Method for recovering lithium from lithium-containing minerals

Abstract

This embodiment can provide a method for recovering lithium, including: preparing a lithium-containing mineral powder obtained by crushing a lithium-containing mineral ore; mixing the lithium-containing mineral powder with a solvent to prepare a slurry; introducing the slurry into a reactor to perform a hydrothermal reaction; and separating a product obtained in the heating step.

Description

[Technical Field]

[0001] The present embodiment relates to a method for recovering lithium from a lithium-containing mineral, and more specifically to a method for recovering lithium by mixing a lithium-containing mineral with an additive and water and carrying out a hydrothermal reaction. [Background technology]

[0002] Among the ores containing lithium, the most common type that exists in nature is pegmatite minerals. In their naturally occurring state, lithium cannot be leached into inorganic acids such as sulfuric acid, so the lithium must be converted into a form that is easier to leach before it can be leached.

[0003] The main method for converting lithium into a form that is easy to leach is by heat treatment at 900~1,100℃. Even after the lithium form is converted by heat treatment, it is not easy to leach it into inorganic acid at room temperature, so it is heated at a high temperature or mixed with a strong acid such as sulfuric acid and then roasted.

[0004] The use of sulfuric acid inevitably requires an excessive amount of acid, resulting in the leaching of impurities other than lithium. Most impurity elements precipitate in the alkaline range, necessitating an additional process to remove the impurities. Furthermore, the main forms of industrial lithium salts are lithium carbonate or lithium hydroxide, which precipitate in the alkaline range, so an alkaline substance is required to convert the acidic leaching solution to the alkaline range.

[0005] These methods for recovering lithium from lithium-containing minerals require high-energy processes or calcination / roasting processes, and alkali is required to recover industrially usable lithium salts from the acidic leaching solution. Acid leaching methods not only consume a lot of energy and are complicated, increasing manufacturing costs, but also pose problems such as environmental impacts due to the use of strong acids such as sulfuric acid and large amounts of alkaline substances in the lithium extraction process.

[0006] Furthermore, because of the high energy requirements and the large amount of carbon dioxide generated, it is necessary to develop an efficient, environmentally friendly and stable method for recovering lithium. Summary of the Invention [Problem to be solved by the invention]

[0007] In one embodiment of the present invention, an improved method for recovering lithium from lithium-containing minerals is provided. [Means for solving the problem]

[0008] A method for recovering lithium according to one embodiment of the present invention may include: preparing a lithium-containing mineral powder obtained by crushing a lithium-containing mineral ore; mixing the lithium-containing mineral powder with a solvent to prepare a slurry; introducing the slurry into a reactor to perform a hydrothermal reaction; and separating a product obtained from the hydrothermal reaction.

[0009] The lithium-containing mineral powder obtained in the step of preparing the lithium-containing mineral powder may be mixed with a solvent to prepare a slurry without undergoing a treatment that causes a phase change.

[0010] In the step of preparing a slurry by mixing the lithium-containing mineral powder with a solvent, water is used as the solvent, and no acid is added.

[0011] The step of introducing the slurry into a reactor and subjecting it to a hydrothermal reaction can be carried out at a temperature ranging from 200°C to 270°C.

[0012] The step of introducing the slurry into the reactor and subjecting it to a hydrothermal reaction can be carried out for 1 to 3 hours.

[0013] Alternatively, the reactor may be a continuous reactor.

[0014] In the step of preparing a slurry by mixing the lithium-containing mineral powder with a solvent, an additive may be additionally mixed to prepare the slurry.

[0015] The additive may be one or more selected from alkali metal compounds or alkaline earth metal compounds, and may specifically include one or more selected from NaOH, Na2CO3, NaHCO3, NaCl, Na2SO4, KOH, K2CO3, KHCO3, KCl, K2SO4, Ca(OH)2, CaO, Ca(NO3)2, CaSO4, Mg(OH)2, MgO, Mg(NO3)2, MgSO4, or CaCO3.

[0016] In addition, the additive may be mixed in an amount ranging from 10 wt % to 60 wt % based on the weight of the lithium-containing mineral powder.

[0017] In the step of preparing a slurry by mixing the lithium-containing mineral powder with a solvent, an auxiliary additive may be further mixed in addition to the additive to prepare the slurry.

