RU220087U1 - Granule for lithium sorption from an aqueous solution - Google Patents

Abstract

The utility model relates to the extraction of lithium from lithium-containing chloride brines, from natural brines, process solutions and wastewater from oil and gas, chemical, chemical-metallurgical and biochemical industries.

The granule for lithium sorption from an aqueous solution contains a waterproof spherical core coated with a solution-permeable composite of DHAL-Cl sorbent particles and a hydrophilic binder. The hydrophilic binder has an open-pore structure. The maximum binder content in terms of dry residue is not more than 40% by weight of the sorbent particles. The average granule size is not less than 0.3 mm and not more than 3.0 mm, preferably not less than 0.5 mm and not more than 1.0 mm. The average particle size of the sorbent does not exceed 50 microns, preferably 10 microns. The average thickness of the sorption coating of the core does not exceed 150 microns, preferably 100 microns.

The technical result of the proposed solution is to increase the efficiency of the process of lithium sorption from oil-, fat-, oil-contaminated aqueous solution and desorption of lithium from granules.

Description

The utility model relates to the extraction of lithium from lithium-containing chloride brines, from natural brines, process solutions and wastewater from oil and gas, chemical, chemical-metallurgical and biochemical industries.

The closest to the proposed solution is a sorbent granule for the extraction of lithium from lithium-containing brines under the conditions of production of commercial lithium products (RF patent No. -Cl). The disadvantage of the known solution is the low efficiency of the process of lithium sorption from oil-, fat-, oil-contaminated aqueous solution and desorption of lithium from granules, since:

The central part of the granule (core) of the sorbent works inefficiently in the case of dynamic (time-limited) sorption.

The granules are formed entirely from the sorbent, which sharply increases the cost of granules from expensive sorbent (DHAL-Cl) and the internal diffusion resistance to the sorption process, increasing the sorption time and reducing productivity.

Granules formed entirely from a sorbent with a porous structure throughout the volume have a high retention capacity for parasitic salts from the initial target solution, which require a long process of washing out during desorption.

When using an ascending sorption / desorption flow, a low speed of brine and washing liquid is set through a layer of granular sorbent to prevent entrainment of sorbent granules, which has a particularly negative effect on the efficiency of the process due to the high cost of the sorbent.

Sorbent granules are contaminated with oil, fat, oil products contained in the brine, which reduces the capacity of the sorbent.

The technical result of the proposed solution is to increase the efficiency of the process of lithium sorption from oil-, fat-, oil-contaminated aqueous solution and desorption of lithium from granules due to:

The surface layer of the sorbent granule works more efficiently, since its capacity is fully utilized within a limited sorption/desorption time.

Replacement of the sorbent of the inner part of the granule with the core, which reduces the cost of the granules and the internal diffusion resistance to the sorption process, reducing the sorption time and increasing productivity.

Increasing the efficiency of washing the sorbent by reducing the amount and easier and faster washing out of parasitic salts.

Increasing (expanding the range) the rate of filtration of the solution and washing liquid through a layer of granular sorbent, since by changing the material of the core, its density and other parameters, it is possible to significantly reduce the entrainment of sorbent granules by the flow of solution and washing liquid.

Prevention of contamination of sorbent granules with oil, grease, oil contamination due to the use of a hydrophilic binder, which ensures the creation and retention of a protective water shell around the granule, which prevents the interaction of oil, grease, oil contamination contained in the filtered solution with the granule.

This technical result is achieved by the fact that in the granule for sorption of lithium from an aqueous solution containing sorbent particles from a chlorine-containing variety of aluminum and lithium double hydroxide, the granule contains a waterproof spherical core coated with a solution-permeable composite of sorbent particles and a hydrophilic binder. The hydrophilic binder has an open-pore structure. The hydrophilic binder is sparingly soluble in water at the granulation stage. The maximum binder content in terms of dry residue is not more than 40% by weight of the sorbent particles. The average granule size is not less than 0.3 mm and not more than 3.0 mm, preferably not less than 0.5 mm and not more than 1.0 mm. The average particle size of the sorbent does not exceed 50 microns, preferably 10 microns. The average thickness of the sorption coating of the core does not exceed 150 microns, preferably 100 microns. The granule can be covered with a protective layer of tripoli with an average particle size of not more than 10 microns. The core may be made of glass or a binder. The core of the granule can be made hollow. The value of adhesion between the core and the binder should not be less than the cohesion value of the binder.

