Method for obtaining lithium hydroxide monohydrate

Abstract

The present invention relates to the field of chemical engineering, and more particularly to methods and devices for obtaining lithium hydroxide from brines by bipolar electrodialysis. The present method utilizes energy-efficient purification and electrochemical conversion techniques in the processing of mineral brines. The proposed method and plant for the implementation thereof make it possible to obtain high-purity lithium hydroxide monohydrate from natural calcium chloride-type brines, inter alia in the form of produced water that is a byproduct of the oil production process.

Description

[0001] METHOD FOR PRODUCING LITHIUM HYDROXIDE MONOHYDRATE

[0002] Field of technology.

[0003] The invention relates to the field of chemical technology, namely to methods and installations for producing lithium hydroxide monohydrate from natural calcium chloride brines by conducting bipolar electrodialysis.

[0004] State of the art.

[0005] A method for obtaining lithium hydroxide monohydrate from brines is known according to patent RU2656452C2 [1], in which primary lithium concentrate is obtained from brine containing LiCl at a level of 4-6 kg / m3. 3 , sorption followed by desorption on a sorbent. The primary lithium concentrate is subjected to reverse osmosis concentration to produce a stream of demineralized water and a stream of reverse osmosis brine with a total mineralization of 50-60 kg / m3. 3, then the lithium concentrate is purified from calcium and magnesium impurities by converting them into insoluble compounds using lithium hydroxide and carbon dioxide as reagents and separating the resulting solid phase from a lithium chloride solution with a concentration of 45-55 kg / m3 3 The lithium chloride solution obtained by filtration after removal of calcium and magnesium is acidified with hydrochloric acid to a pH of 6.0-6.5 and subjected to electrodialysis concentration at a current density of 210-220 A / m 2 with obtaining a dialysate flow with a LiCl content at the level of 10-14 kg / m3 3 and a flow of electrodialysis lithium concentrate with a LiCl content of 190-205 kg / m3 3 , the flow of electrodialysis lithium concentrate is deeply purified from the residual amount of calcium and magnesium on the Lewatit-208-TP ion exchanger in Li-form, the electrodialysis lithium concentrate that has undergone ion exchange purification is subjected to thermal evaporation to a LiCl concentration of 450 kg / m3 3with the simultaneous salting out of sodium and potassium chlorides; after separation of the sodium and potassium salts, the evaporated solution is diluted to a lithium chloride content of 350-380 kg / m3 3 and is used as a productive make-up solution for anolyte in the operation of electrochemical conversion of LiCl to LiOH by membrane electrolysis,

[0006] 1

[0007] SUBSTITUTE SHEET (RULE 26) membrane electrolysis is carried out at a current density of 1-4 kA / m 2 and the concentration of lithium chloride in the anolyte at the level of 115-125 kg / m3 3 for which purpose the productive make-up solution of lithium chloride is fed into the circulation anode circuit of the conversion electrochemical system, the flow of spent anolyte is subjected to reagent purification from sulfate ions and combined with electrodialysis concentrate, the content of NH3 in the solution obtained in the electrochemical conversion operation is maintained within the range of 50-80 kg / m3 3The solution is evaporated to obtain OH-H2O crystals. The crystals are separated from the mother liquor, washed counter-currently with demineralized water or condensate, and dried under vacuum in a closed system. Part of the anodic chlorine is absorbed with an aqueous urea solution to obtain a hydrochloric acid solution.

[0008] The disadvantages of this technical solution include the use of electrolysis for the electrochemical conversion of NHCl to NHOH, which is more energy-intensive than the modern method of bipolar membrane electrodialysis. The use of electrolysis is also associated with the formation of by-products in the form of gaseous chlorine and hydrogen, which require disposal or processing and further increase the overall hazard level of such production.

[0009] The method does not provide for preliminary purification of the brine before the operation of obtaining primary lithium concentrate on the sorbent, which can lead to a reduction in the service life of the sorbent and equipment.

[0010] The method does not provide for the purification of brine from boron impurities, the presence of which in the final product reduces its quality.

[0011] A method for producing lithium hydroxide monohydrate from brines is known according to patent RU2470861C2 [2], in which lithium hydroxide monohydrate is obtained from lithium-containing brine, which contains sodium, potassium, magnesium, calcium salts, as well as sulfates and boron as impurities. The method involves concentrating the original brine with the precipitation of sodium and potassium salts from it (as necessary), followed by reagent purification from impurities of boron, magnesium, calcium, sulfate (as necessary) and residual sodium and potassium. After purification, the pH of the brine is raised to 10.5-11 pH units, which allows for the removal of other cations other than lithium. Then, additional purification of the brine occurs through ion exchange in order to reduce the total concentration of calcium and magnesium to a level of less than 150 parts per billion. The brine prepared in this way (composition: Ca <120 ppb, Mg <50 ppb, Sr

[0012] 2

[0013] SUBSTITUTE SHEET (RULE 26) <750 ppb, Ba <lppm, Na < 1000 ppm, К <500 ppm, SO4 <500 ppm, Si <1000 ppm, В <20ppm) направляют на электролиз, на выходе из которого получают раствор гидроксида лития, а также молекулярные хлор и водород (как побочные продукты). Полученный раствор гидроксида лития концентрируют и кристаллизуют с получением моногидрата гидроксида лития. В качестве вариации конечного продукта полученный гидроксид лития переводят в карбонат лития высокой чистоты.

[0014] The disadvantages of the technical solution include the use of reagent purification of brine to remove impurities of boron, magnesium, calcium, and sulfate.

[0015] Another disadvantage of this technical solution is the use of electrolysis for the electrochemical conversion of LiCl to LiOH, which is more energy-intensive than the modern method of bipolar membrane electrodialysis. The use of electrolysis is also associated with the formation of by-products in the form of gaseous chlorine and hydrogen, which require disposal or recycling and further increase the overall hazard level of such production.

