WO2020073610A1 - 锂的高效分离与富集的方法 - Google Patents

锂的高效分离与富集的方法 Download PDF

Info

Publication number
WO2020073610A1
WO2020073610A1 PCT/CN2019/078649 CN2019078649W WO2020073610A1 WO 2020073610 A1 WO2020073610 A1 WO 2020073610A1 CN 2019078649 W CN2019078649 W CN 2019078649W WO 2020073610 A1 WO2020073610 A1 WO 2020073610A1
Authority
WO
WIPO (PCT)
Prior art keywords
nanofiltration
lithium
concentration
reverse osmosis
separation
Prior art date
Application number
PCT/CN2019/078649
Other languages
English (en)
French (fr)
Inventor
王敏
赵有璟
李燕
王怀有
Original Assignee
中国科学院青海盐湖研究所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中国科学院青海盐湖研究所 filed Critical 中国科学院青海盐湖研究所
Priority to US16/954,539 priority Critical patent/US11219864B2/en
Publication of WO2020073610A1 publication Critical patent/WO2020073610A1/zh

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00—Lithium compounds
    • C01D15/04—Halides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/027—Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/029—Multistep processes comprising different kinds of membrane processes selected from reverse osmosis, hyperfiltration or nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/04—Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/06—Energy recovery
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/14—Ultrafiltration; Microfiltration
    • B01D61/145—Ultrafiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/422—Electrodialysis
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B26/00—Obtaining alkali, alkaline earth metals or magnesium
    • C22B26/10—Obtaining alkali metals
    • C22B26/12—Obtaining lithium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/005—Separation by a physical processing technique only, e.g. by mechanical breaking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/04—Specific process operations in the feed stream; Feed pretreatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/06—Specific process operations in the permeate stream
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/08—Specific process operations in the concentrate stream
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/25—Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed
    • B01D2311/251—Recirculation of permeate
    • B01D2311/2512—Recirculation of permeate to feed side
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/25—Recirculation, recycling or bypass, e.g. recirculation of concentrate into the feed
    • B01D2311/252—Recirculation of concentrate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2311/00—Details relating to membrane separation process operations and control
    • B01D2311/26—Further operations combined with membrane separation processes
    • B01D2311/2649—Filtration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2317/00—Membrane module arrangements within a plant or an apparatus
    • B01D2317/02—Elements in series
    • B01D2317/022—Reject series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2317/00—Membrane module arrangements within a plant or an apparatus
    • B01D2317/02—Elements in series
    • B01D2317/025—Permeate series
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2317/00—Membrane module arrangements within a plant or an apparatus
    • B01D2317/08—Use of membrane modules of different kinds