[0018] The auxiliary additive may be a compound containing one or more metal elements selected from Al or Ca, and may specifically include one selected from Al(OH)3, Al(NO3)3, Al2(SO4)3, AlCl3, Ca(OH)2, Ca(NO3)2, CaSO4, and hydrates thereof, or CaCl2.

[0019] The auxiliary additive may be mixed in an amount ranging from 5 wt % to 40 wt % based on the weight of the lithium-containing mineral powder.

[0020] In the step of preparing a lithium-containing mineral powder obtained by crushing the lithium-containing mineral ore, the lithium-containing mineral powder may include one or more selected from petalite mineral, spodumene mineral, lepidolite mineral, hectorite mineral, eucryptite mineral, jardarite mineral, zinnwaldite mineral, and amblygonite, and specifically, the lithium-containing mineral powder may be petalite mineral powder. [Effects of the Invention]

[0021] According to one embodiment of the present invention, an improved method for recovering lithium from lithium-containing minerals can be provided, specifically, an environmentally friendly method for recovering lithium that can efficiently recover lithium without using a strong acid can be provided. It is also possible to provide a lithium recovery method that requires less energy. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating a lithium recovery method according to one embodiment of the present invention. [Figure 2] 1 shows the results of XRD analysis of petalite mineral powder and spodumene mineral powder. [Figure 3] 1 shows the results of XRD analysis of the solid materials finally produced in Examples 1 and 2. [Figure 4] 1 shows the results of XRD analysis of the solid material finally produced in Comparative Example 3. [Figure 5] 1 shows the results of XRD analysis of the solid material finally produced in Comparative Example 4 and the spodumene mineral powder heat-treated at 1,050° C. DETAILED DESCRIPTION OF THE INVENTION

[0023] In describing the present invention, terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are used to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Therefore, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0024] The terminology used herein is merely for the purpose of referring to particular embodiments and is not intended to limit the present invention. As used herein, the singular form includes the plural form unless the context clearly dictates otherwise. As used in the specification, the meaning of "comprising" embodies certain properties, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other properties, regions, integers, steps, operations, elements, and / or components.

[0025] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted as having an ideal or very formal meaning unless defined.

[0026] DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the present invention is given by way of example only, and the present invention is not limited thereto, but is defined only by the scope of the claims set forth below.

[0027] FIG. 1 is a schematic diagram illustrating a lithium recovery method according to one embodiment of the present invention. Referring to FIG. 1, a lithium recovery method according to one embodiment of the present invention may include a step of preparing a lithium-containing mineral powder (S0), a step of preparing a slurry (S1), a hydrothermal reaction step (S2), and a separation step (S3).

[0028] First, in the step (S0) of preparing the lithium-containing mineral powder, the lithium-containing mineral powder may be obtained by crushing a lithium-containing mineral ore. In the present invention, the lithium-containing mineral ore that has not undergone a phase change after crushing the lithium-containing mineral ore is used as a raw material for recovering lithium. The lithium-containing mineral ore may be a mineral containing lithium, and may be one or more selected from petalite, spodumene, lepidolite, hectorite, eucryptite, jardarite, zinnwaldite, and amblygonite.

[0029] In the slurry preparation step (S1), the lithium-containing mineral powder obtained by pulverizing the lithium-containing mineral ore and a solvent are mixed to prepare a slurry.

[0030] The lithium-containing mineral powder obtained in the step of preparing the lithium-containing mineral powder may be mixed with a solvent to prepare a slurry without undergoing a treatment that causes a phase change.

[0031] In the present invention, the solvent may be pure water or distilled water, and no acid such as sulfuric acid is added to the solvent, which has the advantage of enabling lithium to be recovered in an environmentally friendly manner.

[0032] Meanwhile, in the slurry preparation step (S1), additives may be added to prepare the slurry. The additive may be one or more selected from alkali metal compounds or alkaline earth metal compounds, specifically, one or more selected from alkali metal oxides, alkali metal hydroxides, alkali metal salts, alkaline earth metal oxides, alkaline earth metal hydroxides, or alkaline earth metal salts. More specifically, the additive may be one or more selected from NaOH, Na2CO3, NaHCO3, NaCl, Na2SO4, KOH, K2CO3, KHCO3, KCl, K2SO4, Ca(OH)2, CaO, Ca(NO3)2, CaSO4, Mg(OH)2, MgO, Mg(NO3)2, MgSO4, or CaCO3.

