Method for producing anhydrous lithium chloride special for electrolyzing by using lithium recovered from lithium-containing pharmaceutical waste water

Abstract

The invention discloses a method for producing anhydrous lithium chloride special for electrolyzing lithium by using lithium recovered from lithium-containing pharmaceutical waste water. The method comprises the following steps of: (a) preparing materials and removing impurities; (b) initially removing organic matters; (c) performing microelectrolysis and deeply removing the organic matters; (d) concentrating to separate sodium out; (e) evaporating and crystallizing; (f) performing centrifugal separation; (g) drying; and (h) cooling and packaging. By the method, the anhydrous lithium chloride special for producing and electrolyzing the lithium can be directly obtained by using the lithium recovered from the lithium-containing pharmaceutical waste water, so that the product impurity is more than 99 percent, the content of the sodium is less than 0.25 percent, and the whiteness of the products is high.

Description

technical field [0001] The invention relates to a preparation method of special anhydrous lithium chloride for electrolysis, in particular to a method for producing special anhydrous lithium chloride for electrolysis by recovering lithium from lithium-containing pharmaceutical wastewater. Background technique [0002] At present, many manufacturers of pharmaceutical intermediates use metal lithium, butyllithium or other organic lithium compounds as catalysts for the reaction of pharmaceutical intermediates. After completion, the lithium-containing catalyst components that have not been fully recycled are discharged into the pharmaceutical wastewater treatment system. In addition to lithium chloride, the pharmaceutical wastewater also contains residual organic substances such as ethyl trichloroacetate, diisopropylamine, tetrahydrofuran, and sodium salts. , Calcium salt, sulfate and other impurities, if the pharmaceutical wastewater is directly discharged, it will cause seriou...

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Problems solved by technology

This patent realizes the direct preparation of anhydrous lithium chloride from lithium waste liquid, but there is no sodium removal process in this method, and all sodium (1.5%~3%) in lithium waste liquid enters the product, and the product purity is not high, which affects the follow-up The quality of electrolytic lithium metal, at the same time, there are potential safety hazards due to the high sodium content in the raw materials during the electrolysis process

[0005] Both of the above two patents use natural phase separation to separate the organic matter from the lithium chloride solution, but this method cannot completely separate the organic matter from the solution, and there are still more organic matter in the final product, resulting in a poor appearance of the product. When used as an electrolytic raw material During electrolysis, the electrolytic cell is easy to catch fire, and there are potential safety hazards. At the same time, the quality of the electrolytic lithium metal is poor, and it cannot meet the quality requirements for anhydrous lithium chloride, which is directly used for the production of lithium metal by molten salt electrolysis.

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