Purification process for sodium fluoride and silicon dioxide

A silicon dioxide and sodium fluoride technology, applied in the direction of silicon dioxide, silicon oxide, alkali metal fluoride, etc., can solve problems affecting product quality and achieve the effect of improving yield and purity

Inactive Publication Date: 2018-11-06
HUNAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, with the existing separation and purification technology, sodium fluoride products tend to carry silica impurities (the content is usually greater tha

Method used

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  • Purification process for sodium fluoride and silicon dioxide

Examples

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Embodiment 1

[0024] Example 1: A separation and purification process of sodium fluoride and silica, which uses sodium fluorosilicate, a by-product of phosphate fertilizer, to produce sodium fluoride and co-produce white carbon black. The process includes the following steps:

[0025] (1) Metathesis reaction: Weigh 482 g of solid sodium carbonate, add 1100 g of mother liquor to prepare a 30% solution, heat to 85°C, press Na 2 SiF 6 : Na 2 CO 3 =1:1.05~1.1 for batching, slowly add 400 g of solid sodium fluorosilicate, the feeding time is 30 minutes, and the reaction is continued at 90 ℃ for 1 hour to obtain a solution of sodium fluoride crystals and silica precipitation;

[0026] (2) Preliminary separation: The mixed solution of sodium fluoride and silicon dioxide is settled in a separating scrubber, and then the supernatant is removed to obtain 529.6 g crude sodium fluoride and 123.0 g crude silica. The crude sodium fluoride contains 4.00 g silica, and the crude silica contains 3.76 g sodium fluo...

Embodiment 2

[0029] Example 2: A separation and purification process of sodium fluoride and silicon dioxide, which uses sodium fluorosilicate, a by-product of phosphate fertilizer, to produce sodium fluoride and co-produce white carbon black. The process includes the following steps:

[0030] (1) Metathesis reaction: Weigh 482 g of solid sodium carbonate, add 482 g of mother liquor to prepare a 50% solution, raise the temperature to 95°C, press Na 2 SiF 6 : Na 2 CO 3 =1:1.05~1.1 for batching, slowly add 400 g of solid sodium fluorosilicate, the feeding time is 30 minutes, and the reaction is continued at 90 ℃ for 1 hour to obtain a solution of sodium fluoride crystals and silica precipitation;

[0031] (2) Preliminary separation: The mixed solution of sodium fluoride and silicon dioxide is settled in a separating scrubber, and then the supernatant is removed to obtain 529.6 g crude sodium fluoride and 123.0 g crude silica. The crude sodium fluoride contains 4.00 g of silica, and the crude silica...

Embodiment 3

[0034] Example 3: A separation and purification process of sodium fluoride and silica, which uses sodium fluorosilicate, a by-product of phosphate fertilizer, to produce sodium fluoride and co-produce white carbon black. The process includes the following steps:

[0035] (1) Metathesis reaction: Weigh 482 g of solid sodium carbonate, add 1100 g of mother liquor to prepare a 30% solution, heat to 90°C, press Na 2 SiF 6 : Na 2 CO 3 =1:1.05~1.1 for batching, slowly add 400 g of solid sodium fluorosilicate, the feeding time is 30 minutes, and the reaction is continued at 90 ℃ for 1.5 hours to obtain a solution of sodium fluoride crystals and silica precipitation;

[0036] (2) Preliminary separation: The mixed solution of sodium fluoride and silicon dioxide is settled in a separating scrubber, and then the supernatant is removed to obtain 529.6 g crude sodium fluoride and 123.0 g crude silica. The crude sodium fluoride contains 4.00 g silica, and the crude silica contains 3.76 g sodium f...

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Abstract

The invention relates to a separation and purification process for sodium fluoride and silicon dioxide. Sodium fluosilicate as a byproduct of phosphate fertilizer is used for producing sodium fluorideand co-producing white carbon black; the method comprises the following steps: a sodium fluoride and silicon dioxide mixed solution is subjected to settling separation in a separation scrubber, and crude sodium fluoride and crude silicon dioxide are obtained; crude sodium fluoride is dispersed in mother liquor, slightly excessive sodium hydroxide is added, so that a small quantity of silicon dioxide impurities are converted into soluble sodium silicate, filtering, washing and drying are performed, a high-purity sodium fluoride product is obtained, and the mother liquor is conveyed to a silicon dioxide purification tank continuously; silicon dioxide is dispersed in the mother liquor in the silicon dioxide purification tank, slightly excessive ferric oxalate is added, a small quantity of sodium fluoride impurities are converted into a soluble complex, filtering, washing and drying are performed, and a high-purity white carbon black product is obtained. According to the process, large quantities of acids and bases are not needed to be consumed, less mother liquor is produced in the separation and purification process, yield and purity of the sodium fluoride and white carbon black products are improved, and the mother liquor can be recycled.

Description

Technical field [0001] The invention relates to a separation process of sodium fluoride crystals and silicon dioxide, and is particularly suitable for co-producing white carbon black with sodium fluorosilicate, a by-product of phosphate fertilizer. Background technique [0002] Sodium fluoride is a colorless shiny crystal or white powder. It is slightly soluble in alcohol and soluble in water. The aqueous solution is alkaline and can corrode glass. Reacts with hydrofluoric acid to produce sodium fluoride hydride. Sodium fluoride is an important fluoride salt, mainly used as agricultural fungicide, insecticide, wood preservative, water treatment agent, light metal fluoride salt electrolysis flux. In the nuclear industry, it is used as a UF3 adsorbent and as a raw material for the manufacture of other fluorine compounds. It is also used in enamel, medicine, and papermaking. The traditional methods of sodium fluorosilicate mainly include the neutralization method, melt leaching, ...

Claims

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Application Information

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IPC IPC(8): C01B33/18C01D3/02C01D3/16
CPCC01B33/18C01D3/02C01D3/16C01P2006/80
Inventor 李广利胡舜钦贺全国刘军刘四化罗小平
Owner HUNAN UNIV OF TECH
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