Method for obtaining a lithium concentrate from a lithium-containing solution by sorption

Abstract

The proposed invention relates to the field of lithium extraction. Proposed is a method for obtaining a lithium concentrate from a lithium-containing solution by sorption, which includes: a sorption stage that entails passing a lithium-containing solution through a sorbent for lithium extraction; a sorbent washing stage; and a desorption stage. At the sorbent washing stage, a washing fluid containing spent raffinate and / or spent eluate is used, wherein the spent raffinate is a solution drawn from the first 0.4-1.5 column volumes of a solution produced at the sorption stage as a result of contact between the lithium-containing solution and the sorbent, and the spent eluate is a solution drawn from the fourth, fifth, sixth, seventh or eighth column volumes of a solution produced at the desorption stage as a result of contact between a desorbing solution and the sorbent. The technical result of the claimed invention consists in a reduction in the volume of lithium recycled with the washing solution, an increase in the purity of the lithium concentrate, a reduction in the amount of lithium lost with the washing solution, and an improvement in the washing of the sorbent without detriment to the mechanical integrity thereof.

Description

[0001] METHOD OF SORPTION OBTAINING LITHIUM CONCENTRATE FROM A LITHIUM-CONTAINING SOLUTION

[0002] Field of technology

[0003] The proposed invention relates to the field of lithium hydrometallurgy and can be used to extract lithium from natural solutions, also called natural brines and waters, process solutions and wastewater from various industries.

[0004] Prior art

[0005] Currently, one of the types of raw materials used for the production of lithium and its compounds are lithium-containing natural waters and brines. Since the concentration of lithium ions in this raw material is low against the background of a significant content of alkali and alkaline earth metal ions and other accompanying components, then for the enrichment of brines for lithium, the use of sorption technology using lithium-selective sorbents is promising.

[0006] In the publication of the abstract for the degree of Doctor of Technical Sciences by Ryabtsev A.D., Processing of lithium-bearing polycomponent hydromineral raw materials based on their enrichment in lithium, Tomsk, 2011 (URL: https: / / earchive.tpu.rU / bitstream / l 1683 / 6742 / l / thesis_tpu-2012-03. pdf), a method is disclosed for reagent-free sorption enrichment in lithium of the target non-traditional lithium-bearing hydromineral raw materials with the production of primary lithium concentrate, which uses a step-countercurrent mode of contact of brine with a granulated sorbent, when the lithium-depleted brine contacts a fresh sorbent, and the partially saturated sorbent is treated with the original brine. When the brine temperature increases from 20°C to 40°C, the sorption rate increases by 1.5 times. However, a further increase in temperature is undesirable in order to avoid crystallization of the particles of the [E1Al2(OH)6]Cl3H2O compound.In this work it was established that the optimal conditions for selective sorption extraction of lithium by granulated sorbent DGAL-S1 from brine with a total mineralization of 450-500 g / m. 3 and containing lithium chloride in a concentration of 2.0-2.2 g / m3 3are a three-stage counter-current contact of the brine with the sorbent at L:S = 8.0 - 8.5; contact time of 45-50 minutes; temperature of 35-40°C at each of the stages. In this case, the degree of selective extraction of lithium from the brine reaches a value of 93-96%, and the working volumetric capacity of the granulated sorbent is about 70% of the value of the full sorption capacity. For desorption of lithium from the spent sorbent, it is also preferable to use a step-counter-current phase contact mode. Depending on the degree of saturation of the sorbent with lithium, the optimal number of contact stages at L:S = 2.5-3.0, temperature of 35-40°C and contact time at each stage of 15-20 minutes is 3 or 4. In this case, the maximum content of lithium chloride in the resulting lithium concentrate reaches a level of 6-8 g / l.

[0007] After completion of the sorption operation, the brine from the granular layer of the sorbent is displaced using the lithium concentrate obtained in the desorption operation. The optimal linear velocity of the displacement solution in the cross-section of the granular layer of the sorbent is within the range of 0.5-0.6 m / h' 1 .

