Granular sorbents for lithium recovery and method of preparing same for use

Abstract

The present invention relates to chemical technology, and more particularly to granular aluminium hydroxide-based sorbents which can be used for recovering lithium from lithium-containing solutions. The aim of the present invention is to support the extraction of lithium from solutions using a durable and effective granular lithium recovery sorbent based on polyvinyl chloride and a chlorine-containing species of an aluminium-lithium double hydroxide. The proposed technical solutions allow a sorbent based on a polyvinyl chloride binder to retain its integrity during storage, transportation, dwell time in lithium recovery equipment and use, the sorbent further having a high sorption capacity and supporting a high rate of sorption and desorption.

Description

[0001] GRANULAR SORBENTS FOR LITHIUM EXTRACTION AND A METHOD FOR THEIR PREPARATION FOR USE

[0002] Field of technology.

[0003] The present invention relates to chemical technology, specifically to granular sorbents based on aluminum hydroxide, which can be used to extract lithium from lithium-containing solutions.

[0004] State of the art.

[0005] In the processes of extracting lithium from hydromineral raw materials and lithium solutions, sorbents based on a chlorine-containing variety of double aluminum and lithium hydroxide (LiCl-2Al(OH)3 nH2O) have found wide application, which ensures the sorption of lithium due to the intercalation process.

[0006] At the same time, the compound ЫС1-2А1(ОН)з пН2О in its pure form is of little use in industrial methods of lithium extraction, since it is a powder that forms an emulsion during the process of working with solutions, requiring separation, while the loss of sorbent, clogging of pipelines and other technological difficulties are inevitable.

[0007] For this reason, industrial methods for extracting lithium from hydromineral raw materials and solutions are based on the use of ЫС1-2А1(ОН)З ПН2О in the composition of granulated sorbents, which ensures the technological efficiency of the process.

[0008] The prior art discloses methods for producing granular sorbents based on a chlorine-containing variety of double aluminum and lithium hydroxide, for example, RU2009714C1 (priority date 2277..0011..11999922)) "A method for producing a granular sorbent for extracting lithium from brines", RU2657495C1 (priority date 09 / 25 / 2017) "A method for producing a granular sorbent for extracting lithium from brines under conditions of commercial lithium product production", RU2804183C1 (priority date 09 / 12 / 2021) "A method for producing a granular sorbent for extracting lithium from brines under conditions of commercial lithium product production", sorbent for extracting lithium from lithium-containing brines”, RU2801465C1 (priority date 12 / 30 / 2022) “Method for producing granulated sorbent DGAL-C1”, RU2821512C1 (priority date

[0009] 1 07.11.2023) “Method for obtaining a sorbent and its granulation for extracting lithium from brines.”

[0010] These patent documents do not disclose the properties of the resulting sorbent that affect the efficiency of the lithium extraction process.

[0011] A granule for lithium sorption is known from the prior art according to the invention patent RU2805741C1 (priority date 07 / 05 / 2023) "Granule for lithium sorption from an aqueous solution" and according to the patent for utility model RU220087U1 (priority date 07 / 05 / 2023) "Granule for lithium sorption from an aqueous solution", which is a granule based on a chlorine-containing variety of double aluminum and lithium hydroxide, which contains a waterproof spherical core coated with a solution-permeable composite of sorbent particles and a hydrophilic binder, and the hydrophilic binder has an open-pore structure.

[0012] Moreover, as dependent features of the invention formula, it is stated that the average size of the granules is from 0.3 mm to 3.0 mm, the average size of the sorbent particles is less than 50 μm, the average thickness of the sorption coating of the core is less than 150 μm, the granule can be covered with a protective layer of tripoli with an average particle size of no more than 10 μm.

[0013] The presence of a water-impermeable spherical core in the sorbent granule is claimed to be an advantage that ensures a reduction in the amount of expensive sorbent (DGAL-C1) in the granule, a reduction in the time of lithium sorption-desorption, due to the fact that a decrease in the thickness of the sorbent layer reduces the internal diffusion resistance to the sorption-desorption process, an expansion of the range of filtration rates of the solution and washing liquid through the granule layer, since it is possible to change the material of the core, its density and other parameters.

[0014] The claimed technical results can indeed be achieved using this granular sorbent; however, this granule configuration also has drawbacks. Reducing the specific amount of DGAL-C1 and the thickness of the DGAL-C1 layer leads to a decrease in the sorbent's sorption capacity. Ensuring a high filtration rate of solutions through the sorbent layer at the expense of sorbent capacity is impractical for systems with large column volumes due to the risk of granule breakage, carryover, localized compaction, uneven movement of the liquid front in the column, and other effects that reduce the efficiency of sorption, washing, and desorption. Therefore, the claimed solution is not universally applicable. The granule characteristics claimed in the invention are also not adapted to ensure a balance between sorption capacity and strength for granules based on coreless polyvinyl chloride.

