RU2816073C1 - Method for sorption production of lithium concentrate from lithium-containing solution - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to lithium hydrometallurgy. Method for sorption production of a lithium concentrate from a lithium-containing solution includes: a sorption step involving passing a lithium-containing solution through a sorbent to extract lithium, a step for washing said sorbent and a desorption step. At the stage of washing of said sorbent, washing liquid containing depleted raffinate and/or depleted eluate is used for washing. Depleted raffinate is a solution taken from first 0.4–1.5 column volumes of the solution obtained at the sorption step as a result of contact of the lithium-containing brine with said sorbent. Depleted eluate is a solution taken from any of 4th, 5th, 6th, 7th or 8th column volumes of the solution obtained at the desorption step as a result of contact of the desorbing solution with said sorbent.

EFFECT: reduced volume of recycled lithium with washing solution, higher purity of lithium concentrate, reduced losses of lithium with washing solution, high purity of the lithium concentrate, high quality of washing the sorbent while maintaining mechanical strength of the sorbent.

7 cl, 2 tbl

Description

Field of technology

The present 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.

Prior Art

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 associated components, the use of sorption technology using lithium-selective sorbents is promising for enriching brines with lithium.

In the publication of the abstract for the degree of Doctor of Technical Sciences, A.D. Ryabtsev. Processing of lithium-bearing polycomponent hydromineral raw materials based on their lithium enrichment, Tomsk, 2011 (URL: https://earchive.tpu.ru/bitstream/11683/6742/1/thesis_tpu-2012-03.pdf), a method of reagent-free sorption enrichment is disclosed for lithium of the target non-traditional lithium-bearing hydromineral raw materials to obtain a primary lithium concentrate, in which a step-countercurrent mode of contact of the brine with a granular sorbent is used, when the lithium-depleted brine is in contact with the 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 1.5 times. However, a further increase in temperature is undesirable in order to avoid crystallization of particles of the compound [LiAl ₂ (OH) ₆ ]Cl⋅mH ₂ O. In this work, it was established that the optimal conditions for the selective sorption extraction of lithium with granular sorbent DGAL-Cl from brine having a total mineralization of 450-500 g/m ³ and containing lithium chloride in a concentration of 2.0-2.2 g/m ³ are three-stage countercurrent contact of the brine with the sorbent at W:T = 8.0 - 8.5; contact time 45-50 minutes; temperature 35-40°C at each stage. In this case, the degree of selective extraction of lithium from brine reaches 93-96%, and the working volumetric capacity of the granular sorbent is about 70% of the total sorption capacity. For the desorption of lithium from a spent sorbent, it is also preferable to use a stepwise countercurrent 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 35-40°C and contact time at each stage of 15-20 minutes is 3 or 4. In this case, the maximum content lithium chloride in the resulting lithium concentrate reaches a level of 6-8 g/l.

After completion of the sorption operation, the brine is displaced from the granular layer of the sorbent 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 in the range of 0.5-0.6 m.h ^-1 .

If the optimal parameters for conducting the main technological operations of the process of sorption enrichment of LHMS are observed, the resulting commercial lithium concentrate has an R value of no higher than 5, and the total loss of sorbed lithium (in terms of chloride) when removing brine does not exceed 10%.

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

From patent RU2659968, publ. 07/04/2018, there is a known method for producing lithium concentrate from lithium-bearing natural brines by sorption enrichment of lithium using a granular sorbent based on a chlorine-containing variety of aluminum and lithium double hydroxide, which includes sorption-washing-desorption cycles. The method uses 4 columns with sorbent: two at the stage of LiCl sorption, one at the stage of washing the sorbent from brine, one at the stage of LiCl desorption 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 stage of washing the sorbent from the brine, the rest also move forward along the stages of the cycle. The cycle is repeated according to an experimentally proven cyclogram. The linear velocity of the liquid phases in the columns at all stages of the production of primary lithium concentrate is maintained at the level of 5-7 m/h. Washing the sorbent from the brine is carried out by first draining the brine from the column, then by stepwise washing the sorbent with five portions of washing liquid in a bottom-to-top direction, each with a volume of 1/3 of the volume of the sorbent in the column, four of the five portions are washing liquids with different contents of components brine in order of decreasing their content by washing stages, and the fifth portion represents the volume of fresh water. Each subsequent portion displaces the previous one. The first portion is mixed with natural lithium brine, cleared of suspended particles. Each subsequent portion becomes n-1 portions in the next wash cycle (the second becomes the first, etc.), so the first portion will always be the most concentrated.

