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A method for producing mixed salt and recovering lithium chloride in the production process of polyphenylene sulfide

A production process, polyphenylene sulfide technology, applied in the direction of lithium halide, alkali metal halide purification, etc., can solve the problems of inability to obtain high-purity sodium chloride, incomplete separation of mixed salts, and poor salt quality

Active Publication Date: 2021-08-24
山东智永化工产业技术研究院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This recovery method has the following disadvantages: 1) lithium carbonate has a certain solubility in water, resulting in a low recovery rate of lithium chloride. The recovery rate of lithium chloride in this method is generally 80%, up to 85%; 2) chlorine Sodium chloride contains a certain amount of lithium chloride, which affects the downstream use of sodium chloride
However, this method has the following disadvantages (1) The solid salt is directly incinerated. Since the solid salt contains a large amount of NMP, a large amount of nitrogen oxides will be produced during the incineration process, and the tail gas treatment measures are complicated and the treatment cost is high; (2) Removal Dissolving the organic matter again will cause high energy consumption; (3) This method cannot obtain high-purity sodium chloride and lithium chloride, and the separation of mixed salts is not complete
[0007] Patent CN 103965476 A Lithium salt and solvent recycling method in the preparation of polyphenylene sulfide, the method is to separate sodium chloride from NMP solvent, lithium chloride has a large solubility in NMP, resulting in sodium chloride Contains a lot of NMP, the quality of the salt is poor

Method used

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  • A method for producing mixed salt and recovering lithium chloride in the production process of polyphenylene sulfide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Take 1069.1g of mixed salt solution of sodium chloride and lithium chloride (in which the concentration of sodium chloride is 9.36%, and the concentration of lithium chloride is 4.64%) to the distillation device, distill at atmospheric pressure, and when 851g of distillate is produced, filter at high temperature , filtration temperature is 70 ℃, obtains filtrate 116.04g and solid sodium chloride salt 102.06g, the concentration of lithium chloride in the filtrate is 42.03%; Continuing to carry out atmospheric distillation experiment to filtrate, obtains solid lithium chloride salt 47.61g (105 °C to a constant weight solid).

[0028] After analysis, the sodium chloride content in the solid sodium chloride salt is 93.62%, the lithium chloride content is 1.95%, and the water content is 4.43%; the lithium chloride content in the solid lithium chloride salt is 100%, and does not contain sodium chloride.

[0029] The obtained sodium chloride salt is washed with a saturated aqu...

Embodiment 2

[0032] Take 1073.8g of mixed salt solution of sodium chloride and lithium chloride (in which the concentration of sodium chloride is 9.36%, and the concentration of lithium chloride is 4.64%) to the distillation device, and distill at atmospheric pressure. Filter, filtration temperature is 80 ℃, obtains filtrate 108.6g and solid sodium chloride salt 102.8g, the concentration of lithium chloride in the filtrate is 44.93%; Filtrate is continued to carry out atmospheric distillation experiment, obtains solid lithium chloride salt 47.56g ( Dry at 105°C to constant weight solid).

[0033] After analysis, the sodium chloride content in the solid sodium chloride salt is 92.8%, the lithium chloride content is 2.2%, and the water content is 5%; the lithium chloride content in the solid lithium chloride salt is 100%, and does not contain sodium chloride.

[0034] The obtained sodium chloride salt is washed with saturated aqueous sodium chloride solution, washed with saturated aqueous so...

Embodiment 3

[0037] Take 1173 g of mixed salt solution of sodium chloride and lithium chloride (in which the concentration of sodium chloride is 9.36%, and the concentration of lithium chloride is 4.64%) to the distillation device, distill at atmospheric pressure, and filter at high temperature when 943 g of distillate is produced , filtration temperature is 75 ℃, obtains filtrate 117.55g and solid sodium chloride salt 112.45g, the concentration of lithium chloride in the filtrate is 45.28%; Continuing to carry out atmospheric distillation experiment to filtrate, obtains solid lithium chloride salt 51.77g (105 °C to a constant weight solid).

[0038]After analysis, the sodium chloride content in the solid sodium chloride salt is 92.28%, the lithium chloride content is 2.37%, and the water content is 5.35%; the lithium chloride content in the solid lithium chloride salt is 100%, and does not contain sodium chloride.

[0039] The obtained sodium chloride salt is washed with a saturated aqueo...

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Abstract

The invention discloses a method for recovering lithium chloride from mixed salt produced in the production process of polyphenylene sulfide. The mixed aqueous solution containing sodium chloride and lithium chloride mixed salt is taken, distilled, and filtered at high temperature to obtain sodium chloride solid and filtrate ; The filtrate was concentrated to obtain lithium chloride. The present invention proposes for an aqueous solution containing sodium chloride and lithium chloride, and realizes the separation and recovery of the two through the sequence of firstly separating the sodium chloride and then separating the lithium chloride. The method effectively separates and recovers sodium chloride and lithium chloride, the recovery rate of lithium chloride can reach more than 99%, and the purity of sodium chloride can also reach more than 99%.

Description

technical field [0001] The invention relates to the technical field of recovery of polyphenylene sulfide catalysts, in particular to a method for recovering lithium chloride from mixed salts produced during the production of polyphenylene sulfide. Background technique [0002] Polyphenylene sulfide is a new type of high-performance thermoplastic resin, which has the advantages of high mechanical strength, high temperature resistance, chemical resistance, flame retardancy, good thermal stability, and excellent electrical properties. It is widely used in electronics, automobiles, machinery and chemical industries. There are a wide range of applications. [0003] Lithium chloride is generally used as a catalyst in the production process of polyphenylene sulfide. The market unit price of lithium chloride is 70,000 yuan / ton, which is relatively high. Therefore, the recovery rate of lithium chloride is directly related to the production cost of polyphenylene sulfide. Therefore, i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01D15/04C01D3/14
CPCC01D3/14C01D15/04C01P2006/80
Inventor 侯永生李盼盼朱素娟徐淑强马华青吴国军冯雁金
Owner 山东智永化工产业技术研究院有限公司