[0015] A patent for a composition for sorption of lithium is known from the prior art according to the patent for invention RU2734857C1 (Priority date 21.03.2017) "Matrices containing lithium aluminates", which is a granulated sorbent based on a polymer and a chlorine-containing variety of double aluminum and lithium hydroxide, wherein the polymer contains from 0.5 to 3 equivalents of side amino groups per liter of the composition in the form of particles, the average pore size of the granules is from 5 to 100 nm, the average harmonic diameter of the granules is 200-1000 μm, the surface area of ​​the granules is from 20 to 150 m 2 / g, and aluminum is present in an amount of 14.5% or more by weight of aluminum atoms based on the total weight of the particulate composition.

[0016] This composition is the closest to the technical solutions claimed in the present invention.

[0017] The disadvantages of this granular sorbent include its use of a polymer base containing 0.5 to 3 equivalents of side-chain amino groups per liter of particulate composition. This base is complex and expensive to produce, requiring polymerization of a monomer mixture to produce copolymer granules, functionalization of the copolymer by chloromethylation, followed by amination.

[0018] The disadvantage of this technical solution is that, using the specified parameters of sorbent particles, it is impossible to obtain sorbent particles based on available polyvinyl chloride while ensuring the required strength characteristics of the sorbent.

[0019] Another drawback of this technical solution is that it fails to take into account the influence of granule properties on the strength characteristics of the sorbent. The granule characteristics claimed in the invention are also not adapted to ensure a balance between sorption capacity and strength for polyvinyl chloride-based granules.

[0020] The essence of the invention.

[0021] Granular sorbents based on a chlorine-containing variety of double aluminum hydroxide are actively used in the lithium mining industry.

[0022] The aim of the present invention is to provide the production of lithium extraction from solutions with a durable and effective granular sorbent for the extraction of lithium based on polyvinyl chloride and a chlorine-containing variety of double aluminum hydroxide and lithium.

[0023] The technical result to which the invention is directed is the preservation of the integrity of a sorbent based on polyvinyl chloride and a chlorine-containing variety of double aluminum and lithium hydroxide during its storage, transportation and placement in lithium extraction equipment.

[0024] The technical result to which the invention is directed is to ensure a high sorption capacity of the sorbent, a high rate of sorption and desorption while ensuring the strength of the sorbent, maintaining its integrity during operation, and increasing the service life of the sorbent by reducing its wear.

[0025] The technical result to which the invention is directed is the rapid and economical transfer of the sorbent from the transport state to the working state.

[0026] The technical result is achieved in that the sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide is characterized by the fact that the sorbent granules have a size of 0.5 to 3 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 5 to 20 m 2 / g, the bulk density of the granulated sorbent is from 0.45 to 1.0 g / cm 3 , wherein the sorbent granules contain particles of a chlorine-containing variety of double aluminum and lithium hydroxide of a size less than 200 μm and polyvinyl chloride as a binder, wherein the sorbent granules contain regions distributed in the volume filled with the use of at least alkali or alkaline earth metal halides.

[0027] The technical result is achieved in that the sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide is characterized by the fact that the sorbent granules have a size of 0.5 to 3 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 25 to 70 m 2 / g, the bulk density of the granulated sorbent is from 0.35 to 0.9 g / cm 3, wherein the sorbent granules contain particles of a chlorine-containing variety of aluminum lithium double hydroxide less than 200 μm in size and polyvinyl chloride as a binder, wherein the sorbent granules contain pores distributed throughout the volume. The modal mesopore size of the granules may be 3-5 nm. The median mesopore size of the granules may be 5-50 nm. The modal micropore size may be 4-10 angstroms. The median micropore size may be 4-10 angstroms. The sorbent for extracting lithium from brine based on a chlorine-containing variety of aluminum lithium double hydroxide may be obtained by washing the sorbent with a solvent that ensures the dissolution and leaching of at least alkali or alkaline earth metal halides from the sorbent granules with the formation of pores in their volume.

[0028] The technical result is achieved by washing an inactivated sorbent with a solvent to extract lithium, producing an activated sorbent. This solvent ensures the dissolution and leaching of at least alkali or alkaline earth metal halides from the sorbent granules, creating pores within them. The inactivated sorbent is a chlorine-containing variety of aluminum lithium double hydroxide, characterized by granules ranging in size from 0.5 to 3 mm, and a granule sorption surface area, determined by the BET method, ranging from 5 to 20 m. 2 / g, the bulk density of the granulated sorbent is from 0.45 to 1.0 g / cm 3, the sorbent granules contain particles of a chlorine-containing variety of aluminum-lithium double hydroxide less than 200 μm in size and polyvinyl chloride as a binder, while the sorbent granules contain regions distributed throughout the volume filled with at least alkali or alkaline earth metal halides. In this case, the activated sorbent is a sorbent based on a chlorine-containing variety of aluminum-lithium double hydroxide and is characterized in that the sorbent granules have a size of 0.5 to 3 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 25 to 70 m 2 / g, the bulk density of the granulated sorbent is from 0.35 to 0.9 g / cm 3The sorbent granules contain particles of a chlorine-containing variety of aluminum-lithium double hydroxide less than 200 µm in size and polyvinyl chloride as a binder. The sorbent granules also contain pores distributed throughout their volume. Organic or inorganic solvents, including water and alcohols, can be used as solvents for granule activation.

