Arsenic Removal from Tungsten Mud and Recycle

Tungsten smelting wastewater containing 3 ~ 7mg / L of arsenic as the main sludge factor, except for arsenic sludge is mainly generated in the process of wastewater arsenic removal. Arsenic removal process mainly includes calcium salt precipitation method, iron salt precipitation method or calcium salt - iron salt joint precipitation method. At present, the combined method of calcium salt and iron salt is the most stable method for arsenic removal from tungsten smelting wastewater, but it will produce more arsenic-removing sludge. The final destination is solid landfill, cement solidification or lime solidification treatment. These methods subsequent processing and potential hazards can be reduced. But in fact, the tungsten mud also contains other valuable metals, there is room for further processing.

Removing arsenic from tungsten slag to achieve environmental protection standard and can be used for recirculation process extraction. The main steps are:

(1) Mixing the de-arsenic sludge and water to obtain a slurry;

(2) Mixing the slurry with the first acid solution and filtering to obtain a filtrate containing calcium ions and iron ions and a residue containing tungsten oxide;

(3) Mixing the tungsten smelting wastewater with the second acid solution and the filtrate containing calcium ions and iron ions to obtain a first arsenic removal sludge and an arsenic removal filtrate, and filtering the first arsenic removal arsenic wherein the tungsten smelting wastewater contains at least one of sodium hydroxide, sodium chloride, sodium arsenate, sodium silicate and tungsten oxide in the sludge returning step (1).

(4) Mixing the residue containing tungsten oxide with the lye and filtering to obtain the tungstate-containing filtrate and the residue.

Processing method for removing arsenic sludge by mixed slurry liquid and sludge removal of arsenic acid, can be arsenic removal in sludge containing calcium carbonate and iron hydroxide into soluble calcium salt and ferric salt, which can be obtained by filtration containing calcium ions and iron ions in the filtrate and containing tungsten oxide residue, and then obtained with calcium ions and iron ions in the filtrate as arsenic removal reagent was mixed with tungsten smelting wastewater, tungsten smelting wastewater of sodium arsenate with calcium and iron ions in the filtrate combined into ferric arsenate and calcium arsenate. It can not only effectively recover valuable elements in arsenic removal sludge, but also significantly reduce the treatment cost of tungsten smelting wastewater, and significantly reduce the content of arsenic in tungsten smelting wastewater, so that it can discharge well after removing fluoride and pH.

Arsenic is a hazardous solid waste of tungsten in the mud, in the application, in addition to slurry liquid arsenic sludge was mixed with acid, can be arsenic removal in sludge containing calcium carbonate and iron hydroxide into soluble calcium salt and ferric salt, not only can effectively recycle arsenic removal in sludge of valuable elements, it can also significantly reduce the cost of wastewater treatment of tungsten smelting.

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