[0008] If the optimal parameters for conducting the main technological operations of the sorption enrichment process of LGMS are observed, the resulting commercial lithium concentrate has an R value of no higher than 5, and the total losses of sorbed lithium (in terms of chloride) during the removal of brine do not exceed 10%.

[0009] The main disadvantage of the known method is the significant return of lithium to the recycling, which is typical for any methods where the eluate is used as a washing liquid, which itself has a high concentration of lithium. At the same time, for the current level of technology, the loss of sorbed lithium (in terms of chloride) when removing brine in the specified range of up to 10% is unacceptable for the efficiency of the process.

[0010] A method for producing lithium concentrate from lithium-bearing natural brines by means of its sorption enrichment in lithium using a granulated sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide, which includes sorption-washing-desorption cycles, is known from patent RU2659968, published on 04.07.2018. The method uses 4 columns with a sorbent: two at the LiCl sorption stage, one at the sorbent washing stage from the brine, and one at the LiCl desorption stage from the sorbent. As the sorbent in the first column along the brine flow is completely saturated with lithium chloride, it is transferred to the sorbent washing stage from the brine, the others are also shifted forward in the cycle stages. The cycle is repeated according to an experimentally substantiated cyclogram. The linear velocity of liquid phases in columns at all stages of primary lithium concentrate production is maintained at a level of 5-7 m / h.The sorbent is washed from the brine by preliminary draining the brine from the column, then by stepwise washing of the sorbent successively with five portions of the washing liquid in the direction from bottom to top with a volume equal to 1 / 3 of the sorbent volume in the column each, four portions out of five are washing liquids with different contents of brine components in the order of decreasing their content by washing stages, and the fifth portion is a volume of fresh water. Each subsequent portion displaces the previous one. The first portion is mixed with natural lithium-bearing brine purified from suspended particles. Each subsequent portion becomes the n-1 portion in the next washing cycle (the second will become the first, etc.), thus the first portion will always be the most concentrated.

[0011] The disadvantage of this method is the high consumption of fresh water and relatively low lithium extraction.

[0012] From the publication of international application WO2017039724, published on 03 / 09 / 2017, a method for obtaining a high-purity lithium solution from a starting lithium solution containing dissolved Na + , Sa 2+ and Mg 2+ , by passing a starting lithium solution through a sorbent bed consisting of hydrated aluminum oxide intercalated with LiX, preferably LiCl, to extract lithium from the starting lithium solution into the sorbent; washing the sorbent bed with a dilute aqueous solution of LiCl to remove lithium from the sorbent to obtain a lithium eluent with an increased concentration of Li + ; nanofiltration of eluent to obtain lithium permeate from which Ca is simultaneously removed 2+ , Mg 2+ and other components amenable to nanofiltration to produce a permeate solution with 25% or less and a retentate solution with 75% or more Ca 2+ and Mg 2+compared to the eluent from the wash; and subjecting the permeate solution to forward osmosis to obtain a solution containing 13,000-25,000 ppm of dissolved lithium.

[0013] The disadvantage of the known method is the insufficient removal of boron impurities, since boron penetrates through the nanofiltration membrane. In addition, in the known method there will be large losses of lithium with washing solutions due to mixing of the displaced brine with a diluted aqueous solution of LiCl.

[0014] A method for extracting lithium is known from the publication of application CN114797171 A, published on July 29, 2022, in which a lithium-containing brine is sent from a tank to a primary adsorption column consisting of three parts for extracting lithium and magnesium. The raffinate after sorption is sent to a tank with a lithium-containing brine. Desorption of magnesium and lithium is carried out with permeate obtained at the stage of reverse osmosis concentration of the eluate. The permeate is fed to the lower part of the primary adsorption column, the raffinate from the lower part of the column is sent to the middle part, the raffinate from the middle part is sent to the upper part of the column, from which the raffinate goes to a tank with the original brine. The desorption eluate goes to a two-stage removal of magnesium, after which a "secondary eluate" with a high lithium content is obtained. The “secondary eluate” enters the reverse osmosis unit, the permeate from which is desorbed, and the concentrate is sent to other stages to obtain lithium carbonate.

