A method for producing high-quality sodium fluoride using fluorine-containing wastewater as raw material

Abstract

A method for producing high-quality sodium fluoride using fluorine-containing wastewater as a raw material, which includes directly adding excess sodium carbonate salt to fluoride-containing wastewater, so that the fluorine in the solution is completely crystallized in the form of sodium fluoride, or first Ammonium fluoride solution is obtained by adding ammonia to the fluorine-containing wastewater solution, or the fluorine precipitation and enrichment in the fluorine-containing wastewater is firstly enriched, and then the fluorine in the fluoride precipitation enrichment is converted into an ammonium fluoride solution with an ammonium salt solution, and then fluoride Add excess sodium carbonate salt to the ammonium solution to completely crystallize the fluorine in the form of sodium fluoride, and filter to obtain sodium fluoride filter cake and fluorine sinking liquid; the sodium fluoride filter cake is washed and dried by ammonium fluoride solution A high-quality sodium fluoride product with a purity of more than 99.25% is obtained. The sodium carbonate salt in the liquid after fluoride sinking is crystallized and recovered, and the mother liquid of sodium carbonate salt crystallization is further desalted and reused as reclaimed water. The invention has the advantages of simple operation, high recovery rate of fluorine, low production cost, good quality of sodium fluoride product, no fluorine-containing waste and the like.

Description

technical field [0001] The invention belongs to the fields of chemical industry and metallurgy, and in particular relates to a method for producing high-quality sodium fluoride by using fluorine-containing wastewater as a raw material. Background technique [0002] Sodium fluoride is an important chemical raw material, widely used in chemical industry, metallurgy, wood preservatives, agricultural pesticides, brewing fungicides, pharmaceutical preservatives, welding flux, alkaline zincate galvanizing additives and enamel , Paper industry and other industries. At present, the main production methods of sodium fluoride are: melting leaching method, neutralization method, sodium fluorosilicate method, ion exchange method, etc. [0003] The immersion method is to calcinate fluorite, soda ash and quartz sand at a temperature of 800-1000 ° C, then leaching with water, and then evaporate, crystallize, and dry to obtain the finished product of sodium fluoride; the neutralization met...

AI Technical Summary

Problems solved by technology

Because the concentration of fluorine in the solution is low, the production process of sodium fluoride requires a large amount of evaporation and concentration, which is economically uneconomical

At present, low-concentration fluorine-containing wastewater at home and abroad, and complex fluorine-containing wastewater are generally treated by lime precipitation, which not only causes a serious waste of fluorine resources, but also produces a large amount of fluorine-containing solid waste