Definitions

  • the present application belongs to the technical field of solution separation and purification, and particularly relates to a method for efficiently separating and enriching lithium.
  • Lithium is a very important strategic resource. As the lightest metal element, lithium exists in nature in two forms: solid ore and liquid ore. China has abundant lithium resource reserves, and the proven industrial reserves of lithium resources rank second in the world, of which lithium brine accounts for 79%. The prospective reserves of salt lake brine in the Qinghai-Tibet Plateau area are equivalent to the total proven reserves of other countries in the world. . According to estimates, Qinghai Salt Lake's lithium resource reserves (in lithium) are 1.5 million tons, ranking first in the country, so salt lake brine extraction of lithium technology has become the top priority of China's competition for energy strategic highlands, and is a major strategic demand of the country.
  • salt lake brine in terms of the composition characteristics of salt lake brine in China, it is very difficult to extract lithium from salt lake brine. This is mainly because one of the salient features of salt lake brines is high magnesium and low lithium (ie, the content of magnesium ions is much higher than the content of lithium ions), and the mass ratio of magnesium to lithium in most salt lake brines is higher than 40, such as the magnesium in the salt lake of Qarhan. / Lithium mass ratio is as high as 1800, Dachaidan salt lake is 114, and the magnesium-lithium ratio of Qinghai salt lake brine is also very high. Due to the similar chemical properties of magnesium and lithium, the existence of a large amount of magnesium makes the separation and extraction of lithium more difficult, so it is necessary to develop new methods for the separation and extraction of salt lake brine magnesium and lithium and other important resources.
  • Existing magnesium-lithium separation methods mainly include: precipitation method, adsorption method, extraction method, etc.
  • the above methods are somewhat restrictive.
  • the precipitation method is suitable for brines with relatively low magnesium and lithium.
  • the adsorption method has the problem of low adsorption capacity of the adsorbent and high cost;
  • the requirements of the extractant are relatively high, and it is easy to cause environmental pollution and equipment corrosion during the extraction process.
  • the above method can achieve lithium enrichment to a certain extent in the process of reducing the ratio of magnesium to lithium brine, the lithium ion content of the finally obtained lithium-rich brine has not yet reached the concentration of high-purity lithium salt preparation, and needs Further enrichment and concentration.
  • the Chinese invention patent with application number 03108088.X describes a method for separating magnesium and enriching lithium from salt lake brine by nanofiltration. Although this method reduces the magnesium-to-lithium ratio of salt lake brines to a certain extent and achieves the enrichment of lithium brines, the lithium ion content of the finally obtained lithium-rich brines has not reached the lithium concentration required for the preparation of high-purity lithium salts. Lithium enrichment and concentration are continued and the lithium ion yield is low during the separation process. Therefore, it is necessary to optimize the existing magnesium-lithium separation technology to solve the problems of lithium ion enrichment efficiency and process cost.
  • the present application provides a method for efficiently separating and enriching lithium.
  • the method includes the following steps:
  • Pre-treatment Dilute and filter the old brine in Yantian to obtain the brine after pre-treatment;
  • the brine after the pretreatment is separated through a nanofiltration separation system to obtain nanofiltration freshwater and nanofiltration concentrated water; the operating pressure of the nanofiltration separation system is 1.0MPa to 5.0MPa;
  • First concentration The nanofiltration fresh water is subjected to the first concentration through the reverse osmosis system to obtain reverse osmosis concentrated liquid and reverse osmosis fresh water;
  • Second concentration The reverse osmosis concentrated solution is subjected to an electrodialysis system for a second concentration to obtain electrodialysis concentrated water and electrodialysis fresh water.
  • the electrodialysis concentrated water is a solution enriched with lithium ions.
  • the nanofiltration separation system uses a monovalent ion selective nanofiltration membrane
  • the nanofiltration separation system includes at least two stages of nanofiltration separation devices, and each stage of the nanofiltration
  • the separation device is composed of multiple stages of nanofiltration separation units connected in series; the pretreated brine first passes through multiple stages of the nanofiltration separation unit of the first stage nanofiltration separation unit for magnesium-lithium separation, and then passes through the multiple stages of the next stage nanofiltration separation unit
  • the nanofiltration separation unit performs magnesium-lithium separation, and after multiple stages of nanofiltration separation, the nanofiltration freshwater and the nanofiltration concentrated water are obtained, wherein the nanofiltration concentrated water is recycled by an energy recovery device.
  • the nanofiltration separation system includes a two-stage nanofiltration separation device, and each stage of the nanofiltration separation device is composed of three stages of nanofiltration separation units connected in series. In any stage of the nanofiltration separation device, three stages The number ratio of the nanofiltration membranes of the nanofiltration separation unit is 35-85: 43-70: 25-55; the concentration of lithium ions in the nanofiltration freshwater is 0.2g / L-2.0g / L, the sodium The mass ratio of magnesium ions to lithium ions in filtered fresh water is 0.02 ⁇ 0.5: 1.
  • the number ratio of the nanofiltration membranes of the three-stage nanofiltration separation unit is 55-65: 52-68: 35-45; the operation of the nanofiltration separation system
  • the pressure is 3.6 MPa to 5.0 MPa
  • the concentration of lithium ions in the nanofiltration fresh water is 0.5 g / L to 1.2 g / L
  • the mass ratio of magnesium ions to lithium ions in the nanofiltration fresh water is 0.05 to 0.2: 1.
  • the pretreatment step is: after the first dilution of the salt field old brine, it is sequentially sent to a multi-media filter for filtration, then sent to an ultrafiltration system for filtration, and then a second dilution is performed to obtain the The brine after pretreatment.
  • the concentration of lithium ions in the salt pan old halogen is 0.2 g / L to 5.0 g / L, and the mass ratio of magnesium ions to lithium ions is 6 to 180: 1; the salt pan
  • the first dilution of old brine is 0.5 to 4.5 times, and the second dilution after filtration by the ultrafiltration system is 3.5 to 20 times.
  • the concentration of lithium ions in the salt pan old halogen is 2.5 g / L to 4.0 g / L, and the mass ratio of magnesium ions to lithium ions is 6 to 55: 1; the salt pan
  • the dilution rate of the old brine after two dilutions is 5-20 times.
  • the dilution ratio of the salt field old brine after two dilutions is 14-16 times.
  • the reverse osmosis system is composed of multiple sections of reverse osmosis units connected in series, and the nanofiltration fresh water passes through the reverse osmosis units of each section for the first concentration to obtain the reverse osmosis concentrated liquid and the reverse osmosis fresh water, The reverse osmosis fresh water is circulated back to the pretreatment step for dilution of the salt pan old brine.
  • the reverse osmosis system is composed of three sections of reverse osmosis units connected in series, and the quantity ratio of the reverse osmosis membranes of the reverse osmosis units of each section is 22 to 62:15 to 45: 5 to 43; the first concentration
  • the operating pressure in the step is 2.0 MPa to 10.0 MPa
  • the lithium ion concentration in the obtained reverse osmosis concentrate is 2.0 g / L to 10 g / L
  • the mass ratio of magnesium ions to lithium ions in the reverse osmosis concentrate It is 0.05 ⁇ 3.0: 1.
  • the quantity ratio of the reverse osmosis membranes of the reverse osmosis unit in each section is 38-46: 25-35: 20-28; the operating pressure in the first concentration step is 3.5MPa-7.0MPa to obtain
  • the lithium ion concentration in the reverse osmosis concentrated solution is 3.0 g / L to 5.0 g / L, and the mass ratio of magnesium ions to lithium ions in the reverse osmosis concentrated solution is 0.07 to 0.2: 1.
  • the ion selective membrane used in the electrodialysis system is one of a homogeneous membrane, a semi-homogeneous membrane or a heterogeneous membrane; the electrodialysis fresh water is circulated back to the
  • the first concentration step is used to concentrate lithium ions; the concentration of lithium ions in the electrodialysis concentrated water is 8 g / L to 21 g / L, and the mass ratio of magnesium ions to lithium ions in the electrodialysis concentrated water It is 0.05 ⁇ 1.0: 1.
  • the ion selective membrane used in the electrodialysis system is a homogeneous membrane, and the cation selective membrane is a CMX homogeneous membrane, and the anion selective membrane is an AMX homogeneous membrane;