[0029] The technical result is achieved by sorbent granules ranging in size from 0.5 to 3 mm, which is the optimal granule size for industrial sorbent applications. The use of smaller fractions increases the risk of granule carryover, while larger fractions require more time for sorption, washing, and desorption due to the difficulty of solution penetration into the granule's depth. Moreover, larger and smaller fractions of granules based on a polyvinyl chloride binder, obtained by known methods, such as the method described in patents RU2801465C1 and RU2657495C1, exhibit greater relative deviations in granule shape compared to the 0.5 to 3 mm fraction. This negatively impacts the strength of the granules and their abrasion resistance, as well as lower sorption rates for larger fractions.Thus, sorbent granules with a binder in the form of polyvinyl chloride with a size of 0.5 to 3 mm provide the necessary strength and wear resistance of the sorbent and maintain the required rate of sorption and desorption of lithium.

[0030] The technical result is achieved by using polyvinyl chloride as a binder in the granules. Polyvinyl chloride possesses high chemical resistance and mechanical strength, remaining unchanged both in a dry state and in solvent environments (its dimensional properties do not change when exposed to solvents), which positively impacts the strength of the granules. In the present invention, polyvinyl chloride should be understood to include its various types, such as, for example, chlorinated polyvinyl chloride.

[0031] The technical result is achieved in that the sorbent granules with a binder in the form of polyvinyl chloride have regions distributed in the volume, filled with the use of at least alkali or alkaline earth metal halides, while the sorption surface area of ​​the granules, determined by the BET method, is from 5 to 20 m 2 / g, and the bulk density of the granulated sorbent is from 0.45 to 1.0 g / cm 3The presence of cavities filled with alkali or alkaline earth metal halides improves the strength of the sorbent granules during storage, transportation, and placement in equipment. This is also ensured by maintaining the specified granule surface area and density. Excessive pores within the granule, which represent unfilled areas, lead to a decrease in density and an increase in the granule surface area, thereby reducing its strength. If necessary, alkali or alkaline earth metal halides can be effectively dissolved and removed from the cavities to form pores; a wide range of solvents can be used for this process.

[0032] The technical result is achieved by the fact that the particles of the chlorine-containing variety of aluminum-lithium double hydroxide in the sorbent granules have a size of less than 200 μm. This, together with the achieved porosity, ensures the sorption capacity of the sorbent of up to 5.4 g of lithium per 1 liter of granulated sorbent in 3 hours. Moreover, 4.0 g per 1 liter of granulated sorbent is achieved in 1.5 hours in the dynamic sorption mode with a recovery rate of 96%. An increase in the particle size of the chlorine-containing variety of aluminum-lithium double hydroxide in the granules leads to a decrease in the sorption capacity, including due to a decrease in the uniformity of particle distribution in the binder and an increase in the influence of diffusion effects during sorption and desorption. Thus, the use of particles with a fraction of less than 200 μm in the sorbent ensures high sorption capacity and the rate of lithium sorption and desorption.

[0033] The technical result is achieved in that the sorbent granules with a binder in the form of polyvinyl chloride contain pores distributed throughout the volume, while the granules have a sorption surface area, determined by the BET method, from 25 to 70 m 2 / g, while the bulk density of the granulated sorbent is from 0.35 to 0.9 g / cm 3 This provides a sorption capacity of up to 5.4 g of lithium per 1 liter of granulated sorbent due to the participation of the pore area in sorption and desorption. This also ensures the necessary strength of the sorbent granules, as excessive pore volume leads to increased fragility of the granules, while reduced pore volume leads to a decrease in sorption capacity. Thus, maintaining these characteristics for sorbent granules ensures high sorption capacity while maintaining the required strength and wear resistance of the sorbent.

[0034] The technical result is achieved by the fact that the modal value of the mesopore size of the sorbent granules can be 3 - 5 nm, which provides the necessary surface area, determined by the BET method, to maintain high sorption capacity, the necessary strength and wear resistance of the granules.

[0035] The technical result is achieved by the fact that the median value of the mesopore size of the granules is 5 - 50 nm, which provides the necessary surface area, determined by the BET method, to maintain high sorption capacity and the necessary strength of the granules.

[0036] The technical result is achieved by the fact that the modal value of the micropore size is 4 - 10 angstroms, which provides the necessary surface area, determined by the BET method, to maintain high sorption capacity and the required strength of the granules.

[0037] The technical result is achieved by the fact that the median value of the micropore size is 4 - 10 angstroms, which provides the necessary surface area, determined by the BET method, to maintain high sorption capacity and the required strength of the granules.

