Preparation method of lithium hexafluorophosphate

A technology of lithium hexafluorophosphate and hexafluorophosphoric acid, which is applied in chemical instruments and methods, phosphorus compounds, lead-acid batteries, etc., can solve the problems of insufficient equipment operation continuity, low purity of lithium hexafluorophosphate and high raw material cost, and is easy to popularize, apply and produce. The effect of low cost and high product quality

Active Publication Date: 2012-07-11
DO FLUORIDE CHEM CO LTD
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  • Summary
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Problems solved by technology

The disadvantage of this method is that the cost of raw materials is high and the continuity of equipment operation is not good enough
[0005] The Chinese Patent Gazette also discloses an invention patent application with the application number: 200510115856.4, and the invention name is: a preparation method of lithium hexafluorophosphate, which includes reacting lithium fluoride with a phosphorus source, wherein the lithium fluoride is composed of lithium carbonate and It is produced by the reaction of hydrogen fluoride. The purity of lithium hexafluorophosphate produced by this method is relatively low and it is not easy to purify

Method used

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Examples

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Effect test

Embodiment 1

[0019] The preparation method of lithium hexafluorophosphate of the present invention comprises the following steps:

[0020] (1) Formation of hexafluorophosphoric acid

[0021] In a closed container, add 790g of concentrated phosphoric acid under the protection of nitrogen, and slowly add 1235g of liquid anhydrous hydrogen fluoride under stirring and cooling, keep the system temperature below 20°C, and the addition time is 2 hours;

[0022] (2) Formation of phosphorus pentafluoride

[0023] Take 1008g of hexafluorophosphoric acid generated in step (1), slowly add 1595g of oleum under cooling and stirring, keep the system at 25-32°C for 3 hours, and the generated phosphorus pentafluoride gas passes through -40°C cooler , remove impurities and collect.

[0024] (3) Synthesis of lithium hexafluorophosphate

[0025] In 1# reactor, dissolve 55g of high-purity lithium fluoride in 1000g of anhydrous hydrogen fluoride to form anhydrous hydrogen fluoride solution of lithium fluorid...

Embodiment 2

[0029] Return 1250 g of mother liquor after crystallization and filtration in 1# and 2# reactors in Example 1 to 1# and 2# reactors respectively, and add 55 g of high-purity lithium fluoride and anhydrous hydrogen fluoride solution under stirring to form fluoride Anhydrous hydrogen fluoride solution of lithium, repeat the reaction process of embodiment 1, obtain 300g lithium hexafluorophosphate product. Test results: product purity greater than 99.9%, product free acid (calculated by HF) 95ppm, moisture (Karl Fischer method) 5ppm, alkali metal ion content (calculated by K, Na) 4ppm, heavy metal ion content (calculated by Fe) 2ppm , Insoluble matter content 450ppm.

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PUM

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Abstract

The invention relates to a preparation method of lithium hexafluorophosphate. The method comprises the following steps: (1), enabling anhydrous hydrogen fluoride and strong phosphoric acid to react under the protection of inert gas to prepare hexafluorophosphoric acid; (2), adding oleum to the hexafluorophosphoric acid prepared in the step (1) under cooling stirring to prepare phosphorus pentafluoride gas; (3), dissolving high-purity lithium fluoride in an anhydrous hydrogen fluoride solution to form an anhydrous hydrogen fluoride solution containing the lithium fluoride; (4), cooling and guiding the phosphorus pentafluoride gas into the anhydrous hydrogen fluoride solution containing the lithium fluoride, reacting, crystallizing, separating and drying to obtain a pure lithium hexafluorophosphate product; and (5), continuously guiding the unreacted and cooled phosphorus pentafluoride gas to the anhydrous hydrogen fluoride solution containing the lithium fluoride and continuously reacting to obtain a lithium hexafluorophosphate finished product. The phosphorus pentafluoride in the process is cooled to fully react so as to prevent incomplete reacted phosphorus pentafluoride powder from causing environmental-protection pressure.

Description

technical field [0001] The invention relates to a preparation method of lithium hexafluorophosphate. Background technique [0002] In recent years, lithium hexafluorophosphate (LiPF 6 ) is selected as the electrolyte of the lithium-ion secondary battery, and lithium hexafluorophosphate is dissolved in some non-aqueous organic solvents to form the electrolyte of the lithium-ion secondary battery. Lithium-ion secondary battery is an internationally recognized ideal chemical energy source. It is widely used in mobile phones, laptop computers and laptops due to its advantages of small size, large capacity, 500 times of repeated charge and discharge, and only 3% reduction in capacity. Video cameras, etc., are also used in the electronics industry as a dopant for making wafers and as a catalyst for organic synthesis. When the lithium-ion secondary battery is charged, lithium ions enter and attach to the hole in the cathode; while the lithium-ion secondary battery is discharged, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/455H01M10/08
CPCY02E60/126Y02E60/10
Inventor 李世江侯红军杨华春薛旭金于贺华闫春生刘海霞李云峰李凌云
Owner DO FLUORIDE CHEM CO LTD
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