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

Abstract

A process for preparing the low-Mg high-Li bitter from the raw bittern of salt lake includes sunning the raw bittern in salt pan and one-stage or multi-stage electric dialyzing by use of selective ion exchange membrane.

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...

Examples

Embodiment

[0041] 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.

[0042] 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

[0045] 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.

[0046] Li + , g / L

[0047] 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

[0049] 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.

[0050] the element ...

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...

Examples

Embodiment

[0041] 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.

[0042] 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

[0045] 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.

[0046] Li + , g / L

[0047] 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

[0049] 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.

[0050] the element ...