[0015] The disadvantage of this method is that it is not suitable for brines with a high content of impurities and low lithium concentration.

[0016] A method for extracting lithium is known from patent CN113368537B, published on 24.05.2022, in which a lithium-containing brine is sent to a column filled with a sorbent, into which an eluent is then introduced to desorb magnesium. After removing magnesium from the sorbent, lithium is desorbed by feeding from the bottom up, the volume of solution squeezed out of the column is used as an eluent for desorption.

[0017] The disadvantage of this method is the lack of washing of the sorbent from impurities of boron and sulfates.

[0018] The method described in application WO2019221932A1 is selected as a prototype and includes filling columns with a sorbent with an initial brine, which is then displaced by an eluate, then desorption of the sorbent is carried out using the eluate, at the outlet an eluate is obtained, from which the fraction with the poorest lithium content is separated and one part of it is sent to the preparation of the eluate, and the other to displacing the initial brine from the sorbent. After desorption, the remains of the eluate are displaced using raffinate in the direction from top to bottom, then the saturated eluate is sent to reverse osmosis concentration.

[0019] The disadvantage of the prototype is that after desorption, when the raffinate displaces the eluate residues from the column in the top-down direction, part of the raffinate gets into the eluate, which leads to its contamination. If the raffinate contains more salts than the eluate, then the displacement of the eluate will not occur, the raffinate will mix with the eluate and the raffinate impurities will get into the finished eluate, which will ultimately require a more complex impurity purification system and, as a consequence, a more complex process flow chart.

[0020] Based on table 2 of the prototype, based on the composition of the brine supplied for sorption and the coefficients of impurity transfer at the sorption stage from the brine to the eluate “% Reporting to CCAD Product”, the composition of the raffinate is calculated in the table below:

[0021] From this table it is evident that the salt content, and consequently the density of the raffinate is higher than that of the eluate. This will lead to the fact that when feeding a denser raffinate into the column from top to bottom, as described in the prototype, the denser solution will go down, and the eluate, which is lighter in density, will be pulled up, as a result of which the layers will mix and the displacement of the eluate by the raffinate will not occur, and moreover, the eluate will be contaminated with impurities of the raffinate, which, as was indicated above, will require its additional purification from undesirable impurities.

[0022] Disclosure of invention

[0023] The objective of the present invention is to develop an effective method for processing a lithium-containing solution, which makes it possible to reduce the volume of lithium returned to recycling with the wash solution, increase the purity of the lithium concentrate, and also reduce the number of stages in the possible further processing of the resulting eluate (desorbate) into commercial lithium-containing products.

[0024] The technical result of the claimed invention consists in reducing the volume of lithium returned to recycling with the washing solution, increasing the purity of the lithium concentrate, reducing the loss of lithium with the washing solution, increasing the purity of the lithium concentrate, improving the quality of washing the sorbent while maintaining the mechanical strength of the sorbent.

[0025] In order to solve the stated problem and achieve the technical result, a method is proposed for the sorption production of lithium concentrate from a lithium-containing solution, comprising: a sorption stage, including passing a lithium-containing solution through a sorbent for extracting lithium, a stage of washing said sorbent, a desorption stage, characterized in that at the stage of washing said sorbent, a washing liquid containing a depleted raffinate and / or a depleted eluate is used for washing, wherein the depleted raffinate is a solution taken from the first 0.4-1.5 column volumes of the solution obtained at the sorption stage as a result of contact between the lithium-containing solution and said sorbent, and the depleted eluate is a solution taken from any of the 4th, 5th, 6th column volumes of the solution obtained at the desorption stage as a result of contact between the desorbing solution and said sorbent.And for sorbents characterized by high sorption capacity as a depleted eluate, in accordance with the present invention, a solution selected not only from any of the 4th, 5th, or 6th, but also from the 7th or 8th column volumes of the solution obtained at the desorption stage as a result of contact of the desorbing solution with the sorbent can be used.

[0026] Wash liquid - a liquid used to displace a solution from a sorption-desorption module before the desorption stage and / or remove impurities from the sorbent before desorption to minimize or even eliminate impurities in the eluate that is formed further as a result of desorption.