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

From the publication of international application WO2017039724, publ. 03/09/2017, a known method for obtaining a high-purity lithium solution from a lithium source solution containing dissolved Na ⁺ , Ca ²⁺ and Mg ²⁺ by passing the source lithium solution through a sorbent layer consisting of hydrated alumina intercalated with LiX, preferably LiCl, to extract lithium from the initial lithium solution into the sorbent; washing the sorbent layer 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 the eluent to obtain a lithium permeate from which Ca ²⁺ , Mg ²⁺ and other components amenable to nanofiltration are simultaneously removed to obtain a permeate solution with 25% or less and a retentate solution with 75% or more Ca ²⁺ and Mg ²⁺ by compared to the eluent from washing; and subjecting the permeate solution to forward osmosis to obtain a solution containing 13,000-25,000 ppm of dissolved lithium.

The disadvantage of this 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 the washing solutions due to mixing of the displaced brine with a dilute aqueous solution of LiCl.

From application publication CN114797171A, publ. 07/29/2022, a method for extracting lithium is known, in which lithium-containing brine is sent from a reservoir to a primary adsorption sorption column, consisting of three parts, to extract lithium and magnesium. After sorption, the raffinate is sent to a tank with lithium-containing brine. Desorption of magnesium and lithium is carried out with the permeate obtained at the stage of reverse osmosis concentration of the eluate. The permeate is fed to the lower part of the primary adsorption sorption column, the raffinate from the bottom 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 the reservoir with the original brine. The desorption eluate is used for 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 goes for desorption, and the concentrate goes to other stages to produce lithium carbonate.

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

From patent CN113368537B, publ. 05/24/2022, a known method for extracting lithium, in which a lithium-containing brine is sent to a column filled with a sorbent, into which an eluent is then introduced for desorption of magnesium. After removing magnesium from the sorbent, lithium is desorption by feeding from bottom to top; the volume of solution squeezed out of the column is used as an eluent for desorption.

The disadvantage of this method is the lack of washing the sorbent from boron and sulfate impurities.

The method described in the application WO2019221932A1 was chosen as a prototype and includes filling columns with a sorbent with the original brine, which is then displaced by the eluate, then desorption of the sorbent is carried out using the eluate, at the output an eluate is obtained, from which the fraction poorest in lithium content is separated and one part of it is sent to prepare the eluate, and the other to displace the original brine from the sorbent. After desorption, the remaining eluate is displaced using raffinate in the top-to-bottom direction, then the saturated eluate goes to reverse osmosis concentration.

The disadvantage of the prototype is that after desorption, when raffinate displaces the remaining eluate from the column in the top-to-bottom direction, part of the raffinate enters the eluate, which leads to its contamination. If the raffinate contains more salts than the eluate, then displacement of the eluate will not occur, the raffinate will mix with the eluate and impurities of the raffinate will end up in the finished eluate, which as a result will require a more complex system for removing impurities and, as a result, a more complex technological scheme.

Based on Table 2 of the prototype, based on the composition of the brine supplied for sorption and the transfer coefficients of impurities at the stage of sorption from brine to eluate “% Reporting to CCAD Product”, the table below calculates the composition of the raffinate:

CCAD Product (mg/L)
Salt content in the eluate
mg/l Salt content in raffinate, according to conversion, mg/l Li 3,250 17.8 Ca 407 50,847 Mg 1.64 102 Na 117 76,402 K 39 22,627

From this table it can be seen 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 a denser raffinate is fed into the column from top to bottom, as described in the prototype, the denser solution will go down, and the lighter-density eluate will be pulled up, as a result, the layers will mix and displacement of the eluate by raffinate will not occur, and moreover, the eluate will be contaminated with raffinate impurities, which, as stated above, will require its additional purification from undesirable impurities.