  • the electrodialysis The concentration of lithium ions in concentrated water is 14 g / L to 21 g / L, and the mass ratio of magnesium ions to lithium ions in the electrodialysis concentrated water is 0.07 to 0.2: 1.
  • this application uses the advantages of different membrane separation technologies to couple several different membrane separation technologies to make Yantian Laohai pass through the ultrafiltration system, nanofiltration system, reverse osmosis system and electrodialysis system in order to achieve magnesium lithium Separation and enrichment of lithium.
  • all mechanical impurities are filtered through the ultrafiltration system; the nanofiltration system realizes the full separation of magnesium ions and lithium ions and increases the concentration of lithium ions.
  • the mass ratio of magnesium ions to lithium ions in freshwater nanofiltration It has been greatly reduced from the original 6 ⁇ 180: 1 in Yantian Laoliang to 0.02 ⁇ 0.5: 1, which shows that the separation step of this application has effectively achieved the separation of magnesium and lithium; then the lithium ion is concentrated through the reverse osmosis system to reduce the overall The energy consumption of the process and the rationality of the entire process and system are improved. Finally, the lithium-containing concentrated liquid is further concentrated through the electrodialysis system, so that the lithium ion content is greatly increased from 0.2g / L to 5.0g / L of the original salt field old brine.
  • the nanofiltration membrane can withstand the ultra-high operating pressure of 3.6MPa to 5.0MPa, so it can greatly improve the separation process
  • the water flux helps to improve the separation effect of magnesium and lithium and ensure the lithium ion yield during the nanofiltration process.
  • a reverse osmosis system composed of a series of multi-stage reverse osmosis units is used.
  • the lithium ion concentration is effectively increased during the reverse osmosis process.
  • the present application has also studied and limited the quantity ratio of each section of the reverse osmosis membrane in the multi-stage reverse osmosis unit, so as to more fully reduce the permeability of lithium ions in reverse osmosis carbon water.
  • a multi-stage, multi-stage nanofiltration separation method is adopted, and at the same time, an efficient nanofiltration membrane that can work under ultra-high pressure conditions is also used.
  • the multi-stage nanofiltration separation device can perform multi-stage nanofiltration on the brine after pretreatment. After multi-stage nanofiltration, the magnesium-to-lithium ratio of Yantian old brine is greatly reduced, and efficient magnesium-lithium is achieved Separate.
  • this application recovers and recycles the nanofiltration concentrated water produced in the nanofiltration process and the reverse osmosis freshwater produced in the reverse osmosis process, which can effectively reduce the energy consumption of the entire method, reduce the discharge of wastewater and save the process cost.
  • FIG. 1 is a flowchart of the method for separating and enriching lithium in Embodiment 1.
  • FIG. 1 is a flowchart of the method for separating and enriching lithium in Embodiment 1.
  • the salt pan old brine in the examples of the present application comes from a sulfate salt lake in the Qinghai region.
  • the concentration of lithium ions in the salt pan old brine is 2.5g / L
  • the concentration of magnesium ions is 125g / L
  • the mass ratio of magnesium ions to lithium ions is 50: 1.
  • This embodiment provides a method for separating and enriching lithium.
  • the process shown in FIG. 1 is shown in this embodiment.
  • the method in this embodiment includes the following steps:
  • Pre-treatment first dilute the above-mentioned salt pan old brine, and then send the first-diluted salt pan old brine to a multi-media filter to remove some sediment and other mechanical impurities, and then send it to an organic ultrafiltration system for complete removal
  • the dilution factor after the two dilutions is 15 times to obtain the brine after pretreatment.
  • the brine after pretreatment is separated through a nanofiltration separation system to obtain nanofiltration freshwater and nanofiltration concentrated water, wherein the concentration of lithium ions in the nanofiltration freshwater is 0.8g / L, and the concentration of magnesium ions is reduced to 0.11g / L ,
  • the mass ratio of magnesium ions to lithium ions is 0.125: 1. specifically is:
  • the nanofiltration separation system uses a monovalent ion selective nanofiltration membrane.
  • the nanofiltration separation system includes two stages of nanofiltration separation devices, and each stage of the nanofiltration separation device is composed of three stages of nanofiltration separation units connected in series.
  • the brine after the pretreatment first undergoes the three-stage nanofiltration separation unit of the first-stage nanofiltration separation device for magnesium-lithium separation, and then passes through the three-stage nanofiltration separation unit of the second-stage nanofiltration separation device for further magnesium-lithium separation.
  • nanofiltration freshwater and nanofiltration concentrated water are obtained, and the nanofiltration concentrated water is recovered and utilized by an energy recovery device to reduce the discharge of wastewater.
  • the number ratio of the nanofiltration membranes of the three-stage nanofiltration separation unit is 55-65: 52-68: 35-45 in order, and the operating pressure of the nanofiltration separation system is 3.6MPa-5.0 MPa, because the nanofiltration membrane of this embodiment can withstand the ultra-high operating pressure of 3.6MPa to 5.0MPa, it can greatly increase the water flux in the separation process, help to improve the separation effect of magnesium and lithium, and ensure the nanofiltration process Lithium ion yield.
  • the first concentration the nanofiltration fresh water is subjected to the first concentration through the reverse osmosis system to obtain the reverse osmosis concentrated liquid and the reverse osmosis fresh water, wherein the lithium ion concentration in the reverse osmosis concentrated liquid is 5.12g / L, magnesium ion and lithium ion
  • the mass ratio is 0.129: 1.
  • the reverse osmosis system is composed of three sections of reverse osmosis units connected in series. Each section of reverse osmosis units contains a different number of reverse osmosis membranes.
  • Nanofiltration fresh water passes through each section of reverse osmosis units for the first concentration to obtain reverse osmosis concentration Liquid and reverse osmosis fresh water, and the reverse osmosis fresh water is recycled back to the pre-treatment step for the dilution of salt pan old brine to improve the utilization rate of reverse osmosis fresh water.
  • the number ratio of the reverse osmosis membranes of the reverse osmosis unit in each section is 38-46: 25-35: 20-28, and the operating pressure of the first concentration is 7.0 MPa.
  • the second concentration using a homogeneous membrane as the ion selective membrane of the electrodialysis system, the reverse osmosis concentrated liquid is subjected to the second concentration through the electrodialysis system to obtain electrodialysis concentrated water and electrodialysis fresh water, in which the lithium ion in the electrodialysis concentrated water
  • the concentration of 20.5g / L and the mass ratio of magnesium ion to lithium ion is 0.128: 1. Therefore, after the second concentration, the concentration of lithium ion enriched in this example has reached the level required for the preparation of high-purity lithium salt
  • the lithium ion concentration can be used in the subsequent process steps of preparing lithium salts.
  • electrodialysis fresh water is recycled back to the first concentration step for the concentration of lithium ions.
  • the electrodialysis fresh water is blended with the nanofiltration fresh water obtained from the separation step.
  • the reverse osmosis system realizes the recovery of residual lithium and the reuse of electrodialysis fresh water.
  • the method of this embodiment realizes the magnesium-lithium separation of sulfate-type salt lake brine and the efficient enrichment of lithium.
  • the resulting electrodialysis concentrated water (that is, the second concentrated solution) has a high lithium ion concentration, so It can be directly used to prepare high-purity lithium salt.
  • the lithium ion yield in the entire magnesium-lithium separation process is greater than 87%, and the lithium ion yield in the entire lithium ion concentration process is greater than 95%. It can be seen that the method of this embodiment can effectively improve the utilization rate of lithium ions in the entire process.
  • This embodiment provides a method for separating and enriching lithium, including the following steps:
  • Pre-treatment first dilute the above-mentioned salt pan old brine, and then send the first-diluted salt pan old brine to a multi-media filter to remove some sediment and other mechanical impurities, and then send it to an organic ultrafiltration system for complete removal
  • the dilution factor after the two dilutions is 15 times to obtain the brine after pretreatment.
  • the brine after pretreatment is separated through a nanofiltration separation system to obtain nanofiltration freshwater and nanofiltration concentrated water, wherein the concentration of lithium ions in the nanofiltration freshwater is 0.35g / L, and the concentration of magnesium ions is reduced to 0.12g / L ,
