Method for recovering lithium, rubidium and cesium elements from lepidolite

Abstract

The present application belongs to the field of mineral recovery, and specifically relates to a method for recovering lithium, rubidium and cesium elements in lepidolite, which comprises the following steps: placing a mixed solution containing dispersed lepidolite, inhibitors and alkali liquor in a sealed container and performing pressure alkali leaching at a temperature above 200 DEG C, then performing solid-liquid separation to obtain a leaching solution; using organic phase A to extract the lithium, rubidium and cesium-rich solution to obtain a lithium extraction residual liquid and a lithium-loaded organic phase; the organic phase A comprises component a, component b and a hydrophobic diluent; using organic phase B to extract the lithium extraction residual liquid to obtain a rubidium and cesium extraction residual liquid and a rubidium and cesium-loaded organic phase; the organic phase B comprises component c and a hydrophobic diluent; the component C is a compound with the structure of formula 3. The present application provides a roasting-free method for recovering valuable elements in lepidolite, which can effectively directly recover valuable elements in lepidolite and realize selective extraction separation of lithium, rubidium and cesium.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to a method for the comprehensive recovery of valuable metals from lepidolite ore. Background Technology

[0002] Lithium is widely used in batteries, pharmaceuticals, petrochemicals, rubber industry, nuclear industry, aerospace and other industries, and is hailed as the energy metal of the 21st century, white petroleum, and an important element driving the world forward. Lepidolite is an important lithium extraction resource, and it also contains valuable alkali metals such as rubidium and cesium.

[0003] Currently, the main method for treating valuable elements in lepidolite is leaching after calcination. For example, Chinese patent document CN118724028A discloses a method for preparing lithium carbonate from lepidolite, specifically a scheme involving mixing lepidolite with sulfate, calcining, and then leaching. This method has a high lithium extraction rate, but low rubidium and cesium leaching rates, high energy consumption, and large reagent consumption. While the sulfuric acid method can achieve simultaneous leaching of lithium, rubidium, and cesium, it results in large amounts of waste acid, severe equipment corrosion, difficulty in impurity removal, and significant lithium loss.

[0004] For example, Chinese patent document CN116103513A discloses a method for extracting lithium from lepidolite by microwave roasting. Specifically, it discloses a scheme of microwave roasting a composite of lepidolite ore, charcoal, and calcium chloride, followed by leaching.

[0005] While the roasting-leaching process achieves good extraction results, it suffers from high impurity content, and the separation of alkali metals requires further improvement in terms of both difficulty and selectivity. Furthermore, it suffers from high energy consumption and severe equipment corrosion. Therefore, there is an urgent need to develop a new lepidolite processing technology to achieve the clean and efficient recovery of valuable metals from lepidolite. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for recovering lithium, rubidium, and cesium elements from lepidolite, and to provide a method that achieves efficient and selective separation of lithium, rubidium, and cesium without calcination.

[0007] To address the problems of existing roasting-leaching processes, this invention initially attempted to provide a direct leaching process involving high-temperature, high-pressure alkaline leaching without roasting. However, earlier research revealed that this approach consumes a significant amount of alkali. Therefore, the inventors further explored a cyclic direct alkaline leaching process. However, during the development phase, it was found that this cyclic direct high-pressure alkaline leaching process easily leads to the continuous accumulation of Na and K during the processing, which affects the separation efficiency and selectivity of lithium, rubidium, and cesium. To address this problem, this invention, after in-depth research, provides the following solution:

[0008] A method for recovering lithium, rubidium, and cesium elements from lepidolite, comprising the following steps:

[0009] Step (1): Circulating alkaline leaching

[0010] Step (1a): Pressure alkali leaching:

[0011] A mixture containing lepidolite, inhibitor, and alkaline solution was placed in a sealed container and subjected to pressure alkali leaching at a temperature above 200°C. Subsequently, solid-liquid separation was performed to obtain the leachate.