Disclosure of the Invention

The objective of the present invention is to develop an effective method for processing a lithium-containing solution, providing the ability to reduce the volume of lithium returned to recycling with the washing solution, increasing the purity of the lithium concentrate, as well as reducing the number of stages for possible further processing of the resulting eluate (desorbate) into commercial lithium-containing products.

The technical result of the claimed invention is to reduce the volume of lithium returned to recycling with the washing solution, increasing the purity of the lithium concentrate, reducing losses 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.

To solve the problem and achieve a technical result, a method is proposed for the sorption production of lithium concentrate from a lithium-containing solution, including:

a sorption stage, including passing a lithium-containing solution through a sorbent to extract lithium,

the stage of washing said sorbent,

desorption stage,

characterized in that

at the stage of washing the specified sorbent, a washing liquid containing a depleted raffinate and/or a depleted eluate is used for washing,

wherein the depleted raffinate is a solution selected 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,

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 of the desorption solution with the specified 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 8 column volumes of the solution obtained at the desorption stage as a result of contact of the desorbing solution with the sorbent.

Washing liquid is 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, which is formed further as a result of desorption.

Raffinate is a solution formed at the sorption stage as a result of contact of a lithium-containing solution with a sorbent to extract lithium.

Eluate is a solution formed at the desorption stage as a result of contact of the desorbing solution with the sorbent to extract lithium.

The depleted raffinate is a solution selected 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 sorbent.

In other words, a lithium-containing solution is supplied to the installation (sorption-desorption enrichment module), which is in contact with the sorbent. The resulting solution from the installation is raffinate. From the entire volume of raffinate leaving the installation, the very first 0.4-1.5 column volumes are selected, which are removed as depleted raffinate for subsequent use in the wash liquid.

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 contact of the desorption solution with the sorbent.

In other words, a desorbing solution is supplied to the installation (sorption-desorption enrichment module), which is in contact with the sorbent. The resulting solution from the installation is an eluate. From the entire volume of eluate leaving the installation, it is taken from any of the 4th, 5th, 6th, 7th or 8th column volumes (that is, the 1st, 2nd and 3rd column volumes are allocated to other needs), which are removed as a depleted eluate for subsequent use in the washing liquid.

After production, the depleted raffinate and depleted eluate are taken into one common or separate containers for subsequent use as part of the washing liquid, while the depleted raffinate and depleted eluate can be obtained both within one installation and within several installations, for example, when several sorption-desorption modules are installed in parallel. Moreover, in some modules there may be no function for removing lean raffinate and lean eluate at all, and the specified lean raffinate and lean eluate can be obtained from another module.

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

The lithium recovery sorbent may be any sorbent known in the art that allows lithium recovery, for example, lithium alumina intercalate derived from hydrated alumina, layered lithium aluminum chloride double hydroxide, layered double hydroxide modified activated alumina , a layered double hydroxide impregnated into an ion exchange resin or copolymer or molecular sieve or zeolite, a layered aluminate polymer. It is more preferable to use a granular sorbent based on a chlorine-containing version of double hydroxide of aluminum and lithium ([LiAl ₂ (OH) ₆ ]Cl⋅mH ₂ O), which has recently become widely used in industry.

In the scope of the above set of features, the technical result, in our opinion, is achieved for the following reasons.

We unexpectedly found that both the lean raffinate and the lean eluate exhibit a better ability to remove unwanted impurities from the sorbent at the washing stage, compared to washing the sorbent with a conventional eluate or raffinate, as is done in the prior 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 sources of lithium-containing solution of different nature.

Without being bound by any theory, the authors of the present invention assume that the specified depleted raffinate and depleted eluate contain a unique residual salt composition, which determines their ability not only to strengthen the sorbent, but also to more effectively remove impurities at the sorbent washing stage.

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

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

The greatest effect is achieved by washing with lean raffinate and/or lean eluate, both individually and in their various ratios.

