodium hydroxide 10-30kg/t, and the first process is repeated by adding the smectite tailings again, so that the cycle leaching is repeated, and finally the concentration of white tungsten is obtained. High leachate;

(3) Desiliconization of the leachate: Under heating, the dilute hydrochloric acid obtained in the step (2) is slowly added with dilute hydrochloric acid at a mass percentage of 10-30%, and the amount is 10-20 kg/t; After that, magnesium chloride is further added to further desiliconize;

(4) White tungsten precipitation: using a calcium chloride having a percentage concentration of 10-30% as a precipitant of tungstic acid, adding it to the leach solution after desiliconization and decontamination obtained in (3), stirring for 5-30 min, the temperature is At 40-60 ° C, the scheelite concentrate is finally precipitated.

The above method is effective for scheelite tailings, white tungsten embedding fine and harmful elements, and alkali leaching is used to avoid leaching of harmful elements to the utmost extent, and at the same time reduce the requirements of the process equipment; adopting the process of circulating leaching The content of WO₃ in the leachate is increased, the cost of leaching is significantly reduced, and a high-grade scheelite concentrate can be obtained.

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