[0012] Step (1b): Impurity Removal

[0013] Add impurity removal agent to the leachate to remove aluminum, silicon and fluorine, and obtain purified solution;

[0014] Step (1c): Loop

[0015] The purified solution is reused as an alkaline solution in step (1a) and cyclically participates in the pressurized alkaline leaching step to obtain a lithium-rich rubidium-cesium leaching solution; wherein the molar amount of sodium hydroxide in the lithium-rich rubidium-cesium leaching solution is 5-10 M.

[0016] Step (2): Lithium recovery:

[0017] The lithium-rich rubidium-cesium solution was extracted using organic phase A to obtain the lithium extraction residue and the lithium-loaded organic phase.

[0018] The organic phase A includes component a, component b, and a hydrophobic diluent;

[0019] The component a is a compound having the structure of Formula 1.

[0020] Component b is a compound having the structure of Formula 2;

[0021]

[0022] R1, R2, and R3 are C4 to C8 alkyl groups;

[0023]

[0024] R4 is C1~C 12 Alkyl groups;

[0025] Step (3): Recover rubidium and cesium:

[0026] The lithium extraction residue was extracted using organic phase B to obtain the rubidium-cesium extraction residue and the rubidium-cesium-supported organic phase.

[0027] Organic phase B includes component c and a hydrophobic diluent; component c is a compound with the structure of formula 3;

[0028]

[0029] R5 is a C1-C6 alkyl group, and R6 is H or a C1-C6 alkyl group;

[0030] The residual liquid from the rubidium-cesium extraction is reused as an alkaline solution in step 1a.

[0031] This invention provides a method for recovering valuable elements from lepidolite without roasting. It innovatively involves directly subjecting lepidolite to pressurized alkaline leaching and cyclic pressurized alkaline leaching, and directly extracting lithium and rubidium and cesium under high alkaline conditions. This method can effectively and directly recover valuable elements from lepidolite and achieve selective extraction and separation of lithium and rubidium and cesium.

[0032] In this invention, in step (1a), the inhibitor is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0033] In this invention, the inhibitor is 10% to 80% of the weight of lepidolite.

[0034] In this invention, the alkaline solute in the alkaline solution includes at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

[0035] In this invention, the concentration of alkaline solute in the alkaline solution is controlled at 5–10 M.

[0036] In this invention, the temperature of the pressurized alkali leaching stage is 200–280°C;

[0037] Preferably, the pressure alkali immersion time is 1 to 8 hours;

[0038] Preferably, the liquid-to-solid ratio during the pressurized alkali leaching stage is 5 / 1 to 50 / 1.

[0039] In this invention, in step (1b), the impurity removal agent is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0040] Preferably, the amount of impurity remover added is 5–30 g / L;

[0041] Preferably, the temperature during the impurity removal stage is 25℃~90℃;

[0042] Preferably, the impurity removal time is 1 to 8 hours.

[0043] Preferably, the lithium concentration in the leaching solution is 1–5 g / L during the cyclic leaching process.

[0044] In this invention, the purified liquid is recycled for leaching, thus realizing the recycling of alkali. Moreover, a high-alkalinity (4-8M) leaching solution can be obtained. This high-alkalinity leaching system can be directly used for subsequent extraction treatment. Compared with the industry-standard extraction system of pH 8-14, it can unexpectedly further enhance the extraction rate and extraction selectivity of lithium, rubidium, and cesium.

[0045] In this invention, in step (2), the hydrophobic diluent in organic phase A includes at least one of sulfonated kerosene, xylene, cyclohexane, and diethylbenzene.

[0046] In this invention, in the organic phase A, the content of component a is 5-30 vol%, and the volume fraction of component b is 5-30 vol%.

[0047] In this invention, in step (2), the concentration of alkaline components in the aqueous phase during the extraction stage is 4–10 M;

[0048] Preferably, the O / A ratio during the extraction stage is 5 / 1 to 1 / 10.

[0049] In this invention, the lithium-loaded organic phase is washed and then back-extracted to obtain a lithium-rich back-extraction solution.

[0050] Preferably, the washing solution is pure water or an acid solution with a concentration of 5–20 g / L;

[0051] Preferably, the O / A volume ratio during the washing stage is 5 / 1 to 50 / 1;

[0052] Preferably, the back-extraction solution is a solution containing at least one acidic solute selected from sulfuric acid, hydrochloric acid, and phosphoric acid, and the concentration of the acidic solute is 100–900 g / L.