Preferably, the lean raffinate is a solution taken from the first 0.5-1.3, more preferably the first 0.6-1.1, most preferably the first 0.7-0.9 column volumes of the solution obtained in step sorption as a result of contact of a lithium-containing solution with a sorbent,

Preferably, 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 at the desorption stage as a result of contact of the desorption solution with the sorbent .

The indicated preferred and more preferred column volumes of the depleted eluate or depleted raffinate used make it possible to achieve a higher technical result in terms of a complex of effects such as the mechanical strength of the sorbent, its dynamic capacity for lithium and the degree of purification from impurities. In addition, these preferred volumes make it possible to expand the possibilities for mixing other process liquids into the washing solution. However, it is worth noting that it is not advisable to go beyond the above-mentioned ranges of used column volumes of depleted eluate or depleted raffinate, since on the one hand this can lead to leveling out 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 washing liquid , which will negatively affect the washing of the sorbent from impurities.

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.

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.

We have found that at the stage of washing the lithium-saturated sorbent, carried out by the specified 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, impurities are displaced alkali and alkaline earth metals from the intergranular space of the sorbent and desorption of boron and sulfate ions (SO ₄ ^2- ) absorbed from the solution and other impurities that may be contained in certain types of natural solutions, such as silicon, iron, zinc and other impurities . In this case, due to the concentration of salts in the washing liquid, desorption of lithium from the sorbent does not occur, unlike washing with demineralized water.

The use of washing liquid in a volume of less than 80% is not enough to displace the remaining solution and accompanying impurities from the intergranular space. Using washing liquid in a volume of more than 110% 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%, it will lead to high values of lithium returned to the recycle, depleting the finished eluate in lithium.

Subsequent desorption of lithium with demineralized water from a sorbent previously washed with such a solution makes it possible to obtain a desorbate containing lithium chloride with a minimum content of undesirable impurities.

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

These preferred and more preferred ratios of lean eluate or lean raffinate make it possible to achieve a higher technical result in terms of maintaining the dynamic capacity of the sorbent.

In a preferred embodiment, the washing liquid additionally contains permeate and/or demineralized water and/or retentant 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 not more than 30% of the total volume of washing liquid.

We also found that in order to save water and optimize the entire technological process for producing lithium carbonate, other process fluids known from the prior art and traditionally used for washing similar sorbents can be mixed with the specified depleted raffinate and/or depleted eluate. Moreover, the more traditionally used liquids are mixed into the lean raffinate and/or lean eluate, the lower the technical result described above achieved by the present invention. Therefore, in order to maintain the claimed effect, it is undesirable to use more than 50% of traditionally used liquids based on the total volume of washing liquid based on lean raffinate and/or lean eluate. It is preferable to use no more than 40%, more preferably no more than 30% of conventionally used liquids based on the total volume of lean raffinate and/or lean eluate wash liquid.

Such liquids can be used, for example, demineralized or demineralized water, or process liquids formed at the stages of the lithium carbonate production process, for example, permeate, retentate, condensate, filtrate, and so on. But, as noted above, the best technical result is achieved when using only lean raffinate and/or lean eluate.

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

Retentate is part of the flow during reverse osmosis concentration of the eluate, which is retained by the membrane.

In a preferred embodiment, the lithium recovery sorbent is a granular sorbent based on a chlorine-containing form of aluminum-lithium double hydroxide.

Embodiments of the Invention

Best Mode for Carrying Out the Invention

As a raw material, a source solution is used, which is a natural solution, which is also called natural brine (for example, produced formation water during oil production, water from geothermal sources, salar brine, etc.), a process solution or wastewater from oil and gas production, chemical, chemical and metallurgical production.

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 (revolving) circuit, loaded with granular sorbent based on a chlorine-containing variety of double hydroxide of aluminum and lithium.

Sorption of lithium from the initial solution is carried out in a sorption-desorption module with a fixed layer of sorbent by filtering the initial solution into a flow stream or in portions in the direction of filtration from bottom to top.

The method is carried out as follows.

1. Carry out the sorption stage.

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

The solution selected 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 as part of the washing liquid.

