Method for recovering lithium from lithium ore

Abstract

The present invention relates to a lithium recovery method, comprising: a step of pulverizing a lithium ore to obtain a lithium ore powder; mixing the lithium ore powder with a solvent to prepare a slurry; putting the slurry into a reactor, and carrying out a hydrothermal reaction; and a step for separating the product obtained in the hydrothermal reaction step.

Description

Technical Field

[0001] This embodiment relates to a method for recovering lithium from lithium ore. Specifically, it is a method for recovering lithium by mixing lithium ore with an additive and water and performing a hydrothermal reaction. Background Art

[0002] Among lithium-containing ores, the main ore existing in nature is pegmatite. Since lithium cannot be leached by inorganic acids such as sulfuric acid in the natural mining state, it is necessary to convert lithium into an easily leachable form before leaching.

[0003] The main method for converting lithium into an easily leachable form is to perform heat treatment at 900 - 1100 °C. Even after this heat treatment, the form of lithium has changed, but it is still not easily leached by inorganic acids at room temperature. Therefore, it is necessary to heat at a high temperature or mix with strong acids such as sulfuric acid before performing the leaching process.

[0004] When using sulfuric acid, an excessive amount of acid is necessarily required, which will leach impurities other than lithium together. Since most impurity elements precipitate in the alkaline region, additional processes are required to remove impurities. In addition, the main forms of industrial lithium salts are lithium carbonate or lithium hydroxide, which precipitate in the alkaline region. Therefore, alkaline substances are required to convert the acidic leaching solution into the alkaline region.

[0005] The method for recovering lithium from lithium ore requires high-energy processes such as calcination / leaching processes, and in order to recover industrial lithium salts from acidic leaching solutions, alkaline conditions are required. This acid leaching method not only has high energy consumption and complex processes, resulting in increased manufacturing costs, but also uses strong acids such as sulfuric acid and a large amount of alkaline substances in the lithium extraction process, and problems such as environmental impact are also very prominent.

[0006] In addition, due to high energy consumption and high carbon dioxide emissions, there is currently a need to develop an efficient, environmentally friendly, and stable lithium recovery method. Summary of the Invention

[0007] Technical Problem to be Solved

[0008] In one embodiment of the present invention, it aims to provide an improved method for recovering lithium from lithium ore.

[0009] Technical Solution

[0010] The lithium recovery method according to an embodiment of the present invention includes: a step of crushing lithium ore to obtain lithium ore powder; a step of mixing the lithium ore powder with a solvent to prepare a slurry; a step of putting the slurry into a reactor for hydrothermal reaction; and a step of separating the product obtained in the hydrothermal reaction step.

[0011] The lithium ore powder obtained in the step of preparing the lithium ore powder is mixed with a solvent to prepare a slurry without undergoing a treatment that causes a phase change.

[0012] In the step of mixing the lithium ore powder with a solvent to prepare a slurry, water is used as the solvent and no acid is added.

[0013] The step of putting the slurry into a reactor for hydrothermal reaction is carried out in a temperature range of 200 °C to 270 °C.

[0014] Moreover, the step of putting the slurry into a reactor for hydrothermal reaction is carried out for 1 to 3 hours.

[0015] In addition, the reactor is a continuous reactor.

[0016] In the step of mixing the lithium ore powder with a solvent to prepare a slurry, an additive is further mixed to formulate the slurry.

[0017] The additive includes at least one of an alkali metal compound or an alkaline earth metal compound. Specifically, the additive may include at least one 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.

[0018] The mixing amount of the additive is 10 wt% to 60 wt% of the weight of the lithium ore powder.

[0019] In the step of mixing the lithium ore powder with a solvent to prepare a slurry, in addition to the additive, a co-additive is further mixed.

[0020] The co-additive is a compound containing at least one metal element selected from Al or Ca. Specifically, the co-additive includes one selected from Al(OH)3, Al(NO3)3, Al2(SO4)3, AlCl3, Ca(OH)2, Ca(NO3)2, CaSO4 and its hydrates or CaCl2.

[0021] The mixing amount of the co-additive is 5 wt% to 40 wt% of the weight of the lithium ore powder.