[0053] Preferably, the O / A volume ratio during the back-extraction stage is 5 / 1 to 50 / 1.

[0054] In this invention, the compound of formula 3 is preferably the compound of formula 3-1.

[0055] Wherein, R5 is a C3-C5 alkyl group, preferably tert-butyl. R6 is H, methyl, or ethyl.

[0056] This finding indicates that using the preferred R5, preferably tert-butyl of formula 3, is unexpectedly better suited to high-alkalinity extraction, which helps to obtain better rubidium-cesium extraction selectivity.

[0057] In this invention, the concentration of component c in the organic phase B is 0.5 mol / L to 3 mol / L;

[0058] Preferably, in step (3), the volume ratio of O / A extracted is 5 / 1 to 1 / 5.

[0059] In this invention, the rubidium- and cesium-loaded organic phase is washed and then back-extracted to obtain a rubidium- and cesium-rich back-extract.

[0060] Preferably, the washing solution is pure water;

[0061] Preferably, the O / A volume ratio during the washing stage is 5 / 1 to 10 / 1;

[0062] Preferably, the back-extraction solution is a solution containing at least one acidic solute selected from sulfuric acid and hydrochloric acid, and the concentration of the acidic solute is 50-400 g / L.

[0063] Preferably, the O / A volume ratio during the back-extraction stage is 2 / 1 to 50 / 1.

[0064] Beneficial effects:

[0065] This invention employs a direct circulating pressurized alkaline leaching process to leach lepidolite. To address the challenges of this process, it innovatively performs extraction directly at high alkalinity and further coordinates the combined control of the extracted components. This unexpectedly achieves synergy, enhancing the extraction rates and separation coefficients of lithium, rubidium, and cesium.

[0066] The method of this invention achieves comprehensive and efficient recovery of lithium, rubidium, and cesium from lepidolite. The overall process is clean, low-carbon, and short. It can not only significantly improve the recovery rate of lithium, rubidium, and cesium, but also achieve alkali recycling and near-zero wastewater discharge. Attached Figure Description

[0067] Figure 1 This is a process flow diagram from Embodiment 1 of the present invention. Detailed Implementation

[0068] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0069] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0070] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0071] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a method for the comprehensive recovery of valuable metals from lithium mica, which can realize the simultaneous and efficient extraction of lithium, rubidium and cesium, improve the utilization efficiency of associated rubidium and cesium resources, realize the recycling of alkali and near-zero wastewater discharge, and solve the contradiction between the difficulty in balancing the leaching rate of lithium, rubidium and cesium and the alkali consumption in the traditional open-circuit process.

[0072] A method for the comprehensive recovery of valuable metals from lepidolite includes the following steps:

[0073] (1) Pressure alkaline leaching: Lithium mica, alkaline solution and inhibitor are added to a pressure reactor for leaching to obtain leaching solution;

[0074] (2) Removal of aluminum, silicon and fluorine: Add impurity removal agent to the leachate to remove aluminum, silicon and fluorine, and obtain purified solution;

[0075] (3) Circulating alkaline leaching: After adding alkali to the purified solution, it is added to a pressurized reactor along with lepidolite and inhibitor for circulating alkaline leaching to obtain lithium-rich rubidium-cesium leachate;

[0076] (4) Lithium recovery: The lithium-rich rubidium-cesium solution is extracted to obtain lithium extraction residue and lithium-enriched organic phase; the lithium-rich organic phase is washed and back-extracted to obtain lithium-containing back-extraction solution;

[0077] (5) Recovery of rubidium and cesium: The lithium extraction residue is extracted again to obtain the rubidium and cesium extraction residue and the rubidium and cesium-enriched organic phase; the rubidium and cesium-enriched organic phase is washed and back-extracted to obtain the rubidium and cesium-containing back-extract.

[0078] (6) After adding alkali to the remaining rubidium and cesium extract, return it to the alkali pressure cooking.

