Method for producing high-purity lithium carbonate by using lithium concentrate

Abstract

The invention relates to a method for producing high-purity lithium carbonate by using lithium concentrate. The method is characterized by comprising the following steps of: preparing an acid clinker, preparing a mixing size, preparing a lithium sulfate leaching solution, preparing a lithium sulfate purification liquid, preparing a lithium sulfate finishing solution, preparing a sodium carbonate solution, performing primary lithium deposition reaction, preparing a sodium separating mother liquor, preparing excellent lithium carbonate in a sweating manner, and preparing 99.99% of high-purity lithium carbonate. By adopting the method, the principle of removing calcium and magnesium ions is ingeniously utilized in preparation of common lithium carbonate; a fussy procedure of removing calcium and magnesium by ion exchange resin is avoided when the common lithium carbonate is purified to prepare the high-purity lithium carbonate; a method of recycling after separating out sodium sulfate in a freezing manner is adopted to process the primary lithium settling mother liquor; the high-purity lithium carbonate mother liquor in precipitation of the high-purity lithium carbonate is used as an optimal lithium carbonate washing liquor for primary lithium sedimentation after being recycled for a plurality of times. Thus, the method has the characteristics of simple process, high production efficiency, high recovery rate and low production cost.

Description

technical field [0001] The invention relates to a method for preparing high-purity lithium carbonate, in particular to a method for producing high-purity lithium carbonate with lithium concentrate. Background technique [0002] There are two traditional preparation methods of 99.99% high-purity lithium carbonate: [0003] One is to use lithium concentrate as a raw material to prepare ordinary lithium hydroxide after roasting, acidification, and leaching, then recrystallize and purify ordinary lithium hydroxide, and then dissolve the purified lithium hydroxide in pure water. Enter carbon dioxide and carry out carbonization into high-purity lithium carbonate, and this method is carried out recrystallization purification to common lithium hydroxide, and the residual lithium hydroxide amount in mother liquor is relatively large, and yield is low. [0004] The other is to use lithium concentrate or salt lake brine as a raw material, and the extracted lithium is first reacted wit...

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Problems solved by technology

[0003] One is to use lithium concentrate as a raw material to prepare ordinary lithium hydroxide after roasting, acidification, and leaching, then recrystallize and purify ordinary lithium hydroxide, and then dissolve the purified lithium hydroxide in pure water. Carbon dioxide is added into carbon dioxide to be carbonized into high-purity lithium carbonate. When ordinary lithium hydroxide is recrystallized and purified, the residual lithium hydroxide amount in the mother liquor is relatively large and the yield is low.

[0004] The other is to use lithium concentrate or salt lake brine as a raw material, and the extracted lithium is first reacted with sodium carbonate to obtain lithium sinking mother liquor and ordinary lithium carbonate. The lithium sinking mother liquor is treated by evaporation, and ordinary lithium carbonate is input as high-purity lithium carbonate Pass carbon dioxide into pure water for carbonization and dissolution into lithium bicarbonate, then pass the lithium bicarbonate solution through ion exchange resin to remove calcium and magnesium ions, and then heat up the solution after calcium and magnesium removal to precipitate high-purity lithium carbonate. Until the use of high-cost ion exchange resins to remove calcium and magnesium ions, and the steam consumption and sodium carbonate consumption are relatively high when preparing ordinary lithium carbonate, ion exchange resin regeneration will also lose part of lithium, and acid and alkali treatment Resin will also produce a relatively large amount of waste water