Nano-filtration method for separating magnesium and enriching lithium from salt lake brine

A salt lake brine and nanofiltration technology, applied in chemical instruments and methods, semi-permeable membrane separation, lithium compounds, etc., can solve the problems of large turnover of materials, large amount of evaporated water, complicated operations, etc., and achieve simple and reasonable process flow, raw materials The effect of abundant resource reserves and reliable operation

Inactive Publication Date: 2004-11-03
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

Among them, electrolysis and membrane electrolysis are aimed at producing lithium salt compounds, but magnesium and calcium still need to be removed in advance, and a large amount of hydrogen and chlorine will be generated, which is seriously unfavorable to production
The tributyl phosphate extraction method uses concentrated lithium-rich and high-magnesium brine as the production raw material, and the yield is relatively high, but the process is long, the equipment is severely corroded, and the production cost is high, so it is difficult to realize industrialization
The adsorption method uses resin to selectively adsorb lithium ions, but the resin is expensive, has low adsorption capacity, is easily polluted by brine and is difficult to regenerate, and its industrialization is limited by both scale and cost.
The precipitation method is feasible, but the process is long, the yield is low, the turnover of materials is large, the operation is complicated for multiple calcination and filtration, the concentration of lithium in the hydrothermal decomposition or roasting leaching solution is low, and a large amount of water needs to be evaporated when concentrating

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] This example illustrates the separation effect of a primary nanofilter.

[0036] Separation of salt lake brine with CML-DC nanofiltration membrane, the effective membrane area of ​​the membrane is 1.77m 2 . The nanofilter is composed of membrane modules, security filters, raw water pumps, high-pressure pumps, raw water tanks and product water tanks. Put the raw brine containing lithium 0.369g / L, magnesium 7.0g / L, boron 0.392g / L and sulfate 1.508g / L, pH=5.5 into the raw water tank, at 18-30°C and a pressure difference of 850kPa Next, the raw brine is separated. The separation operation is an intermittent cycle operation, that is, the concentrated liquid at the outlet returns to the raw liquid tank for circulation. Sampling analysis after 4.5 hours, each feed liquid composition is as shown in table 1:

[0037] Table 1.

[0038] Liquid flow g / L Li g / L Mg g / L B g / L SO 4 2-

[0039] Raw brine 0.369 7.0 0.392 1.508

[...

Embodiment 2

[0050] This example illustrates the effect of operating temperature on the separation and permeation performance of nanofiltration. Same as embodiment one. The raw brine was separated and enriched at 25-40°C, and after 4.5 hours, each sample was sampled and analyzed. The results are shown in Table 2:

[0051] Table 2

[0052] Liquid flow g / L Li g / L Mg g / L B g / L SO 4 2-

[0053] Raw brine 0.368 6.96 0.392 1.506

[0054] Concentrated water 0.288 9.00 0.505 2.385

[0055] Permeate 0.655 2.99 0.254 0.049

[0056] Separation factor 6.9 4.5 111.8

[0057] When it can be seen that increasing temperature, compared with embodiment one, the separation performance of nanofiltration membrane will be slightly low, but the permeate yield is brought up to 42% by 35%, and the single stage yield of lithium is brought up to by 65% 75%, improving the utilization rate of raw materials.

Embodiment 3

[0059] This example illustrates the separation effect of multi-stage nanofiltration. Same as embodiment one. Send the raw material brine containing 0.202g / L lithium, 20.1g / L magnesium, 0.357g / L boron and 0.943g / L sulfate, pH=6.0 into the stock solution tank. The raw material brine is subjected to three-stage circulation separation under the action of the difference, that is, the lithium-rich product liquid obtained by the first and second nanofilters is used as the raw material brine separated by the second and third nanofilters, and the lithium-poor concentrated solution obtained by the second and third nanofilters is used as the raw material brine. Water is respectively used as the batching mother liquor of the stock solution separated by the primary and secondary nanofilters. The main feed liquid composition and separation factor obtained from the separation are shown in Table 3:

[0060] table 3

[0061] Liquid flow g / L Li ...

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Abstract

The nanofiltration process is suitable for Mg-Li separation and Li enriching of Li containing bittern or Li containing solution from salt lake to prepare lithium carbonate or lithium chloride with the Li enriching bittern. Nanofiltration membrane is used in separating and enriching lithium from lithium containing bittern, which contains Mg, Ca and other cations and sulfate radical and other anions and has Li ion concentration of 0.1-11.5 g/L and Mg/Li ion weight ratio 1-200, to obtain lithium enriched bittern suitable for preparing lithium carbonate or lithium chloride. The said process is effective, and can obtain lithium enriched bittern with Mg/Li ion weight ratio 0.6-5 and Li ion content of 0.6-20 g/L.

Description

technical field [0001] The invention relates to a method for separating magnesium and enriching lithium from salt lake brine by nanofiltration, in particular to a method for separating magnesium and enriching lithium from lithium-containing brine or lithium-containing solution obtained from salt lake. Background of the invention [0002] In the traditional process of extracting lithium from ores, sulfuric acid and spodumene are first roasted together, and then the roasted product is soaked with water, and the obtained lithium sulfate solution is treated with lime and soda ash to remove magnesium and calcium, and then Lithium carbonate precipitated out. Other treatment methods include the so-called alkali method and ion exchange method. The lithium solution obtained by these methods is lithium hydroxide, lithium chloride or lithium sulfate. These methods also include the steps of removing magnesium and calcium from the solution with lime and soda ash. [0003] However, the e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D61/00C01D15/00C02F1/44C22B3/22
CPCY02P10/20
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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