[0079] In the above method, the preferred step (1) specifically includes the following steps: drying, crushing, and grinding lepidolite to obtain lepidolite powder; adding lepidolite powder, alkaline solution, and inhibitor to a pressure reactor for hydrothermal leaching; the hydrothermal leaching reaction temperature is 200-280℃, the time is 1-8h, the liquid-solid ratio is 5 / 1-50 / 1, the alkaline solution is at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate, and the inhibitor is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0080] Step (2) specifically includes the following steps: adding a decontaminant to the leachate to remove aluminum, silicon, and fluorine, wherein the decontaminant is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0081] The temperature for removing aluminum, silicon, and fluorine is 25℃~90℃, and the time is 1~8h.

[0082] Step (3) specifically includes the following steps: after adding alkali to the purified liquid, it is added to a pressurized reactor along with lepidolite and inhibitor for cyclic alkali leaching. The inhibitor is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0083] The circulating alkaline leaching temperature is 200–280°C, the time is 1–8 hours, the liquid-to-solid ratio is 5 / 1–50 / 1, and the alkaline solution is at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

[0084] Step (4) specifically includes the following steps: When extracting the lithium-rich rubidium-cesium solution, the extractant is component a of formula 1, the modifier is component b of formula 2, the volume fraction of the extractant is 5% to 30%, the volume fraction of the modifier is 5% to 30%, the diluent is sulfonated kerosene, and the ratio O / A is controlled to be 5 / 1 to 1 / 10; pure water or sulfuric acid or hydrochloric acid with a concentration of 5 to 20 g / L is used to extract the Li-rich solution. + The organic phase is washed, and the ratio O / A is controlled to be 5 / 1 to 50 / 1. The washed organic phase is then back-extracted with sulfuric acid, hydrochloric acid or phosphoric acid at a concentration of 100 to 900 g / L, and the ratio O / A is controlled to be 5 / 1 to 50 / 1, to obtain a lithium-rich back-extraction solution.

[0085] Step (5) specifically includes the following steps: when extracting the lithium residue, a substituted phenolic extractant is used, the concentration of component c of formula 3 is 0.5 mol / L to 3 mol / L, and the phase O / A is controlled to be 5 / 1 to 1 / 5; the organic phase enriched with rubidium and cesium is washed with pure water, and the phase O / A is controlled to be 5 / 1 to 10 / 1; the washed organic phase is back-extracted with sulfuric acid or hydrochloric acid with a concentration of 50 to 400 g / L, and the phase O / A is controlled to be 2 / 1 to 50 / 1, to obtain a rubidium- and cesium-rich back-extraction solution.

[0086] The step (6) specifically includes the following steps: after adding alkali to the rubidium and cesium extraction residue, add it to a pressurized reactor along with lepidolite and an inhibitor for cyclic alkali leaching. The inhibitor is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

[0087] The circulating alkaline leaching temperature is 200–280°C, the time is 1–8 hours, the liquid-to-solid ratio is 5 / 1–50 / 1, and the alkaline solution is at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

[0088] The following are typical examples:

[0089] Example 1 - Leaching

[0090] Example 1-A:

[0091] Lithium mica powder (200 mesh) and an alkaline solution were sealed in a pressure-resistant container and leached under pressure at 280°C. The alkaline solution was an aqueous solution of potassium hydroxide and potassium carbonate, with a molar ratio of 8:2 and a potassium hydroxide concentration of 12M. The liquid-to-solid ratio was 5:1 ml / g, and the amount of calcium sulfate inhibitor added was 25 g / L. The pressure leaching reaction time was 5 h. After solid-liquid separation, lithium, rubidium, and cesium leachates were obtained, with leaching rates of 94.56%, 94.88%, and 92.32%, respectively.

[0092] Example 1-B:

[0093] Lithium mica powder (200 mesh) and an alkaline solution were sealed in a pressure-resistant container and leached under pressure at 200°C. The alkaline solution was an aqueous solution of sodium hydroxide with a concentration of 6M and a liquid-to-solid ratio of 50:1 ml / g. The amount of magnesium hydroxide inhibitor added was 10 g / L. The pressure leaching reaction time was 8 hours. After solid-liquid separation, lithium, rubidium, and cesium leachates were obtained, with leaching rates of 96.54%, 96.12%, and 94.83%, respectively.