[0038] The technical result is achieved by washing the non-activated sorbent for lithium extraction with a solvent to obtain an activated sorbent, using a solvent that ensures the dissolution and washing out of at least alkali or alkaline earth metal halides from the sorbent granules with the formation of pores in their volume, which ensures high strength characteristics of the sorbent at the stage of transportation, storage and placement in sorption-desorption units, and easy transfer of the sorbent to a working state with a decrease in strength characteristics to acceptable levels, but with a significant increase in sorption capacity.In this case, the removal of alkaline or alkaline earth metals from the sorbent granules is carried out by conventional washing, which does not require the use of specialized equipment and can be carried out directly in the sorption-desorption unit by passing the solvent through the sorbent layer, this ensures simplicity, cost-effectiveness and speed of transferring the sorbent to a working state.

[0039] The technical result is achieved by the fact that when activating the granules, available organic or inorganic solvents, including water and alcohols, can be used as a solvent, which ensures the simplicity and cost-effectiveness of the method.

[0040] Description of drawings.

[0041] Fig. 1. - Sorption kinetic curve. Sample 36.

[0042] Table 1 - Samples of granules with DGAL-C1 particles smaller than 200 µm.

[0043] Table 2 - Samples of granules with DGAL-C1 particles smaller than 50 µm.

[0044] Table 3 - Non-activated samples of sorbent with DGAL-C1 particles smaller than 200 µm.

[0045] Table 4 - Non-activated samples of sorbent with DGAL-C1 particles smaller than 50 µm.

[0046] In its most general form, the sorbent according to the present invention is a granular sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide, characterized in that the sorbent granules have a size of 0.5 to 3.0 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 25 to 70 m 2 / g, the bulk density of the granulated sorbent is from 0.35 to 0.9 g / cm 3, wherein the sorbent granules contain particles of a chlorine-containing variety of aluminum lithium double hydroxide less than 200 μm in size and polyvinyl chloride as a binder, while the sorbent granules contain pores distributed throughout the volume. This sorbent is used to extract lithium from lithium chloride solutions. In the most common embodiment, the sorbent is placed inside a vertical column and a lithium chloride solution is passed through the sorbent layer. Lithium is sorbed due to intercalation by the compound LiCl-2Al(OH)3 nH2O, the particles of which are located within the volume of the sorbent granules, access to which is carried out, among other things, through the pores. After the sorption stage, the remaining lithium chloride solution is drained or displaced from the column with a washing liquid, and the sorbent is washed. Water or brine, which can be diluted to varying degrees, can serve as a washing liquid.

[0047] After washing, lithium is desorbed by passing the desorbing liquid through a layer of sorbent; water is usually used as the desorbing liquid, whereby lithium passes into the desorbing liquid, producing an eluate rich in lithium.

[0048] The sorbent washing step increases the purity of the eluate, as the remnants of the original lithium chloride solution, which may contain impurities that can enter the eluate along with the desorbing liquid, are removed from the sorbent layer.

[0049] For industrial use of the sorbent, a high sorption capacity and sorption and desorption rates are important; they directly affect the speed and profitability of the lithium extraction process.

[0050] Pure LiCl-2Al(OH)3 nH2O has a sorption capacity of approximately 12 g of lithium per 1 kg. This value is unattainable for granular sorbent, but the higher the sorption capacity, the more efficient the process. This capacity can be increased, among other things, by increasing the porosity of the sorbent granules and decreasing the granule size. Porosity and small granule size provide a large contact area between the lithium chloride solution and LiCl-2Al(OH)3 nH2O particles, which positively impacts the sorption and desorption rates and sorption capacity. However, the issue of sorbent strength becomes more pressing, as large pore volumes make the granules brittle, while small granule sizes complicate handling. Sorbent granules are prone to wear and tear during processing; ensuring the sorbent's strength is essential for practical application.

[0051] To assess the strength of the activated sorbent, a method for determining the mechanical strength of granules during abrasion was adopted.

[0052] The essence of the method consists of mechanical abrasion of the sorbent sample by shaking the granules in the working environment on a reciprocating shaker, separating the resulting fraction smaller than 0.25 mm and determining its percentage (volume) content.

[0053] The strength of the sorbent is calculated using the formula (P, %): n = (Vi-V2) / Vi x 100, where Vi is the volume of the sorbent sample, cm 3 ; V2 - volume of sorbent with fraction less than 0.25 mm, cm 3 .

[0054] A sample of sorbent with a volume of 100 cm 3 placed in a graduated cylinder with a volume of 250 cm 3 , pour 150 cm 3 water and close the cylinder. The cylinder is secured horizontally on a vibrating apparatus and shaken at a rate of 120 strokes per minute with a stroke length of 60 mm for 10 hours.

[0055] Sufficient strength of the sorbent for its industrial use can be considered to be a strength of at least 95%, calculated in the specified way.

[0056] This strength indicator allows us to reduce sorbent losses associated with mechanical wear to a level of less than 5% per year, under continuous operation conditions with an operating pressure of 1 atm.

[0057] In order to ensure this indicator and at the same time good sorption properties, the granulated sorbent with a binder in the form of polyvinyl chloride and with a lithium-sorbing component in the form of 1LSG2A1(OH)3 PN2O has a granule size of 0.5-3 mm, a bulk density of 0.35-0.9 g / cm 3 , the particle size of 1лСГ2А1(ОН)з пН2О in the granules is less than 200 μm, the sorption surface area of ​​the granules is from 25 to 70 m 2 / g, which is provided, among other things, due to the pore surface.