  • the mass ratio of magnesium ions to lithium ions is 0.34: 1. specifically is:
  • the nanofiltration separation system uses a monovalent ion selective nanofiltration membrane.
  • the nanofiltration separation system includes two stages of nanofiltration separation devices, and each stage of the nanofiltration separation device is composed of three stages of nanofiltration separation units connected in series.
  • the brine after the pretreatment first undergoes the three-stage nanofiltration separation unit of the first-stage nanofiltration separation device for magnesium-lithium separation, and then passes through the three-stage nanofiltration separation unit of the second-stage nanofiltration separation device for further magnesium-lithium separation.
  • nanofiltration freshwater and nanofiltration concentrated water are obtained, and the nanofiltration concentrated water is recovered and utilized by an energy recovery device to reduce the discharge of wastewater.
  • the number ratio of the nanofiltration membranes of the three-stage nanofiltration separation unit is 55-65: 52-68: 35-45 in order, and the operating pressure of the nanofiltration separation system is 1.0MPa-2.5 MPa, using the ratio of the number of nanofiltration membranes in each section above, can achieve more effective separation of magnesium and lithium, and because the nanofiltration separation of this embodiment can be separated under ultra-high pressure conditions, it helps to further improve the separation of magnesium and lithium Effect, increase the content of lithium ions in nanofiltration freshwater.
  • the first concentration the nanofiltration fresh water is subjected to the first concentration through the reverse osmosis system to obtain the reverse osmosis concentrated liquid and the reverse osmosis fresh water, in which the lithium ion concentration in the reverse osmosis concentrated liquid is 2.5g / L, magnesium ion and lithium ion
  • the mass ratio is 0.38: 1. specifically is:
  • the reverse osmosis system is composed of three sections of reverse osmosis units connected in series. Each section of reverse osmosis units contains a different number of reverse osmosis membranes. Nanofiltration fresh water passes through each section of reverse osmosis units for the first concentration to obtain reverse osmosis concentrated liquid and reverse osmosis liquid. Osmotic fresh water, in which the reverse osmosis fresh water is recycled back to the pre-treatment step for dilution of the old brine in the salt field to improve the utilization rate of the reverse osmosis fresh water.
  • the number ratio of the reverse osmosis membranes of the reverse osmosis unit in each section is 22-34: 15-22: 32-43, and the operating pressure of the first concentration is 7.0 MPa.
  • the second concentration using a homogeneous membrane as the ion selective membrane of the electrodialysis system, the reverse osmosis concentrated liquid is subjected to the second concentration through the electrodialysis system to obtain electrodialysis concentrated water and electrodialysis fresh water, in which the lithium ion in the electrodialysis concentrated water Has a concentration of 11g / L and a mass ratio of magnesium ions to lithium ions of 0.44: 1. Therefore, after secondary concentration, the concentration of lithium ions enriched in this example has reached the lithium required for the preparation of high-purity lithium salts Ion concentration.
  • electrodialysis fresh water is recycled back to the first concentration step for the concentration of lithium ions.
  • the electrodialysis fresh water is blended with the nanofiltration fresh water obtained from the separation step.
  • the reverse osmosis system realizes the recovery of residual lithium and the reuse of electrodialysis fresh water.
  • the method of this embodiment realizes the magnesium-lithium separation of sulfate-type salt lake brine and the efficient enrichment of lithium.
  • the resulting electrodialysis concentrated water (that is, the second concentrated solution) has a high lithium ion concentration, so It can be directly used to prepare high-purity lithium salt.
  • the yield of lithium ions in the entire magnesium-lithium separation process is greater than 70%, and the yield of lithium ions in the entire lithium ion concentration process is greater than 80%. It can be seen that the method of this embodiment can effectively improve the utilization rate of lithium ions in the entire process.
  • This embodiment provides a method for separating and enriching lithium, including the following steps:
  • Pre-treatment first dilute the above-mentioned salt pan old brine, and then send the first-diluted salt pan old brine to a multi-media filter to remove some sediment and other mechanical impurities, and then send it to an organic ultrafiltration system for complete removal
  • the dilution factor after the two dilutions is 15 times to obtain the brine after pretreatment.
  • the brine after pretreatment is separated through a nanofiltration separation system to obtain nanofiltration freshwater and nanofiltration concentrated water, wherein the concentration of lithium ions in the nanofiltration freshwater is 0.81g / L, and the concentration of magnesium ions is reduced to 0.29g / L ,
  • the mass ratio of magnesium ion to lithium ion is 0.36: 1. specifically is:
  • the nanofiltration separation system uses a monovalent ion selective nanofiltration membrane.
  • the nanofiltration separation system includes two stages of nanofiltration separation devices, and each stage of the nanofiltration separation device is composed of three stages of nanofiltration separation units connected in series.
  • the brine after the pretreatment first undergoes the three-stage nanofiltration separation unit of the first-stage nanofiltration separation device for magnesium-lithium separation, and then passes through the three-stage nanofiltration separation unit of the second-stage nanofiltration separation device for further magnesium-lithium separation.
  • nanofiltration freshwater and nanofiltration concentrated water are obtained, and the nanofiltration concentrated water is recovered and utilized by an energy recovery device to reduce the discharge of wastewater.
  • the number ratio of the nanofiltration membranes of the three-stage nanofiltration separation unit is sequentially 45-60: 45-60: 30-50, and the operating pressure of the nanofiltration separation system is 4.5 MPa.
  • the ratio of the number of nanofiltration membranes in the above sections can achieve more effective separation of magnesium and lithium.
  • the nanofiltration separation of this embodiment can be separated under ultrahigh pressure conditions of 4.5 MPa, which helps to further improve the separation of magnesium and lithium Effect, increase the content of lithium ions in nanofiltration freshwater.
  • the first concentration the nanofiltration fresh water is subjected to the first concentration through the reverse osmosis system to obtain the reverse osmosis concentrated liquid and the reverse osmosis fresh water, wherein the lithium ion concentration in the reverse osmosis concentrated liquid is 4.5g / L, magnesium ion and lithium ion
  • the mass ratio is 0.36: 1. specifically is:
  • the reverse osmosis system is composed of three sections of reverse osmosis units connected in series. Each section of reverse osmosis units contains a different number of reverse osmosis membranes. Nanofiltered fresh water passes through each section of reverse osmosis units for the first concentration to obtain reverse osmosis concentrate and reverse osmosis Osmotic fresh water, in which the reverse osmosis fresh water is recycled back to the pre-treatment step for dilution of the old brine in the salt field to improve the utilization rate of the reverse osmosis fresh water.
  • the number ratio of the reverse osmosis membranes of the reverse osmosis unit in each section is 35-43: 20-30: 20-28, and the operating pressure of the first concentration is 7.0 MPa.
  • the second concentration using a homogeneous membrane as the ion selective membrane of the electrodialysis system, the reverse osmosis concentrated liquid is subjected to the second concentration through the electrodialysis system to obtain electrodialysis concentrated water and electrodialysis fresh water, in which the lithium ion in the electrodialysis concentrated water Has a concentration of 19.8g / L and a mass ratio of magnesium ions to lithium ions of 0.35: 1. Therefore, after secondary concentration, the concentration of lithium ions enriched in this example has reached the level required for the preparation of high-purity lithium salts Lithium ion concentration.
  • electrodialysis fresh water is recycled back to the first concentration step for the concentration of lithium ions. Specifically, the electrodialysis fresh water is blended with the nanofiltration fresh water obtained from the separation step.
  • the reverse osmosis system realizes the recovery of residual lithium and the reuse of electrodialysis fresh water.
  • the method of this embodiment realizes the magnesium-lithium separation of sulfate-type salt lake brine and the efficient enrichment of lithium.
  • the resulting electrodialysis concentrated water (that is, the second concentrated solution) has a high lithium ion concentration, so It can be directly used to prepare high-purity lithium salt.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Nanotechnology (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Urology & Nephrology (AREA)
  • Health & Medical Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

