Method for producing high-quality sodium fluoride from fluorine-containing wastewater as raw material

A sodium fluoride, high-quality technology, applied in the purification of alkali metal fluoride and alkali metal halide, etc., can solve the problems of low fluorine concentration, waste of fluorine resources, and uneconomical economy.

Active Publication Date: 2017-06-13
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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-containi...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Take tantalum and niobium neutralization mother liquor 2.5m from the tantalum and niobium smelter 3 , heat up to 95°C, stir and slowly add sodium carbonate to crystallize the fluorine in the form of sodium fluoride. After the bubbles in the solution gradually disappear, continue to add sodium carbonate to make the Na in the solution 2 CO 3 The concentration of the mixture rose to 350g / L, and then stirred for 1.5h to obtain a sodium fluoride filter cake and a solution containing sodium carbonate. The ammonia-containing gas generated during the reaction was purified by a lime column and returned to the tantalum-niobium neutralization process for recycling. The obtained sodium fluoride filter cake is added with 185g / L NH 4 In solution F, stir and wash at 65°C for 1.5h, filter to obtain refined sodium fluoride and ammonium fluoride solution, return the ammonium fluoride solution to the filter cake washing process for continued use, and dry the refined sodium fluoride to ob...

Embodiment 2

[0062] Take tantalum-niobium ore extract raffinate 2m 3 , stir at room temperature and feed ammonia gas, adjust the pH to 8.7 inversion, continue to stir for 2h, filter to obtain inversion slag filter cake and NH-containing 4 Filtrate of F. The resulting NH 4 Heat the filtrate of F to 85°C, stir and slowly add sodium carbonate to crystallize the fluorine in the solution in the form of sodium fluoride, and volatilize the ammonium in the form of ammonia gas. After the bubbles in the solution gradually disappear, continue to add sodium carbonate to make the Na in the solution 2 CO 3Concentration rises to 200g / L, then stir for 2 hours, filter to obtain sodium fluoride filter cake and sodium carbonate solution, and the ammonia-containing gas generated during the reaction process is returned to the cleaning and extraction raffinate transformation process for recycling. The obtained sodium fluoride filter cake is added with 89g / L NH 4 In solution F, stir and wash at 85°C for 0.5h...

Embodiment 3

[0065] Processing of titanium materials produces 3 m of washing waste liquid containing nitric acid to hydrofluoric acid 3 , first use diffusion dialysis to recover the free nitric acid and hydrofluoric acid in it, the resulting diffusion dialysis raffinate is passed through ammonia gas to adjust the pH to 8.5, stir at room temperature for 2 hours, and filter to obtain metatitanic acid filter cake and NH-containing 4 Filtrate of F. Heat the obtained filtrate to 90°C, stir and slowly add sodium carbonate to crystallize the fluorine in the form of sodium fluoride, and volatilize the ammonium in the form of ammonia gas. After the bubbles in the solution gradually disappear, continue to add sodium carbonate to make the Na in the solution 2 CO 3 Concentration rises to 400g / L, then stir for 1.5h, filter to obtain sodium fluoride filter cake and sodium carbonate solution, and the ammonia-containing gas generated during the reaction process is returned to the diffusion dialysis raffi...

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PUM

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Abstract

The invention discloses a method for producing high-quality sodium fluoride from fluorine-containing wastewater as a raw material. The method comprises the following steps: directly adding excessive sodium carbonate into the fluorine-containing wastewater to completely crystallize and separate fluorine in the solution in a mode of sodium fluoride, or firstly, adding amino into the fluorine-containing wastewater so as to obtain an ammonium fluoride solution, or firstly, precipitating and enriching the fluorine in the fluorine-containing wastewater, secondly, converting a precipitated and enriched product into an ammonium fluoride solution by using an ammonium salt solution, adding excessive sodium carbonate into the ammonium fluoride solution to completely crystal and separate the fluorine in the mode of sodium fluoride, and filtering so as to obtain sodium fluoride filter cakes and a post fluorine precipitation liquid; and washing the sodium fluoride filter cakes by using the ammonium fluoride solution, drying so as to obtain a high-quality sodium fluoride product of which the purity is up to 99.25% or greater, crystallizing the post fluorine precipitation liquid to recycle sodium carbonate in the post fluorine precipitation liquid, further desalting a sodium carbonate crystallization mother liquid, and recycling reclaimed water. The method has the advantages of being simple and convenient to operate, high in fluorine recycling rate, low in production cost, good in sodium fluoride product quality, free of 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...

Claims

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Application Information

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IPC IPC(8): C01D3/02C01D3/14
CPCC01D3/02C01D3/14C01P2006/80
Inventor 王学文王明玉葛奇孟钰麒
Owner CENT SOUTH UNIV
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