[0016] A method for obtaining lithium hydroxide monohydrate from brine is known according to patent RU2713360C2 [3], in which reagent removal of calcium and magnesium in the form of insoluble compounds from lithium chloride concentrate is carried out, decarbonization of lithium chloride concentrate purified from calcium and magnesium by acidification is carried out, purification from solid-phase impurities is carried out by filtration, primary lithium concentrate is obtained on sorption-desorption columns with a fixed bed of selective granular sorbent DGAL-C1 in the form of an aqueous solution containing lithium chloride at a level of 4-6 kg / m 3and macrocomponents of the brine in the form of impurities, the resulting flow of primary lithium concentrate is decarbonated by acidification and sent to a nanofiltration operation for reagent-free purification from the main amount of impurities in the form of magnesium, calcium and sulfate ions, reverse osmosis concentration of the primary lithium concentrate is carried out to obtain a permeate flow in the form of a demineralized aqueous solution and a flow of reverse osmosis lithium concentrate with a total mineralization of 50-60 kg / m3 3 , electrodialysis concentration of lithium chloride concentrate purified from calcium and magnesium and decarbonated is carried out to obtain a flow of lithium-containing dialysate mixed with the primary lithium concentrate before the operation of its reverse osmosis concentration and a flow of electrodialysis lithium concentrate,

[0017] 3

[0018] SUBSTITUTE SHEET (RULE 26) involves deep ion-exchange purification of lithium chloride concentrate using Lewatit 208-TP ion exchange resin in the Li form, electrochemical conversion of the productive lithium chloride solution via membrane electrolysis to produce cathodic hydrogen, anodic chlorine, which is recycled into chlorine-containing commercial products, and an aqueous lithium hydroxide solution, followed by evaporation of the lithium hydroxide solution, crystallization of lithium hydroxide monohydrate, washing of the crystals, and drying. This method was selected as a prototype.

[0019] The disadvantages of this technical solution include the use of electrolysis for the electrochemical conversion of LiCl to LiOH, which is more energy-intensive than the modern method of bipolar membrane electrodialysis. The use of electrolysis is also associated with the formation of by-products in the form of gaseous chlorine and hydrogen, which require disposal or processing and further increase the overall hazard level of such production.

[0020] Another disadvantage of this technical solution is the formation of production waste in the form of insoluble calcium and magnesium salts that require disposal.

[0021] The method proposed in the present invention surpasses the technical solutions known from the prior art and does not contain the indicated disadvantages, makes it possible to obtain high-purity lithium hydroxide monohydrate from natural calcium chloride-type brines, including in the form of formation waters accompanying the oil production process.

[0022] The essence of the invention.

[0023] The aim of the present invention is to obtain high-purity lithium hydroxide monohydrate from natural calcium chloride brines, including those with a neutral environment, without the formation of chlorine and hydrogen in the process, which complicate and increase the danger of production.

[0024] The proposed method allows for the effective purification of the initial brine, which has a beneficial effect on the subsequent process of obtaining primary lithium concentrate using a lithium-selective sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide.

[0025] The proposed installation according to the present invention ensures the implementation of the method claimed in the invention.

[0026] The technical result of the present invention is the production of high-purity lithium hydroxide monohydrate from natural

[0027] 4

[0028] SUBSTITUTE SHEET (RULE 26) for calcium chloride brines, including those in the form of formation waters associated with oil production, including those with a neutral environment, using energy-efficient methods of electrochemical conversion and purification. Achieving the required product purity is ensured by the sequence and composition of the presented processing methods.

[0029] The technical result is achieved in that lithium hydroxide monohydrate is obtained from lithium-bearing brines of the calcium chloride type, by purifying the initial brine from solid-phase impurities by filtration to obtain a productive lithium-bearing brine, sorption production from the productive lithium-bearing brine of primary lithium concentrate by sorption of lithium with a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, washing the sorbent and desorbing lithium from the sorbent, directing the primary lithium concentrate to nanofiltration for purification from magnesium and calcium, reverse osmosis concentration of purified primary lithium concentrate followed by electrodialysis concentration and obtaining electrodialysis lithium concentrate, deep ion-exchange purification on an ion exchanger of electrodialysis lithium concentrate, electrochemical conversion to obtain a lithium hydroxide solution, evaporation of the lithium hydroxide solution,crystallization of lithium hydroxide monohydrate, washing and drying of lithium hydroxide monohydrate crystals, before filtering the initial brine it is treated by increasing the pH and aerating with air, oxygen or a mixture of ozone and oxygen, before electrodialysis concentration the reverse osmosis lithium concentrate is subjected to ion exchange purification from boron, deep ion exchange purification on the ion exchanger of the electrodialysis lithium concentrate is carried out until the total content of residual impurities of calcium and magnesium is 0.1 mg / dm, 3 and less, the electrochemical conversion of purified electrodialysis lithium concentrate is carried out by bipolar membrane electrodialysis to obtain a lithium hydroxide solution with a concentration of 2-3 mol / dm3 3and a solution of hydrochloric acid; in a particular case of implementing the method, the lithium hydroxide crystals can be separated by centrifugation, after washing the lithium hydroxide crystals, they can be recrystallized, and after drying, they can be further ground; in a particular case of implementing the method, a solution of hydrochloric acid obtained in the process of electrochemical conversion of purified electrodialysis lithium

[0030] 5

[0031] SUBSTITUTE SHEET (RULE 26) concentrate, may have a concentration of 2-3 mol / dm 3; in a particular case of implementing the method, a hydrochloric acid solution can be used for regenerating ion exchangers at the stage of cleaning from calcium and magnesium or boron impurities; in a particular case of implementing the method, a hydrochloric acid solution can be used for washing membranes at the stage of nanofiltration and reverse osmosis concentration; in a particular case of implementing the method, thermal concentration can be used for additional concentration of purified reverse osmosis lithium concentrate; in a particular case of implementing the method, reverse osmosis with high-pressure membranes up to 120 bar can be used for additional concentration of purified reverse osmosis lithium concentrate; in a particular case of implementing the method, the mother liquor after separating the lithium hydroxide monohydrate crystals can be used to obtain lithium carbonate;in a particular case of implementing the method, the mother liquor after the extraction of lithium carbonate from it can be subjected to thermal concentration with the extraction of sodium chloride from it and the subsequent use of the solution for bipolar electrodialysis; in a particular case of implementing the method, the mother liquor after the extraction of lithium carbonate from it can be subjected to neutralization with hydrochloric acid to obtain solutions of sodium and potassium chlorides; in a particular case of implementing the method, the solution of hydrochloric acid formed in the stage of bipolar electrodialysis can be used to neutralize the alkali solution after the stage of extracting lithium carbonate.