提供一种锂的高效分离与富集的方法，包括：前处理，对盐田老卤进行稀释过滤，得到前处理后的卤水；分离，将前处理后的卤水经纳滤分离系统分离，得到纳滤淡水和纳滤浓水；纳滤分离系统的操作压力为1.0MPa~5.0MPa；第一次浓缩，将纳滤淡水经反渗透系统进行第一次浓缩，得到反渗透浓缩液和反渗透淡水；第二次浓缩，将反渗透浓缩液经电渗析系统进行第二次浓缩，得到电渗析浓水和电渗析淡水，电渗析浓水为富集有锂离子的溶液。该方法将不同的膜分离技术进行耦合，在纳滤过程中采用具有良好分离性能的一价离子选择性纳滤膜，可承受超高操作压力，提高镁锂分离效率和富集锂的效率。

Description

锂的高效分离与富集的方法 技术领域
本申请属于溶液分离与纯化技术领域，尤其涉及一种锂的高效分离与富集的方法。
背景技术
锂是一种非常重要的战略资源，作为最轻的金属元素，锂在自然界中有固体矿和液体矿两种存在形式。我国锂资源储量丰富，已探明的锂资源工业储量位居世界第二，其中卤水锂占79％，仅青藏高原地区盐湖卤水锂的远景储量就与世界其他国家目前已探明的总储量相当。据估算，青海盐湖锂资源储量(以锂计)150万吨，居全国首位，故盐湖卤水提锂技术成为我国争夺能源战略高地的重中之重，是国家的重大战略需求。但就我国盐湖卤水的组成特点来看，从盐湖卤水中提取锂的难度很大。这主要是由于盐湖卤水的一个显著特点是高镁低锂(即镁离子的含量远高于锂离子的含量)，大多数盐湖卤水中镁/锂质量比高于40，例如察尔汗盐湖镁/锂质量比高达1800，大柴旦盐湖为114，青海盐湖卤水的镁锂比也非常高。由于镁、锂的化学性质相近，大量镁的存在导致分离、提取锂的难度增大，因此实有必要开发盐湖卤水镁、锂等重要资源分离、提取的新方法。
现有的镁锂分离方法主要包括：沉淀法、吸附法、萃取法等。在分离过程中，上述方法均具有一定程度的限制性。比如：沉淀法适用于镁锂比较低的卤水，当镁锂比较高时存在沉淀剂消耗过大，成本较高的问题；吸附法存在吸附剂的吸附量低，成本高的问题；萃取法对萃取剂的要求比较高，在萃取过程中容易产生环境污染及设备腐蚀等问题。除此之外，虽然上述方法能够在降低卤水镁锂比的过程中一定程度上实现锂的富集，但是最终获得的富锂卤水中锂离子含量尚未达到制备高纯锂盐的浓度、还需要进一步的富集浓缩。
除上述分离方法之外，还有一些利用膜分离技术进行盐湖卤水中镁锂分离的相关研究。例如，申请号为03108088.X的中国发明专利介绍了一种利用纳滤法从盐湖卤水中分离镁和富集锂的方法。虽然该方法在一定程度上降低了盐湖卤水的镁锂比，实现了卤水锂的富集，但是最终获得的富锂卤水中锂离子含量还未达到制备高纯度锂盐所需的锂浓度，需继续进行锂的富集浓缩且分离过程中锂离子收率低。因此，实有必要对现有的镁锂分离技术进行优化，以解决锂离子的 富集效率与工艺成本等问题。
发明内容
为克服现有技术的不足，本申请人进行了潜心研究，在付出了大量创造性劳动和经过深入实验探索后，从而完成了本申请。
为实现前述发明目的，本申请采用的技术方案包括：
本申请提供一种锂的高效分离与富集的方法，所述方法包括以下步骤：
前处理：对盐田老卤进行稀释和过滤，得到前处理后的卤水；
分离：将所述前处理后的卤水经过纳滤分离系统分离，得到纳滤淡水和纳滤浓水；所述纳滤分离系统的操作压力为1.0MPa～5.0MPa；
第一次浓缩：将所述纳滤淡水经过反渗透系统进行第一次浓缩，得到反渗透浓缩液和反渗透淡水；
第二次浓缩：将所述反渗透浓缩液经过电渗析系统进行第二次浓缩，得到电渗析浓水和电渗析淡水，所述电渗析浓水为富集有锂离子的溶液。
进一步地，在所述分离的步骤中，所述纳滤分离系统采用一价离子选择性纳滤膜，所述纳滤分离系统包括至少两级纳滤分离装置，且每一级所述纳滤分离装置由多段纳滤分离单元串联组成；所述前处理后的卤水先经过一级纳滤分离装置的多段所述纳滤分离单元进行镁锂分离，再经过下一级纳滤分离装置的多段所述纳滤分离单元进行镁锂分离，经过多级纳滤分离后，得到所述纳滤淡水和所述纳滤浓水，其中所述纳滤浓水通过能量回收装置回收利用。
进一步地，所述纳滤分离系统包括两级纳滤分离装置，且每一级所述纳滤分离装置由三段纳滤分离单元串联组成，在任一级所述纳滤分离装置中，三段所述纳滤分离单元的纳滤膜的数量比为35～85:43～70:25～55；所述纳滤淡水中锂离子的浓度为0.2g/L～2.0g/L，所述纳滤淡水中镁离子与锂离子的质量比为0.02～0.5:1。
优选地，在任一级所述纳滤分离装置中，三段所述纳滤分离单元的纳滤膜的数量比为55～65:52～68:35～45；所述纳滤分离系统的操作压力为3.6MPa～5.0MPa，所述纳滤淡水中锂离子的浓度为0.5g/L～1.2g/L，所述纳滤淡水中镁离子与锂离子的质量比为0.05～0.2:1。
进一步地，所述前处理的步骤是：将所述盐田老卤进行第一次稀释后，依次送入多介质过滤器过滤、送入超滤系统过滤，再进行第二次稀释，得到所述前处理后的卤水。
进一步地，在所述前处理步骤中，所述盐田老卤中锂离子的浓度为0.2g/L～5.0g/L，镁离子与锂离子的质量比为6～180:1；所述盐田老卤第一次稀释的倍数为0.5～4.5倍，经所述超滤系统过滤后进行第二次稀释的倍数为3.5～20倍。
优选地，在所述前处理步骤中，所述盐田老卤中锂离子的浓度为2.5g/L～4.0g/L，镁离子与锂离子的质量比为6～55:1；所述盐田老卤经过两次稀释后的稀释倍数为5～20倍。
更优选地，所述盐田老卤经过两次稀释后的稀释倍数为14～16倍。
进一步地，所述反渗透系统由多段反渗透单元串联组成，所述纳滤淡水依次经过各段所述反渗透单元进行第一次浓缩，得到所述反渗透浓缩液和所述反渗透淡水，所述反渗透淡水循环回到所述前处理的步骤中、用于所述盐田老卤的稀释。
进一步地，所述反渗透系统由三段反渗透单元串联组成，各段所述反渗透单元的反渗透膜的数量比为22～62:15～45:5～43；所述第一次浓缩的步骤中的操作压力为2.0MPa～10.0MPa，得到的所述反渗透浓缩液中锂离子浓度为2.0g/L～10g/L，所述反渗透浓缩液中镁离子与锂离子的质量比为0.05～3.0:1。
优选地，各段所述反渗透单元的反渗透膜的数量比为38～46:25～35:20～28；所述第一次浓缩的步骤中的操作压力为3.5MPa～7.0MPa，得到的所述反渗透浓缩液中锂离子浓度为3.0g/L～5.0g/L，所述反渗透浓缩液中镁离子与锂离子的质量比为0.07～0.2:1。
进一步地，在所述电渗析的步骤中，所述电渗析系统采用的离子选择膜为均相膜、半均相膜或非均相膜中的一种；所述电渗析淡水循环回到所述第一次浓缩的步骤中，用于对锂离子进行浓缩；所述电渗析浓水中锂离子的浓度为8g/L～21g/L，所述电渗析浓水中镁离子与锂离子的质量比为0.05～1.0:1。
优选地，在所述电渗析的步骤中，所述电渗析系统采用的离子选择膜为均相膜，且阳离子选择膜为CMX均相膜，阴离子选择膜采用AMX均相膜；所述电渗析浓水中锂离子的浓度为14g/L～21g/L，所述电渗析浓水中镁离子与锂离子的质量比为0.07～0.2:1。
本申请的有益效果如下：
首先，本申请利用不同膜分离技术的优势，将几种不同的膜分离技术进行耦合，使盐田老卤依次经过超滤系统、纳滤系统、反渗透系统和电渗析系统的处理，实现镁锂分离以及锂的富集。具体是：通过超滤系统滤去全部机械杂质；通过纳滤系统实现镁离子与锂离子的充分分离、提高锂离子的浓度，经过纳滤后，纳滤淡水中镁离子与锂离子的质量比已经从最初盐田老卤中的 6～180:1大幅降低至0.02～0.5:1，可见本申请的分离步骤高效地实现了镁锂分离；再通过反渗透系统对锂离子进行浓缩，以降低整个方法工艺的能耗、提高整个工艺和系统的合理性，最后再通过电渗析系统进一步浓缩含锂浓缩液，使锂离子含量由最初盐田老卤的0.2g/L～5.0g/L大幅提升至8g/L～21g/L，真正实现锂离子的富集，不仅提高了富集效率，而且保证富集后锂离子的浓度可达到制备高纯度锂盐的要求。综上，经过本专利发明人的系统研究，提出了上述膜分离系统的耦合顺序，能够保证充分利用不同系统的工艺特点，实现盐湖卤水的镁锂分离以及锂的高效浓缩富集，达到制备高纯锂盐所需锂离子的浓度。
其次，由于本申请在纳滤过程中采用具有良好分离性能的一价离子选择性纳滤膜，该纳滤膜可承受3.6MPa～5.0MPa的超高操作压力，故能够大幅度提升分离过程中的水通量，有助于提高镁锂分离效果，保证纳滤过程中的锂离子收率。
再次，本申请的方法在第一次浓缩步骤中，采用了由多段反渗透单元串联组成的反渗透系统，通过多段反渗透操作，有效地在反渗透过程中提高锂离子浓度。尤其是本申请还对多段反渗透单元中各段反渗透膜的数量配比进行了研究与限定，以更加充分地降低反渗透碳水中锂离子的透过率。
另外，本申请在分离步骤中，采用多段、多级的纳滤分离方式，同时还采用了高效、可在超高压条件下工作的纳滤膜。将前处理后的卤水送入纳滤分离系统的高压侧，利用纳滤膜两侧的压差以及纳滤膜对一价、二价离子选择性的差异可实现卤水中镁锂较为充分的分离，由此可有效降低卤水中镁离子和锂离子的质量比，并有助于提高纳滤淡水中锂离子的浓度。不仅如此，通过多级设置的纳滤分离装置，可对前处理后的卤水进行多级纳滤，通过多级纳滤后，使得盐田老卤的镁锂比得到大幅下降，实现高效的镁锂分离。
最后，本申请对纳滤过程产生的纳滤浓水和反渗透过程产生的反渗透淡水进行回收和循环利用，可有效降低整个方法的能耗、减少废水的排放和节省工艺成本。
附图说明
图1是实施例1用于分离与富集锂的方法的流程图。
具体实施方式
本申请实施例中的盐田老卤来自青海地区硫酸盐型盐湖，该盐田老卤中锂离子的浓度为2.5g/L，镁离子的浓度为125g/L，镁离子与锂离子的质量比为50:1。
实施例1
本实施例提供一种用于分离与富集锂的方法，结合图1所示为本实施例的流程，本实施例的方法包括以下步骤：
前处理：将上述盐田老卤进行第一次稀释，将第一次稀释后的盐田老卤先送入多介质过滤器过滤除去部分泥沙等机械杂质，再送入有机超滤系统过滤进行完全除杂，然后进行第二次稀释，两次稀释后的稀释倍数为15倍，得到前处理后的卤水。