[0027] Raffinate is a solution formed at the sorption stage as a result of contact between a lithium-containing solution and a sorbent for lithium extraction.

[0028] Eluate is a solution formed at the desorption stage as a result of contact between the desorbing solution and the sorbent for lithium extraction.

[0029] The depleted raffinate is a solution taken from the first 0.4-1.5 column volumes of the solution obtained at the sorption stage as a result of contact between the lithium-containing solution and the sorbent.

[0030] In other words, a lithium-containing solution is fed into the unit (sorption-desorption enrichment module), which contacts the sorbent. The resulting solution leaving the unit is raffinate. From the entire volume of raffinate leaving the unit, the very first 0.4-1.5 column volumes are selected, which are removed as depleted raffinate for subsequent use in the composition of the washing liquid.

[0031] The depleted eluate is a solution taken from any of the 4th, 5th, 6th, 7th or 8th column volumes of the solution obtained at the desorption stage as a result of the contact of the desorbing solution with the sorbent. In other words, a desorbing solution is fed into the unit (sorption-desorption enrichment module), which contacts the sorbent. The resulting solution leaving the unit is the eluate. Of the total volume of eluate leaving the unit, some is taken from any of the 4th, 5th, 6th, 7th or 8th column volumes (i.e. the 1st, 2nd and 3rd column volumes are diverted for other needs), which is diverted as depleted eluate for subsequent use in the washing liquid.

[0032] The depleted raffinate and depleted eluate after production are discharged into one common or separate containers for subsequent use as part of the washing liquid, wherein the depleted raffinate and depleted eluate can be produced both within the framework of one unit and within the framework of several units, for example, when several sorption-desorption modules are installed in parallel. In this case, some modules may not have the function of discharge of the depleted raffinate and depleted eluate at all, and the said depleted raffinate and depleted eluate can be produced from another module.

[0033] Column volume (VO) is understood as a volume of liquid equal to the volume of sorbent involved in the technological stage / operation.

[0034] The sorbent for lithium extraction may be any sorbent known from the prior art that allows lithium extraction, for example, a lithium-aluminum oxide intercalate obtained from hydrated aluminum oxide, a layered double hydroxide of lithium-aluminum chloride, a layered activated aluminum oxide modified with a double hydroxide, a layered double hydroxide impregnated in an ion-exchange resin or copolymer, or a molecular sieve, or zeolite, a layered aluminate polymer. It is more preferable to use a granulated sorbent based on a chlorine-containing variety of aluminum and lithium double hydroxide ([LiAl2(OH)6]Cl mH2O), which has recently found wide application in industry.

[0035] In the volume of the above set of features, the technical result, as we believe, is achieved for the following reasons.

[0036] We unexpectedly found that both the depleted raffinate and the depleted eluate exhibit a better ability to extract undesirable impurities from the sorbent at the washing stage, compared to washing the sorbent with a conventional eluate or raffinate, as is done in the state of the art. The use of depleted raffinate and depleted eluate turned out to be especially effective for complex combinations of certain impurities that are inherent in different sources of lithium-containing solution.

[0037] Without being bound by any theory, the authors of the present invention assume that the said depleted raffinate and depleted eluate contain a unique residual composition of salts, which determines their ability not only to strengthen the sorbent, but also to perform more effective washing from impurities at the stage of washing the sorbent.

[0038] The authors found that, depending on the nature of the lithium-containing solution, either the depleted eluate or the depleted raffinate is more effective in removing sodium, potassium, magnesium, calcium, boron, sulfates and other impurities.

[0039] However, if the depleted eluate and depleted raffinate are combined, a previously unknown cumulative effect is observed for some solutions.

[0040] The greatest effect is achieved by washing with depleted raffinate and / or depleted eluate, both separately and in various ratios.