[0032] The technical result is achieved in that lithium hydroxide monohydrate is obtained from lithium-bearing brines of the calcium chloride type using an installation comprising: a device for aerating the initial brine, providing aeration with air, oxygen or a mixture of ozone and oxygen; a device for filtering the initial brine, from which, as a result of filtration, a productive lithium-bearing brine is obtained; an installation for the sorption separation of lithium, consisting of at least one column filled with a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, in which the sorption of lithium is ensured by passing the productive lithium-bearing brine through the sorbent layer, washing the sorbent and desorbing lithium from the sorbent with the production of primary lithium concentrate; a nanofiltration device for purifying the primary lithium concentrate by filtration from calcium and magnesium and obtaining

[0033] 6

[0034] SUBSTITUTE SHEET (RULE 26) purified primary lithium concentrate, including at least one membrane filter for nanofiltration; a reverse osmosis concentration device that ensures reverse osmosis concentration of purified primary lithium concentrate to obtain a reverse osmosis lithium concentrate and includes at least one semipermeable membrane; an ion-exchange device for boron purification that ensures contact between the reverse osmosis lithium concentrate and an ion exchanger to remove boron ions from the reverse osmosis lithium concentrate and obtain purified reverse osmosis lithium concentrate; an electrodialysis concentration device that includes ion-exchange membranes and at least two electrodes, which ensures concentration of the purified reverse osmosis lithium concentrate to obtain an electrodialysis lithium concentrate;a device for ion exchange purification from calcium and magnesium, providing contact between electrodialysis lithium concentrate and ion exchanger with the removal of magnesium and calcium ions from the reverse osmosis lithium concentrate and the production of purified electrodialysis lithium concentrate; a bipolar membrane electrodialyzer, including bipolar membranes and at least two electrodes, providing electrochemical conversion of purified electrodialysis lithium concentrate with the production of a lithium hydroxide solution with a concentration of 2-3 mol / dm; 3and a hydrochloric acid solution; an evaporator for concentrating the lithium hydroxide solution with salting out lithium hydroxide monohydrate crystals; a solid phase separation device for separating the salted out lithium hydroxide monohydrate crystals from the mother liquor; a washing device for washing the lithium hydroxide monohydrate crystals; a dryer for removing water from the lithium hydroxide monohydrate crystals, wherein the device for aerating the initial brine is connected to a device for filtering the initial brine, the device for filtering the initial brine is connected to a lithium sorption separation unit, the lithium sorption separation unit is connected to a nanofiltration device, the nanofiltration device is connected to a reverse osmosis concentration device, the reverse osmosis concentration device is connected to a device for ion-exchange purification from boron, the ion-exchange purification device from

[0035] 7

[0036] SUBSTITUTE SHEET (RULE 26) boron is connected to an electrodialysis concentration device, the electrodialysis concentration device is connected to an ion-exchange purification device for calcium and magnesium, the ion-exchange purification device for calcium and magnesium is connected to a bipolar membrane electrodialyzer, the bipolar membrane electrodialyzer is connected to an evaporator, the evaporator is connected to a solid phase separation device, the solid phase separation device is connected to a washing device, the washing device is connected to a dryer, in a particular case of implementing the design of the unit, the solid phase separation device can be a centrifuge; in a particular case of implementing the design of the unit, the bipolar membrane electrodialyzer can be connected to a line for removing hydrochloric acid solution, which is formed during the bipolar membrane electrodialysis;in a particular case of the implementation of the design of the plant, the line for the drainage of the hydrochloric acid solution can be connected to the device for ion-exchange purification of boron; in a particular case of the implementation of the design of the plant, the line for the drainage of the hydrochloric acid solution can be connected to the device for ion-exchange purification of calcium and magnesium;in the particular case of the implementation of the design of the installation, the line for draining the hydrochloric acid solution can be connected to the nanofiltration device, in the particular case of the implementation of the design of the installation, the line for draining the hydrochloric acid solution can be connected to the reverse osmosis concentration device, in the particular case of the implementation of the design of the installation, it can additionally contain an auxiliary evaporator, which is installed between the reverse osmosis concentration device and the ion-exchange purification device for boron, in the particular case of the implementation of the design of the installation, it can additionally contain a reverse osmosis concentration device with high-pressure membranes, ensuring operation at a pressure of up to 120 bar, which is installed between the ion-exchange purification device for boron and the electrodialysis concentration device.

[0037] The technical result is achieved by the fact that before filtering the original lithium-bearing brine, it is processed by increasing the pH and aerating it with air, oxygen or a mixture of ozone and oxygen, which ensures the formation of poorly soluble compounds of iron and manganese with an increase in pH (recommended level 6.7-6.8).

[0038] 8

[0039] SUBSTITUTE SHEET (RULE 26) Aeration ensures the oxidation of iron and manganese impurities, as well as flotation purification of petroleum products from impurities. This treatment allows for the removal of impurities, including during the subsequent filtration stage.

[0040] An advantage of the pH increasing method is its ease of implementation due to the use of an available alkali, such as sodium hydroxide.

[0041] In the installation for implementing the method, this technical result is achieved by the fact that, in order to provide aeration with air, oxygen or a mixture of ozone and oxygen, the installation includes a device for aerating the initial brine.

[0042] The technical result is achieved in that the sorption production of primary lithium concentrate from productive lithium-bearing brine is carried out by sorption of lithium with a sorbent based on a chlorine-containing variety of double aluminum-lithium hydroxide, washing the sorbent and desorption of lithium from the sorbent, which ensures the transfer of a minimum amount of impurities from the purified product lithium-bearing brine into the primary lithium concentrate, which in turn affects the purity of the product and simplifies the process of further purification of lithium-bearing brines.

[0043] In the composition of the installation for implementing the method, this technical result is achieved in that the installation includes an installation for the sorption separation of lithium, consisting of at least one column filled with a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, in which the sorption of lithium is ensured by passing productive lithium-bearing brine through the sorbent layer, washing the sorbent and desorbing lithium from the sorbent to obtain primary lithium concentrate.

[0044] The technical result is achieved by sending the primary lithium concentrate to nanofiltration for magnesium and calcium removal, which ensures the removal of up to 90% of calcium and up to 50% of magnesium from the primary lithium concentrate. Removal of calcium and magnesium impurities is necessary because their content is strictly controlled in the final product and is detrimental to the electrodialysis process, as calcium and magnesium hydroxides are insoluble and will clog the membrane.

[0045] As part of the installation for implementing the method, this technical result is achieved in that the installation includes a nanofiltration device for filtration of primary lithium concentrate from calcium and magnesium and obtaining purified primary

[0046] 9

[0047] SUBSTITUTE SHEET (RULE 26) lithium concentrate, including at least one membrane filter for nanofiltration.

[0048] The technical result is achieved by carrying out reverse osmosis concentration of purified primary lithium concentrate, which leads to an increase in the concentration of salts, including impurities, and allows for their most effective removal at subsequent stages of lithium concentrate preparation.

[0049] In the composition of the installation for implementing the method, this technical result is achieved in that the installation includes a reverse osmosis concentration device, which ensures reverse osmosis concentration of purified primary lithium concentrate to obtain a reverse osmosis lithium concentrate and includes at least one semipermeable membrane.

[0050] The technical result is achieved by subjecting the reverse osmosis lithium concentrate to ion-exchange boron removal before electrodialysis concentration, ensuring high-quality lithium concentrate for further purification. Boron removal at this stage of the process is most effective, as it is concentrated in the preceding step, whereas prior to this, the boron content in the concentrate is low, and ion-exchange purification would not have the desired effect. The removal of boron impurities positively impacts the final quality of the product.