分离：将前处理后的卤水经过纳滤分离系统分离，得到纳滤淡水和纳滤浓水，其中纳滤淡水中锂离子的浓度为0.8g/L，镁离子的浓度降低至0.11g/L，镁离子与锂离子的质量比为0.125:1。具体是：
该纳滤分离系统采用一价离子选择性纳滤膜，纳滤分离系统包括两级纳滤分离装置，且每一级所述纳滤分离装置由三段纳滤分离单元串联组成。前处理后的卤水先经过第一级纳滤分离装置的三段纳滤分离单元进行镁锂分离，再经过第二级纳滤分离装置的三段纳滤分离单元进行进一步地镁锂分离，经过两级纳滤分离操作后，得到纳滤淡水和纳滤浓水，其中的纳滤浓水通过能量回收装置回收利用，以减少废水的排放。在本实施例的纳滤分离装置中，三段纳滤分离单元的纳滤膜的数量比依次为55～65:52～68:35～45，纳滤分离系统的操作压力为3.6MPa～5.0MPa，由于本实施例的纳滤膜可承受3.6MPa～5.0MPa的超高操作压力，故能够大幅度提升分离过程中的水通量，有助于提高镁锂分离效果，保证纳滤过程中的锂离子收率。
第一次浓缩：将纳滤淡水经过反渗透系统进行第一次浓缩，得到反渗透浓缩液和反渗透淡水，其中反渗透浓缩液中锂离子的浓度为5.12g/L，镁离子与锂离子的质量比为0.129:1。具体是：该反渗透系统由三段反渗透单元串联组成，每段反渗透单元分别含有不同数量的反渗透膜，纳滤淡水依次经过各段反渗透单元进行第一次浓缩，得到反渗透浓缩液和反渗透淡水，其中的反渗透淡水循环回到前处理的步骤中、用于盐田老卤的稀释，以提高反渗透淡水的利用率。在本实施例的反渗透系统中，各段所述反渗透单元的反渗透膜的数量比为38～46:25～35:20～28，第一次浓缩的操作压力为7.0MPa。通过采用多段、不同反渗透膜数量配比的方式，能够充分降低反渗透淡水中锂的透过率，有助于反渗透浓缩液中锂的富集。
第二次浓缩：采用均相膜作为电渗析系统的离子选择膜，将反渗透浓缩液经过电渗析系统进行第二次浓缩，得到电渗析浓水和电渗析淡水，其中电渗析浓水中锂离子的浓度为20.5g/L，镁离子与锂离子的质量比为0.128:1，由此，经过二次浓缩后，使本实施例富集的锂离子浓度已达 到制备高纯锂盐所需的锂离子浓度，可用于后续制备锂盐工艺步骤。另外，电渗析淡水则循环回到第一次浓缩的步骤中，用于对锂离子进行浓缩，具体是电渗析淡水与从分离步骤中得到的纳滤淡水进行共混，通过第一次浓缩的反渗透系统实现对残余锂的回收和对电渗析淡水的再利用。
本实施例中采用的盐田老卤和分离浓缩各阶段中溶液的组成如下表1所示：
表1 实施例1中盐田老卤和分离浓缩各阶段中溶液的组成
Figure PCTCN2019078649-appb-000001
本实施例的方法实现了硫酸盐型盐湖卤水的镁锂分离及锂的高效富集，最终得到的电渗析浓水(也即第二次浓缩液)由于其中具有较高的锂离子浓度，因此可直接用于制备高纯锂盐。在整个镁锂分离过程中锂离子的收率大于87％，整个锂离子浓缩过程中锂离子的收率大于95％，可见本实施例的方法可有效提高整个过程中锂离子的利用率。
实施例2
本实施例提供一种用于分离与富集锂的方法，包括以下步骤：
前处理：将上述盐田老卤进行第一次稀释，将第一次稀释后的盐田老卤先送入多介质过滤器过滤除去部分泥沙等机械杂质，再送入有机超滤系统过滤进行完全除杂，然后进行第二次稀释，两次稀释后的稀释倍数为15倍，得到前处理后的卤水。
分离：将前处理后的卤水经过纳滤分离系统分离，得到纳滤淡水和纳滤浓水，其中纳滤淡水中锂离子的浓度为0.35g/L，镁离子的浓度降低至0.12g/L，镁离子与锂离子的质量比为0.34:1。具体是：
该纳滤分离系统采用一价离子选择性纳滤膜，纳滤分离系统包括两级纳滤分离装置，且每一级所述纳滤分离装置由三段纳滤分离单元串联组成。前处理后的卤水先经过第一级纳滤分离装置的三段纳滤分离单元进行镁锂分离，再经过第二级纳滤分离装置的三段纳滤分离单元进行进一 步地镁锂分离，经过两级纳滤分离操作后，得到纳滤淡水和纳滤浓水，其中的纳滤浓水通过能量回收装置回收利用，以减少废水的排放。在本实施例的纳滤分离装置中，三段纳滤分离单元的纳滤膜的数量比依次为55～65:52～68:35～45，纳滤分离系统的操作压力为1.0MPa～2.5MPa，采用上述各段纳滤膜的数量配比，能够更有效地实现镁锂分离，同时由于本实施例的纳滤分离可在超高压条件下进行分离，故有助于进一步提高镁锂分离效果、提高纳滤淡水中锂离子含量。
第一次浓缩：将纳滤淡水经过反渗透系统进行第一次浓缩，得到反渗透浓缩液和反渗透淡水，其中反渗透浓缩液中锂离子的浓度为2.5g/L，镁离子与锂离子的质量比为0.38:1。具体是：
该反渗透系统由三段反渗透单元串联组成，每段反渗透单元分别含有不同数量的反渗透膜，纳滤淡水依次经过各段反渗透单元进行第一次浓缩，得到反渗透浓缩液和反渗透淡水，其中的反渗透淡水循环回到前处理的步骤中、用于盐田老卤的稀释，以提高反渗透淡水的利用率。在本实施例的反渗透系统中，各段所述反渗透单元的反渗透膜的数量比为22～34:15～22:32～43，第一次浓缩的操作压力为7.0MPa。通过采用多段、不同反渗透膜数量配比的方式，能够充分降低反渗透淡水中锂的透过率，有助于反渗透浓缩液中锂的富集。
第二次浓缩：采用均相膜作为电渗析系统的离子选择膜，将反渗透浓缩液经过电渗析系统进行第二次浓缩，得到电渗析浓水和电渗析淡水，其中电渗析浓水中锂离子的浓度为11g/L，镁离子与锂离子的质量比为0.44:1，由此，经过二次浓缩后，使本实施例富集的锂离子浓度已达到制备高纯锂盐所需的锂离子浓度。另外，电渗析淡水则循环回到第一次浓缩的步骤中，用于对锂离子进行浓缩，具体是电渗析淡水与从分离步骤中得到的纳滤淡水进行共混，通过第一次浓缩的反渗透系统实现对残余锂的回收和对电渗析淡水的再利用。
本实施例中采用的盐田老卤和分离浓缩各阶段中溶液的组成如下表2所示：
表2 实施例2中盐田老卤和分离浓缩各阶段中溶液的组成
Figure PCTCN2019078649-appb-000002
本实施例的方法实现了硫酸盐型盐湖卤水的镁锂分离及锂的高效富集，最终得到的电渗析浓水(也即第二次浓缩液)由于其中具有较高的锂离子浓度，因此可直接用于制备高纯锂盐。在整个镁锂分离过程中锂离子的收率大于70％，整个锂离子浓缩过程中锂离子的收率大于80％，可见本实施例的方法可有效提高整个过程中锂离子的利用率。
实施例3
本实施例提供一种用于分离与富集锂的方法，包括以下步骤：
前处理：将上述盐田老卤进行第一次稀释，将第一次稀释后的盐田老卤先送入多介质过滤器过滤除去部分泥沙等机械杂质，再送入有机超滤系统过滤进行完全除杂，然后进行第二次稀释，两次稀释后的稀释倍数为15倍，得到前处理后的卤水。
分离：将前处理后的卤水经过纳滤分离系统分离，得到纳滤淡水和纳滤浓水，其中纳滤淡水中锂离子的浓度为0.81g/L，镁离子的浓度降低至0.29g/L，镁离子与锂离子的质量比为0.36:1。具体是：
该纳滤分离系统采用一价离子选择性纳滤膜，纳滤分离系统包括两级纳滤分离装置，且每一级所述纳滤分离装置由三段纳滤分离单元串联组成。前处理后的卤水先经过第一级纳滤分离装置的三段纳滤分离单元进行镁锂分离，再经过第二级纳滤分离装置的三段纳滤分离单元进行进一步地镁锂分离，经过两级纳滤分离操作后，得到纳滤淡水和纳滤浓水，其中的纳滤浓水通过能量回收装置回收利用，以减少废水的排放。在本实施例的纳滤分离装置中，三段纳滤分离单元的纳滤膜的数量比依次为45～60:45～60:30～50，纳滤分离系统的操作压力为4.5MPa，采用上述各段纳滤膜的数量配比，能够更有效地实现镁锂分离，同时由于本实施例的纳滤分离可在4.5MPa的超高压条件下进行分离，故有助于进一步提高镁锂分离效果、提高纳滤淡水中锂离子含量。
第一次浓缩：将纳滤淡水经过反渗透系统进行第一次浓缩，得到反渗透浓缩液和反渗透淡水，其中反渗透浓缩液中锂离子的浓度为4.5g/L，镁离子与锂离子的质量比为0.36:1。具体是：
该反渗透系统由三段反渗透单元串联组成，每段反渗透单元分别含有不同数量的反渗透膜，纳滤淡水依次经过各段反渗透单元进行第一次浓缩，得到反渗透浓缩液和反渗透淡水，其中的反渗透淡水循环回到前处理的步骤中、用于盐田老卤的稀释，以提高反渗透淡水的利用率。在本实施例的反渗透系统中，各段所述反渗透单元的反渗透膜的数量比为35～43:20～30:20～28，第一 次浓缩的操作压力为7.0MPa。通过采用多段、不同反渗透膜数量配比的方式，能够充分降低反渗透淡水中锂的透过率，有助于反渗透浓缩液中锂的富集。
第二次浓缩：采用均相膜作为电渗析系统的离子选择膜，将反渗透浓缩液经过电渗析系统进行第二次浓缩，得到电渗析浓水和电渗析淡水，其中电渗析浓水中锂离子的浓度为19.8g/L，镁离子与锂离子的质量比为0.35:1，由此，经过二次浓缩后，使本实施例富集的锂离子浓度已达到制备高纯锂盐所需的锂离子浓度。另外，电渗析淡水则循环回到第一次浓缩的步骤中，用于对锂离子进行浓缩，具体是电渗析淡水与从分离步骤中得到的纳滤淡水进行共混，通过第一次浓缩的反渗透系统实现对残余锂的回收和对电渗析淡水的再利用。
本实施例中采用的盐田老卤和分离浓缩各阶段中溶液的组成如下表3所示：
表3 实施例3中盐田老卤和分离浓缩各阶段中溶液的组成
Figure PCTCN2019078649-appb-000003
本实施例的方法实现了硫酸盐型盐湖卤水的镁锂分离及锂的高效富集，最终得到的电渗析浓水(也即第二次浓缩液)由于其中具有较高的锂离子浓度，因此可直接用于制备高纯锂盐。
应当理解的是，上述实施例仅用于说明本申请而非意欲限制本申请的保护范围。同时，也应当理解的是，在阅读了本申请的技术内容之后，本领域技术人员可以在不脱离本申请原理的前提下，对发明的技术方案中的条件和步骤作适当改变，来实现最终的技术方案，所有的这些等同形式同样落于本申请所附权利要求书所限定的保护范围之内。