[0058] These characteristics combined ensure high sorption rates, with a sorption capacity of up to 5.4 g of lithium per 1 L of granular sorbent, and a high capacity build rate of up to 4.0 g per 1 L of granular sorbent in 1.5 hours in dynamic sorption mode with a recovery rate of 96%, while maintaining high sorbent strength of up to 98%. The capacity build rate characterizes the rate of sorption and desorption of the sorbent and is defined as the amount of lithium absorbed per unit time by a unit volume of granular sorbent when passing a lithium-containing liquid through a sorption column. Moreover, the longer the minimum lithium concentration is observed at the column outlet, the more effective the sorbent.

[0059] Increasing the particle size of the chlorine-containing aluminum lithium double hydroxide in the granules leads to a decrease in sorption capacity, partly due to a decrease in the uniformity of particle distribution in the binder and an increase in the influence of diffusion effects during sorption and desorption. Therefore, the use of particles with a fraction of less than 200 µm in the sorbent, combined with the achieved porosity, ensures high sorption capacity and the rate of lithium sorption and desorption.

[0060] Use as a binder of polyvinyl chloride, providing a granule size from 0.5 to 3 mm, bulk density of 0.35 to 0.9 g / cm 3 and the surface area of ​​granule sorption is up to 70 m 2 / g ensures the sorbent's resistance to abrasion and destruction.

[0061] The sorption surface area of ​​granules is from 25 to 70 m 2 / g and their size from 0.5 to 3 mm provide high sorption capacity and the rate of sorption and desorption.

[0062] This sorbent will be further referred to in the text as an activated sorbent.

[0063] In a particular case of the invention implementation, the sorption surface area indicators determined by the BET method are from 25 to 70 m 2 / g, are ensured due to the preferred sizes of mesopores and micropores in the sorbent granules.

[0064] In a particular case of the invention implementation, the modal value of the mesopore size of the sorbent granules may be 3 - 5 nm.

[0065] In a particular case of the invention implementation, the median value of the mesopore size of the sorbent granules may be 5 - 50 nm.

[0066] In a particular case of the invention implementation, the modal value of the micropore size of the sorbent granules can be 4 - 10 angstroms.

[0067] In a particular case of the invention implementation, the median value of the micropore size of the sorbent granules can be 4 - 10 angstroms.

[0068] Using these preferred pore sizes, the desired sorption surface area can be achieved, while the sorption surface area of ​​the present invention can also be achieved using other pore sizes or features of the internal geometry of the sorbent.

[0069] An activated sorbent with a granule sorption surface area of ​​25 to 70 m 2 / g and bulk density from 0.35 to 0.9 g / cm 3 , can be obtained by washing the non-activated sorbent with a solvent.

[0070] The non-activated sorbent is a granular sorbent for the extraction of lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide, characterized by the fact that the sorbent granules have a size of 0.5 to 3 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 5 to 20 m 2 / g, the bulk density of the granulated sorbent is from 0.45 to 1.0 g / cm 3 , wherein the sorbent granules contain particles of a chlorine-containing variety of double aluminum and lithium hydroxide of a size less than 200 μm and polyvinyl chloride as a binder, wherein the sorbent granules contain regions distributed in the volume filled with the use of at least alkali or alkaline earth metal halides.

[0071] The non-activated sorbent differs from the working sorbent by the presence in its volume of regions filled with at least alkali or alkaline earth metal halides, with a bulk density of 0.45 to 1.0 and a sorption surface area of ​​5 to 20 m 2 / G.

[0072] These differences in bulk density and sorption surface area are ensured by the fact that the sorbent granules contain areas filled with at least alkali or alkaline earth metal halides; when these areas are cleaned, they become pores, and the sorption surface area of ​​the granules increases to values ​​of 25-70 m 2 / g, and the bulk density of the granules decreases to values ​​of 0.35-0.90 g / cm 3 .

[0073] Purification of cavities from alkali or alkaline earth metal halides, creating additional pores, is accomplished by washing the unactivated sorbent with solvents. These solvents can be organic or inorganic, with water or alcohols being the most preferred. The presence of filled cavities in the unactivated sorbent increases the strength of the sorbent granules during storage, transportation, and placement in equipment. The strength of such granules, determined according to GOST R 55873, is 97.41–99.91%, which is 4.01–5.30% higher than the strength determined for dry sorbent in its working (activated) form.

[0074] The specified bulk density and surface area of ​​the non-activated sorbent also characterize its porosity, which is associated with strength; an excessive number of pores in the volume of the granule, which are unfilled areas, leads to a decrease in density and an increase in the surface area of ​​the granule, while its strength decreases.

[0075] The method according to the present invention consists of obtaining a working sorbent from a non-activated one.

[0076] In the most general case, the method is carried out as follows: an unactivated sorbent, the cavities in the granules of which include sodium chloride crystals, is loaded into a column to carry out the process of sorption and desorption of lithium.