[0033] The additive may be mixed in a range of 10 wt% to 60 wt% based on the weight of the lithium-containing mineral powder, specifically, in a range of 30 wt% to 60 wt%. When the additive is mixed in this range, it is advantageous for efficiently recovering lithium while minimizing the generation of pollutants in the subsequent process.

[0034] In addition to the additives, auxiliary additives may be added. The auxiliary additives may be compounds containing one or more metal elements selected from Al and Ca. Specifically, the auxiliary additives may be one or more selected from Al(OH)3, Al(NO3)3, Al2(SO4)3, AlCl3, Ca(OH)2, Ca(NO3)2, CaSO4 and its hydrates, or CaCl2. The auxiliary additives and the lithium-containing mineral powder may be mixed in a range of 5 wt% to 40 wt% of the auxiliary additive based on the weight of the lithium-containing mineral powder.

[0035] In the slurry preparation step, the lithium-containing mineral powder and the additives can be mixed with water to prepare a slurry, and the amount of lithium-containing mineral powder mixed per volume of water can be in the range of 50 g / L to 400 g / L, specifically 50 g / L to 300 g / L. When the lithium-containing mineral powder and water are mixed in this range, the hydrothermal reaction described below can be carried out effectively, which is advantageous for efficient lithium extraction.

[0036] In the hydrothermal reaction step (S2), the prepared slurry is introduced into a reactor to carry out a hydrothermal reaction. The hydrothermal reaction temperature may be 200°C or higher, specifically, 200°C to 270°C. The hydrothermal reaction may be carried out under a pressure equal to or higher than the vapor pressure generated by heating. In one embodiment of the present invention, the hydrothermal reaction may be carried out for 0.5 to 5 hours, specifically, 1 to 3 hours. Carrying out the hydrothermal reaction for such a period of time has the advantage of improving lithium leaching efficiency while reducing energy consumption.

[0037] In addition, the reactor for the hydrothermal reaction may be a continuous reactor, which has the advantages of reducing energy consumption and improving overall productivity.

[0038] The separation step (S3) may be a step of separating the solid and liquid substances produced in the hydrothermal reaction step, and the separation method is not particularly limited as long as the solid and liquid substances can be effectively separated. [Example]

[0039] DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the present invention is given by way of example only, and the present invention is not limited thereto, but is defined only by the scope of the claims set forth below.

[0040] (Preparation of lithium-containing mineral powder) Petalite and spodumene minerals were prepared as lithium-containing mineral powders obtained by crushing lithium-containing mineral ore. The contents of major elements were analyzed using ICP (inductively coupled plasma) and are summarized in Table 1 below.

[0041] [Table 1]

[0042] Figure 2 shows the XRD analysis results of the petalite mineral powder and spodumene mineral powder. Specifically, Figure 2(a) shows the XRD analysis results of the petalite mineral powder, and Figure 2(b) shows the XRD analysis results of the spodumene mineral powder.

[0043] Referring to Figure 2, the main component of petalite mineral is LiAlSiO 10 It can be confirmed that the main component of spodumene mineral is LiAlSi2O6.

[0044] Example 1 200 g of the prepared petalite mineral powder and 100 g of Na2CO3 were added to 1 L of distilled water and stirred to prepare a slurry. The slurry was placed in a pressure reactor, heated to 250° C., and maintained at that temperature for 2 hours. During this time, the slurry in the pressure reactor was stirred at a stirring speed of 350 rpm. After the reaction was completed, the mixture was cooled to room temperature and then subjected to solid-liquid separation. After solid-liquid separation, the cake was washed with distilled water in an amount five times its weight and then dried at 45°C until it reached a constant weight, and the resulting solid material was analyzed.

[0045] Example 2 The same procedure as in Example 1 was carried out, except that 6 g of Al(OH)3, which corresponds to 6% of the petalite mineral powder, was added during the slurry preparation step, and the solid material obtained after drying was analyzed.

[0046] FIG. 3 shows the XRD analysis results of the solid materials finally produced in Examples 1 and 2. Referring to FIG. 3, the solid material Na 1.71 Al 1.806 Si 4.194 O 12 It can be confirmed that 2.16H2O has been produced.

[0047] Meanwhile, the XRD quantitative analysis results and Li recovery rates of the solid materials finally produced in Examples 1 and 2 are summarized in Table 2 below.