The implementation of a granule with a waterproof spherical core increases the efficiency of the process of lithium sorption from oil-, fat-, oil-contaminated aqueous solution and lithium desorption from granules due to:

reducing the amount of expensive sorbent (DGAL-Cl) per granule, and, accordingly, reducing the cost of the granule;

reducing the time of lithium sorption-desorption, since a decrease in the thickness of the sorbent layer reduces the internal diffusion resistance to the sorption-desorption process;

expands the range of the rate of filtration of the solution and washing liquid through a layer of granules, as it allows you to change the material of the core, its density and other parameters.

Making the core waterproof shortens the desorption time as it prevents the solution from entering the interior of the pellet.

Making the core spherical makes it possible to obtain granules of a more regular spherical shape and more accurately maintain their dimensions, which improves the filtration process through a layer of granules, as it provides a more uniform layer porosity, reduces the likelihood of layer seals, formation of stagnant zones and punching channels.

The sorbent particles, together with the hydrophilic binder, create a sorbent composite shell (sorption coating) around the granule, which is permeable to the solution and protects the granule from oil, grease, and oil contaminants contained in the filtered solution. The hydrophilicity and porosity of the sorbent shell makes it possible to create a protective water shell around the granule.

The open-pore structure of the hydrophilic binder significantly increases the wettability of the binder surface with an aqueous medium and the integrity of the protective water shell around the granule due to the capillary effect.

The use of a hydrophilic binder, sparingly soluble in water at the granulation stage, makes it possible to increase the porosity of the binder and, accordingly, the sorption coating. If the maximum content of the granule binder in terms of dry residue is not more than 40% of the mass of the granule sorbent particles, then this ensures the creation of open pores between the sorbent particles that are not filled with the binder.

To prevent carryover of the granules, the average granule size should be at least 0.3 mm (preferably at least 0.5 mm). To maximize the sorption surface, the average granule size should be no more than 3.0 mm (preferably no more than 1.0 mm), and the average particle size of the sorbent should not exceed 50 μm (preferably 10 μm). To reduce the internal diffusion resistance to the sorption process, the average thickness of the sorption coating of the core should not exceed 150 μm, preferably 100 μm.

To increase the efficiency of protecting the granules from oil, fat, oil pollution contained in the filtered solution, the granule can be additionally (on top of the sorption coating) covered with a protective layer of tripoli with an average particle size of not more than 10 microns. The open-pore structure of tripoli and the pores formed between its particles ensure the effective creation and retention of a protective water shell around the granule. When using a tripoli fraction of more than 10 μm, the protective oleophobic coating loses its continuity and strength of binding to the sorbent layer. Since tripoli is a soft rock, its large particles are the least durable part of the coating, and as a result, upon contact with the aquatic environment, the tripoli coating is easily destroyed by mechanical action. This is especially evident when the pellets are in water for a long time.

The core of the granule can be made from various substances, in particular from glass or a binder. The core can also be made, for example, from a metal, in particular from lead (when more weight is required) or from ceramic (when increased strength, manufacturability, chemical neutrality or low cost are required). The core can be, depending on the characteristics of the sorption process, solid (when more weight and/or strength is required) or hollow (when it is necessary to reduce the weight and/or hydraulic fineness of the granule).

To increase the porosity of the binder, materials can be used in which the adhesion between the core and the binder will be no less than the cohesion of the binder. Then, when the binder dries (dries out), under impact load or when heated (if the core of the granule is made of a substance with a thermal expansion coefficient greater than that of the binder), the binder will crack, creating additional pores, but will remain attached to the core.

Examples of specific implementation.

