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A method for reclaiming lithium in lithium carbonate lithium sinking mother liquor as high-purity lithium phosphate

A technology of sinking lithium mother liquor and pure lithium phosphate, applied in the field of lithium recovery, can solve the problems of low economic efficiency, high cost and low purity of lithium phosphate in phosphorus utilization

Active Publication Date: 2018-02-02
JIANGSU RONGHUI GENERAL LITHIUM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Chinese patent CN104925837A discloses a method for recovering lithium-precipitating mother liquor. This method uses relatively expensive phosphoric acid and sodium hydroxide as raw materials, and the cost is relatively high. The purity of lithium phosphate produced during the recovery of lithium in the mother liquor is relatively low. Only as a transition product, it needs to be converted into other substances to recover and use lithium, and the higher-value phosphorus enters the low-value calcium phosphate, and the utilization of phosphorus is not economical.

Method used

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Examples

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Comparison scheme
Effect test

Embodiment 1

[0017] A method for reclaiming lithium in lithium carbonate heavy lithium mother liquor as high-purity lithium phosphate, comprising the following steps:

[0018] (1) Carbonate removal: Add sulfuric acid to the lithium-precipitating mother liquor produced during lithium carbonate preparation to adjust the pH to 5, heat up to 70°C and stir for 20 minutes to fully volatilize the carbon dioxide in the lithium-precipitating mother liquor;

[0019] (2) Calcium and magnesium complexation: add sodium hydroxide to the lithium precipitation mother liquor treated in step (1) to adjust the pH value to 12.5, and measure the concentration of lithium ions in the mother liquor to be 0.21mol / L, then take 16000L of the mother liquor and add Put it into a 20000L reactor, add 0.8Kg EDTA, stir for 20 minutes to fully complex the calcium and magnesium in the mother liquor;

[0020] (3) Precipitation of high-purity lithium phosphate: Add 16Kg lithium phosphate seed crystals to the lithium phosphate...

Embodiment 2

[0023] A method for reclaiming lithium in lithium carbonate heavy lithium mother liquor as high-purity lithium phosphate, comprising the following steps:

[0024] (1) Carbonate removal: add sulfuric acid to the lithium-precipitating mother liquor produced during the preparation of lithium carbonate to adjust the pH to 5, heat up to 75°C and stir for 25 minutes to fully volatilize the carbon dioxide in the lithium-precipitating mother liquor;

[0025] (2) Calcium and magnesium complexation: add sodium hydroxide to the lithium precipitation mother liquor treated in step (1) to adjust the pH value to 12.8, and measure the concentration of lithium ions in the mother liquor to be 0.21mol / L, then take 16000L of the mother liquor and add Put it into a 20000L reactor, add 4Kg EDTA, stir for 25 minutes to fully complex the calcium and magnesium in the mother liquor;

[0026] (3) Precipitation of high-purity lithium phosphate: Add 40Kg lithium phosphate seed crystals to the lithium phos...

Embodiment 3

[0029] A method for reclaiming lithium in lithium carbonate heavy lithium mother liquor as high-purity lithium phosphate, comprising the following steps:

[0030] (1) Carbonate removal: add hydrochloric acid to the lithium precipitation mother liquor produced during the preparation of lithium carbonate to adjust the pH value to 5.5, heat up to 78°C and stir for 30 minutes to fully volatilize the carbon dioxide in the lithium precipitation mother liquor;

[0031] (2) Calcium and magnesium complexation: add sodium hydroxide to the lithium precipitation mother liquor treated in step (1) to adjust the pH value to 13, and measure the concentration of lithium ions in the mother liquor to be 0.21mol / L, then take 16000L of the mother liquor and add Put it into a 20000L reactor, add 8Kg EDTA, and stir for 30 minutes to fully complex the calcium and magnesium in the mother liquor;

[0032] (3) Precipitation of high-purity lithium phosphate: Add 80Kg lithium phosphate seed crystals to th...

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Abstract

The invention discloses a method for recycling lithium in lithium carbonate lithium-settling mother liquor into high-purity lithium phosphate. The method comprises the steps such as carbonate removal, calcium and magnesium complexing, high-purity lithium phosphate settling and drying. According to the method, carbonate removal is firstly carried out on lithium-settling mother liquor of lithium carbonate, and calcium and magnesium in the mother liquor are complexed under an alkaline condition, and the calcium and magnesium react with cheap sodium phosphate to generate lithium phosphate with purity being higher than 99%; and the lithium phosphate can be directly used as a positive electrode material for producing a lithium battery, so that the high-value effective utilization of phosphor and lithium are realized.

Description

technical field [0001] The invention relates to a method for recovering lithium, in particular to a method for recovering lithium in lithium carbonate lithium precipitation mother liquor as high-purity lithium phosphate. Background technique [0002] At present, the method of recovering lithium from the mother liquor in the production of lithium carbonate is either to return the mother liquor to the salt field to concentrate and recover the lithium in the mother liquor, or to use forced evaporation to concentrate and recover the lithium in the mother liquor. Both of these methods will take away a lot of losses when the sodium salt crystallizes out. Therefore, it is extremely important to choose an economical lithium recovery method. [0003] Chinese patent CN104925837A discloses a method for recovering lithium-precipitating mother liquor. This method uses relatively expensive phosphoric acid and sodium hydroxide as raw materials, and the cost is relatively high. The purity o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/30
CPCC01B25/308C01P2006/80
Inventor 何国端李南平蒋燕锋
Owner JIANGSU RONGHUI GENERAL LITHIUM IND CO LTD