RU2455063C2 - Method of producing granular sorbent for extracting lithium from lithium-containing brine - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to production of inorganic sorbents. The method of producing a sorbent - a chlorine-containing form of a double hydroxide of aluminium and lithium: LiCl·2Al(OH)₃·mH₂O (DGAL-Cl) involves chemical reaction in aluminium chloride solution in the presence of lithium ions with an alkaline reactant. After washing and drying, the obtained powdered DGAL-Cl is granulated while adding methylene chloride chlorinated in the solution. The obtained paste is extruded to obtain 2±0.5 mm granules.

EFFECT: granular material obtained using the invention has sorption exchange capacity of 6,8-7,2 mg Li per gram sorbent and can selectively extract lithium from chloride brine of any type.

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Description

Technical field

The present invention relates to the field of inorganic sorbents, in particular to methods for producing a sorbent for the extraction of lithium from lithium-containing solutions and natural brines.

At present, salars, brine lakes, and a brine of the marine type (USA, Chile, Argentina) are widely used to obtain lithium compounds. An alternative source of lithium raw materials is also underground highly saline brines, associated water and brines of oil, diamond and other deposits (Irkutsk region, the Republic of Sakha, Western Siberia, Russia). Extraction of lithium from such brines is proposed to be carried out using sorbents selective for lithium, providing a high degree of its extraction.

State of the art

A known method of extracting lithium from brines using the hydrated form of the double compound of aluminum and lithium LiCl · 2Al (OH) ₃ in the microcrystalline state obtained in the pores of an ion-exchange resin (US Pat. No. 4,347,327 dated 02/19/79) [1]. The method involves treating the ion-exchange macroporous resin sequentially with solutions of aluminum chloride, lithium hydroxide, hydrochloric acid or lithium chloride with intermediate washing of the resin from the excess of reagents used.

The hydrated compound LiCl · 2Al (OH) ₃ obtained in the pores of the resin is proposed to be repeatedly used in sorption-desorption cycles, using lithium to extract from brines. The method is complicated in execution, and the content of LiCl · 2Al (OH) ₃ in the pores of the resin does not exceed 50%. Sorption and desorption of lithium is carried out at elevated temperatures (40-50 ° C). The operating time of the sorbent is limited, due to the difficulties of its regeneration and the rapid destruction of the compound. Thus, the described method is multi-stage with a limited life of the sorbent in the sorption-desorption cycles of lithium.

Known methods for producing a sorbent based on a chlorine-containing form of double hydroxide of aluminum and lithium, similar in composition to the ideal formula LiCl · 2Al (OH) ₃ · mH ₂ O (DGAL-Cl). DGAL-Cl powder is obtained by anodic dissolution of Al in 0.5–3.0 M lithium chloride solutions [2]. The preparation of DHAL-Cl for sorption of lithium from brines containing LiCl, NaCl, MgCl ₂ , CaCl ₂ and other chlorides is carried out by treatment with water, in which part of LiCl goes into the liquid phase. The result is DHAL-Cl with a deficiency of lithium in its composition, which provides a reversible sorbent capacity of 5.0-8.0 mg Li per 1 g of dry matter. The selected capacity interval is optimal because allows you to save the defective structure of DHAL-Cl, responsible for the high selectivity of the sorbent to lithium.

A known method of producing lithium aluminate by forming a crystalline chlorine-containing variety of double aluminum hydroxide and lithium DGAL-Cl with stirring a stoichiometric mixture of aluminum hydroxide and lithium chloride or its crystalline hydrate LiCl · H ₂ O in a mixer, and to obtain a defective structure of the compound by subsequent processing in a continuous centrifugal mill activator [3].

Despite the reduction in energy consumption compared to the method [2], the mechanochemical synthesis has limited productivity due to the impossibility of scaling the activator mills. So, the productivity of the used continuous centrifugal mill-activator (TsMA-06) does not exceed 12 kg / h. With a further increase in productivity, the degree of activation of crystalline DHAL-Cl decreases and the reversible capacity of the sorbent decreases.

When treated with DGAL-Cl water, obtained under selected conditions, up to 7.8 mg of Li per gram of DGAL-Cl can be removed from the compound. The resulting lithium-deficient compound in the composition can sorb the same amount of lithium from a lithium-containing brine, thereby restoring its composition. The reversible capacity of the sorbent is maintained during multiple sorption-desorption cycles.

The disadvantages of the methods [2, 3] are the high energy intensity and low productivity of the proposed processes. In addition, in the methods [2, 3] granulation of the powder is not provided.

