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CN-117585844-B - Brine pretreatment method for salt lake

CN117585844BCN 117585844 BCN117585844 BCN 117585844BCN-117585844-B

Abstract

The invention provides a method for pretreating brine of a salt lake, which relates to the technical field of salt lake resource utilization and comprises the steps of sequentially adding an oxidant, an improver and an adsorption filter into salt lake brine, and respectively performing a first reaction, a second reaction and a third reaction, sequentially modifying, improving and adsorbing the salt lake brine, and sequentially performing primary filtration and secondary filtration to complete pretreatment of the salt lake brine and obtain purified brine. The pretreatment method for the brine in the salt lake can remove more than 99% of silt and suspended matter impurities in the salt lake brine, 30% -60% of organic matters and colloid and 20% -60% of chromaticity, so that the salt lake brine is purified, the subsequent lithium extraction process is facilitated, and the pretreatment method has the characteristics of short flow, high lithium yield and low investment and running cost, and achieves good economic and social benefits.

Inventors

  • YANG ZHANCAI
  • LI SHENGBIN
  • YU ZAIYANG
  • Mai Jixin
  • LU JINTAO
  • LI QIYONG
  • YANG ZHANJUN
  • MA SHIJIE
  • ZHU JINLEI

Assignees

  • 上海源依青科技有限责任公司
  • 青海清源锂业科技有限公司

Dates

Publication Date
20260508
Application Date
20231207

Claims (20)

  1. 1. A method for pretreating brine of a salt lake, which is characterized by comprising the following steps: Sequentially adding an oxidant, an improver and an adsorption filter into salt lake brine, respectively performing a first reaction, a second reaction and a third reaction, and sequentially performing primary filtration and secondary filtration to complete pretreatment of the salt lake brine to obtain purified brine, wherein the purified brine is used for extracting lithium; The oxidant comprises any one or a combination of at least two of sodium hypochlorite, ozone or liquid chlorine; the addition amount of the oxidant accounts for 0.001-0.1% of the mass of the salt lake brine; the modifier comprises high-performance multi-chain liquid resin, and in the second reaction, based on the modifier, suspended matters and organic jelly in salt lake brine are modified by flocculation and complexation by utilizing the adsorption and bridging principles.
  2. 2. The method for pretreatment of brine of salt lake according to claim 1, wherein the brine of salt lake comprises any one of raw brine, brine of salt field process or old brine.
  3. 3. The method for pretreatment of brine of salt lake according to claim 1, wherein the water quality of brine of salt lake comprises turbidity of 5-500 NTU, suspended matter of 1-300 mg/L and viscosity of 1-10 mPa S, TOC is 0.1-1.0 g/L, and chromaticity is 50-500.
  4. 4. The method for pretreatment of brine in salt lake according to claim 1, wherein the purified brine comprises turbidity <10NTU and viscosity of 1-6 mPa S, TOC is 0.05-0.5 g/L, and chromaticity is 20-200.
  5. 5. A method of pretreatment of salt lake brine according to claim 1, wherein salt lake brine is heated prior to adding the oxidizing agent.
  6. 6. The method for pretreatment of brine in a salt lake according to claim 5, wherein the temperature of the brine in the salt lake is controlled to be 5-60 ℃.
  7. 7. The method for pretreatment of brine of a salt lake of claim 1 wherein the oxidizer comprises any one or a combination of at least two of sodium hypochlorite, hydrogen peroxide, ozone or liquid chlorine.
  8. 8. The method for pretreatment of brine in a salt lake according to claim 1, wherein the mechanical stirring speed of the first reaction is 200 to 300rpm.
  9. 9. The method for pretreatment of brine in a salt lake according to claim 1, wherein the reaction time of the first reaction is 0.5 to 1h.
  10. 10. The method for pretreatment of brine in a salt lake according to claim 1, wherein the modifier is composed of a high-property multi-chain liquid resin; the addition amount of the modifier accounts for 0.05-0.5% of the mass of the salt lake brine.
  11. 11. The method for pretreatment of brine in a salt lake according to claim 1, wherein the mechanical stirring speed of the second reaction is 100 to 200rpm.
  12. 12. The method for pretreatment of brine in a salt lake according to claim 1, wherein the reaction time of the second reaction is 0.5 to 1h.
  13. 13. The method of pretreatment of brine of a salt lake of claim 1 wherein the adsorption filter comprises any one or a combination of at least two of a cationic active agent, an anionic active agent, polyacrylamide, diatomaceous earth, perlite, cellulose, asbestos, graphite powder, sawdust, magnesium oxide, gypsum, activated carbon, or acid clay.
  14. 14. The method for pretreatment of brine in a salt lake according to claim 1, wherein the addition amount of the adsorption filter agent is 0.1% -1.0% by mass of the brine in the salt lake.
  15. 15. The method for pretreatment of brine in a salt lake according to claim 1, wherein the mechanical stirring speed of the third reaction is 20 to 100rpm.
  16. 16. The method for pretreatment of brine in a salt lake according to claim 1, wherein the reaction time of the third reaction is 0.5 to 1h.
  17. 17. The method for pretreatment of brine in a salt lake according to claim 1, wherein the filtering means for the primary filtration comprises any one of a titanium rod filter, a self-cleaning filter, a ceramic membrane filter, a microporous filter, a candleholder filter, a filter bag filter, a fiber filter, a plate-and-frame filter press, a rotary disc filter, and a sintered filter rod filter.
  18. 18. The method for pretreatment of brine in a salt lake according to claim 17, wherein the filtering device adopted in the primary filtration is provided with water lifters and/or air lifters in a matched manner.
  19. 19. The method for pretreatment of brine in a salt lake of claim 17, wherein the primary filtration pressure is 0.1-1.2 mpa.
  20. 20. The method for pretreatment of brine in a salt lake according to claim 17, wherein the primary filtration has a filtration accuracy of 10 to 200 μm.