[0022] In the step of crushing the lithium ore to obtain the lithium ore powder,

[0023] The lithium ore powder may include at least one selected from the group consisting of petalite ore, spodumene ore, lepidolite ore, hectorite ore, nepheline spodumene ore, Jardarite ore, triphylite ore, and lithiophilite ore. Specifically, the lithium ore powder may be petalite ore powder.

[0024] Advantageous Effects

[0025] According to an embodiment of the present invention, an improved method for recovering lithium from a lithium ore can be provided. Specifically, an environmentally friendly recovery method for efficiently recovering lithium without using strong acids can be provided.

[0026] In addition, a lithium recovery method that reduces energy consumption can be provided. Brief Description of the Drawings

[0027] Figure 1 is a schematic diagram of a lithium recovery method according to an embodiment of the present invention.

[0028] Figure 2 Shows the X-ray diffraction analysis results of petalite ore powder and spodumene ore powder.

[0029] Figure 3 Shows the XRD analysis results of the solid substances finally produced according to Example 1 and Example 2.

[0030] Figure 4 Shows the XRD analysis results of the solid substance finally produced according to Comparative Example 3.

[0031] Figure 5 Shows the XRD analysis results of the solid substance finally produced according to Comparative Example 4 and spodumene ore powder heat-treated at 1050 °C. Detailed Description of the Embodiments

[0032] In the present specification, terms such as first, second, and third are used to describe each part, component, region, layer, and / or section, but these parts, components, regions, layers, and / or sections should not be limited by these terms. These terms are only used to distinguish one part, component, region, layer, and / or section from another part, component, region, layer, and / or section. Therefore, without departing from the scope of the present invention, the first part, component, region, layer, and / or section described below may also be described as the second part, component, region, layer, and / or section.

[0033] The terms used in this document are only for describing specific embodiments and are not intended to limit the present invention. Unless the context clearly indicates the contrary, the singular forms used are also intended to include the plural forms. It should also be understood that the term "comprising" used in the specification may specifically refer to a certain property, field, integer, step, action, element, and / or component, but does not exclude the existence or addition of other properties, fields, integers, steps, actions, elements, and / or components.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention belongs. For terms defined in a dictionary, they should be interpreted as having a meaning consistent with the relevant technical literature and the content disclosed herein, and should not be interpreted in an idealized or overly formal sense.

[0035] Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention belongs can easily implement the present invention. However, the present invention can be implemented in various different ways and is not limited to the embodiments described herein.

[0036] Figure 1 is a schematic diagram of a lithium recovery method according to an embodiment of the present invention.

[0037] Referring to Figure 1 , in an embodiment of the present invention, the lithium recovery method may include a step S0 of preparing lithium ore powder, a step S1 of preparing a slurry, a hydrothermal reaction step S2, and a separation step S3.

[0038] First, the step S0 of preparing the lithium ore powder may be to obtain lithium ore powder by crushing lithium ore. In the present invention, after crushing the lithium ore, the lithium ore without phase change is used as the lithium recovery raw material. The lithium ore may be a lithium-containing mineral and may be at least one selected from the group consisting of petalite ore, spodumene ore, lepidolite ore, hectorite ore, nepheline syenite ore, jadarite ore, and lithiophilite ore.

[0039] The slurry manufacturing step S1 may prepare a slurry by mixing the crushed lithium ore powder with a solvent.

[0040] The lithium ore powder obtained in the stage of preparing the lithium ore powder may be mixed with a solvent without undergoing a phase change treatment to prepare a slurry.

[0041] In the present invention, the solvent may be pure water or distilled water. In addition, acidic substances such as sulfuric acid are not added to the solvent. By this method, lithium can be recovered in an environmentally friendly manner, which has advantages.

[0042] On the other hand, in the slurry preparation stage S1, the slurry can be prepared by adding additives.

[0043] The additive can be one or more selected from alkali metal compounds or alkaline earth metal compounds. Specifically, it can be 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 can 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.

[0044] According to the weight of the lithium ore powder, the additive can be mixed in the range of 10 wt% to 60 wt%, specifically, in the range of 30 wt% to 60 wt%. When the additive is mixed within this range, it is beneficial to minimize the generation of downstream pollutants while effectively recovering lithium.