[0041] In a preferred embodiment, the depleted raffinate is a solution taken from the first 0.5-1.3, more preferably from the first 0.6-1.1, most preferably from the first 0.7-0.9 column volumes of the solution obtained in the sorption stage as a result of contact of the lithium-containing solution with the sorbent,

[0042] In a preferred embodiment, the depleted eluate is a solution taken from any of the 4th, 5th or 6th, more preferably from the 5th or 6th, column volume of the solution obtained in the desorption stage as a result of contact of the desorbing solution with the sorbent.

[0043] The specified preferred and more preferred column volumes of the used depleted eluate or depleted raffinate allow achieving a higher technical result in terms of a set of such effects as the mechanical strength of the sorbent, its dynamic capacity for lithium and the degree of purification from impurities. In addition, the specified preferred volumes allow expanding the possibilities for mixing other process liquids with the wash solution. However, it should be noted that it is not advisable to go beyond the above-specified ranges of the used column volumes of the depleted eluate or depleted raffinate, since on the one hand this can lead to the leveling of the effect of the unique composition of the salt background of such liquids, and on the other hand to an increase in the total salt background of the wash liquid, which will negatively affect the washing of the sorbent from impurities.

[0044] In a preferred embodiment, the washing liquid is supplied in a volume equal to 80-150% of the volume of the sorbent for lithium extraction.

[0045] In a preferred embodiment, the washing liquid is supplied in a volume equal to 90-110% of the volume of the sorbent for lithium extraction, more preferably in a volume equal to 100% of the volume of the sorbent for lithium extraction, i.e. 1 column volume.

[0046] We have established that at the stage of washing the lithium-saturated sorbent, carried out by the said washing liquid, supplied in the direction opposite or coinciding with the direction of supply of the initial lithium-containing solution to the sorbent, in an amount equal to 80 to 150% of the volume of the sorbent in the column, the displacement of alkali and alkaline earth metal impurities from the intergranular space of the sorbent and desorption of the absorbed from the solution, including boron and sulfate ions (SO4 2') and other impurities that may be contained in certain types of natural solutions, such as silicon, iron, zinc and other impurities. At the same time, due to the concentration of salts in the washing liquid, lithium desorption from the sorbent does not occur, unlike washing with demineralized water.

[0047] Using less than 80% of the washing liquid is insufficient to displace the solution residues and associated impurities from the intergranular space. Using more than 110% of the washing liquid is possible, but increasing the volume will begin to lead to a decrease in the overall efficiency of the process and, if the volume exceeds 150%, will lead to high values ​​of lithium returned to the recycle, depleting the finished eluate in lithium.

[0048] Subsequent desorption of lithium with demineralized water from a sorbent previously washed with such a solution allows obtaining a desorbate containing lithium chloride with a minimum content of undesirable impurities.

[0049] In a preferred embodiment, the washing liquid contains depleted raffinate and depleted eluate in a volume ratio of 0.5-1.5 to 1, preferably 0.7-1.2 to 1, more preferably 1 to 1.

[0050] The indicated preferred and more preferred ratios of depleted eluate or depleted raffinate make it possible to achieve a higher technical result from the point of view of maintaining the dynamic capacity of the sorbent.

[0051] In a preferred embodiment, the washing liquid additionally contains permeate and / or demineralized water and / or retentate and / or condensate in an amount of no more than 50% of the total volume of the washing liquid, preferably in an amount of no more than 40% of the total volume of the washing liquid, preferably in an amount of no more than 30% of the total volume of the washing liquid.

[0052] We have also found that in order to save water and optimize the entire technological process for obtaining lithium carbonate, other process liquids known from the prior art and traditionally used for washing similar sorbents can be mixed with the said depleted raffinate and / or depleted eluate. In this case, the more traditionally used liquids are mixed with the depleted raffinate and / or depleted eluate, the lower the above-described technical result achieved according to the present invention. Therefore, in order to preserve the claimed effect, it is undesirable to use more than 50% of the traditionally used liquids based on the total volume of washing liquid based on the depleted raffinate and / or depleted eluate. It is preferable to use no more than 40%, more preferably no more than 30% of the traditionally used liquids based on the total volume of washing liquid based on the depleted raffinate and / or depleted eluate.

