Method for preparing lithium carbonate by taking lithium fluoride mother liquor as raw material

A technology of lithium fluoride and lithium carbonate, applied in the direction of lithium carbonate;/acid carbonate, alkali metal fluoride, etc., can solve the problems of high cost and low product quality

Pending Publication Date: 2021-06-04
SICHUAN SIDANENG ENVIRONMENTAL PROTECTION TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a method for preparing lithium carbonate with lithium fluoride mother liquor as a raw material, so as to solve the technical problems of high cost and low product quality of evaporation crystallization in the prior art

Method used

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  • Method for preparing lithium carbonate by taking lithium fluoride mother liquor as raw material
  • Method for preparing lithium carbonate by taking lithium fluoride mother liquor as raw material
  • Method for preparing lithium carbonate by taking lithium fluoride mother liquor as raw material

Examples

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Embodiment 1

[0038] This embodiment provides the first specific implementation of the treatment method of lithium fluoride mother liquor and the first specific implementation of the treatment system of lithium fluoride mother liquor, wherein the lithium fluoride mother liquor is lithium salt and fluoride salt Or the lithium fluoride slurry generated by hydrofluoric acid reaction is obtained through crystallization and solid-liquid separation.

[0039] The processing method of lithium fluoride mother liquor comprises the following steps:

[0040] (1) Defluorination

[0041] Step1: Add calcium chloride to the lithium fluoride mother liquor to convert fluoride ions into calcium fluoride precipitates, and obtain a post-reaction liquid after the precipitation reaction is completed;

[0042] Step2: Perform solid-liquid separation on the reacted liquid to obtain the first filtrate; plate and frame filtration is used for solid-liquid separation, and the first filtrate includes the permeate and th...

Embodiment 2

[0059] This embodiment provides the second specific implementation of the treatment method of lithium fluoride mother liquor and the second specific implementation of the treatment system of lithium fluoride mother liquor, wherein the lithium fluoride mother liquor is lithium salt and fluoride salt Or the lithium fluoride slurry generated by hydrofluoric acid reaction is obtained through crystallization and solid-liquid separation.

[0060] The difference compared with Example 1 is that the step (1) of the treatment method of the lithium fluoride mother liquor of the present embodiment specifically includes:

[0061] Step1: Add calcium chloride to the lithium fluoride mother liquor to convert fluoride ions into calcium fluoride precipitates;

[0062] Step2: Continue to add sodium carbonate to convert excess calcium ions into calcium carbonate precipitation, and obtain a post-reaction liquid after the precipitation reaction is completed;

[0063] Step3: Perform solid-liquid se...

Embodiment 3

[0072] This embodiment provides the first embodiment of the method for preparing lithium carbonate from lithium fluoride mother liquor (that is, the third embodiment of the treatment method of lithium fluoride mother liquor) and the treatment system of lithium fluoride mother liquor The third specific implementation manner of the present invention, wherein the lithium fluoride mother liquor is obtained by crystallization and solid-liquid separation of lithium fluoride slurry formed by the reaction of lithium salt and fluoride radical salt or hydrofluoric acid.

[0073] The method for preparing lithium carbonate as raw material with lithium fluoride mother liquor comprises steps:

[0074] (1) Defluorination

[0075] Step1: Add calcium chloride to the lithium fluoride mother liquor to convert fluoride ions into calcium fluoride precipitates;

[0076] Step2: Continue to add sodium carbonate to convert excess calcium ions into calcium carbonate precipitation, and obtain a post-re...

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Abstract

The invention discloses a method for preparing lithium carbonate by taking lithium fluoride mother liquor as a raw material. The method comprises the following steps: (1) fluorine removal: removing fluorine ions in the lithium fluoride mother solution to obtain a fluorine-removed solution; (2) concentrating; step 1, carrying out primary membrane concentration on the feed liquid to obtain a first concentrated solution with the lithium ion concentration of greater than or equal to 5g / L and a first thin solution with TDS of less than or equal to 100mg / L; step 2, performing secondary membrane concentration on the first concentrated solution to obtain a second concentrated solution with the lithium ion concentration being greater than or equal to 25g / L and a second thin solution; the feed liquid comprises fluorine-removed liquid and second thin liquid; and (3) lithium precipitation reaction: converting lithium ions in the second concentrated solution into lithium carbonate precipitate to obtain lithium carbonate slurry. Compared with a resource recovery mode adopting evaporative crystallization, the method has the advantages that the fluorine ions in the lithium fluoride mother liquor are effectively removed, the purity of a lithium carbonate product can be remarkably improved, the lithium carbonate product which can be sold can be obtained, economic benefits are remarkably improved, and corrosion of the fluorine ions to follow-up equipment and pipelines can be reduced.

Description

technical field [0001] The invention relates to the technical field of lithium fluoride mother liquor resource recovery, in particular to a method for preparing lithium carbonate by using lithium fluoride mother liquor as a raw material. Background technique [0002] Lithium fluoride is generally used to produce lithium hexafluorophosphate electrolyte. Generally, high-purity lithium salt is reacted with fluoride salt or hydrofluoric acid to form lithium fluoride slurry, and then lithium fluoride crystals are obtained through crystallization and solid-liquid separation. The mother liquor obtained by solid-liquid separation is a by-product containing lithium fluoride resources. [0003] For the resource recovery of lithium fluoride mother liquor, lithium fluoride is mainly recovered by evaporation and crystallization. However, the general input and operating costs of the evaporator are very expensive, fluorine corrodes stainless steel very seriously, and the recovered lithiu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D15/08C01D3/02
CPCC01D15/08C01D3/02
Inventor 何志许锦鹏肖松林
Owner SICHUAN SIDANENG ENVIRONMENTAL PROTECTION TECH CO LTD
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