2. The stage of washing the sorbent is carried out.

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 a carousel (revolving) scheme and the layer of granular sorbent is washed from the solution with a washing liquid (compositions are indicated in Table 1) in the direction from top to bottom in a volume equal to 80 up to 150% of the volume of granular sorbent used in the sorption-desorption enrichment module, depending on the required degree of washing from impurities and the completeness of desorption of impurities, and the displaced solution is directed into the flow of the initial lithium-containing solution supplied to the sorption-desorption enrichment module for processing the next portion initial lithium-containing chloride solution.

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.

3. A desorption stage is carried out to obtain an eluate.

Next, lithium is desorption by passing demineralized water through a sorption-desorption enrichment module onto a flow path or in portions in the direction of flow from top to bottom.

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

The solution selected 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 as part of the washing liquid.

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

The following abbreviations are used in Table 1:

E - eluate

R - raffinate

OE - depleted eluate

OR - lean raffinate

P - permeate

DV - demineralized water

Composition of the 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 (SO ₄ ^2- ) - 6.5.

Composition of the 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 (SO ₄ ^2- ) - 10.1; boron - 0.5.

Sorbent used: granular, binder-free sorbent-chlorine-containing double hydroxide of aluminum and lithium of the following formula LiCl⋅2.2Al(OH)3 with a moisture mass fraction of 50%. Li:Al ratio = 1.0:2.2.

The volume of sorbent in the column is 5 liters.

Table 1. Start Examples Comparative in terms of technology According to the present invention 1 2 3 4 5 6 7 8 9 10 eleven 12 13 14 No. of initial solution No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 Volume of sorbent in the column, l 5 Washing liquid, as well as the volumetric ratio of the components of the washing liquid Far East R E OR OE OR:OE
1:1 OR:OE:P
1:1:2 Volume of washing liquid, l 5 Sorption mode Feed from bottom to top, speed 3 KO/h Flushing mode Feed from top to bottom, 6 KO/h Desorption mode Demineralized water, supply from top to bottom, 1.5 KO/h Parameter under study Mechanical strength (at 100 cycle) 82 80 93 92 95 94 93 91 94 92 96 96 91 90 Loss of sorbent in the column from the initial volume % (at cycle 100) 17 20 5 5 2 3 5 7 3 5 1 1 6 7 Dynamic exchange capacity of the sorbent (at cycle 30) 1.01 0.97 0.78 0.74 0.78 0.76 0.99 0.96 1.05 1.03 1.10 1.10 1.08 1.06 Dynamic exchange capacity of the sorbent (at 100 cycles) 0.73 0.70 0.71 0.67 0.78 0.75 0.94 0.91 0.99 0.97 1.01 1.00 0.96 0.94 Return of lithium to recycling at cycle 30, % 10.2 10.1 11.1 10.9 12.0 11.9 6.5 6.3 7.4 7.3 4.7 4.7 6.5 6.4 Degree of washing from Ca ²⁺ , % 98.6 94.2 9.9 9.5 69.0 66.0 78.9 76.3 88.7 86.2 83.8 81.6 93.7 91.5 Degree of cleaning from Mg ²⁺ , % 98.2 93.0 9.8 9.3 68.7 65.2 78.6 76.4 88.4 85.1 83.5 80.3 93.3 89.9 Degree of washing from Na ⁺ , % 95 96 9.5 9.0 66.5 67.1 76.0 76.5 85.5 86.0 80.8 80.0 90.3 90.0 Degree of washing from K ⁺ , % 99 99 9.9 9.7 69.3 69.2 79.2 79.0 89.1 89.2 84.2 83.9 94.1 94.0 Degree of boron removal, % - 70 - 3.0 - 60.0 - 65.0 - 67.0 - 66.0 - 68.0 Degree of cleaning from SO ₄ ^2- , % 96 95.5 9.6 9.2 67.2 66.0 76.8 74.1 86.4 85.1 81.6 79.9 91.2 89.7