[0053] Such liquids may be, for example, demineralized or desalinated water, or process liquids formed at the stages of the technological process of obtaining lithium carbonate, such as permeate, retentate, condensate, filtrate, etc. But, as noted above, the best technical result is achieved by using only depleted raffinate and / or depleted eluate.

[0054] Permeate is a solution formed as a result of reverse osmosis concentration of the eluate. Permeate is a liquid that has passed (penetrated) through the filter membrane.

[0055] Retentate is the part of the flow during reverse osmosis concentration of eluate that is retained by the membrane.

[0056] In a preferred embodiment, the sorbent for extracting lithium is a granular sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide.

[0057] Variants of carrying out the invention. The best variant of carrying out the invention

[0058] The raw material used is the initial solution, which is a natural solution, also called natural brine (for example, formation water produced during oil production, water from geothermal sources, salar brine, etc.), process solution or waste water from oil and gas production, chemical, chemical and metallurgical industries.

[0059] The initial solution is fed into a sorption-desorption enrichment module, which is a vertical column or a system of columns connected in series according to a carousel (revolver) scheme, loaded with a granulated sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide.

[0060] Sorption of lithium from the initial solution is carried out in a sorption-desorption module with a fixed sorbent layer by filtering the initial solution in a flow or in portions in the direction of filtration from the bottom up.

[0061] The method is carried out as follows.

[0062] 1. Carry out the sorption stage.

[0063] The lithium-containing solution is passed through a sorbent located in the column to extract lithium.

[0064] The solution, taken from the first 0.4-1.5 column volumes of the solution obtained at the sorption stage as a result of contact of the lithium-containing solution with the specified sorbent, is removed as a depleted raffinate into a separate container for subsequent use in the composition of the washing liquid.

[0065] 2. Carry out the sorbent washing stage.

[0066] Upon reaching saturation of the sorbent with lithium in the column, the filtration of the initial lithium-containing solution through it is stopped, switching the flows according to the carousel (revolving) scheme and the layer of granulated sorbent is washed from the solution with a washing liquid (the compositions are indicated in Table 1) in the direction from top to bottom in a volume equal to 80 to 150% of the volume of the granulated sorbent used in the sorption-desorption enrichment module, depending on the required degree of washing from impurities and the completeness of the desorption of impurities, and the displaced solution is directed into the flow of the initial lithium-containing solution fed to the sorption-desorption enrichment module for processing the next portion of the initial lithium-containing chloride solution.

[0067] To wash the sorbent, a washing liquid containing depleted raffinate and / or depleted eluate is used, as well as liquids traditionally used for washing similar sorbents.

[0068] 3. The desorption stage is carried out to obtain an eluate.

[0069] And then lithium is desorbed by passing desalinated water through a sorption-desorption enrichment module in a flow or in portions in the direction of flow from top to bottom.

[0070] The solution obtained as a result of desorption is a lithium concentrate in the form of lithium chloride with ammonium chloride impurities, practically free of alkali and alkaline earth metal impurities, sulfates, and other impurities.

[0071] The solution taken from the 4th, 5th and 6th column volumes of the solution obtained at the desorption stage as a result of contact of the desorbing solution with the specified sorbent is removed as a depleted eluate into a separate container for subsequent use in the composition of the washing liquid.

[0072] In accordance with the above description, experiments were carried out, the results of which are presented in Table 1, which shows the effect of the selected solution for washing the sorbent on the efficiency of sorption / washing / desorption.

[0073] The following abbreviations are used in Table 1:

[0074] E - eluate

[0075] R - raffinate

[0076] EE - depleted eluate

[0077] OR - lean raffinate

[0078] P - permeate

[0079] DV - demineralized water

[0080] Composition of initial solution No. 1: underground formation water (in g / l): lithium Li + - 0.435; sodium Na + - 114.5; potassium K + - 9.4; chlorine Cl' - 196.0; magnesium Mg 2+ - 3.6; calcium Ca 2+ - 1.7; sulfates (SO4 2 ') - 6.5.

