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Method for separating magnesium and concentrating lithium from brine in salt lake

A technology of salt lake brine and concentrated solution, applied in magnesium halide, lithium halide, electrodialysis and other directions, can solve the problem of high cost, and achieve the effect of convenient operation, improved utilization rate and good product quality

Inactive Publication Date: 2006-10-25
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Disclosed in the Chinese patent application 01128816.7 is a method of separating magnesium and lithium from high-magnesium-lithium ratio salt lake brine by carbonization to produce lithium carbonate. The method is to evaporate and separate out potassium-magnesium mixed salt, In the old brine after deboronation, alkali is added to precipitate magnesium and lithium in the form of hydroxide, carbonate, phosphate, or oxalate, and the precipitate is calcined and decomposed, and then carbonized or carbonated , so that lithium dissolves into the solution, magnesium remains in the precipitate, so as to achieve the separation of magnesium and lithium, and then carry out deep removal of impurities on the lithium-rich solution, followed by evaporation and concentration or precipitation with soda ash to prepare lithium carbonate, the cost will also be very high

Method used

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Examples

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Effect test

Embodiment

[0040] Send the concentrated lithium-containing old brine in the salt field, which is composed of monovalent and divalent cations such as lithium and magnesium, and anions such as chloride, sulfate and borate, or composed of the above-mentioned ions, into the desalination chamber of the electrodialyzer, which consists of Composed of desalination chamber, concentration chamber and pole chamber.

[0041] The end faces of the concentrating chamber and the desalination chamber are equipped with monovalent cation selective ion exchange membranes and monovalent anion selective ion exchange membranes. The number of membrane pairs in each membrane stack of the electrodialyzer is 1 to 500, and the cathode chamber and the anode chamber are respectively equipped with cathode and anode. When the salt field sent to the desalination chamber of the electrodialyzer is evaporated by the sun, the brine contains Li + The concentration is 0.02-20g / L, the brine is in a turbulent state, and the wo...

Embodiment 1

[0044] Electrodialyzer made of rectangular plexiglass, 10 desalting chambers, 9 concentrating chambers. The models of monovalent ion selective membranes are CMI-7000 and AMI-7000. The anode material is a platinum plate, and the cathode is a stainless steel plate. The total salt concentration of raw brine entering the desalination chamber is 520g / L, which contains 6g / L Li + , 120g / L Mg 2+ ; The initial liquid into the concentration chamber is 0.5M HCl; the initial liquid into the electrode chamber is 0.5M NaCl. Turbulent state, current density 100A / m 2 . Desalted solution, concentrated solution, and electrode solution are circulated separately. Analysis of Li in desalted and concentrated solutions + , Mg 2+ Concentration, and calculate (Mg 2+ / Li + ) Constr , the results are shown in Table I.

[0045] Li + , g / L

[0046] Find out from the result of table 1, (Mg 2+ / Li + ) Constr For 2.1, lithium carbonate can be produced directly by alkali precipitat...

Embodiment 2

[0048] The fastened small electrodialysis device consists of 50 desalting chambers and 51 concentrating chambers, and the monovalent ion selective membrane models are CMS and ACM. The anode is made of titanium-ruthenium-coated plate, and the cathode is titanium-ruthenium-coated plate or stainless steel galvanized plate. The total salt concentration of raw brine entering the desalination chamber is 510g / L, which contains 6g / L Li + , 108g / L Mg 2+ ; The initial liquid entering the concentration chamber is a self-preparation liquid; the initial liquid entering the electrode chamber is 0.5M Na 2 SO 4 . The linear velocity in the desalination chamber is 8cm / sec., and the current density is 100A / m 2 . Desalted solution, concentrated solution, and electrode solution are circulated separately. Analysis of Li in desalted and concentrated solutions + , Mg 2+ Concentration, and calculate (Mg 2+ / Li + ) Constr , the results are shown in Table II.

[0049] the element ...

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Abstract

The invention relates to a method for separating magnesium and concentrating lithium from salt lake brine, which is suitable for the separation of magnesium, borate, sulfate and lithium from salt lake brine containing magnesium and lithium and concentrated old brine containing magnesium and lithium in salt fields; 1. Divalent cations such as Mg 2+ , Ca 2+ and anions such as Cl - , SO 4 2- , B 2 o 3 Lithium-containing concentrated brine is obtained by evaporating the salt fields in the sun, which contains Li + Concentration 0.02~20g / L, (Mg 2+ / Li + ) with a weight ratio of 1:1 to 300:1, through a one-stage or multi-stage electrodialyzer, using a monovalent selective ion exchange membrane to circulate (continuous, continuous partial circulation or batch circulation) process to concentrate lithium to obtain rich Lithium low magnesium brine; The method of the present invention can make Li + The recovery rate ≥ 80%, Mg 2+ The removal rate ≥ 95%, B 3+ The removal rate ≥ 99%, SO 4 2- The removal rate is ≥99%; it solves the problem of separating magnesium and other impurities in high magnesium-lithium ratio salt lake brine, and the lithium-rich brine (Mg 2+ / Li + ) with a weight ratio of 0.3:1 to 10:1, containing Li + The concentration is 2~20g / L.

Description

technical field [0001] The invention relates to a method for separating magnesium and recovering lithium from a solution, in particular to a method for separating magnesium and concentrating lithium from lithium-containing salt lake brine and concentrated lithium-containing old brine in salt fields. Background technique [0002] Lithium ions coexist with a large amount of alkali metals and alkaline earth metals. To economically recover lithium from the natural multi-water salt system with high magnesium-lithium ratio salt lake brine depends not only on the concentration of lithium but also on the concentration of magnesium and calcium ions. Due to the similar chemical properties of magnesium and lithium, the separation of magnesium and lithium is difficult. Lithium extraction from brine produced abroad is limited to brine with low magnesium concentration, and the ratio of magnesium to lithium is less than 6:1, while the ratio of magnesium to lithium in Qinghai Salt Lake brin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01D15/04C01F5/26B01D61/42
Inventor 马培华邓小川温现民
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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