[0048] [Table 2]

[0049] The Li recovery rate was calculated as the difference between the amount of lithium in the raw mineral matter and the amount of lithium in the final solid material, and the percentage of the amount of lithium in the raw mineral matter.

[0050] Referring to Table 2, it can be seen that the Li recovery rates according to Examples 1 and 2 of the present invention are 76% and 93%, respectively.

[0051] (Comparative Example 1) 100g of the prepared petalite mineral powder was added to 1L of 5% sulfuric acid and stirred at room temperature for 1 hour. After solid-liquid separation, the Li concentration in the solution was measured using ICP. The Li concentration in the solution was 10ppm, and it was confirmed that only 0.5% of the Li in the petalite mineral dissolved. Therefore, it was confirmed that the lithium contained in petalite cannot be efficiently leached using sulfuric acid at room temperature.

[0052] (Comparative Example 2) Petalite mineral was heat-treated at 1,100°C for 1 hour, cooled, and crushed in a mortar to obtain calcined petalite mineral powder. 100g of the calcined petalite mineral powder was placed in a crucible, and 19.9g of sulfuric acid (98%) was added and stirred until thoroughly mixed to produce a mixture. The mixture was placed in a pressure reactor and heat-treated at 250°C for 1 hour. After cooling and furnace cooling, the mixture was mixed with distilled water in a 1:2 weight ratio and stirred at room temperature for 1 hour. The solid and liquid phases were then separated, and the Li concentration in the resulting liquid was measured. The cake obtained by separating the solid and liquid phases was washed five times with distilled water equivalent to 5 times the cake weight and dried at 45°C to a constant weight, and the resulting solid material was analyzed.

[0053] The Li concentration in the liquid was 7.7 g / L, and it was confirmed that the Li recovery rate was about 90%. That is, when petalite mineral was treated at room temperature using sulfuric acid in Comparative Example 1, almost no Li was leached, but when petalite mineral was heat-treated at 1,100°C and roasted with sulfuric acid (250°C) in Comparative Example 2, a considerable amount of Li was leached. In other words, it can be seen that high-energy acid treatment through high-temperature heat treatment at 1,100°C and heat treatment with sulfuric acid at 250°C as in Comparative Example 2 allows for efficient leaching of Li from petalite mineral.

[0054] (Comparative Example 3) 89 g of the prepared spodumene mineral powder and Na2CO3, which corresponds to 7.0 equivalents of the lithium content of spodumene mineral (LiAlSi2O6 + Na2CO3 + H2O → NaAlSi2O6 · H2O + Li2CO3), were mixed in 400 mL of distilled water to prepare a slurry.

[0055] The slurry was placed in a pressure reactor, heated to 220° C., and maintained at that temperature for 2 hours. During this time, the slurry in the pressure reactor was stirred at a stirring speed of 350 rpm. After the reaction was completed, the mixture was cooled to room temperature and then subjected to solid-liquid separation. After solid-liquid separation, the cake was washed with distilled water in an amount five times its weight and then dried at 45°C until it reached a constant weight, and the resulting solid material was analyzed.

[0056] FIG. 4 shows the XRD analysis results of the solid material finally produced in Comparative Example 3. Referring to FIG. 4, it can be seen that Comparative Example 3 shows that spodumene mineral hardly reacts.

[0057] Comparative Example 4 The prepared spodumene mineral powder was heat-treated at 1,050°C for 1 hour, and then 89g of the heat-treated spodumene mineral powder and Na2CO3, which corresponds to 2.0 equivalents of the lithium content in the spodumene mineral (LiAlSiO6 + Na2CO3 + H2O → NaAlSiO6 · H2O + Li2CO3), were added to 400mL of distilled water and mixed to prepare a slurry.

[0058] The slurry was placed in a pressure reactor, heated to 220° C., and maintained at that temperature for 2 hours. During this time, the slurry in the pressure reactor was stirred at a stirring speed of 350 rpm. After the reaction was completed, the mixture was cooled to room temperature and then subjected to solid-liquid separation. After solid-liquid separation, the cake was washed with distilled water in an amount five times its weight and then dried at 45°C until it reached a constant weight, and the resulting solid material was analyzed.

[0059] FIG. 5 shows the results of XRD analysis of the solid material finally produced in Comparative Example 4 and the spodumene mineral powder heat-treated at 1,050°C.