[0081] Composition of initial solution No. 2: salar brine (in g / l): lithium Li + - 0.35; sodium Na + - 105.2; potassium K+ - 12.0; chlorine Cl' - 285.1; magnesium Mg 2+ - 40.0; calcium Ca 2+ - 0.8; sulfates (SO4 2 ') - Yu,1; boron - 0.5.

[0082] The sorbent used: granulated binder-free sorbent - chlorine-containing double aluminum and lithium hydroxide of the following formula LiCl-2.2Al(OH)3 with a moisture content of 50%. The ratio Li:Al = 1.0:2.2.

[0083] The volume of sorbent in the column is 5 l.

[0084]

[0085] SUBSTITUTE SHEET (RULE 26)

[0086]

[0087] SUBSTITUTE SHEET (RULE 26) During the research, we tested various known sorbents based on chlorine-containing double lithium / aluminum hydroxides. The research showed that the technical result in the volume of the declared set of features is achieved on all tested varieties of sorbents of this class.

[0088] As can be seen from the information presented above, the method, implemented in the scope of the set of essential features included in the invention formula, ensures the achievement of the declared technical result and has the following advantages compared to the prototype:

[0089] - increasing the efficiency of lithium extraction from lithium-containing solutions by reducing the content of impurities in the desorbate, eliminating lithium losses with wash water, and increasing the effective working capacity of the sorbent;

[0090] - improving the quality of sorbent washing while maintaining the mechanical strength of the sorbent;

[0091] - absence of discharge of acid and alkali solutions and solutions of additional reagents required for the prototype method for additional purification of lithium chloride from impurities of calcium, magnesium, potassium, sodium, boron and sulfates.

[0092] The described examples of implementation are given solely for illustrative purposes. It will be obvious to a specialist that other embodiments are possible without changing the essence of the invention.

Claims

Invention formula 1. A method for the sorption production of lithium concentrate from a lithium-containing solution, comprising: a sorption stage comprising passing a lithium-containing solution through a sorbent for extracting lithium, a stage of washing said sorbent, a desorption stage, characterized in that at the stage of washing said sorbent, a washing liquid containing a depleted raffinate and / or a depleted eluate is used for washing, wherein the depleted raffinate is a solution taken from the first 0.4-1.5 column volumes of the solution obtained in the sorption stage as a result of contact between a lithium-containing brine and said sorbent, and the depleted eluate is a solution taken from any of the 4th, 5th, 6th, 7th or 8th column volumes of the solution obtained in the desorption stage as a result of contact between the desorbing solution and said sorbent.

2. The method according to claim 1, characterized in that the depleted raffinate is a solution taken from the first 0.5-1.3, more preferably from the first 0.6-1.1, most preferably from the first 0.7-0.9 column volumes of the solution obtained in the sorption stage as a result of contact of the lithium-containing brine with the sorbent, and the depleted eluate is a solution taken from any of the 4th, 5th or 6th, more preferably from the 5th or 6th column volumes of the solution obtained in the desorption stage as a result of contact of the desorbing solution with the sorbent.

3. The method according to paragraph 1, characterized in that the washing liquid is supplied in a volume equal to 80-150% of the volume of the sorbent for extracting lithium.

4. The method according to claim 1, characterized in that the washing liquid is supplied in a volume equal to 90-110% of the volume of the sorbent for extracting lithium, more preferably in a volume equal to 100% of the volume of the sorbent for extracting lithium. 16 SUBSTITUTE SHEET (RULE 26) 5. The method according to claim 1, characterized in that the washing liquid contains depleted raffinate and depleted eluate in a volume ratio of 0.5-1.5 to 1, preferably 0.7-1.2 to 1, more preferably 1 to 1.

6. The method according to claim 5, characterized in that the washing liquid additionally contains permeate and / or demineralized water and / or retentate and / or condensate in an amount of no more than 50% of the total volume of the washing liquid, preferably in an amount of no more than 40% of the total volume of the washing liquid, preferably in an amount of no more than 30% of the total volume of the washing liquid.

7. The method according to claim 1, characterized in that the sorbent for extracting lithium is a granulated sorbent based on a chlorine-containing variety of double aluminum and lithium hydroxide. SUBSTITUTE SHEET (RULE 26)

Images