[0051] In the installation for implementing the method, this technical result is achieved in that the installation includes an ion-exchange device for boron purification, which ensures contact between the reverse osmosis lithium concentrate and the ion exchanger with the removal of boron ions from the reverse osmosis lithium concentrate and the production of purified reverse osmosis lithium concentrate.

[0052] In the installation for implementing the method, this technical result is achieved in that the installation includes an electrodialysis concentration device, including ion-exchange membranes and at least two electrodes, which ensures the concentration of purified reverse osmosis lithium concentrate to obtain electrodialysis lithium concentrate.

[0053] The technical result is achieved by carrying out ion exchange purification of electrodialysis lithium concentrate on an ion exchanger until the total content of residual calcium impurities is reached and

[0054] 10

[0055] SUBSTITUTE SHEET (RULE 26) magnesium 0.1 mg / dm 3 and less, which ensures the most complete purification from calcium and magnesium, the content of which is strictly controlled in the final product and their removal improves its quality.

[0056] Further purification from these impurities at this stage is also necessary to ensure high quality of the lithium concentrate fed to the bipolar membrane electrodialysis unit, since calcium and magnesium hydroxides are insoluble and will clog the membrane.

[0057] In the installation for implementing the method, this technical result is achieved in that the installation includes an ion exchange device for cleaning calcium and magnesium, which ensures contact between the electrodialysis lithium concentrate and the ion exchanger with the removal of magnesium and calcium ions from the reverse osmosis lithium concentrate and the production of purified electrodialysis lithium concentrate.

[0058] The technical result is achieved in that the electrochemical conversion of purified electrodialysis lithium concentrate is carried out by bipolar membrane electrodialysis to obtain a lithium hydroxide solution with a concentration of 2-3 mol / dm3. 3 , which has higher values ​​compared to membrane electrolysis, which further allows for a reduction in energy costs for obtaining the final product.

[0059] In the installation for implementing the method, this technical result is achieved in that the installation includes a bipolar membrane electrodialyzer, including bipolar membranes and at least two electrodes, providing electrochemical conversion of purified electrodialysis lithium concentrate to obtain a lithium hydroxide solution with a concentration of 2-3 mol / dm3. 3 and a solution of hydrochloric acid.

[0060] The technical result is achieved by evaporating the lithium hydroxide solution to crystallize lithium hydroxide monohydrate from it. This is the simplest and fastest method when energy resources (including associated gas) are readily available. The resulting steam and condensate can be recycled back into the overall product production process. The condensate can also be used for washing lithium hydroxide monohydrate crystals. These factors ensure the simplicity and availability of the technical equipment for isolating lithium hydroxide monohydrate crystals.

[0061] As part of the installation for implementing the method, this technical result is achieved by the fact that the installation includes an evaporator,

[0062] 11

[0063] SUBSTITUTE SHEET (RULE 26) ensuring the concentration of lithium hydroxide solution with the salting out of lithium hydroxide monohydrate crystals.

[0064] The technical result is achieved by washing the isolated crystals of lithium hydroxide monohydrate, which ensures additional removal of impurities and increases the purity of the final product.

[0065] In the installation for implementing the method, this technical result is achieved in that the installation includes a washing device that ensures the washing of lithium hydroxide monohydrate crystals.

[0066] In a particular case, the technical result is achieved by the fact that in a particular case of the method implementation, the separation of lithium hydroxide crystals can be carried out by centrifugation, which ensures the effective separation of crystals, while the process is simple and easy to implement, including the possibility of continuously carrying out the separation process.

[0067] As part of the installation for implementing the method, this technical result is achieved by the fact that the installation can include a centrifuge.

[0068] In a particular case, the technical result is achieved by the possibility of recrystallizing lithium hydroxide crystals, which ensures additional removal of impurities and increases the purity of the final product.

[0069] In a particular case, the technical result is achieved by the fact that after drying, lithium hydroxide crystals can be further crushed, which ensures the required crystal size in the product and increases its consumer qualities.

[0070] In a particular case, the technical result is achieved by the fact that in the process of electrochemical conversion of purified electrodialysis lithium concentrate, a solution of hydrochloric acid with a concentration of 2-3 mol / dm can be obtained 3, which is the optimal concentration and allows the effective use of the acid solution at other stages of the lithium hydroxide monohydrate production process, including the acid solution can be used to regenerate ion-exchange resins at the stage of purification from calcium and magnesium or boron impurities, to wash membranes at the stage of nanofiltration and reverse osmosis concentration, to neutralize the alkali solution after the stage of lithium carbonate extraction (if this stage is present).

[0071] As part of the installation for implementing the method, this technical result is achieved by the fact that the bipolar membrane electrodialyzer

[0072] 12

[0073] SUBSTITUTE SHEET (RULE 26) may be connected to the line for removing hydrochloric acid solution, which is formed during the bipolar membrane electrodialysis; in a particular case of the implementation of the plant design, the line for removing hydrochloric acid solution may be connected to the ion-exchange device for boron purification; in a particular case of the implementation of the plant design, the line for removing hydrochloric acid solution may be connected to the ion-exchange device for calcium and magnesium purification; in a particular case of the implementation of the plant design, the line for removing hydrochloric acid solution may be connected to the nanofiltration device, in a particular case of the implementation of the plant design, the line for removing hydrochloric acid solution may be connected to the reverse osmosis concentration device.

[0074] In a particular case, the technical result is achieved by the fact that additional concentration of purified reverse osmosis lithium concentrate can be carried out by thermal concentration, which ensures a reduction in the requirements for the degree of concentration during reverse osmosis concentration, and in the case of an additional increase in concentration, an improvement in the quality of subsequent ion-exchange purification is achieved.

[0075] In the installation for implementing the method, this technical result is achieved in that the installation additionally contains an auxiliary evaporator, which is installed between the reverse osmosis concentration device and the ion-exchange device for boron purification.

[0076] In a particular case, the technical result is achieved by the fact that additional concentration of purified reverse osmosis lithium concentrate can be carried out using a reverse osmosis unit with high-pressure membranes up to 120 bar, which reduces the requirements for the degree of concentration during primary reverse osmosis concentration, and in the case of an additional increase in concentration, an improvement in the quality of subsequent ion-exchange purification is achieved.

[0077] In the installation for implementing the method, this technical result is achieved in that the installation additionally contains a reverse osmosis concentration device with high-pressure membranes, ensuring operation at a pressure of up to 120 bar, which is installed between the ion-exchange device for boron purification and the electrodialysis concentration device.

[0078] 13

[0079] SUBSTITUTE SHEET (RULE 26) In a particular case, the technical result is achieved by the fact that the mother liquor after separating the lithium hydroxide monohydrate crystals can be used to obtain lithium carbonate, which reduces the loss of lithium during the production of the product, leading to an increase in the profitability of the process.