Claims (10)

  1. 一种锂的高效分离与富集的方法，其特征在于，所述方法包括以下步骤：
    前处理：对盐田老卤进行稀释和过滤，得到前处理后的卤水；
    分离：将所述前处理后的卤水经过纳滤分离系统分离，得到纳滤淡水和纳滤浓水；所述纳滤分离系统的操作压力为1.0MPa～5.0MPa；
    第一次浓缩：将所述纳滤淡水经过反渗透系统进行第一次浓缩，得到反渗透浓缩液和反渗透淡水；
    第二次浓缩：将所述反渗透浓缩液经过电渗析系统进行第二次浓缩，得到电渗析浓水和电渗析淡水，所述电渗析浓水为富集有锂离子的溶液。
  2. 根据权利要求1所述的方法，其特征在于，在所述分离的步骤中，所述纳滤分离系统采用一价离子选择性纳滤膜，所述纳滤分离系统包括至少两级纳滤分离装置，且每一级所述纳滤分离装置由多段纳滤分离单元串联组成；所述前处理后的卤水先经过一级纳滤分离装置的多段所述纳滤分离单元进行镁锂分离，再经过下一级纳滤分离装置的多段所述纳滤分离单元进行镁锂分离，经过多级纳滤分离后，得到所述纳滤淡水和所述纳滤浓水，其中所述纳滤浓水通过能量回收装置回收利用。
  3. 根据权利要求2所述的方法，其特征在于，所述纳滤分离系统包括两级纳滤分离装置，且每一级所述纳滤分离装置由三段纳滤分离单元串联组成，在任一级所述纳滤分离装置中，三段所述纳滤分离单元的纳滤膜的数量比为35～85:43～70:25～55；所述纳滤淡水中锂离子的浓度为0.2g/L～2.0g/L，所述纳滤淡水中镁离子与锂离子的质量比为0.02～0.5:1。
  4. 根据权利要求3所述的方法，其特征在于，在任一级所述纳滤分离装置中，三段所述纳滤分离单元的纳滤膜的数量比为55～65:52～68:35～45；所述纳滤分离系统的操作压力为3.6MPa～5.0MPa，所述纳滤淡水中锂离子的浓度为0.5g/L～1.2g/L，所述纳滤淡水中镁离子与锂离子的质量比为0.05～0.2:1。
  5. 根据权利要求1所述的方法，其特征在于，所述前处理的步骤是：将所述盐田老卤进行第一次稀释后，依次送入多介质过滤器过滤、送入超滤系统过滤，再进行第二次稀释，得到所述前处理后的卤水。
  6. 根据权利要求5所述的方法，其特征在于，在所述前处理步骤中，所述盐田老卤中锂离子的 浓度为0.2g/L～5.0g/L，镁离子与锂离子的质量比为6～180:1；所述盐田老卤第一次稀释的倍数为0.5～4.5倍，经所述超滤系统过滤后进行第二次稀释的倍数为3.5～20倍。
  7. 根据权利要求1所述的方法，其特征在于，所述反渗透系统由多段反渗透单元串联组成，所述纳滤淡水依次经过各段所述反渗透单元进行第一次浓缩，得到所述反渗透浓缩液和所述反渗透淡水，所述反渗透淡水循环回到所述前处理的步骤中、用于所述盐田老卤的稀释。
  8. 根据权利要求7所述的方法，其特征在于，所述反渗透系统由三段反渗透单元串联组成，各段所述反渗透单元的反渗透膜的数量比为22～62:15～45:5～43；所述第一次浓缩的步骤中的操作压力为2.0MPa～10.0MPa，得到的所述反渗透浓缩液中锂离子浓度为2.0g/L～10g/L，所述反渗透浓缩液中镁离子与锂离子的质量比为0.05～3.0:1。
  9. 根据权利要求1所述的方法，其特征在于，在所述电渗析的步骤中，所述电渗析系统采用的离子选择膜为均相膜、半均相膜或非均相膜中的一种；所述电渗析淡水循环回到所述第一次浓缩的步骤中，用于对锂离子进行浓缩；所述电渗析浓水中锂离子的浓度为8g/L～21g/L，所述电渗析浓水中镁离子与锂离子的质量比为0.05～1.0:1。
  10. 根据权利要求9所述的方法，其特征在于，在所述电渗析的步骤中，所述电渗析系统采用的离子选择膜为均相膜，且阳离子选择膜为CMX均相膜，阴离子选择膜采用AMX均相膜；所述电渗析浓水中锂离子的浓度为14g/L～21g/L，所述电渗析浓水中镁离子与锂离子的质量比为0.07～0.2:1。
PCT/CN2019/078649 2018-10-10 2019-03-19 锂的高效分离与富集的方法 WO2020073610A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US16/954,539 US11219864B2 (en) 2018-10-10 2019-03-19 Method for efficient separation and enrichment of lithium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201811178789.4A CN109437252B (zh) 2018-10-10 2018-10-10 锂的高效分离与富集的方法
CN201811178789.4 2018-10-10

