Method for synthesis of cryolite from tetrafluoro aluminum sodium

A technology of sodium tetrafluoroaluminum and cryolite, which is applied in the direction of aluminum fluoride and aluminum halide, can solve the problems of difficult separation, high content of silicon dioxide, and difficulty in meeting the quality indicators of cryolite, and achieve low environmental load and environmental protection. High benefit effect

Active Publication Date: 2015-03-11
YUNNAN CHEM RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage is that the first step is to obtain sodium fluoride and silicon dioxide will be produced at the same time. It is difficult to completely separate the two. The content of silicon dioxide in sodium fluoride is relatively high, and the quality index is difficult to meet the requirements. Naturally, the ice crystals synthesized in the second step Stone quality indicators are also difficult to meet the requirements

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Grind 10g sodium tetrafluoroaluminum sodium by-product and 3g industrial sodium fluoride evenly, put it into a 500°C muffle furnace for calcination for 1h, then lower the temperature to 300°C and keep the temperature constant for 30min, take out the material, cool and weigh 11.5g, then add 4% 60g of hydrofluoric acid, start stirring, stirring rate 200rpm, react for 20min, suction filter, wash, dry to obtain 11.3g cryolite product. After testing, the cryolite content is 87.5%, the silicon content is 0.26%, the molecular ratio is 2.43, and the bulk density is 0.56g / cm 3 .

Embodiment 2

[0026] Grind 10g sodium tetrafluoroaluminum sodium by-product and 5g industrial sodium fluoride evenly, put it into a 600°C muffle furnace for calcination for 2h, then lower the temperature to 300°C and keep the temperature constant for 30min, take out the material, cool and weigh 14.2g, then add 4% 150g of hydrofluoric acid, start stirring, stirring rate 200rpm, react for 30min, suction filter, wash, dry to obtain 13.9g cryolite product. After testing, the cryolite content is 97.4%, the silicon content is 0.21%, the molecular ratio is 2.72, and the bulk density is 0.69g / cm 3 .

Embodiment 3

[0028] Grind 10g sodium tetrafluoroaluminum sodium by-product and 7g industrial sodium fluoride evenly, put it in a muffle furnace at 700°C for 3h, then lower the temperature to 300°C and keep the temperature constant for 30min, take out the material, cool and weigh 16.2g, then add 4% 200g of hydrofluoric acid, start stirring, stirring rate 200rpm, react for 40min, suction filter, wash, dry to obtain 15.9g cryolite product. After testing, the cryolite content is 98.5%, the silicon content is 0.17%, the molecular ratio is 2.84, and the bulk density is 0.77g / cm 3 .

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Abstract

The invention discloses a method for synthesis of cryolite from tetrafluoro aluminum sodium, and belongs to the technical field of inorganic fluorine chemical industry. The technical scheme of the method is as follows: first, grinding uniformly a certain amount of tetrafluoro aluminum sodium and sodium fluoride to obtain a grey solid mixture; secondly, putting the grey solid mixture in a muffle furnace for calcining, controlling the calcination temperature and calcination time to obtain calcined product cryolite, then cooling to 300 DEG C and keeping constant temperature for 30min to improve the physical properties of the cryolite; finally, removing silicon with hydrofluoric acid with the concentration of 4% to obtain a qualified cryolite product. The product synthesis method can be implemented and realized by use of equipment in the prior art by large-scale industrial production verification.

Description

technical field [0001] The invention relates to a method for synthesizing cryolite with tetrafluoroaluminum sodium. It belongs to the field of inorganic fluorine chemical industry. Background technique [0002] Cryolite is mainly used in electrolytic aluminum industry. Since the reform and opening up, my country's electrolytic aluminum industry has made great progress, especially after 2002, the electrolytic aluminum industry has shown a trend of rapid development, and the number of electrolytic aluminum production enterprises has increased to nearly 150. By 2009, my country's electrolytic aluminum production capacity has reached 19.5 million tons, and the actual annual output has also reached 13 million tons. It takes about 10-12kg of cryolite to produce one ton of electrolytic aluminum. Therefore, the annual demand for cryolite in the electrolytic aluminum industry is about 130,000 tons. In various electrolytic aluminum plants in my country, low molecular ratio cryolit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/54
CPCC01F7/54
Inventor 肖勇梁雪松杨云松
Owner YUNNAN CHEM RES INST
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