[0080] In a particular case, the technical result is achieved by the fact that the mother liquor, after the extraction of lithium carbonate from it, can be subjected to thermal concentration with the extraction of sodium chloride from it and the subsequent use of the solution for bipolar electrodialysis, which ensures the production of an additional product in the form of sodium chloride and the recovery of substances in the process of obtaining lithium hydroxide monohydrate (water savings), which leads to an increase in the profitability of the process.

[0081] In a particular case, the technical result is achieved by the fact that the mother liquor, after the extraction of lithium carbonate from it, can be neutralized with hydrochloric acid to obtain solutions of sodium and potassium chlorides, which ensures the production of a product for the further extraction of potassium chloride and sodium chloride, increasing the profitability of the process.

[0082] The technical result is achieved for calcium chloride brines, including in the form of formation waters accompanying the oil production process, due to the fact that the method includes increasing the pH; a procedure for aeration with air, oxygen or a mixture of ozone and oxygen to remove impurities of iron, manganese and oil products; sorption production of lithium-bearing brine; nanofiltration for purifying the lithium-bearing brine from impurities of calcium and magnesium; reverse osmosis concentration of purified primary lithium concentrate; ion-exchange purification from boron followed by electrodialysis concentration of lithium concentrate; ion-exchange purification of electrodialysis lithium concentrate for the final removal of impurities of calcium and magnesium; electrochemical conversion of purified electrodialysis lithium concentrate by the method of bipolar membrane electrodialysis to obtain a lithium hydroxide solution with a concentration of 2-3 mol / dm 3; by evaporating the resulting lithium hydroxide solution to obtain crystalline lithium hydroxide monohydrate, followed by washing it to increase the purity of the final product.

[0083] In its most general form, the method of the present invention can be carried out as follows, but is not limited thereto.

[0084] 14

[0085] SUBSTITUTE SHEET (RULE 26) Description of drawings.

[0086] Fig. 1. Example of a diagram for implementing the method.

[0087] Fig. 2. Example of a diagram of an installation for implementing the method.

[0088] An example of the method implementation scheme is shown in Fig. 1, according to this scheme, the initial brine in the form of a lithium-bearing brine of the calcium chloride type is subjected to treatment in order to increase the pH, aerated using air, oxygen or a mixture of ozone with oxygen and then filtered, whereby the removal of metal impurities and oil products, in particular iron and manganese, is achieved, with the production of a productive lithium-bearing brine, which is sent to the stage of sorption extraction of lithium with a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide with the production of an eluate in the form of a primary lithium concentrate, which is sent to nanofiltration for purification from magnesium and calcium with the production of purified primary lithium concentrate, reverse osmosis concentration of the purified primary lithium concentrate is carried out with the production of a reverse osmosis lithium concentrate,which is subjected to ion-exchange purification from boron to obtain purified reverse osmosis lithium concentrate, which is subjected to electrodialysis concentration to obtain electrodialysis lithium concentrate, the electrodialysis lithium concentrate is subjected to deep ion-exchange purification from calcium and magnesium to ensure a total content of their impurities of 0.1 mg / dm3, 3 and less, thus obtaining purified electrodialysis lithium concentrate, which is sent to bipolar electrodialysis, during which a lithium hydroxide solution with a concentration of 2-3 mol / dm3 is obtained 3 and a solution of hydrochloric acid, the lithium hydroxide solution also contains impurities of sodium and potassium hydroxides, the lithium hydroxide solution is evaporated with the salting out of lithium hydroxide monohydrate crystals, the precipitate is centrifuged with the separation of lithium hydroxide monohydrate crystals, which are then washed and dried.

[0089] The diagram shows an expanded version of the method, which includes the precipitation of lithium carbonate from the mother liquor of the lithium hydroxide solution evaporation operation by introducing sodium carbonate, then the mother liquor of the lithium carbonate precipitation operation is evaporated and sent to the bipolar electrodialysis operation.

[0090] 15

[0091] SUBSTITUTE SHEET (RULE 26) An example of a diagram of an installation for implementing the method according to the present invention is shown in Fig. 2, according to this diagram, the initial brine is fed through the initial brine feed line (2) to the initial brine aeration device (3), where aeration occurs with gas, which can be air, oxygen or a mixture of ozone and oxygen, the gas is fed through the gas feed line (4) from a gas source (5), excess gas is removed from the initial brine aeration device (3) through the gas outlet line (1), the initial brine, having undergone aeration, is fed through the initial brine outlet line (6) to the initial brine filtration device (7), where productive lithium-bearing brine is obtained by filtration, which is fed through the productive lithium-bearing brine line (8) to the lithium sorption separation unit (9),in the lithium sorption separation unit, lithium is sorbed from the productive lithium-bearing brine by a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, then the sorbent is washed and lithium is desorbed from the sorbent to obtain a primary lithium concentrate, the primary lithium concentrate is fed through the primary lithium concentrate outlet line (10) to the nanofiltration device (11), where calcium and magnesium impurities are removed on a membrane filter to obtain a purified primary lithium concentrate, which is discharged through the purified primary lithium concentrate line (13) to the reverse osmosis concentration device (14), the calcium- and magnesium-rich brine from the nanofiltration device (11) is discharged through the waste brine outlet line (12),in the reverse osmosis concentration device (14), a reverse osmosis lithium concentrate is obtained from purified primary lithium concentrate using a semi-permeable membrane, the reverse osmosis lithium concentrate is fed through the reverse osmosis lithium concentrate outlet line (16) to the ion-exchange device for boron purification (17), the permeate obtained in the reverse osmosis concentration unit (14) is discharged through the permeate discharge line (15), the ion-exchange device for boron purification (17) contains a boron-selective ion exchanger, during the passage of the reverse osmosis lithium concentrate through which purified reverse osmosis lithium concentrate is obtained, which is fed through the reverse osmosis lithium concentrate line (18) to the electrodialysis concentration device (19), in which, under the action of a magnetic field using ion-exchange membranes, purified reverse osmosis lithium concentrate is obtained from the purified reverse osmosis lithium concentrate,

[0092] 16

[0093] SUBSTITUTE SHEET (RULE 26) electrodialysis lithium concentrate, which is fed through the electrodialysis lithium concentrate line (21) to the ion-exchange device for cleaning calcium and magnesium (22), the water flow obtained as a result of electrodialysis is discharged through the water discharge line (20), the ion-exchange device for cleaning calcium and magnesium (22) contains an ion exchanger, during the passage of the electrodialysis lithium concentrate through which purified electrodialysis lithium concentrate is obtained, which is fed through the purified electrodialysis lithium concentrate line (23) to the bipolar membrane electrodialyzer (24), at the outlet of which a hydrochloric acid solution and a lithium hydroxide solution are obtained, the hydrochloric acid solution is discharged through the hydrochloric acid solution discharge line (25), and the lithium hydroxide solution is fed through the lithium hydroxide solution line (26) to the evaporator (27),In the evaporator, the lithium hydroxide solution is concentrated by evaporation with salting out of lithium hydroxide monohydrate crystals, which are separated from the liquid phase in the separation device (28), the separated lithium hydroxide monohydrate crystals are sent through the discharge channel (29) to the washing device (30), in which the lithium hydroxide monohydrate crystals are washed with water, the washed lithium hydroxide monohydrate crystals are fed through the discharge channel (31) to the dryer (32), where excess water is removed by evaporation.