Description

Brine pretreatment method for salt lake Technical Field The invention relates to the technical field of salt lake resource utilization, in particular to a method for pretreating brine in a salt lake. Background Lithium is an extremely important energy metal as the lightest metal in nature, and is widely used in the fields of glass, ceramics, electric tanks, nuclear industry, and the like. The domestic salt lake brine has rich lithium resource reserves, and the salt lake brine for extracting lithium has obvious resource and cost advantages. The existing development process for extracting lithium from salt lake brine is also relatively wide, and mainly comprises a solvent extraction method, an electrodialysis method, an electrodeintercalation method, an adsorption method, a membrane method lithium extraction technology and the like, wherein the method can effectively recover lithium resources in the salt lake brine, and meanwhile, no matter which method is adopted, certain requirements are imposed on the water quality of the salt lake brine. For example, the extraction method is easy to cause extraction failure due to impurities in brine, the electrodialysis and electrodeintercalation method is easy to cause membrane stack blockage due to impurities in brine due to narrow flow passage, the resistance is increased, the efficiency is reduced and the like, and the adsorption method is easy to cause adsorbent poisoning failure due to blockage of adsorbent pore channels due to impurities such as suspended matters contained in brine. The membrane method lithium extraction technology is an important technology which is currently suitable for extracting lithium from domestic salt lake brine and recycling resources, and has the advantages of good separation effect, high recovery rate, low environmental protection cost and the like. However, the membrane method lithium extraction technology is limited by membrane materials, has high requirements on the quality of water, and particularly has the defects of short service life, high process cost and the like because suspended matters, colloid and organic matters easily cause membrane pollution. As described above, if the brine is not subjected to suitable pretreatment, the application of the method in extracting lithium from salt lake brine is severely restricted, and the development of the technology for extracting lithium from salt lake brine is also restricted. The salt lake brine is used as one of sources of lithium resources in the lithium extraction of the salt lake, the water quality is complex, and the salt lake brine must be pretreated before entering the lithium extraction process. To remove suspended matters, colloid, silt impurities, organic matters and the like. The main method for removing suspended matters and silt impurities in the wastewater is natural precipitation, or auxiliary precipitation by adding flocculating agent and coagulant, then filtering, wherein the natural precipitation requires larger equipment occupation area, the effect is poor, the auxiliary precipitation by adding medicine is more, and the mud amount is larger. The method for removing colloid in waste water mainly includes coagulation method, ultrafiltration interception, etc. The colloid components in the salt lake brine are complex, the viscosity is high, the traditional method is difficult to be effective, and the ultrafiltration membrane is extremely easy to pollute. The main method for removing the organic matters in the wastewater comprises traditional biochemistry, advanced oxidation, adsorption and the like, wherein the biochemistry method is not suitable for the characteristics of high salinity of salt lake brine, the advanced oxidation such as Fenton is too much in adding of a medicament, and severe in control condition, iron ion pollution is easily brought in, other advanced oxidation such as ozone is easy, the efficiency is low because of the high salt ion effect of the salt lake brine, the degradation efficiency of the organic matters is low, the investment is large, the adsorption method proves to be an effective method for removing the organic matters, but the adsorption method is often selective for adsorbing the organic matters, has good effect on low-molecular and open-chain organic matters, and often needs to be subjected to pre-oxidation modification and improvement to achieve good effect on the macromolecular organic matters. The current common salt lake brine pretreatment method mainly comprises dilution, medium filtration, ultrafiltration, a filtration device, or a combination process and the like, wherein the dilution can reduce viscosity and increase the flux of subsequent filtration, but increases the brine treatment capacity, simultaneously dilutes lithium in brine, does not fundamentally remove impurities in brine, the medium filtration is easy to cause penetration phenomenon, the water quality exceeds standard, influences the downstream process, and regula