[0077] Water is fed into the column as a flow, which causes the sodium chloride crystals to dissolve and be removed from the sorbent granules, producing a sodium chloride solution and additional pores in the volume of the granules; the sodium chloride solution is removed from the column.

[0078] Washing is carried out until the required mass of lithium chloride is removed from the sorbent structure, while the removal of sodium chloride from the sorbent occurs by more than 99%, which ensures the formation of a porous structure.

[0079] Thus, an inactivated sorbent can be defined as an intermediate product that can be converted into the final product (the working sorbent) by washing with a solvent. This conversion can occur directly during lithium extraction by feeding an aqueous lithium solution to the sorbent during the desorption stage. Thus, even an inactivated sorbent can be used in lithium extraction, and its conversion to a working state and effective sorption (conversion into a working sorbent) will occur directly during the sorption-desorption cycle. It is also worth noting that even before the transition to a working state is achieved, an inactivated sorbent can still sorb lithium in small quantities.

[0080] However, the preferred option is to wash the sorbent with a solvent before the sorption stage.

[0081] As halides of alkali or alkaline earth metals used to fill areas in granules, it is preferable to use: chlorides or bromides of sodium, lithium, potassium, calcium, magnesium, strontium, barium.

[0082] The areas in the granules of the inactivated sorbent can be filled either completely or partially, including, in addition to the declared salt or their mixture, other substances may be present in the cavities, while the cleaning of the cavities is ensured by the dissolution of the salts and their removal.

[0083] In its most general form, the non-activated sorbent is stored and transported to the point of use, loaded into a lithium sorption and desorption unit, washed with water, and used in the working process as described above.

[0084] In this case, the non-activated sorbent and the activated sorbent can act as independent products.

[0085] To provide a more detailed disclosure of the essence of the invention, examples of its implementation are provided.

[0086] Example 1.

[0087] Lithium concentrate was obtained from lithium-bearing brine.

[0088] The initial brine composition was Na - 91.7 g / dm3 3 , K - 7.7 g / dm 3 , Ca - 2.9 g / dm3 3 , Mg - 3.1 g / dm 3 , Li - 1530 mg / dm 3 , C1 - 164.9 g / dm3 3 , SO4 - 3.2 g / dm 3 , B - 0.5 g / dm 3 .

[0089] The lithium concentrate was obtained as follows: the sorbent was activated by passing a stream of water through the sorbent layer in the column at a rate of 5 column volumes (hereinafter referred to as VO) / hour for 4 hours, then the water was drained from the column and brine was supplied at a rate of 2 VO / hour for 4 hours, after which the brine was drained from the column and desorption was carried out with distilled water at a rate of 5 VO / hour.

[0090] For sorption and desorption operations, brine samples at the column outlet were analyzed for lithium content every 0.28 KO. Based on the obtained data, sorption and desorption kinetic curves were constructed.

[0091] In carrying out the process, samples of granulated sorbent based on polyvinyl chloride with the characteristics indicated in Table 1 were used.

[0092] In the sorbent samples, the fraction of DGAL-C1 less than 200 µm was used.

[0093] For each sample of the sorbent in activated and non-activated forms, under the same conditions, the strength was determined using the methods specified in the description of the present invention.

[0094] The sorption capacity of the samples, as well as the sorption rate indicator, are presented in Table 1.

[0095] Based on the kinetic curves, the maximum dynamic sorption capacity, as well as the sorption rate, were determined.

[0096] As a result of the work carried out, it was established that for the given combinations of granule sizes, sorption surface areas and bulk densities, high sorbent strength, the required sorption capacity and high sorption / desorption rate are maintained.

[0097] Table 1

[0098] "Samples of granules with DGAL-C1 particles smaller than 200 µm"

[0099] Example 2.

[0100] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Example 1, with the difference that the DGAL-C1 fraction with a particle size of less than 50 μm was used in the sorbent composition.

[0101] The results are presented in Table 2.

[0102] Based on the kinetic curves, the maximum dynamic sorption capacity, as well as the sorption rate, were determined.

[0103] For sample 36 the graph is shown in Fig. 1.

[0104] As a result, an increase in sorption capacity and sorption / desorption rate was revealed relative to the sorbents presented in Example 1, which is explained by the use of a finer fraction of DGAL-C1. It is obvious that it is possible to use a finer fraction to improve the results. However, the strength properties of the sorbents decreased by an average of 0.6 - 0.8%. Table 2. "Samples of granules with DGAL-C1 particles smaller than 50 µm"

[0105] Example 3.

[0106] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Example 1, with the difference that the DGAL-C1 fraction from 200 to 350 µm was used in the sorbent composition.

[0107] As a result, the sorption capacity of the sorbents was found to decrease by an average of 21%, compared to Example 1. However, the strength properties of the sorbents were maintained. The study showed that the use of DGAL-C1 fractions greater than 200 µm is not promising.

[0108] Example 4.

