System and method for preparing high-purity lithium fluoride

A high-purity lithium fluoride and reaction system technology, which is applied in the field of preparation of high-purity lithium fluoride, can solve the problems of high corrosion resistance of equipment and excessive heavy metals in products, and achieve high reliability, improved service life and separation effect Good results

Active Publication Date: 2013-12-25
陕西延长石油集团氟硅化工有限公司
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  • Claims
  • Application Information

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Problems solved by technology

[0010] In order to solve the technical problem that hydrogen fluoride HF is often used in the existing preparation methods of lithium fluoride, the requirements for corrosion resistance of equipment during the synthesis process are relatively high, and lithium fluoride is precipitated by crystallization method, and the heavy metals in the product exceed the standard. The invention provides a method for preparing high-purity lithium fluoride

Method used

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  • System and method for preparing high-purity lithium fluoride

Examples

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preparation example Construction

[0032] The preparation process of lithium fluoride uses the reaction of gaseous elemental fluorine gas and solid lithium carbonate to synthesize solid lithium fluoride. The reaction equation is as follows: Li 2 CO 3 +F 2 →2LiF+CO 2 +1 / 2O 2

[0033] The process steps are as follows:

[0034] The gas-solid reactor is pre-filled with solid lithium carbonate and heated, the temperature is less than 400°C, and the fluorine gas enters the reaction system. The reaction system is composed of a circulating fan, a gas-solid reactor, a cyclone separator and a combustion aid, and the pressure of the gas-solid reactor and the reaction system is controlled to be less than 0.3 MPa; the combustion aid is not incorporated into the system when the reaction starts, and when the mixed gas in the circulation system reaches When the pressure is constant, turn on the burner, and the temperature of the burner is 400°C, which is incorporated into the circulation system; when the pressure is const...

Embodiment 1

[0038] First add 10 kg of lithium carbonate in advance to the horizontal gas-solid reactor, and then vacuumize it. Turn on the heater of the gas-solid reactor, and when the temperature is lower than 400°C, open the inlet shut-off valve and slowly introduce fluorine gas to control the system pressure of the gas-solid reactor, cyclone separator and circulating fan to less than 0.06MPa. When not increasing, the system incorporates the burner, and the working temperature of the burner is 400°C. The system continues to circulate, and the first cycle is completed when the pressure does not increase; the system is vacuumed, and then the cycle is continued again, a total of 13 cycles, and the product in the gas-solid reactor is sampled and analyzed for a purity of 99.95%.

Embodiment 2

[0040] First add 8 kg of lithium carbonate to the gas-solid reactor in advance, and then vacuumize it. Turn on the heater of the reaction device, and slowly introduce fluorine gas when the temperature is lower than 350°C, and control the system pressure of the reaction device, cyclone separator and fan to be less than 0.1MPa. When the pressure does not increase, the system is incorporated into the burner , The working temperature of the burner is 350°C. The system continues to circulate, and the first cycle is completed when the pressure does not increase; the system is evacuated, and then continues to cycle again, a total of 16 cycles. The product in the gas-solid reactor device is sampled and analyzed for a product purity of 99.99%.

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Abstract

The invention relates to a system and a method for preparing high-purity lithium fluoride. The system comprises a reaction system, a chemical adsorption column and a vacuumizing system, wherein the reaction system comprises a gas-solid reactor for accommodating solid lithium carbonate, a cyclone separator, a combustion booster and a circulating fan; a fluorine gas source is connected with the inlet of the gas-solid reactor through an inlet shut-off valve; the outlet of the gas-solid reactor is connected with the inlet of the cyclone separator; the outlet of the cyclone separator is divided into two ways; one way is connected with the circulating fan through a first shut-off valve; the other way is connected with the circulating fan through a second shut-off valve, the combustion booster and a third shut-off valve; the circulating fan is connected with the gas-solid reactor; the inlet of the chemical adsorption column is connected with the third shut-off valve through a fourth shut-off valve; and the chemical adsorption column is connected with the vacuumizing system. By the system and the method, the technical problem that in the synthesizing process, a requirement on the corrosion resistance of equipment is relatively high because in the conventional preparation method of the lithium fluoride, mostly, hydrogen fluoride HF is used, is solved; the technical process and the equipment are simple; and the reliability is high.

Description

technical field [0001] The invention relates to a method for preparing high-purity lithium fluoride, which is used to prepare lithium-ion battery electrolyte LiPF 6 necessary raw materials. Background technique [0002] Lithium fluoride is a white non-hygroscopic cubic crystal. Lattice constant a=0.402nm, bond length: 0.201nm. It cannot form hydrates and is the most insoluble in alkali metal fluorides, neither in water nor in alcohols and other organic solvents. At high temperature, LiF reacts with hydrofluoric acid to generate unstable lithium hydrogen fluoride LiF·HF, and LiF reacts with lithium hydroxide to generate double salt LiF·2LiOH. The double salt LiF.2LiOH is used as an additive in the production of glaze, glass and ceramics to reduce the firing temperature and enhance the heat resistance, wear resistance and acid resistance of ceramic products. It can also be used as a flux component for aluminum and aluminum alloy welding. Adding 1-2% LiF to the electrolyte ...

Claims

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Application Information

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IPC IPC(8): C01D15/04
Inventor 李立马家琪刘燕聂剑飞孟利涛
Owner 陕西延长石油集团氟硅化工有限公司
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