[0045] In addition, in addition to the additive, a co-additive can be additionally mixed. The co-additive can be a compound containing at least one metal element of aluminum (Al) or calcium (Ca). Specifically, Al(OH)3, Al(NO3)3, Al2(SO4)3, AlCl3, Ca(OH)2, Ca(NO3)2, CaSO4 and their hydrates can be selected, or at least CaCl2 can be selected. The co-additive and the lithium ore powder can be mixed in the range of 5 wt% to 40 wt% according to the weight standard of the lithium ore powder.

[0046] In the slurry manufacturing stage, the lithium ore powder and the additive can be mixed with water to prepare the slurry. The mixing amount of the lithium ore powder per unit volume of water can be in the range of 50 g / L to 400 g / L, specifically, in the range of 50 g / L to 300 g / L. When the lithium ore powder and water are mixed within the above range, the subsequent hydrothermal reaction can proceed effectively, which is beneficial to the efficient extraction of lithium.

[0047] In the hydrothermal reaction step S2, the prepared slurry can be put into a reactor for hydrothermal reaction. At this time, the hydrothermal reaction temperature can be above 200 °C, specifically, in the range of 200 °C to 270 °C. The hydrothermal reaction can be carried out under pressurized conditions higher than the vapor pressure generated by heating. In an embodiment of the present invention, the hydrothermal reaction can be carried out between 0.5 hours and 5 hours, specifically, between 1 hour and 3 hours. Conducting the hydrothermal reaction within this time has the advantages of improving the lithium leaching efficiency while reducing energy consumption.

[0048] In addition, the hydrothermal reaction reactor can adopt a continuous reactor. By applying a continuous reactor, not only is the energy consumption saved, but the overall production efficiency is also improved, which has obvious advantages.

[0049] The separation step S3 can be a step for separating the solid phase and the liquid phase generated in the hydrothermal reaction step, and the separation method is not particularly limited as long as the solid substance and the liquid substance can be effectively separated.

[0050] Embodiments of the invention

[0051] Hereinafter, specific embodiments of the present invention will be described. However, the following embodiments are only specific examples of the present invention, and the present invention is not limited to the following embodiments.

[0052] (Prepare lithium ore powder)

[0053] The lithium ore raw stone was crushed to obtain lithium ore powder, and petalite ore powder and spodumene ore powder were prepared. The main element contents were analyzed by ICP (Inductively Coupled Plasma) and are summarized in Table 1 below.

[0054]

Table 1

[0055]

[0056] Figure 2 Shows the X-ray diffraction analysis results of petalite ore powder and spodumene ore powder.

[0057] Specifically, Figure 2 (a) shows the X-ray diffraction analysis result of petalite ore powder, Figure 2 (b) shows the X-ray diffraction analysis result of spodumene ore powder.

[0058] Referring to Figure 2 , it can be confirmed that the main component of petalite ore is LiAlSi4O 10 , while the main component of spodumene ore is LiAlSi2O6.

[0059] (Example 1)

[0060] 200 g of petalite ore powder and 100 g of Na2CO3 prepared were put into 1 L of distilled water and stirred to prepare a slurry.

[0061] The slurry was added to a pressure reactor, heated to 250 °C, and maintained for 2 hours.

[0062] At this time, the slurry in the pressure reactor was stirred at a stirring speed of 350 rpm. After the reaction was completed, it was cooled to room temperature and then solid-liquid separation was carried out. After the solid was separated, the filter cake was washed with distilled water equivalent to 5 times the weight of the filter cake, and then dried at 45 °C to a constant weight. Finally, the obtained solid substance was analyzed.

[0063] (Example 2)

[0064] In the step of preparing the slurry, except for additionally mixing 6 g of Al(OH)3 equivalent to 6% of the spodumene (Petalite) ore powder, it was carried out in the same manner as in Example 1. After final drying, the obtained solid substance was analyzed.

[0065] Figure 3 The XRD analysis results of the solid substances finally produced according to Example 1 and Example 2 are shown.

[0066] Referring to Figure 3 , it can be confirmed that according to Example 1 and Example 2, the solid substance Na 1.71 Al 1.806 Si 4.194 O 12 ·2.16H2O was finally generated.