An experimental verification of the effectiveness of the proposed solution was carried out on a laboratory installation for measuring dynamic sorption capacity, which is a filter column with an inner diameter of 20 mm and a height of 1000 mm, equipped with mesh separators, thermal insulation and a supply gear pump, corrosion-resistant to the medium under study. Sorption and desorption were carried out in a downward flow mode. The rate of sorption from the model solution was 5.5 m/h at a brine temperature of 40°C, and the rate of desorption with distilled water was 1.5 m/h at a temperature of 20°C. The time of sorption and desorption cycles was constant and amounted to 17 and 6 hours, respectively.

The composition of the chloride model brine for test sorption:

Li - 60 mg/l

Na - 24000 mg/l

K - 1000 mg/l

Ca - 8000 mg/l

Mg - 1300 mg/l.

The mass content of lithium, sodium, potassium, calcium, and magnesium in the composition of the eluate (liquid obtained during the desorption cycle) was controlled by capillary electrophoresis (Kapel-105M KEF system).

The studies are illustrated by graphs, where in Fig. 1 shows the results for example 1; in fig. 2 - results for example 2; in fig. 3 - results for example 3; in fig. 4 and 5 - results for example 4; in fig. 6 - results for example 10.

Example 1

A granular sorbent (granules for sorption of lithium from an aqueous solution) was obtained by coating glass beads with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) using a polymer binder (melamine-formaldehyde resin). The sorbent for application to the glass core (glass beads) was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column.

The bulk density of the sorbent is 910 g/l.

The first cycle is the desorption of lithium, present in the composition of the sorbent upon receipt, with distilled water. The second cycle is the sorption of lithium from brine, the composition of which is the same for all the examples given.

The third cycle is the desorption of lithium accumulated from the model brine with distilled water.

The efficiency of the sorbent was determined by analyzing the lithium content in the resulting eluate: for each sample, a graph was plotted for the dependence of the lithium content in the selected eluate samples on the amount of distilled water passed (one column volume is the bulk volume of the sorbent taken for the test).

The dynamic capacity of the sorbent (the value of the sorbent capacity under dynamic sorption/desorption conditions, i.e. at a fixed time of sorption/desorption cycles and a constant flow rate through the sorbent layer), based on the data obtained (Fig. 1), was 12 grams of lithium per kilogram contained in the sorbent granules (g/kg).

Example 2

The granulated sorbent was obtained by coating glass beads of various fractions (average size from 0.2 to 3.9 mm) with a 100 μm thick layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) on an inclined mixer-granulator (Eirich) and using melamine - formaldehyde resin as a binder. The sorbent for application to the glass core was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column.

The testing methodology is similar to example No. 1.

As a result of testing, the values of the dynamic capacity of the granular sorbent of various fractions were obtained (Fig. 2).

The most preferred range of average sorbent granule size is 0.5 - 1.0 mm. With an average granule size of less than 0.3 mm, the hydraulic resistance of the layer increases significantly, the granules, becoming contaminated, crumple, and the likelihood of material carryover during backwashing also increases. With an average granule size of more than 3.0 mm, the surface area of the granules decreases so much that, under conditions of dynamic sorption, the capacity of the sorbent falls below the values appropriate for use.

Example 3

The granulated sorbent was obtained by coating glass beads with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) of various thicknesses from 50 to 250 μm on an inclined mixer-granulator (Eirich) and using a melamine-formaldehyde resin as a binder. The sorbent for application to the glass core was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column.

The testing methodology is similar to example No. 1.

As a result of testing, the values of the dynamic capacity of the granular sorbent with different thicknesses of the sorbent layer were obtained (Fig. 3).

The optimal value of the sorbent layer thickness is 100 µm. Under conditions of dynamic sorption for a limited time, a layer no thicker than 150 µm effectively participates in sorption. With a further increase in the layer thickness, the capacitance increases slightly.

Example 4

The granulated sorbent was obtained by coating glass beads with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) and using melamine-formaldehyde resin as a binder. . Various sorbent fractions from 5 to 50 µm were used. The sorbent for application to the glass core was preliminarily crushed in a centrifugal disintegrator to the required average particle size. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column.