A known method of producing a composite material formed by the interaction of Al (OH) ₃ with a solution of lithium hydroxide, in which the molar fraction of LiOH: Al (OH) ₃ is from 0.2 to 0.33. Then the composite is treated with a solution of hydrochloric acid and water to transfer it to the sorption active form of the approximate composition LiCl · 3Al (OH) ₃ · mH ₂ O (Pat US No. 6280693) [4].

The disadvantages of the method are: the complexity of preparing a composite of crystalline aluminum hydroxide containing a lithium component - LiX / Al (OH) ₃ and the limited duration of its work as a sorbent.

A known method of producing a sorbent for the extraction of lithium from brines (US Pat. No. 2234367) [5] by chemical interaction of pulp of lithium carbonate and a concentrated solution of aluminum chloride with the formation of DHAL-Cl. At a controlled pH of the solution of not more than 7, to exclude the formation of a carbonate variety of the double compound of aluminum and lithium DHAL-CO ₃ . No CO ₂ was detected in the compound. This method is time-consuming (~ 4 hours), but its advantage is that lithium carbonate precipitates soda from the mother liquor of lithium chloride and returns to the process. The capacity of the sorbent after water treatment is 7.5-8.0 mg / l for lithium.

A known method of producing a sorbent for the extraction of lithium from brine (US Pat. RF No. 2223142) [6] by chemical interaction of concentrated solutions of aluminum chloride and lithium hydroxide or solid reagents in the presence of water at W: T = 1.1-4.4 (solid phase based on anhydrous reagents), as well as water treatment of the resulting compound with the desorption of part of lithium from its composition. The interaction lasts no more than 0.5 hours with the formation of a chlorine-containing double hydroxide of aluminum and lithium - LiCl · 2Al (OH) ₃ · mH ₂ O. After treatment with water, a lithium deficiency in the composition of the compound from 30 to 35% is formed, which allows to obtain a reversible exchange capacity of the sorbent from 7.5 to 8.0 mg Li per 1 g of DGAL-Cl. The method does not provide granulation of the powder.

A known method of producing a granular sorbent for the extraction of lithium from brine (US Pat. 2009714 RF) by granulating DGAL-Cl having a defective structure, using fluoroplastic as a binder and acetone as a solvent. DGAL-Cl powder is obtained by chemical interaction of solutions of lithium chloride, aluminum chloride and sodium hydroxide [7].

The disadvantage of this method is a large excess of lithium chloride (2.7 times) with respect to aluminum chloride, which is necessary according to the stoichiometry of the reaction: LiCl + 2AlCl ₃ + 6NaOH + 12H ₂ O = LiCl · 2Al (OH) ₃ · 12H ₂ O + 6NaCl.

The disadvantage of this method is the use as a binder of fluoropolymer soluble in acetone. The use of acetone is flammable and requires appropriate safety measures.

This method is chosen by us as a prototype.

There is a method of granulating a paste from DGAL-Cl, in which chlorinated polyvinyl chloride resin (PVC-Cl) and a methylene chloride solution as a solvent are used as a binder [8]. The method is the basis of the application PCT / DE 01/0062 [9].

SUMMARY OF THE INVENTION

The technical result is achieved by the fact that the preparation of DGAL-Cl is carried out by chemical interaction of a solution of aluminum chloride containing lithium ions with the addition of an alkaline reagent to a pH of 6-7. The alkaline reagent can be sodium hydroxide or carbonate, and the content of the lithium component in the aluminum-lithium system is provided by the introduction of hydroxide, or carbonate, or lithium chloride to the atomic ratio (at. Rel.) Al: Li, equal to 2.0-2.3. Below is the reaction for the formation of DHAL-Cl when using NaOH as an alkaline reagent: LiOH + 2AlCl ₃ + 5NaOH + 5H ₂ O = LiCl · 2Al (OH) ₃ · 5H ₂ O + 5NaCl.

The technical result is achieved by the fact that after separation and washing with DGAL-Cl, the powder is dried at a temperature not exceeding 70 ° C to a residual moisture content of 4-5%, ground to pass particles through a sieve with a mesh size of 0.16 mm, which allows to obtain the bulk of the powder particles ≤0.1 mm, and after granulation DGAL-Cl high exchange capacity of the sorbent. With increasing particle size DHAL-Cl above 0.16 mm, the capacity of the sorbent decreases (figure 1).

The technical result is achieved by the fact that the crushed powder was mixed with PVC-Cl (producer Russia) or any chlorine-containing organic polymer soluble in methylene chloride, for example, chlorinated polyvinyl chloride - СРХС (brand of foreign manufacturers) or chlorinated polyethylene, etc., and the resulting paste is extruded with obtaining a granule size of 2 ± 0.5 mm. As the size of the granules increases, the degree of lithium extraction from the brine decreases.

The technical result is achieved by the fact that the obtained DHAL-Cl, containing up to 10% of not washed NaCl, after drying and grinding is granulated as described above.