[0067] On the other hand, the XRD quantitative analysis results and lithium recovery rates of the solid substances finally produced according to Example 1 and Example 2 are summarized in Table 2 below.

[0068]

Table 2

[0069]

[0070] The lithium recovery rate is calculated as the percentage of the difference between the lithium content in the original ore and the lithium content in the finally produced solid product to the lithium content in the original ore.

[0071] Referring to Table 2, it can be confirmed that the lithium recovery rates of Example 1 and Example 2 of the present invention are 76% and 93% respectively.

[0072] (Comparative Example 1)

[0073] 100 g of the prepared spodumene (Petalite) ore powder was added to 1 L of 5% sulfuric acid, stirred at room temperature for 1 hour, and then solid-liquid separation was carried out. The lithium concentration in the solution was measured by ICP. The lithium concentration in the solution was 10 ppm, and it was confirmed that only 0.5% of the lithium in the introduced spodumene (Petalite) ore was dissolved. Therefore, it can be seen that sulfuric acid cannot effectively leach the lithium contained in spodumene (Petalite) under room temperature conditions.

[0074] (Comparative Example 2)

[0075] The petalite ore was heat-treated at 1100 °C for 1 hour and then cooled, and the sintered petalite ore powder was obtained by grinding in a mortar. 100 g of the sintered petalite ore powder was placed in a crucible, and 19.9 g of concentrated sulfuric acid (98%) was added, and the mixture was stirred well to obtain a mixture. The mixture was put into a pressure reactor and heat-treated at 250 °C for 1 hour, then cooled and cooled in a furnace, and then the mixture was mixed with distilled water at a weight ratio of 1:2 and stirred at room temperature for 1 hour. Subsequently, solid-liquid separation was carried out, and the lithium concentration in the obtained liquid phase was measured. After washing the separated filter cake 5 times with distilled water equivalent to 5 times the weight of the filter cake and drying at 45 °C, the obtained solid substance was analyzed.

[0076] It was confirmed that the lithium concentration in the liquid was 7.7 g / L and the lithium recovery rate was about 90%.

[0077] That is, in Comparative Example 1, when petalite was treated with sulfuric acid at room temperature, lithium was not leached; however, in Comparative Example 2, after heat-treating petalite at 1100 °C and then performing sulfuric acid leaching at 250 °C, it was confirmed that a considerable amount of lithium was leached.

[0078] As in Comparative Example 2, by high-temperature heat treatment at 1100 °C and sulfuric acid mixed heat treatment at 250 °C, that is, performing high-energy acid treatment, lithium in petalite can be effectively leached.

[0079] (Comparative Example 3)

[0080] 89 g of the prepared spodumene ore powder and Na2CO3 equivalent to 7.0 equivalents of lithium in the spodumene ore

[0081] (LiAlSi2O6 + Na2CO3 + H2O → NaAlSi2O6·H2O + Li2CO3) were put into 400 mL of distilled water for mixing to prepare a slurry.

[0082] The slurry was added to a pressure reactor, heated to 220 °C, and maintained for 2 hours.

[0083] At this time, the slurry in the pressure reactor was stirred at a stirring speed of 350 rpm. After the reaction was completed, it was cooled to room temperature, and solid-liquid separation was carried out. After separating the solid, the filter cake was washed with distilled water equal to 5 times the weight of the filter cake, and then dried at 45 °C, and the obtained solid substance was analyzed.

[0084] Figure 4Shows the XRD analysis results of the finally produced solid substance prepared according to Comparative Example 3.

[0085] Reference Figure 4 , according to Comparative Example 3, it can be confirmed that the spodumene ore hardly reacts.

[0086] (Comparative Example 4)

[0087] The prepared spodumene ore powder was heat-treated at 1050 °C for 1 hour, and then 89 g of the heat-treated spodumene ore powder and 2.0 equivalents of Na2CO3 based on the lithium content in the spodumene ore (LiAlSi2O6 + Na2CO3 + H2O → NaAlSi2O6·H2O + Li2CO3) were added to 400 mL of distilled water and mixed to form a slurry.

[0088] The slurry was placed in a pressure reactor, heated to 220 °C and held for 2 hours.