[0094] Below are specific examples of the implementation of the method according to the present invention.

[0095] Example 1.

[0096] A plant was installed for producing high-purity lithium hydroxide monohydrate from lithium-bearing brines of the calcium chloride type. The plant was installed according to the diagram in Fig. 2 and included: a gas outlet line (1), a feed brine feed line (2), a feed brine aeration device (3), a gas feed line (4), a gas source (5), a feed brine outlet line (6), a feed brine filtration device (7), a productive lithium-bearing brine line (8), a lithium sorption separation unit (9), a primary lithium concentrate outlet line (10), a nanofiltration device (11), a waste brine outlet line (12), a purified primary lithium concentrate line (13), a reverse osmosis concentration device (14), a permeate discharge line (15), a reverse osmosis lithium concentrate outlet line (16), a boron ion exchange purification device (17), a reverse osmosis lithium concentrate line (18), a device

[0097] 17

[0098] SUBSTITUTE SHEET (RULE 26) electrodialysis concentration (19), electrodialysis lithium concentrate line (21), ion-exchange purification device for calcium and magnesium (22), water discharge line (20), ion-exchange purification device for calcium and magnesium (22), purified electrodialysis lithium concentrate line (23), bipolar membrane electrodialyzer (24), hydrochloric acid solution discharge line (25), lithium hydroxide solution line (26), evaporator (27), separation device (28), discharge channel (29), washing device (30) in the form of a reactor with a centrifuge and tanks with liquids for washing, discharge channel (31), dryer (32).

[0099] Natural calcium chloride brine (composition, mg / dm3) was fed to the feed brine supply line (2) 3 : lithium - 80-420; E(Na + , TO + ) = 24000- 39000; Total, Mp 2+ ) = 115-165; L(Ca 2+ , Mg 2+) = 120800-158300; Cl' = 220000- 320000; B = 100-600; oil products - 45-50, pH = 3-5), then it was alkalized by introducing sodium hydroxide to 6.7-6.8 pH units, followed by aeration with air in a device for aerating the original brine (3) for 2 hours, which ensured the precipitation of iron and manganese compounds from the solution, impurities of oil products were removed in the process by flotation, excess air during aeration was removed through the gas outlet line (1), air for aeration was supplied through the gas supply line (4) from a gas source (5), made in the form of an air receiver.

[0100] The initial brine after alkalization and aeration through the initial brine outlet line (6) was fed for filtration into the initial brine filtration device (7), made in the form of a block of flow filters with backwashing; at the outlet of the filter block, a product lithium-bearing brine with a residual content of impurities, mg / dm3, was obtained. 3 : Re О bsh., Mp 2+) = 1.5-3; petroleum products - 0-4, level B was not measured at this stage.

[0101] The resulting product lithium-bearing brine was sent through the productive lithium-bearing brine line (8) to the lithium sorption separation unit (9), made in the form of a sorption-desorption module containing columns filled with a sorbent based on DGAL-S1. In the lithium sorption separation unit, lithium was sorbed by the sorbent, the sorbent was washed, and lithium was desorbed from the sorbent to obtain an eluate in the form of a primary lithium concentrate, which contained 300-500 mg / dm 3 lithium.

[0102] The primary lithium concentrate was sent through the primary lithium concentrate outlet line (10) to the nanofiltration device (11), where up to 90% of calcium and up to 50% of magnesium were removed from it during nanofiltration treatment, and the contaminated brine was discharged through the outlet line.

[0103] 18

[0104] SUBSTITUTE SHEET (RULE 26) of the discharge brine (12), and the purified primary lithium concentrate was fed through the purified primary lithium concentrate line (13) to the reverse osmosis concentration device (14) for reverse osmosis concentration, during concentration the boron concentration was brought to 50-180 mg / dm3 3 and the reverse osmosis lithium concentrate was removed from the process via the reverse osmosis lithium concentrate outlet line (16) into the ion exchange device for boron purification (17), the permeate obtained in the process of reverse osmosis concentration was removed via the permeate discharge line (15).

[0105] Carrying out ion-exchange purification of reverse osmosis lithium concentrate from boron ensured a reduction in boron-containing impurities in it to 4-5 mg / dm3 3, thus, a purified reverse osmosis lithium concentrate was obtained, which was sent through the reverse osmosis lithium concentrate line (18) to the electrodialysis concentration device (19), where electrodialysis concentration was carried out to obtain an electrodialysis lithium concentrate having a total salt content of 90-150 g / dm3 3 The water obtained during electrodialysis concentration was removed through the water discharge line (20).

[0106] The resulting lithium electrodialysis concentrate was sent through the lithium electrodialysis concentrate line (21) to the ion-exchange purification device for calcium and magnesium (22), where calcium and magnesium salts were removed from it using an ion-exchange resin until their residual total content was 0.1 mg / dm3. 3and less, as a result, purified electrodialysis lithium concentrate was obtained, which was sent through the purified electrodialysis lithium concentrate line (23) to a bipolar membrane electrodialyzer (24).

[0107] In a bipolar membrane electrodialyzer, two streams were formed: a solution of hydrochloric acid and a solution of alkalis, mainly in the form of lithium hydroxide, with a concentration of 2-3 mol / dm3 3 .

[0108] A 10.3% concentration hydrochloric acid solution was removed as a commercial product via the hydrochloric acid solution outlet line (25).

[0109] The alkali solution (mainly lithium hydroxide) was removed through the lithium hydroxide solution line (26) into the evaporator (27), where thermal evaporation of the solution was carried out with the precipitation of lithium hydroxide monohydrate crystals, which were separated in the separation device (28), made in the form of a centrifuge, and removed through the channel

[0110] 19

[0111] SUBSTITUTE SHEET (RULE 26) unloading (29) into the washing device (30), made in the form of a reactor with a centrifuge and tanks with liquids for washing. Lithium hydroxide monohydrate crystals were washed in the washing device, from where the washed lithium hydroxide monohydrate crystals were directed through the unloading channel (31) into the dryer (32), where excess water was removed, at the outlet of the dryer, a product was obtained in the form of lithium hydroxide monohydrate with a mass fraction of lithium hydroxide of 56.2%, impurities, %: carbonates - 0.6; potassium + sodium - 0.5; calcium + magnesium - 0.003; iron - 0.001; chlorides - 0.02.

