Method of producing calcium fluoride through bottom mud generated by fluoride waste

Abstract

The invention discloses a method of producing calcium fluoride through bottom mud generated by treating industrial fluoride waste. The method comprises the following step of: separating the ingredients according to different solubility of bottom mud in acids through a one-step alkaline washing and two-step acidification separating method to obtain a calcium fluoride product; the treatment step comprises: alkaline washing, primary acidification separating, secondary acidification separating, drying and burning; in the alkaline washing procedure, a sodium carbonate solution acts with the bottom mud to convert calcium sulfate in the bottom mud into calcium carbonate; the bottom mud is used as a raw material in the primary acidification separating procedure; filtrate obtained in the secondary acidification separating procedure is mixed with washing water to serve as an acid source of the primary acidification; a new acid serves as the acid source of the secondary acidification; and an obtained filter cake is treated in the drying and burning steps. The method provided by the invention both can be used for solving the area occupation and environmental pollution problems of bottom mud produced by treating the industrial fluoride waste, effectively utilizing the fluorine resource in the bottom mud and providing the calcium fluoride product having utilization value.

Description

technical field [0001] The invention relates to a production method of calcium fluoride, in particular to a method for producing calcium fluoride from bottom mud produced from fluorine-containing wastewater. Background technique [0002] Calcium fluoride is mainly used as raw material for hydrofluoric acid production and metallurgical flux. In order to meet the discharge standards, industrial fluorine-containing wastewater needs to undergo defluoridation treatment. The currently widely used method for reducing fluoride is the lime chemical precipitation method, that is, adding lime to fluoride-containing wastewater to combine fluoride ions with calcium ions to form calcium fluoride precipitates that are insoluble in water and remove them. The advantages of this method are low cost and easy operation; the disadvantage is that the generated calcium fluoride precipitate will wrap on the surface of calcium hydroxide particles, so that calcium hydroxide cannot be fully utilized,...

AI Technical Summary

Problems solved by technology

The advantages of this method are low cost and easy operation; the disadvantage is that the generated calcium fluoride precipitate will wrap on the surface of calcium hydroxide particles, so that calcium hydroxide cannot be fully utilized, thus producing a large amount of sediment

At present, there is no better way to deal with the sediment, but to stack it in the open air, which not only takes up land, but also affects the environment, and also causes a serious waste of fluorine resources.

[0003] The first production link of tantalum and niobium powder production is to decompose tantalum and niobium ore with hydrofluoric acid to produce a large amount of fluorine-containing waste liquid; while aluminum fluoride or hydrofluoric acid production enterprises produce a large amount of fluorine-containing waste liquid during the treatment process. Calcified waste residue (bottom sludge), there is no good way to use it

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