Comprehensive Recovery of Tungsten from Waste Water of Ion Exchange Process

In order to extract tungsten from tungsten minerals, at present, China's tungsten metallurgy industry mostly adopts the alkaline smelting system. After high-pressure leaching of sodium tungstate solution, ion exchange is carried out and apt is extracted by evaporation crystallization. At present, there are two outstanding problems in this process that have not been effectively solved: first, the waste water discharge is large. Second, the discharge of waste salt is large.

In order to reduce the discharge of waste water, some scholars have proposed a method of comprehensive recovery and extraction of the liquid after tungsten ion exchange. The steps are as follows:

1)Treatment of sodium carbonate solution containing tungsten with ion exchange resin: the sodium carbonate solution containing tungsten is neutralized with sulfuric acid to pH = 3-6 as the pre crosslinking solution, and the pre crosslinking solution is adsorbed with macroporous weak alkaline anion exchange resin, with the adsorption temperature of 5-50 ℃ and the adsorption time of 2-6 hours.

2)Mixing slurry with barium carbonate: weigh barium carbonate according to 1.0-1.5 times of the molar amount of Na₂SO₄ in all the delivered liquid and put it into the ball mill according to the liquid-solid ratio of 1.0-1.5. Mix it for 0.5-2 hours at room temperature and get the ball mill slurry;

3)Conversion: slowly add the slurry obtained after the ball milling and mixing into the mixing tank filled with the residual liquid after mixing and start the mixing, and then mix and react for 4-10 hours under the condition of 60-90 ℃ and filter.

4)Purification of barium sulfate: transfer the filter cake obtained in step 3) to the ball mill, add water to the ball mill according to the liquid-solid ratio of 0.8-1.0, mix the ball mill slurry for 0.5-2.0 hours at room temperature, mix the ball mill slurry and sulfuric acid solution, mix it for 4-10 hours, filter it, and the filter cake will be the barium sulfate product after being washed by the deionized water.

The new process combines the ion exchange process of high tungsten concentration sodium carbonate solution with the process of treating high sodium sulfate waste water by barium carbonate, and closely cooperates with the decomposition process of sodium carbonate of tungsten mineral raw materials. It integrates seamlessly into a complete system that complements each other. It not only reduces a large number of waste water from the traditional tungsten ion exchange process, but also changes it by treating the high sulfate solution by barium carbonate. Waste as treasure provides raw materials for the process of barium sulfate preparation and alkali recovery from the treatment of high sulfate waste water by barium carbonate, and makes the treated solution reused without discharge, further reducing the discharge of waste water and salt.

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