Method for preparing cryolite and coproducing soluble glass by using hydrof luorosilicic acid

A cryolite, fluorosilicic acid technology, applied in the directions of silicate, alkali metal silicate, aluminum fluoride, etc., can solve the problems of difficult recycling, serious environmental pollution, high cost of raw materials, and achieve easy implementation and application, high purity High and low cost effect

Inactive Publication Date: 2009-10-14
云南云天化国际化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for preparing cryolite that can effectively solve the above problems in view of the shortcomings of the existing cryolite production process, such as high raw material cost, large ammonia loss, difficulty in recycling, and serious environmental pollution.

Method used

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  • Method for preparing cryolite and coproducing soluble glass by using hydrof luorosilicic acid
  • Method for preparing cryolite and coproducing soluble glass by using hydrof luorosilicic acid
  • Method for preparing cryolite and coproducing soluble glass by using hydrof luorosilicic acid

Examples

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Embodiment 1

[0030] (1) Synthesis of sodium fluorosilicate: 10% wet-process phosphoric acid by-product fluosilicic acid solution is added with 28% sodium sulfate solution under stirring, and the sodium sulfate addition is 110% of the theoretically calculated amount, and the feeding time is 30 minutes. After the material is finished, continue to stir and react for 20 minutes, and sodium fluorosilicate crystals are precipitated to generate dilute sulfuric acid mother liquor. The slurry is filtered, and the filter cake is washed with 5% dilute sodium carbonate solution to obtain sodium fluorosilicate with a free water content of 7%, which is ready for use.

[0031] (2) Preparation of sodium fluoride solution and water glass: 42% liquid sodium hydroxide, heated to 92°C, under constant stirring, slowly add the sodium fluorosilicate obtained in (1), maintain the reaction temperature at 92°C, Under alkaline conditions, the stirring reaction was carried out for 60 minutes, and the terminal alkalin...

Embodiment 2～6

[0038]Repeat the same steps as described in Example 1, but in the step of synthesizing sodium fluorosilicate, the concentration of fluorosilicic acid used is respectively 5%, 8%, 15%, 20% or 25%, and the amount of sodium sulfate added They are respectively 105%, 115%, 120%, 125% or 130% of the theoretically calculated amount, and the addition reaction time is respectively 30 minutes, 45 minutes, 60 minutes, 75 minutes and 90 minutes. The control parameters of preparing sodium fluoride solution and water glass step and synthesizing cryolite step are identical with embodiment 1.

Embodiment 7

[0040] Technological process is identical with embodiment 1, only concrete processing condition is:

[0041] The phosphate fertilizer by-product fluosilicic acid with a concentration of 5% is stirred and reacted with sodium sulfate solution at room temperature, the concentration of the recycled sodium sulfate mother liquor is 3%, the concentration of the supplemented sodium sulfate solution is 25%, and the total amount of sodium sulfate added is theoretically calculated The amount is 100%, the synthesis time is 90 minutes, and the sodium fluorosilicate slurry is obtained, and the sodium fluorosilicate slurry is separated from liquid to solid, and the filter cake is washed with normal temperature water to obtain sodium fluorosilicate with a moisture content of 9%, and dried to After the moisture content is lower than 0.3%, it is ready for use. Use 25% liquid caustic soda or make a 25% solution with solid caustic soda, preheat to 85°C, and slowly add the above-mentioned dried so...

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Abstract

The invention discloses a method for preparing cryolite and coproducing soluble glass by using hydrof luorosilicic acid. The method comprises the steps of: adopting phosphoric acid by wet process, phosphate fertilizer and/or hydrof luorosilicic acid which is byproduct of compound phosphate fertilizer to be added to sodium sulfate solution to prepare sodium fluosilicate so as to lead most of impurities such as phosphorus, iron and the like to be distributed to dilute sulphuric acid mother solution for removal; adopting sodium hydroxide to react with the sodium fluosilicate; carrying out filtration washing to obtain sodium fluoride solution; adopting wet filter residue (silica gel) or dried dry filter residue (silica gel) to respectively react with solid sodium hydroxide or sodium hydroxide solution to coproduce soluble glass adopted as an accessory ingredient of phosphorite floatation; and finally adopting the sodium fluoride to react with aluminium sulphate solution to synthesize the cryolite. The invention adopts sodium hydroxide to decompose sodium fluosilicate and the sodium source is rich so as to avoid resupply of sodium in the following synthesis process of the cryolite; the adoption of aluminium sulphate for synthesizing the cryolite can reduce cost and the synthesized cryolite can meet the process requirement of aluminium electrolysis; and sodium sulfate mother solution can be recycled without discharge of wastewater and waste residue.

Description

technical field [0001] The present invention relates to the preparation method of cryolite, more specifically, the present invention relates to the method for preparing cryolite co-production water glass with wet-process phosphoric acid, phosphate fertilizer and / or the by-product fluosilicic acid of compound fertilizer production as raw material. Background technique [0002] Cryolite is a kind of fluoroaluminate of alkali metal and ammonium. The present invention is sodium cryolite, also known as sodium fluoroaluminate, with chemical formula Na 3 AlF 6 , mainly used as a flux for electrolytic aluminum smelting. [0003] At present, the vast majority of cryolite production at home and abroad use fluorite as raw material. As a non-renewable important strategic resource for the development of atomic energy industry, fluorite is valued and protected by countries all over the world. [0004] The main raw materials for traditional cryolite production are hydrofluoric acid, sod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/54C01B33/32
Inventor 明大增王煜资学民杨先张应虎杨跃华
Owner 云南云天化国际化工有限公司
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