[0109] To obtain lithium concentrate from lithium-bearing brine, samples of granular polyvinyl chloride-based sorbent with the characteristics listed in Table 3 were used. The granules contained a fraction of DGAL-C1 smaller than 200 µm. The granules contained cavities filled with sodium chloride crystals.

[0110] The strength of the granules was determined using the method according to GOST R 55873.

[0111] Then, all samples were washed with water, after which they were dried to obtain sorbents similar to those presented in Table 1, the correspondence of sorbents is given in Table 3.

[0112] The dried sorbents, subjected to washing, were tested for strength according to GOST R 55873. The results are presented in Table 3.

[0113] As can be seen from the strength assessment results, the unwashed sorbent significantly exceeds the working sorbent in strength, which allows this form of sorbent to be successfully used during transportation, storage, and loading into industrial lithium extraction plants.

[0114] The dried sorbents from which sodium chloride crystals had been removed were used for lithium sorption in the manner described in Example 1 with the corresponding result.

[0115] Table 3 “Non-activated samples of sorbent with DGAL-C1 particles smaller than 200 µm”

[0116] Example 5.

[0117] To obtain lithium concentrate from lithium-bearing brine, samples of granular polyvinyl chloride-based sorbent with the characteristics listed in Table 4 were used. The granules contained a fraction of DGAL-C1 smaller than 50 µm. The granules contained cavities filled with sodium chloride crystals.

[0118] The granule strength was determined using the method according to GOST R 55873. All samples were then washed with water and then dried to obtain sorbents similar to those presented in Table 2. The correspondence of sorbents is given in Table 4.

[0119] The dried sorbents, subjected to washing, were tested for strength using the method according to GOST R 55873. The results are presented in Table 4.

[0120] As can be seen from the strength assessment results, the unwashed sorbent significantly exceeds the working sorbent in strength, which allows this form of sorbent to be successfully used during transportation, storage, and loading into industrial lithium extraction plants, while the size of the DGAL-C1 fraction has little effect on strength.

[0121] The dried sorbents from which sodium chloride crystals had been removed were used for lithium sorption in the manner described in Example 2 with the corresponding result.

[0122] Table 4 “Non-activated samples of sorbent with DGAL-C1 particles smaller than 50 µm”

[0123] Example 6.

[0124] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 4 and 5, with the difference that the cavities of the granules were filled with lithium chloride crystals.

[0125] The use of lithium chloride allowed the solution after rinsing to be used as a source of lithium chloride.

[0126] The strength characteristics of the granules had minor deviations from those established in Example 4 and Example 5.

[0127] Example 7.

[0128] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 4 and 5, with the difference that the cavities of the granules were filled with potassium chloride crystals.

[0129] The use of lithium chloride made it possible to use the solution after washing as a source of potassium.

[0130] The strength characteristics of the granules had minor deviations from those established in Example 4 and Example 5. Example 8.

[0131] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 4 and 5, with the difference that the cavities of the granules were filled with magnesium chloride crystals.

[0132] The use of lithium chloride made it possible to use the solution after washing as a source of magnesium.

[0133] The strength characteristics of the granules had minor deviations from those established in Example 4 and Example 5.

[0134] Example 9.

[0135] The production of lithium concentrate from lithium-bearing brine was carried out in a manner similar to Examples 4 and 5, with the difference that the cavities of the granules were filled with crystals of magnesium chloride, sodium chloride, potassium chloride, magnesium chloride, barium chloride and strontium chloride.

[0136] The strength characteristics of the granules had minor deviations from those established in Example 4 and Example 5.

[0137] Example 10.

[0138] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 4 and 5, with the difference that the cavities of the granules were filled with crystals of lithium bromide, sodium bromide and potassium bromide.

[0139] The strength characteristics of the granules had minor deviations from those established in Example 4 and Example 5.

[0140] Example I.

[0141] A portion of the non-activated sorbent from the samples used in Examples 4-10 was washed and dried, using ethyl alcohol as the washing liquid.

[0142] The characteristics of the washed sorbent samples did not differ from those obtained by washing with water.

[0143] Example 12.

[0144] A portion of the unactivated sorbent from the samples used in Examples 4-10 was washed and dried, using methyl alcohol as the washing fluid. The characteristics of the washed sorbent samples were no different from those obtained by washing with water.

[0145] Example 13.

[0146] A portion of the non-activated sorbent from the samples used in Examples 4-10 was washed and dried, using distilled water as the washing liquid.

[0147] The characteristics of the washed sorbent samples did not differ from those obtained by washing with water.

[0148] Example 14.

[0149] A portion of the non-activated sorbent from the samples used in Examples 4-10 was washed and dried, using ethyl alcohol as the washing liquid.

[0150] The characteristics of the washed sorbent samples did not differ from those obtained by washing with water.

[0151] Example 15.

[0152] A portion of the non-activated sorbent from the samples used in Examples 4-10 was washed and dried, using ethyl alcohol as the washing liquid.

[0153] The characteristics of the washed sorbent samples did not differ from those obtained by washing with water.

[0154] Example 16.