The testing methodology is similar to example No. 1.

If the average particle size of the sorbent exceeds 50 μm, then it is not possible to maintain the optimal thickness of the sorption coating of the core. It is most preferable to use a sorbent with an average particle size of up to 10 microns (Fig. 4). At the same time, it is very problematic to obtain a sorbent with a dispersion of 5 microns or less: the grinding time increases and its efficiency decreases. The degree of washing of DHAL-Cl from accompanying salts (impurities in the synthesis process) begins to have a great influence on the fineness of grinding.

The values of the attrition of sorbent granules were also measured according to GOST R 51641-2000 (Fig. 5).

It can be seen from the graph that with an increase in the grinding size, the mechanical strength of the sorbent layer sharply decreases. Therefore, the average particle size of the sorbent should not exceed 50 µm. Optimally, if the average particle size of the sorbent does not exceed 10 microns.

Example 5

The granulated sorbent was obtained by coating balls of melamine-formaldehyde resin with a fraction of 0.5–0.9 mm with a 100-μm layer of aluminum-lithium double hydroxide in chloride form (DHAL-Cl) on an inclined mixer-granulator (Eirich) and using melamine- formaldehyde resin as a binder. The sorbent for application to the polymer core was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column.

Among all types of cores used, granules on a melamine-formaldehyde core provide the maximum strength of the surface layer due to the adhesion of the binder to the core. Since the core material and the binder are the same polymer with the same set of functional groups, when the granules are dried, the amino groups of the prepolymer are cross-linked not only in the volume of the sorbent layer, but also with the surface of the core. As a result, it is possible to repeatedly backwash the granular sorbent without destroying the granules.

The testing methodology is similar to example No. 1.

The dynamic capacity of the sorbent for lithium was (13.5 g/kg). The bulk density of the sorbent decreased to 750 g/l.

An increase in the dynamic capacity of the sorbent is due to a change in the morphology of the sorbent surface, namely, the appearance of microcracks due to shrinkage of the binder during drying.

Example 6

The granulated sorbent was obtained by coating the glass spheres with a fraction of 0.3-0.7 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) and using melamine-formaldehyde resin as a binder. . The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent.

The dynamic capacity of the sorbent, based on the data obtained, was 14.85 g/kg. The bulk density of the sorbent with the use of a hollow core decreased to 390 g/l.

Example 7

The sorbent was obtained by granulating double aluminum-lithium hydroxide in the chloride form (DHAL-Cl) on an inclined mixer-granulator (Eirich) and using melamine-formaldehyde resin as a binder. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. Target sorbent fraction for testing: 0.6-1.0 mm.

The dynamic capacity of the sorbent was 7.1 g/kg. The bulk density of the full-bodied sorbent was 800 g/l. The inner part of the granule practically does not take part in the extraction process and is a "ballast". Comparing the sorption capacity of a granule on a glass core from example No. 1 and a full-bodied granule, it becomes obvious that the thickness of the effective sorbent layer is about 100 microns.

Example 8

The granulated sorbent was obtained by coating a silicate porous core (granulated and fired tripoli) with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) with using a polymer binder (melamine-formaldehyde resin). The sorbent for application to the porous core was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent.

The bulk density of the sorbent was 740 g/l. The dynamic sorption capacity for lithium turned out to be significantly lower than expected and amounted to 6.3 g/kg. This is due to the penetration of the primary brine into the porous core and an increase in the mineralization of the eluate during the subsequent desorption of lithium. With an increase in mineralization, the rate of desorption decreases, which affects the dynamic capacity of the sorbent. Also, the obtained eluate contains more impurities than when using a pellet on a waterproof core.

Example 9

The granulated sorbent was obtained by coating glass beads with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) using a solution of a hydrophobic polymer binder (polyvinyl chloride in dichloromethane). The sorbent for application to the glass core (glass beads) was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column. Then passed through the column 10 l of water-oil emulsion with a concentration of oil products of 300 mg/l. Next, sorption/desorption cycles were carried out similarly to point 1.