Thus, the hallmarks of the proposed method are:

1. Reducing the consumption of lithium component to obtain DHAL-Cl, as well as the possibility of using not only chloride, but also lithium hydroxide and its carbonate.

2. The use as an alkaline reagent is not only hydroxide, but also sodium carbonate or potassium analogues (KOH, K ₂ CO ₃ ).

3. The possibility of granulation of the obtained DHAL-Cl containing up to 10% of not washed NaCl.

List of figures, tables

Figure 1. Dependence of the exchange capacity of the sorbent on the particle size of DGAL-Cl and the interaction time: 1 - particle size ≤0.16 mm, 2 - particle size ≤0.65 mm.

Figure 2. Schematic diagram of the production of granular sorbent based on DGAL-Cl with the recovery of methylene chloride (XM).

Information confirming the possibility of implementing the invention are given below in the form of specific examples.

Example 1. In 2.0 l of a solution of aluminum chloride with a concentration of 126 g / l AlCl ₃ was introduced ~ 0.25 l of a solution of LiOH (~ 85 g / l) to atom. Al: Cl ratio = 2.3 (excess AlCl ₃ ~ 15%), then a NaOH solution was added to pH 7.0. The reaction mixture was stirred for 0.5 h without heating. The resulting NaCl solution had a concentration of 125 g / l (2.1 M). The precipitate was pressed on a filter, dried and subjected to granulation without washing. The resulting precipitate contained ~ 10% NaCl, which did not cause granulation complications.

When washing the precipitate twice by pulping it in distilled water at W: T = 2, the NaCl content in the precipitate decreases to ~ 5%. The composition of the obtained precipitate (% wt.): LiCl - 14.5, Al (OH) ₃ - 72.5, NaCl - 5.5 - 26%. At rel. Al: Li = 2.7.

Example 1. In 2.3 l of a solution of aluminum chloride (126 g / l) was introduced pulp of lithium carbonate at the rate of at. rel. Al: Li = 2.1, then a NaOH solution was added until CO _{2 was} completely released and a pH of 7.0 was reached. The precipitate was separated and washed by repulpation in water (W: T = 2: 1), dried at 70 ° C to a residual moisture content of 4.5%. The precipitate had the following composition (% wt.): LiCl - 13.2; Al (OH) ₃ - 60.0; NaCl - 19. At. rel. Al: Li = 2.5. The powder was granulated after additional washing with NaCl.

Example 3. The precipitates obtained in examples 1, 2 were combined, crumpled during drying, the powder was crushed to particles passing through a sieve with a mesh of 0.16 mm A powder containing 90% of particles ≤0.1 mm in size was used for granulation. Granulation was carried out in a closed type mixer. 400 g of DGAL-Cl, 36 g of chlorinated polyvinyl chloride (PVC-Cl), a methylene chloride solution were placed in a mixer and stirred until a paste-like state. The paste was placed in an extruder, the resulting straw was cut into granules 2 ± 0.5 mm long, dried, and mechanical strength was determined. It amounted to 99.5%.

Example 4. To determine the sorption capacity of the granular material, 2.5 kg of granules were loaded into a column with a diameter of 2 cm and a height of 350 cm, through which water was passed at a speed of 2 dm ³ / h. After 6 hours of processing the granules, the amount of desorbed Li was 7.2 mg per 1 g of sorbent. When processing granular DHAL-Cl under dynamic conditions with a brine containing (g / l): LiCl - 2.5; MgCl ₂ - 115; CaCl ₂ - 330, the composition of the compound was restored. The total reversible capacity of the sorbent was 7.15 mg / g Li. The mechanical strength of the granules after 10 cycles of desorption-sorption was 99.5%.

Thus, in comparison with the prototype method, DGAL-Cl obtained by chemical precipitation by reacting AlCl ₃ with LiOH or Li ₂ CO ₃ with the introduction of NaOH or Na ₂ CO ₃ has the same sorption properties as DGAL-Cl obtained in excess lithium component in the form of lithium chloride in the prototype method.

Example 5. The practical implementation of the method is carried out in accordance with figure 2 in the following way. An AlCl ₃ solution (180 g / L) was poured into the stirred reactor and a calculated amount of LiOH was added (atomic rel. Al: Li = 2.3), then the NaOH solution was poured to pH 7.0. Stirred for 30-40 minutes. After completion of the formation of DHAL-Cl, the pulp was fed to a filter washer. The mother liquor was poured into a container. The precipitate was poured with water W: T = 0.3: 1, stirred, the washings were separated and poured into a container with the mother liquor. Washing was repeated 3 times. The total amount of water spent on flushing was W: T = 3: 1. Wet DHAL-Cl was dried, crushed, and sieved through a sieve with a 0.16 mm mesh. The precipitate after washing contained 7.0% NaCl, the atomic ratio Al: Li was 2.45. Granulated powder, as described in example 3, to a particle size of 2 ± 0.5 mm With a granule size> 2.5 mm, lithium recovery from brine is reduced from 90% to 60%. The obtained granular material had a reversible sorbent capacity of 6.9-7.2 mg Li per 1 g of granules.

