A method for separating sodium and lithium from partially ionized sodium-lithium-containing brine

A brine and salt lake brine technology, applied in chemical instruments and methods, lithium halide, alkali metal sulfite/sulfite, etc., can solve the problem that LiOH crystals contain a lot of NaOH impurities, the separation of lithium and sodium is unclear, and the washing is difficult. and other problems, to achieve the effect of overcoming the conversion obstacles, reducing the amount of evaporated water, and ensuring the separation of sodium and lithium

Active Publication Date: 2022-05-06
WUHAN INSTITUTE OF TECHNOLOGY
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  • Claims
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Problems solved by technology

[0005] However, in the technical field of extracting lithium from salt lakes, the main forms of lithium and sodium in the salt lake brine system are lithium chloride and sodium chloride, which cannot be directly separated by the above-mentioned principle of sodium sulfate crystallization. In the chemical field, Cl - System and SO 4 2- The transformation of the system is relatively complicated, so the current extraction of lithium from salt lakes is generally separated by direct evaporation crystallization and pure electrolysis.
The electrolysis method electrolyzes LiCl and NaCl in sodium-lithium brine to form a solution containing LiOH and NaOH. LiOH crystals can be obtained by evaporating the solution and then crystallizing. However, the LiOH crystals obtained by this method contain many NaOH impurities, which are difficult to wash and cause lithium loss. Large; at the same time, direct evaporation crystallization also has technical problems such as unclear separation of lithium and sodium, serious set washing, and large evaporation

Method used

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  • A method for separating sodium and lithium from partially ionized sodium-lithium-containing brine
  • A method for separating sodium and lithium from partially ionized sodium-lithium-containing brine

Examples

Experimental program
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Embodiment 1

[0030] S1: The salt lake brine containing NaCl and LiCl system (n Li+ / n Na+ =8.3) Perform partial electrolysis to obtain LiCl and NaOH solution system, ensuring that 0.98≤nOH in the system - / nNa + ≤1.1;

[0031] S2: Add H to LiOH and LiCl solution system 2 SO 4 , join H 2 SO 4 with Na + The molar ratio is 1:4 to get LiCl and Na 2 SO 4 solution system;

[0032] S3: LiCl and Na 2 SO 4 The solution is evaporated, the evaporation temperature is 40 ° C, so that Na 2 SO 4 In a saturated state, the solution to be frozen is obtained;

[0033] S4: adding a freezing aid to the solution to be frozen; the freezing aid is ethanol;

[0034] S5: The liquid to be frozen with the freezing auxiliary agent is subjected to freezing and crystallization treatment, the freezing temperature is -20°C, and centrifuged to obtain LiCl lithium liquid and Na 2 SO 4 10H 2 O crystals.

Embodiment 2

[0036] S1: The salt lake brine containing NaCl and LiCl system (n Li+ / n Na+ =6.5) Perform partial electrolysis to obtain LiCl and NaOH solution system, ensuring that 0.98≤nOH in the system - / nNa + ≤1.1;

[0037] S2: Add H to LiCl and NaOH solution system 2 SO 4 , join H 2 SO 4 with Na + The molar ratio is 1:4 to get LiCl and Na 2 SO 4 solution system;

[0038] S3: LiCl and Na 2 SO 4 The solution is evaporated, and the evaporation temperature is 80°C, so that Na 2 SO 4 In a saturated state, the solution to be frozen is obtained;

[0039] S4: adding a freezing aid to the solution to be frozen; the freezing aid is isopropyl;

[0040] S5: The liquid to be frozen with the freezing auxiliary agent is subjected to freezing and crystallization treatment, the freezing temperature is -10°C, and centrifuged to obtain LiCl lithium liquid and Na 2 SO 4 10H 2 O crystals.

Embodiment 3

[0042] S1: The salt lake brine containing NaCl and LiCl system (n Li+ / n Na+ =8.8) Perform partial electrolysis to obtain LiCl and NaOH solution system to ensure that 0.98≤nOH in the system - / nNa + ≤1.1;

[0043] S2: Add H to LiCl and NaOH solution system 2 SO 4 , join H 2 SO 4 with Na + The molar ratio is 1:4 to get LiCl and Na 2 SO 4 solution system;

[0044] S3: LiCl and Na 2 SO 4 The solution is evaporated, the evaporation temperature is 100 ° C, so that Na 2 SO 4 In a saturated state, the solution to be frozen is obtained;

[0045] S4: adding a freezing aid to the solution to be frozen; the freezing aid is ethylamine;

[0046] S5: The liquid to be frozen with the freezing auxiliary agent is subjected to freezing and crystallization treatment, the freezing temperature is 5°C, and centrifuged to obtain LiCl lithium liquid and Na 2 SO 4 10H 2 O crystals.

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Abstract

The invention discloses a method for separating sodium and lithium from partially ionized brine containing sodium and lithium, comprising the following steps: S1: performing partial electrolysis on salt lake brine containing NaCl and LiCl systems to obtain LiCl and NaOH solution systems; Add H to the NaOH solution 2 SO 4 , to get LiCl and Na 2 SO 4 Solution system; S3: LiCl and Na 2 SO 4 The solution is evaporated to make Na 2 SO 4 In a saturated state, the solution to be frozen is obtained; S4: adding a freezing auxiliary agent to the solution to be frozen; S5: subjecting the liquid to be frozen with the freezing auxiliary agent to freeze crystallization, and centrifuging to obtain LiCl lithium liquid and Na 2 SO 4 •10H 2 O crystals. The present application converts the chloride system in the original solution into a sulfate radical system, fully utilizes the freezing and crystallization technology of sodium sulfate, realizes the high-efficiency separation of lithium and sodium, and overcomes the system transformation obstacles in the field.

Description

technical field [0001] The invention belongs to the technical field of lithium extraction from salt lakes, and in particular relates to a method for separating sodium and lithium by partially ionizing brine containing sodium and lithium. Background technique [0002] my country is a country with a large amount of lithium resources and has abundant brine resources. Lithium extraction from salt lakes generally needs to use the old brine that has been filtered by sodium and potassium ions as raw materials. After the old brine is re-enriched with lithium, it will be evaporated, magnesium removed, and concentrated to extract lithium ions to produce lithium carbonate. However, since lithium and sodium belong to the same group of elements, their ions are relatively light in mass and have very similar chemical properties, so it is difficult to completely separate them using traditional methods. [0003] At present, in the technical field of caustic soda and the technical field of l...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01D15/04C01D5/00
CPCC01D15/04C01D5/00
Inventor 张勇桑子容韩培林罗喆陈喆
Owner WUHAN INSTITUTE OF TECHNOLOGY
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