When using PVC as a binder and in the presence of oil products, the capacity of the sorbent decreases due to sorption on the surface of oil product granules. For this type of granules, the sorption capacity was 4.3 g/l, which corresponds to a drop in the sorption capacity by 64.2%.

The granules from examples 1 and 3 were tested in a similar way. For a granular sorbent on a glass core using a melamine-formaldehyde binder, the effect of petroleum products reduced the sorption capacity by 11.2%: from 12 to 10.7 g/kg. For a granulated sorbent on a glass core with the addition of tripoli, the sorption capacity decreased by 3.6%: from 12 to 11.7 g/kg.

Example 10

The granulated sorbent was obtained by coating glass beads with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) using a polymer binder (melamine-formaldehyde resin ). The sorbent for application to the glass core (glass beads) was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 10 μm. The amount of binder was from 10 to 60 wt.% on dry matter based on the weight of the sorbent. The dried granular sorbent with a volume of 250 ml was preliminarily weighed, soaked in distilled water, and placed in a sorption column.

With an increase in the amount of binder, the porosity of the layer decreases and the diffusion limitations of sorption/desorption processes for the internal volume of the sorbent increase. This leads to a sharp decrease in the dynamic sorption capacity of the granules with an increase in the amount of binder over 40 wt. % (Fig. 6).

Example 11.

The granulated sorbent was obtained by coating glass beads with a fraction of 0.5-0.9 mm with a layer of aluminum-lithium double hydroxide in the chloride form (DHAL-Cl) with a thickness of 100 μm on an inclined mixer-granulator (Eirich) using a polymer binder (melamine-formaldehyde resin ). The sorbent for application to the glass core (glass beads) was preliminarily crushed in a centrifugal disintegrator to obtain particles with an average size of 100 and 50 µm. The amount of binder was 20 wt.% on dry matter based on the weight of the sorbent.

When using sorbent granules with a particle size of 100 and 50 µm for rolling, it is not possible to obtain an economically viable yield of the required granule fraction. In the granulation products, the content of granules without a glass core, agglomerates of several granules with a core of large DHAL-Cl particles, and granules on a glass core with extremely low sphericity (uneven coating of the core) sharply increases. The resulting granulation products are difficult to recycle and increase the cost of the sorbent.

The conducted studies show that the application of the proposed solution increases the efficiency of the process of lithium sorption from oil-, fat-, oil-contaminated aqueous solution and lithium desorption from granules due to: adding a core to the granule; expanding the range of filtration rate of the solution and washing liquid through a layer of granular sorbent; and preventing contamination of sorbent granules with oil, fat, oil components of the aqueous solution.

Claims (11)

1. Granule for the sorption of lithium from an aqueous solution containing sorbent particles from a chlorine-containing variety of aluminum and lithium double hydroxide, characterized in that the granule contains a waterproof spherical core coated with a solution-permeable composite of sorbent particles and a hydrophilic binder. 2. A granule according to claim 1, characterized in that the hydrophilic binder has an open-pore structure. 3. A granule according to claim 1, characterized in that the maximum content of the binder in terms of dry residue is not more than 40% by weight of the sorbent particles. 4. Granule according to claim 1, characterized in that the average size of the granules is not less than 0.3 mm and not more than 3.0 mm, preferably not less than 0.5 mm and not more than 1.0 mm. 5. A granule according to claim 1, characterized in that the average particle size of the sorbent does not exceed 50 microns, preferably 10 microns. 6. Granule according to claim 1, characterized in that the average thickness of the sorption coating of the core does not exceed 150 microns, preferably 100 microns. 7. A granule according to claim 1, characterized in that the granule is covered with a protective layer of tripoli with an average particle size of not more than 10 microns. 8. Granule according to claim 1, characterized in that the core is made of glass. 9. Granule according to claim 1, characterized in that the core is made of a binder. 10. A granule according to claim 1, characterized in that the core of the granule is hollow. 11. A granule according to claim 1, characterized in that the adhesion between the core and the binder is not less than the cohesion of the binder.