[0112] Example 2.

[0113] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that after washing the lithium hydroxide crystals and before drying them, they were recrystallized, and after drying, they were ground.

[0114] Recrystallization provided an increase in the purity of the final product; a product was obtained with a mass fraction of lithium hydroxide of 56.7%, impurities, %: carbonates - 0.4; potassium + sodium - 0.002; calcium + magnesium - 0.002; iron - 0.001; chlorides - 0.02.

[0115] Additional grinding of crystals ensured commercial quality in the form of powder homogeneity.

[0116] Example 3.

[0117] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that oxygen was used instead of air during the aeration of the initial brine, which made it possible to reduce the aeration time to 35 minutes, while the solution obtained after filtration contained impurities, mg / dm3 3 : S(Fe06ni., Mn 2+ ) = 1.5-3; petroleum products - 0-4.

[0118] Example 4.

[0119] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that during the aeration of the initial brine, a mixture of ozone and oxygen was used instead of air, which made it possible to reduce the aeration time to 5 minutes, while the solution obtained after filtration also contained impurities, mg / dm3 3 : L(Fe06m., Mn 2+ ) - 1.5-3; petroleum products - 0-4.

[0120] Example 5.

[0121] Lithium hydroxide monohydrate was obtained according to Example 1 with the difference that instead of a bipolar membrane

[0122] 20

[0123] SUBSTITUTE SHEET (RULE 26) of the electrodialyzer, a membrane electrolyzer was used, and in order to ensure the removal from the electrolyzer of the same amount of lithium hydroxide in the solution as from the bipolar membrane electrodialyzer according to Example 1, 20% more electricity was spent, and the resulting solution had a concentration of less than 2 mol / dm3 3, which increases energy costs for further evaporation.

[0124] Example 6.

[0125] Lithium hydroxide monohydrate was obtained according to Example 1 with the difference that the hydrochloric acid solution removed from the bipolar membrane electrodialysis process had a concentration of 2-3 mol / dm3. 3 It was redirected for the regeneration of ion exchange resins during the calcium, magnesium, and boron removal stages, as well as for membrane flushing during the nanofiltration and reverse osmosis concentration stages. This allowed for savings on plant maintenance, including the automation of the ion exchange resin and membrane regeneration processes within a single unit. To support these processes, the hydrochloric acid solution drainage line was connected to the corresponding devices.

[0126] Example 7.

[0127] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that the purified reverse osmosis lithium concentrate was additionally evaporated, which improved the quality of subsequent ion exchange purification.

[0128] Example 8.

[0129] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that the purified reverse osmosis lithium concentrate was additionally concentrated using a reverse osmosis unit with high-pressure membranes up to 120 bar, which improved the quality of subsequent ion-exchange purification.

[0130] Example 9.

[0131] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that in the process of separating the lithium hydroxide monohydrate crystals in the separation device (28), made in the form of a centrifuge, the mother liquor was isolated, which was sent to obtain lithium carbonate by mixing with a 20% solution of sodium carbonate, the obtained lithium carbonate was filtered, washed, dried and ground to obtain technical grade lithium carbonate.

[0132] The mother liquor obtained as a result of separation of lithium carbonate was neutralized with a solution of hydrochloric acid obtained in the stage

[0133] 21

[0134] SUBSTITUTE SHEET (RULE 26) bipolar electrodialysis, as a result of the process a solution of sodium and potassium chlorides was obtained.

[0135] This is how secondary products of the process were obtained.

[0136] Example 10.

[0137] Lithium hydroxide monohydrate was obtained according to Example 1, with the difference that in the process of separating the lithium hydroxide monohydrate crystals in the separation device (28), made in the form of a centrifuge, the mother liquor was isolated, which was sent to obtain lithium carbonate by mixing with a 20% solution of sodium carbonate, the obtained lithium carbonate was filtered, washed, dried and ground to obtain technical grade lithium carbonate.

[0138] After removing the lithium carbonate, the mother liquor was evaporated to recover sodium chloride, which was washed, recrystallized, dried, and ground, yielding technical-grade sodium chloride. After separation of the sodium chloride, the mother liquor was returned to bipolar electrodialysis.

[0139] This is how secondary products of the process were obtained.

[0140] Sources of information used:

[0141] 1. Patent RU2656452C2. COID 15 / 02, C25B 1 / 16. Method for producing lithium hydroxide monohydrate from brines and installation for its implementation / Ryabtsev Alexander Dmitrievich (RU), Nemkov Nikolay Mikhailovich (RU), Titarenko Valery Ivanovich (RU), Kotsupalo Natalya Pavlovna (RU). Application 02 / 04 / 2016, publ. 08 / 10 / 2017.

[0142] 2. Patent RU2470861C2. COID 1 / 04, COID 15 / 02, C25B 1 / 16, C01B 7 / 01. Method for producing high-purity lithium hydroxide and hydrochloric acid / Buckley David J. (US), Gendere J. David (US), Atherton Dan (US). Applied 09.04.2009, published 27.05.2012.

[0143] 3. Patent RU2713360C2. COID 15 / 02. Method for obtaining lithium hydroxide monohydrate from brines / Ryabtsev Alexander Dmitrievich (RU), Nemkov Nikolay Mikhailovich (RU), Titarenko Valery Ivanovich (RU), Kotsupalo Natalya Pavlovna (RU), Kurakov Andrey Aleksandrovich (RU), Kochnev Alexander Mikhailovich (RU), Application. 09 / 25 / 2019, publ. 11.11.2019.

[0144] 22

[0145] SUBSTITUTE SHEET (RULE 26)

Claims

CLAUSES OF THE INVENTION 1. A method for producing high-purity lithium hydroxide monohydrate from calcium chloride-type lithium-bearing brines, comprising purifying the initial brine from solid-phase impurities by filtration to obtain a productive lithium-bearing brine, sorption production of primary lithium concentrate from the productive lithium-bearing brine by sorption of lithium with a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, washing the sorbent and desorbing lithium from the sorbent, sending the primary lithium concentrate to nanofiltration for purification from magnesium and calcium, reverse osmosis concentration of the purified primary lithium concentrate followed by electrodialysis concentration and obtaining electrodialysis lithium concentrate, deep ion-exchange purification on an ion exchanger of the electrodialysis lithium concentrate, electrochemical conversion to obtain a lithium hydroxide solution, evaporation of the hydroxide solution lithium, crystallization of lithium hydroxide monohydrate,washing and drying of lithium hydroxide monohydrate crystals, characterized in that before filtering the initial brine, it is treated by increasing the pH and aerating it with air, oxygen or a mixture of ozone and oxygen; before electrodialysis concentration, the reverse osmosis lithium concentrate is subjected to ion-exchange purification from boron; deep ion-exchange purification on the ion exchanger of the electrodialysis lithium concentrate is carried out until the total content of residual impurities of calcium and magnesium is 0.1 mg / dm3, 3 and less, the electrochemical conversion of purified electrodialysis lithium concentrate is carried out by bipolar membrane electrodialysis to obtain a lithium hydroxide solution with a concentration of 2-3 mol / dm3 3 and a solution of hydrochloric acid.