[0060] Referring to Figure 5, when spodumene mineral is heat treated at 1,050℃, it turns out to be β-spodumene (β-LiAlSiO6), and the solid substances produced after the reaction are mainly NaAlSiO6, SiO2, and LiCO3, with no spodumene (LiAlSiO6) being confirmed. Therefore, it can be confirmed that β-spodumene (β-LiAlSiO6) reacts to produce NaAlSiO6 and LiCO3.

[0061] Therefore, it is clear that if spodumene mineral is subjected to high-energy acid treatment by heat treatment at 1,100°C or by heat treatment at 250°C with sulfuric acid, the Li in the spodumene mineral can be efficiently leached.

[0062] The present invention is not limited to the above-described embodiments, but can be manufactured in various different forms, and those skilled in the art will understand that the present invention can be embodied in other specific forms without changing the technical concept or essential features of the present invention. Therefore, it should be understood that the above-described embodiments are illustrative in all respects and are not limiting.

Claims

1. A step of preparing a lithium-containing mineral powder obtained by crushing a lithium-containing mineral ore; mixing the lithium-containing mineral powder with a solvent to prepare a slurry; Adding the slurry to a reactor to carry out a hydrothermal reaction; and Separating the product obtained in the hydrothermal reaction step; The lithium-containing mineral powder obtained in the step of preparing the lithium-containing mineral powder is mixed with a solvent to prepare a slurry without undergoing a treatment that causes a phase change. How to recover lithium.

2. The step of preparing a slurry by mixing the lithium-containing mineral powder with a solvent includes: Use water as the solvent and do not add acid; The method for recovering lithium according to claim 1.

3. The step of introducing the slurry into a reactor and carrying out a hydrothermal reaction includes: carried out at a temperature in the range of 200°C to 270°C, The method for recovering lithium according to claim 1.

4. The step of introducing the slurry into a reactor and carrying out a hydrothermal reaction includes: It takes 1 to 3 hours. The method for recovering lithium according to claim 1.

5. The reactor is a continuous reactor. The method for recovering lithium according to claim 1.

6. The step of preparing a slurry by mixing the lithium-containing mineral powder with a solvent includes: Adding additives to the mixture to produce a slurry; The method for recovering lithium according to claim 1.

7. The additive includes one or more selected from alkali metal compounds and alkaline earth metal compounds. The method for recovering lithium according to claim 6.

8. The additives include NaOH, Na ２ CO ３ , NaHCO ３ , NaCl, Na ２ SO ４ , KOH, K. ２ CO ３ , KHCO ３ , KCl, K ２ SO ４ , Ca(OH) ２ , CaO, Ca(NO ３ ) ２ , CaSO ４ , Mg(OH) ２ , MgO, Mg(NO ３ ) ２ , MgSO ４ , or CaCO ３ One or more selected from The method for recovering lithium according to claim 7.

9. The additive is mixed in an amount of 10 wt % to 60 wt % based on the weight of the lithium-containing mineral powder. The method for recovering lithium according to claim 7.

10. The step of preparing a slurry by mixing the lithium-containing mineral powder with a solvent includes: In addition to the additives, auxiliary additives are further mixed to prepare a slurry. The method for recovering lithium according to claim 6.

11. The auxiliary additive is a compound containing one or more metal elements selected from Al and Ca. The method for recovering lithium according to claim 10.

12. The co-additive is Al(OH) ３ , Al(NO ３ ) ３ , Al ２ (SO ４ ) ３ , AlCl ３ , Ca(OH) ２ , Ca(NO ３ ) ２ , CaSO ４ and its hydrate or CaCl ２ including one selected from The method for recovering lithium according to claim 11.

13. The auxiliary additive is mixed in an amount of 5 wt % to 40 wt % based on the weight of the lithium-containing mineral powder. The method for recovering lithium according to claim 11.

14. In the step of preparing a lithium-containing mineral powder obtained by pulverizing the lithium-containing mineral ore, The lithium-containing mineral powder includes at least one selected from petalite mineral, spodumene mineral, lepidolite mineral, hectorite mineral, eucryptite mineral, jardarite mineral, zinnwaldite mineral, and amblygonite, The method for recovering lithium according to claim 1.

15. The lithium-containing mineral powder is petalite mineral powder. The method for recovering lithium according to claim 14.

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