Industrial applicability

The method of producing a granular sorbent is intended for the selective extraction of lithium from highly mineralized brines of any type and, above all, enriched with salts of magnesium and calcium.

Russian brines (Irkutsk Region, Krasnoyarsk Territory. Rep. Sakha) are enriched in calcium and magnesium chlorides and cannot be processed using well-known technologies adopted in the USA, Chile, Argentina. For lithium-containing brines of chloride Ca-Mg type, a sorption enrichment technology has been developed using granular, lithium-selective sorbents and obtaining practically pure solutions of lithium chloride (LiCl up to 90%) [10, 11], which are used to produce any lithium compounds: carbonate, chloride , fluoride, hydroxide, etc.

The granular sorbent based on DGAL-Cl, obtained by the proposed method, has high technological performance through the use of new technical solutions. The inventive synthesis process of DGAL-Cl eliminates the use of a large excess of lithium reagents, and the mother liquors after deposition of DGAL-Cl are used in the process for the regeneration of NaCl and the return of the alkaline reagent NaOH to the operation for producing DGAL-Cl. The technology for producing granular sorbent is carried out according to a method tested on an industrial scale.

Information sources

1. Pat. US No. 4347327 dated 01.191.79. Recovery of lithium from brines / Lee J.M., Bauman W.C. Publ. 08/31/82.

2. Pat. RF №2028385. A method of producing a sorbent for the extraction of lithium from brine. / Kotsupalo N.P., Sitnikova L.L., Menzherez L.T. Claim 05/25/92.

3. Pat. RF №2113405. A method of producing lithium aluminate. / Kotsupalo N.P., Menzherez L.T., Titarenko V.I., Ryabtsev A.D. Claim 07/09/97.

4. Pat US No. 6280693. Composition for the recovery of lithium values from brines and process of making / using said composition. / Bauman W.C., Burba J.L. Claim 09/20/96. Publ. 08/28/01.

5. Pat. RF №2234367. A method of producing a sorbent for the extraction of lithium from brine. / Ryabtsev A.D., Menzheres L.T., Mamylova E.V., Kotsupalo N.P. Claim 12/15/02. Publ. 08/20/04. Bull. Number 23.

6. Pat. RF №2223142. A method of producing a sorbent for the extraction of lithium from brine. / Ryabtsev A.D., Menzheres L.T., Mamylova E.V., Kotsupalo N.P. Claim 11/22/01. Publ. 02/10/04. Bull. Number 23.

7. Pat. RF №2009714. A method of obtaining a granular sorbent. / Menzherez L.T., Kotsupalo N.P., Orlova L.B., Isupov V.P. Claim 01/27/92 (prototype).

8. Pat. RF №2050184. A method of obtaining a granular sorbent. / Menzherez L.T., Kotsupalo N.P., Orlova L.B. Claim 02.16.93.

9. PCT / DE 01/04062. A method of obtaining a granular sorbent for the extraction of lithium from brines and installation for its implementation. / Ryabtsev A.D .; Kotsupalo N.P., Menzherez L.T. et al. 10/25/01.

10. Pat. RF №2050330. The method of selective extraction of lithium from brines and installation for its implementation. / Ryabtsev A.D., Menzherez L.T., Kotsupalo N.P. and other publ. 12/20/1995. Bull. Number 25.

11. PCT / DE 01/04061. The method of extraction of lithium chloride from brines and installation for its implementation. / Ryabtsev A.D., Menzherez L.T., Kotsupalo N.P. et al. 10/25/01.

Claims (2)

1. A method of producing a granular sorbent for the extraction of lithium from lithium-containing brines, including the production of a chlorine-containing variety of double aluminum hydroxide and lithium (DGAL-Cl) from a solution of aluminum chloride containing lithium by adding an alkaline reagent, granulating a paste from DGAL-Cl powder using a binder and a solvent, characterized in that lithium hydroxide or lithium carbonate is used as a lithium component with an atomic ratio of AL: Li of 2.0-2.3, with the addition of an alkaline reagent to a pH of 6 -7, the dried powder is ground to a particle size of ≤0.10 mm and granulated by adding chlorinated polyvinyl chloride and methylene chloride as a solvent. 2. The method according to claim 1, characterized in that as the alkaline reagent use sodium hydroxide or carbonate.

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