Table 1. Continued Examples According to the present invention 15 16 17 18 19 20 21 22 23 24 No. of initial solution No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 No. 1 No. 2 Volume of sorbent in the column, l 5 Washing liquid, as well as the volumetric ratio of the components of the washing liquid OR:OE:P
1:1:1 OR:OE:DV
1:1:2 OR:OE:DV
1:1:1 OR:OE
1.5:1 OR:OE
0.5:1 Volume of washing liquid, l 5 Sorption mode Feed from bottom to top, speed 3 KO/h Flushing mode Feed from top to bottom, 6 KO/h Desorption mode Demineralized water, supply from top to bottom, 1.5 KO/h Parameter under study Mechanical strength (at 100 cycle) 91 90 88 86 90 89 94 94 95 95 Loss of sorbent in the column from the initial volume % (at cycle 100) 7 7 10 12 8 9 2 2 1.5 1.5 Dynamic exchange capacity of the sorbent (at cycle 30) 1.08 1.06 1.03 1.00 1.05 1.03 1.11 1.1 1.12 1.11 Dynamic exchange capacity of the sorbent (at 100 cycles) 1.01 0.99 0.92 0.89 0.99 0.97 1.0 0.99 1.02 1.0 Return of lithium to recycling at cycle 30, % 5.6 5.4 8.4 8.3 7.4 7.2 4.8 4.8 4.9 4.8 Degree of washing from Ca ²⁺ , % 88.7 86.0 98.6 96.4 88.7 86.1 83.7 81.4 83.7 81.5 Degree of cleaning from Mg ²⁺ , % 88.4 85.1 98.2 95.6 88.4 85.7 83.3 80.1 83.4 80.2 Degree of washing from Na ⁺ , % 85.5 86.0 95.0 95.1 85.5 86.0 80.6 79.8 80.7 79.9 Degree of washing from K ⁺ , % 89.1 89.0 99.0 99.0 89.1 89.0 84.0 83.7 84.1 83.8 Degree of boron removal, % - 67.0 - 70.0 - 67.0 - 66.0 - 67.0 Degree of cleaning from SO ₄ ^2- , % 86.4 84.3 96.0 95.5 86.4 85.4 81.4 79.7 81.5 79.8

In the process of research, we tested various well-known sorbents based on chlorine-containing lithium/aluminum double hydroxides. Research has shown that the technical result in the scope of the declared set of features is achieved on all tested varieties of sorbents of this class.

As can be seen from the information presented above, the method, carried out within the scope of the totality of essential features included in the claims, ensures the achievement of the declared technical result and has the following advantages compared to the prototype:

- 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, increasing the effective working capacity of the sorbent;

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

- no discharge of solutions of acids and alkalis and solutions of additional reagents necessary for the prototype method for the purification of lithium chloride from impurities of calcium, magnesium, potassium, sodium, boron and sulfates.

The described embodiments are provided for illustrative purposes only. It will be obvious to those skilled in the art that other embodiments are possible without changing the essence of the invention.

Claims (15)

1. A method for the sorption production of lithium concentrate from a lithium-containing solution, including: a sorption stage, including passing a lithium-containing solution through a sorbent to extract lithium, the stage of washing said sorbent, desorption stage, characterized in that at the stage of washing said sorbent, a washing liquid containing depleted raffinate and/or depleted eluate is used for washing, wherein the depleted raffinate is a solution selected 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 brine with the specified 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 at the desorption stage as a result of contact of the desorption solution with the specified sorbent. 2. The method according to claim 1, characterized in that the depleted raffinate is a solution selected 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 at 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 volume of the solution obtained in the desorption step by contacting the desorption solution with the sorbent. 3. The method according to claim 1, characterized in that the washing liquid is supplied in a volume equal to 80-150% of the volume of the sorbent for lithium extraction. 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 lithium extraction, more preferably in a volume equal to 100% of the volume of the sorbent for lithium extraction. 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 40% of the total volume of washing liquid, preferably in an amount of no more than 30% of the total volume of washing liquid. 7. The method according to claim 1, characterized in that the sorbent for lithium extraction is a granular sorbent based on a chlorine-containing variety of double hydroxide of aluminum and lithium.