Publications (1)

Publication Number Publication Date
WO2020073610A1 true WO2020073610A1 (zh) 2020-04-16

Family

ID=65546524

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/078649 WO2020073610A1 (zh) 2018-10-10 2019-03-19 锂的高效分离与富集的方法

Country Status (3)

Country Link
US (1) US11219864B2 (zh)
CN (1) CN109437252B (zh)
WO (1) WO2020073610A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113769593A (zh) * 2021-07-09 2021-12-10 上海唯赛勃环保科技股份有限公司 一种用于盐湖提锂的纳滤膜及其制备方法
CN118028623A (zh) * 2024-02-28 2024-05-14 杭州水处理技术研究开发中心有限公司 一种从盐湖卤水中提取锂和硼的方法

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109437252B (zh) 2018-10-10 2020-02-14 中国科学院青海盐湖研究所 锂的高效分离与富集的方法
CN110002476B (zh) 2019-04-12 2021-05-25 中国科学院青海盐湖研究所 一种氢氧化锂的制备方法
CN110028088B (zh) * 2019-04-12 2021-05-28 中国科学院青海盐湖研究所 一种电池级碳酸锂的制备方法
WO2022125547A1 (en) * 2020-12-08 2022-06-16 Larry Lien Concentration of lithium from unconventional water sources
CN114622103A (zh) * 2020-12-14 2022-06-14 南京水联天下海水淡化技术研究院有限公司 一种膜法盐湖卤水提锂系统
CN114890592A (zh) * 2022-04-02 2022-08-12 倍杰特集团股份有限公司 一种含锂废水的回收处理装置及方法
CN115400604B (zh) * 2022-09-06 2023-08-18 西北工业大学 一种用于镁锂分离的正电荷纳滤膜涂层及制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101979339A (zh) * 2010-09-29 2011-02-23 清华大学 采用絮凝剂联合纳滤膜系统去除水中砷、氟的方法及装置
CN106865582A (zh) * 2017-02-17 2017-06-20 中国科学院青海盐湖研究所 一种盐湖含锂卤水中富集锂的方法
CN107720786A (zh) * 2017-10-18 2018-02-23 中国科学院青海盐湖研究所 一种基于膜分离耦合法的电池级氢氧化锂制备方法
CN108264066A (zh) * 2018-03-22 2018-07-10 何朋飞 一种盐湖卤水生产高纯度氯化锂的新工艺
CN108314064A (zh) * 2018-02-09 2018-07-24 陕西省膜分离技术研究院有限公司 由盐湖卤水多级膜浓缩生产提锂母液的全膜分离方法
CN109437252A (zh) * 2018-10-10 2019-03-08 中国科学院青海盐湖研究所 锂的高效分离与富集的方法

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100408705C (zh) 2003-04-30 2008-08-06 中国科学院青海盐湖研究所 纳滤法从盐湖卤水中分离镁和富集锂的方法
US20120067808A1 (en) * 2010-09-16 2012-03-22 Yatin Tayalia Filtration apparatus and process with reduced flux imbalance
WO2012109313A1 (en) * 2011-02-11 2012-08-16 Siemens Pte. Ltd. Sulfate removal from aqueous waste streams with recycle
US20140311980A1 (en) * 2011-07-20 2014-10-23 Robert Charles William Weston System to Provide a Supply of Controlled Salinity Water for Enhanced Oil Recovery
CN103074502B (zh) * 2013-01-29 2014-04-23 中国科学院青海盐湖研究所 用于从高镁锂比的盐湖卤水分离锂的盐湖卤水处理方法
US20180332864A1 (en) * 2017-05-17 2018-11-22 Zhejiang University Of Technology Continuous On-Board Processing of Seafood after Fishing on the Sea

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101979339A (zh) * 2010-09-29 2011-02-23 清华大学 采用絮凝剂联合纳滤膜系统去除水中砷、氟的方法及装置
CN106865582A (zh) * 2017-02-17 2017-06-20 中国科学院青海盐湖研究所 一种盐湖含锂卤水中富集锂的方法
CN107720786A (zh) * 2017-10-18 2018-02-23 中国科学院青海盐湖研究所 一种基于膜分离耦合法的电池级氢氧化锂制备方法
CN108314064A (zh) * 2018-02-09 2018-07-24 陕西省膜分离技术研究院有限公司 由盐湖卤水多级膜浓缩生产提锂母液的全膜分离方法
CN108264066A (zh) * 2018-03-22 2018-07-10 何朋飞 一种盐湖卤水生产高纯度氯化锂的新工艺
CN109437252A (zh) * 2018-10-10 2019-03-08 中国科学院青海盐湖研究所 锂的高效分离与富集的方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113769593A (zh) * 2021-07-09 2021-12-10 上海唯赛勃环保科技股份有限公司 一种用于盐湖提锂的纳滤膜及其制备方法
CN113769593B (zh) * 2021-07-09 2023-12-29 上海唯赛勃环保科技股份有限公司 一种用于盐湖提锂的纳滤膜及其制备方法
CN118028623A (zh) * 2024-02-28 2024-05-14 杭州水处理技术研究开发中心有限公司 一种从盐湖卤水中提取锂和硼的方法

Also Published As

Publication number Publication date
CN109437252B (zh) 2020-02-14
US11219864B2 (en) 2022-01-11
CN109437252A (zh) 2019-03-08
US20200338502A1 (en) 2020-10-29

Similar Documents

Publication Publication Date Title
WO2020073610A1 (zh) 锂的高效分离与富集的方法
WO2020073612A1 (zh) 用于分离与富集锂的方法
WO2020073611A1 (zh) 一种锂的分离与富集的方法
CN108946770B (zh) 一种分离锂镁并富集锂的方法
CN106865582B (zh) 一种盐湖含锂卤水中富集锂的方法
CN109824065B (zh) 一种镁锂分离并富集锂的方法
CN105152190B (zh) 一种从低锂卤水中分离镁和富集锂生产碳酸锂的方法
WO2017005113A1 (zh) 从盐湖卤水中提取锂的方法
CN108314065B (zh) 由盐湖卤水多级纳滤分盐生产提锂母液的全膜分离方法
CN114105173B (zh) 盐湖卤水提锂系统及工艺
CN108314064B (zh) 由盐湖卤水多级膜浓缩生产提锂母液的全膜分离方法
CN112661321A (zh) 一种基于膜分离的盐湖提锂系统与方法
CN103738984A (zh) 一种盐卤氯化锂的提取方法及装置
CN106882816A (zh) 一种盐湖含锂卤水中富集分离硼的方法
CN114906864A (zh) 从高钙氯化物型盐湖卤水中提锂的方法
CN114870633B (zh) 一种盐湖卤水中锂的富集工艺
CN214060200U (zh) 一种基于膜分离的盐湖提锂系统
CN213951311U (zh) 一种膜法盐湖卤水提锂系统
CN218637035U (zh) 一种盐湖吸附解析合格液浓缩除杂装置
CN116332209A (zh) 一种从拜耳法生产氧化铝的精液中提锂的方法及系统
CN114622103A (zh) 一种膜法盐湖卤水提锂系统
CN115321705B (zh) 一种高镁锂比盐湖卤水镁锂分离方法
CN115818673B (zh) 一种盐湖卤水提锂控制解吸液杂质含量的方法
CN222348845U (zh) 一种高品位卤水的提锂装置系统
CN116199385A (zh) 一种水中一价和多价离子的分离方法和盐湖提锂的方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19871401

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19871401

Country of ref document: EP

Kind code of ref document: A1