[0089] At this time, the slurry was stirred in the pressure reactor at a stirring speed of 350 rpm. After the reaction was completed, it was cooled to room temperature, and then solid-liquid separation was carried out. After separating the solid, the filter cake was washed with distilled water equal to 5 times the weight of the filter cake, and then dried at 45 °C, and the obtained solid substance was analyzed.

[0090] Figure 5 Shows the XRD analysis results of the finally produced solid substance and the spodumene ore powder heat-treated at 1050 °C according to Comparative Example 4.

[0091] See Figure 5 , when the spodumene ore is heat-treated at a temperature of 1050 °C, it can be known that it becomes β-spodumene (β-LiAlSi2O6), and the solid substances produced after the reaction are mainly NaAlSi2O6, SiO2, and Li2CO3, and no spodumene (LiAlSi2O6) is confirmed. Therefore, it can be confirmed that β-spodumene (β-LiAlSi2O6) reacts to form NaAlSi2O6 and Li2CO3.

[0092] Therefore, by heat-treating the spodumene ore at a high temperature of 1100 °C and performing high-energy acid treatment by mixing sulfuric acid at 250 °C, the lithium in the spodumene ore can be effectively leached.

[0093] The present invention is not limited to the above embodiments, but can be implemented in various different forms. Those skilled in the art should understand that the present invention can be implemented in other specific forms without changing the technical idea or basic characteristics of the present invention. Therefore, it should be understood that the above embodiments are exemplary in all aspects and not restrictive.

Claims

1. A lithium recovery method, comprising: a step of crushing lithium ore to obtain lithium ore powder; a step of mixing the lithium ore powder with a solvent to prepare a slurry; a step of putting the slurry into a reactor for hydrothermal reaction; and a step of separating the product obtained in the hydrothermal reaction step; wherein, the lithium ore powder obtained in the step of preparing lithium ore powder is mixed with a solvent to prepare a slurry without undergoing a treatment that causes a phase change.

2. The lithium recovery method according to claim 1, wherein, in the step of mixing the lithium ore powder with a solvent to prepare a slurry, water is used as the solvent and no acid is added.

3. The lithium recovery method according to claim 1, wherein, the step of putting the slurry into a reactor for hydrothermal reaction is carried out in a temperature range of 200°C to 270°C.

4. The lithium recovery method according to claim 1, wherein, the step of putting the slurry into a reactor for hydrothermal reaction is carried out for 1 to 3 hours.

5. The lithium recovery method according to claim 1, wherein, the reactor is a continuous reactor.

6. The lithium recovery method according to claim 1, wherein, in the step of mixing the lithium ore powder with a solvent to prepare a slurry, an additive is further mixed to formulate the slurry.

7. The lithium recovery method according to claim 6, wherein, the additive includes at least one of an alkali metal compound or an alkaline earth metal compound.

8. The lithium recovery method according to claim 7, wherein, the additive includes at least one 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.

9. The lithium recovery method according to claim 7, wherein, the mixing amount of the additive is 10 wt% to 60 wt% of the weight of the lithium ore powder.

10. The lithium recovery method according to claim 6, wherein, in the step of mixing the lithium ore powder with a solvent to prepare a slurry, in addition to the additive, a co-additive is further mixed.

11. The lithium recovery method according to claim 10, wherein, the co-additive is a compound containing at least one metal element selected from Al or Ca.

12. The lithium recovery method according to claim 11, wherein, the co-additive includes one selected from Al(OH)3, Al(NO3)3, Al2(SO4)3, AlCl3, Ca(OH)2, Ca(NO3)2, CaSO4 and its hydrates or CaCl2.

13. The lithium recovery method according to claim 11, wherein, the mixing amount of the co-additive is 5 wt% to 40 wt% of the weight of the lithium ore powder.

14. The lithium recovery method according to claim 1, wherein, in the step of crushing the lithium ore to obtain lithium ore powder, The lithium ore powder includes at least one selected from the group consisting of petalite ore, spodumene ore, lepidolite ore, hectorite ore, nepheline syenite ore, jadarite ore, zinnwaldite ore, and lithiophilite ore.

15. The lithium recovery method according to claim 14, wherein the lithium ore powder is petalite ore powder.

Images