[0155] A portion of the non-activated sorbent from the samples used in Examples 4-10 was washed and dried, using calcium chloride brine as the washing liquid.

[0156] The characteristics of the washed sorbent samples did not differ from those obtained by washing with water.

[0157] Example 17.

[0158] Lithium concentrate was obtained from lithium-bearing brine similarly to Examples 1 and 2, with the exception that the modal mesopore size of the sorbent granules was 3–5 nm. The sorbent characteristics were similar to those of samples Nos. 1–54.

[0159] Example 18.

[0160] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 1 and 2, with the difference that the modal value of the micropore size of the sorbent granules was 4–10 angstroms.

[0161] The sorbent characteristics were similar to those of samples No. 1-54.

[0162] Example 19.

[0163] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 1 and 2, with the difference that the median value of the granule mesopore size was 5–50 nm.

[0164] The sorbent characteristics were similar to those of samples No. 1-54.

[0165] Example 20.

[0166] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Example 2, with the difference that the median value of the micropore size of the sorbent granules was 4–10 angstroms.

[0167] The sorbent characteristics were similar to those of samples No. 1-54.

[0168] Example 21.

[0169] The production of lithium concentrate from lithium-bearing brine was carried out in a manner similar to Example 5, with the difference that the sorbent was washed from sodium chloride crystals in a column of an industrial lithium extraction plant as part of a lithium sorption cycle using lithium-containing brine.

[0170] Sorbent activation did not require any additional steps during lithium extraction. Lithium sorption also occurred during sorbent activation. Example 22.

[0171] The production of lithium concentrate from lithium-bearing brine was carried out in a manner similar to Example 5, with the difference that the sorbent was washed from sodium chloride crystals in a column of an industrial lithium extraction plant before the lithium sorption cycle, by passing water through the column.

[0172] To activate the sorbent, a water supply line was used, which was used in the lithium sorption extraction cycle to wash the sorbent after the sorption stage, which eliminated the need for additional costs associated with re-equipping the equipment for sorbent activation.

[0173] Example 23.

[0174] The production of lithium concentrate from lithium-bearing brine was carried out similarly to Examples 4 and 5, with the difference that chlorinated polyvinyl chloride was used as a binder for the granules.

[0175] The strength characteristics of the granules had minor deviations from those established in Example 4 and Example 5, which were within the limits of measurement error.

[0176] The characteristics of the activated sorbent were similar to those of samples No. 1-54.

Claims

CLAUSES OF THE INVENTION 1. A granular sorbent for the extraction of lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide, characterized in that the sorbent granules have a size of 0.5 to 3 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 5 to 20 m 2 / g, the bulk density of the granulated sorbent is from 0.45 to 1.0 g / cm 3 , wherein the sorbent granules contain particles of a chlorine-containing variety of double aluminum and lithium hydroxide of a size less than 200 μm and polyvinyl chloride as a binder, wherein the sorbent granules contain regions distributed in the volume filled with the use of at least alkali or alkaline earth metal halides.

2. A granular sorbent for the extraction of lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide, characterized in that the sorbent granules have a size of 0.5 to 3 mm, the sorption surface area of ​​the granules, determined by the BET method, is from 25 to 70 m 2 / g, the bulk density of the granulated sorbent is from 0.35 to 0.9 g / cm 3 , wherein the sorbent granules contain particles of a chlorine-containing variety of double aluminum and lithium hydroxide with a size of less than 200 μm and polyvinyl chloride as a binder, wherein the sorbent granules contain pores distributed throughout the volume.

3. A granular sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide according to claim 2, characterized in that the modal value of the mesopore size of the granules is 3 - 5 nm.

4. A granular sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide according to paragraphs 2-3, characterized in that the median value of the mesopore size of the granules is 5 - 50 nm.

5. A granular sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide according to paragraphs 2-4, characterized in that the modal value of the micropore size is 4 - 10 angstroms.

6. Granular sorbent for the extraction of lithium from brine based on a chlorine-containing variety of double aluminum hydroxide and lithium according to paragraphs 2-5, characterized in that the median value of the micropore size is 4 - 10 angstroms.

7. A granular sorbent for extracting lithium from brine based on a chlorine-containing variety of double aluminum and lithium hydroxide according to paragraph 2, characterized in that it was obtained by washing the sorbent with a solvent that ensures the dissolution and washing out of at least alkali or alkaline earth metal halides from the sorbent granules with the formation of pores in their volume.

8. A method for producing a granular sorbent for extracting lithium from a brine based on a chlorine-containing variety of double aluminum hydroxide and lithium according to claim 2, characterized in that the granular sorbent is washed for extracting lithium from a brine based on a chlorine-containing variety of double aluminum hydroxide according to claim 1 with a solvent that ensures the dissolution and washing out of at least alkali or alkaline earth metal halides from the sorbent granules with the formation of pores in their volume.

9. The method according to paragraph 8, characterized in that organic or inorganic solvents are used as the solvent.

10. The method according to paragraph 8, characterized in that water is used as a solvent.

11. The method according to paragraph 8, characterized in that alcohols are used as a solvent.

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