2. The method according to paragraph 1, characterized in that the lithium hydroxide monohydrate crystals obtained after crystallization are separated by centrifugation, after washing the lithium hydroxide monohydrate crystals, they are recrystallized, and after drying, they are further ground.

3. The method according to paragraph 1, characterized in that the hydrochloric acid solution obtained in the process of electrochemical conversion of purified electrodialysis lithium concentrate has a concentration of 2-3 mol / dm3. 3 . SUBSTITUTE SHEET (RULE 26) 4. The method according to paragraph 3, characterized in that the hydrochloric acid solution is used to regenerate ion exchangers at the stage of purification from calcium and magnesium or boron impurities.

5. The method according to paragraph 3, characterized in that the hydrochloric acid solution is used to wash the membranes at the stage of nanofiltration and reverse osmosis concentration.

6. The method according to paragraph 1, characterized in that thermal concentration is used for additional concentration of purified reverse osmosis lithium concentrate.

7. The method according to paragraph 1, characterized in that reverse osmosis with high-pressure membranes up to 120 bar is used for additional concentration of purified reverse osmosis lithium concentrate.

8. The method according to claim 1, characterized in that the lithium hydroxide monohydrate crystals obtained after crystallization are separated to obtain a mother liquor, which is used to obtain lithium carbonate.

9. The method according to claim 8, characterized in that the mother liquor, after the extraction of lithium carbonate from it, is subjected to thermal concentration with the extraction of sodium chloride from it and the subsequent use of the solution for bipolar electrodialysis.

10. The method according to claim 8, characterized in that the mother liquor, after the extraction of lithium carbonate from it, is neutralized with hydrochloric acid to obtain solutions of sodium and potassium chlorides.

11. The method according to claim 10, characterized in that the hydrochloric acid solution is a solution of hydrochloric acid obtained at the stage of bipolar electrodialysis.

12. A plant for producing high-purity lithium hydroxide monohydrate from calcium chloride-type lithium-bearing brines by the method of claim 1, comprising: a device for aerating the initial brine, providing aeration with air, oxygen, or a mixture of ozone and oxygen; a device for filtering the initial brine, from which, as a result of filtration, a productive lithium-bearing brine is obtained; a plant for the sorption isolation of lithium, consisting of at least one column filled with a sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, in which the sorption of lithium is ensured by passing the productive lithium-bearing brine through the sorbent layer, washing the sorbent and desorbing lithium from the sorbent to obtain a primary lithium concentrate; a nanofiltration device for purification by filtration 24 SUBSTITUTE SHEET (RULE 26) primary lithium concentrate from calcium and magnesium and obtaining purified primary lithium concentrate, including at least one membrane filter for nanofiltration; a reverse osmosis concentration device that provides reverse osmosis concentration of purified primary lithium concentrate to obtain a reverse osmosis lithium concentrate and includes at least one semipermeable membrane; an ion-exchange device for boron purification that provides contact between the reverse osmosis lithium concentrate and an ion exchanger to remove boron ions from the reverse osmosis lithium concentrate and obtain purified reverse osmosis lithium concentrate; an electrodialysis concentration device that includes ion-exchange membranes and at least two electrodes, which provides concentration of purified reverse osmosis lithium concentrate to obtain an electrodialysis lithium concentrate;a device for ion exchange purification from calcium and magnesium, providing contact between electrodialysis lithium concentrate and ion exchanger with the removal of magnesium and calcium ions from the reverse osmosis lithium concentrate and the production of purified electrodialysis lithium concentrate; a bipolar membrane electrodialyzer, including bipolar membranes and at least two electrodes, providing electrochemical conversion of purified electrodialysis lithium concentrate with the production of a lithium hydroxide solution with a concentration of 2-3 mol / dm; 3and a hydrochloric acid solution; an evaporator for concentrating the lithium hydroxide solution with salting out lithium hydroxide monohydrate crystals; a solid phase separation device for separating the salted out lithium hydroxide monohydrate crystals from the mother liquor; a washing device for washing the lithium hydroxide monohydrate crystals; a dryer for removing water from the lithium hydroxide monohydrate crystals, wherein the device for aerating the initial brine is connected to a device for filtering the initial brine, the device for filtering the initial brine is connected to a lithium sorption separation unit, the lithium sorption separation unit is connected to a nanofiltration device, the nanofiltration device is connected to a reverse osmosis concentration device, the reverse osmosis concentration device is connected to a device for ion-exchange purification from boron, the device for ion-exchange purification from 25 SUBSTITUTE SHEET (RULE 26) boron is connected to an electrodialysis concentration device, the electrodialysis concentration device is connected to an ion-exchange purification device for calcium and magnesium, the ion-exchange purification device for calcium and magnesium is connected to a bipolar membrane electrodialyzer, the bipolar membrane electrodialyzer is connected to an evaporator, the evaporator is connected to a solid phase separation device, the solid phase separation device is connected to a washing device, the washing device is connected to a dryer.

13. The installation according to paragraph 12, characterized in that the device for separating the solid phase is a centrifuge.

14. The installation according to item 12, characterized in that the bipolar membrane electrodialyzer has a line for removing the hydrochloric acid solution that is formed during the bipolar membrane electrodialysis process.

15. The installation according to paragraph 14, characterized in that the line for removing the hydrochloric acid solution is connected to the ion-exchange device for removing boron.

16. The installation according to paragraph 14, characterized in that the line for removing the hydrochloric acid solution is connected to the device for ion exchange purification from calcium and magnesium.

17. The installation according to item 14, characterized in that the line for draining the hydrochloric acid solution is connected to the nanofiltration device.

18. The installation according to paragraph 14, characterized in that the line for draining the hydrochloric acid solution is connected to a reverse osmosis concentration device.

19. The installation according to paragraph 12, characterized in that it additionally contains an auxiliary evaporator, which is installed between the reverse osmosis concentration device and the ion exchange device for boron purification.

20. The installation according to paragraph 12, characterized in that it additionally contains a reverse osmosis concentration device with high-pressure membranes that ensure operation at a pressure of up to 120 bar, which is installed between the ion-exchange device for boron purification and the electrodialysis concentration device. 26 SUBSTITUTE SHEET (RULE 26)

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