[0094] Example 1-C:

[0095] Lithium mica powder (150 mesh) and an alkaline solution were sealed in a pressure-resistant container and leached under pressure at 260°C. The alkaline solution was an aqueous solution of potassium hydroxide with a concentration of 7M and a liquid-to-solid ratio of 25:1 ml / g. The amount of calcium hydroxide inhibitor added was 15 g / L. The pressure leaching reaction time was 5 h. After solid-liquid separation, lithium, rubidium, and cesium leachates were obtained, with leaching rates of 93.34%, 94.78%, and 92.22%, respectively.

[0096] Example 1-D:

[0097] Lithium mica powder (300 mesh) and an alkaline solution were sealed in a pressure-resistant container and leached under pressure at 240°C. The alkaline solution consisted of sodium hydroxide and sodium carbonate in a molar ratio of 5:1, with a sodium hydroxide concentration of 6M and a liquid-to-solid ratio of 15:1 ml / g. The amount of magnesium oxide as an inhibitor was 8 g / L. The pressure leaching reaction was carried out for 3 hours. After solid-liquid separation, lithium, rubidium, and cesium leachates were obtained, with leaching rates of 92.23%, 93.05%, and 91.92%, respectively.

[0098] Example 2

[0099] Step 1: Perform cyclic leaching based on the conditions of Example 1-A. Before leaching, the leachate is treated to remove impurities. The impurity remover is calcium oxide, with an addition amount of 6-8 g / L and a removal time of 1-2 h. The purified solution after impurity removal is used as an alkaline solution for cyclic leaching. After the last leaching, the impurity removal treatment is continued to obtain a lithium-rubidium-cesium concentrated purified solution with Li 1.41 g / L and NaOH 7.25 mol / L.

[0100] Step 2: The above-mentioned lithium rubidium cesium concentrated purification solution is treated with 0.4M of formula 1a (R1 to R3 are all n-octyl formula 1) component a + 0.4M of formula 2a (R4 is n-octyl formula 2) + sulfonated kerosene, and the ratio O / A is controlled to be 1 / 1 to obtain lithium extraction residue and lithium-loaded organic phase.

[0101] The lithium-loaded organic phase was washed with pure water at an O / A ratio of 5:1, followed by back-extraction with 200 g / L sulfuric acid at an O / A ratio of 25:1 to obtain a lithium back-extraction solution (lithium extract). The lithium extraction rate was above 99%, and the lithium concentration in the back-extraction solution was above 20 g / L. Separation coefficient β Li / Na β Li / K β Li / Rb β Li / Cs The values ​​are 309, 842, 4550, and 4760, respectively, indicating that lithium has a good separation effect from other alkali metal ions.

[0102] Step 3: The remaining lithium extraction solution from Step 2 (Rb 1.21 g / L, Cs 66.58 mg / L, K 11.32 g / L, NaOH 6.75 mol / L) is processed using 1 mol / L formula 3a. + Sulfonated kerosene, compared with O / A = 1 / 1, is extracted to obtain a rubidium- and cesium-loaded organic phase and a rubidium- and cesium-extracted residue;

[0103] The rubidium-cesium-loaded organic phase was washed with pure water at an O / A ratio of 5:1, followed by back-extraction with 100 g / L sulfuric acid at an O / A ratio of 10:1, yielding a rubidium + cesium back-extract. The concentration of (rubidium + cesium) in the back-extract was above 10 g / L. Separation coefficient β (Rb+Cs) / Na β (Rb+Cs) / K The values ​​were 450 and 28 respectively, indicating good separation effects of rubidium and cesium from sodium and potassium.

[0104] Step 4: After adding alkali to the remaining rubidium and cesium extraction solution, add an alkaline solution of potassium hydroxide at 280℃ with a liquid-to-solid ratio of 10:1 and a reaction time of 3 hours. Then add magnesium oxide. The leaching rates of lithium, rubidium, and cesium are 95.56%, 95.20%, and 93.88%, respectively.

[0105] Example 3

[0106] Compared with Example 2, the only difference is that the extraction conditions in step 2 are changed. Specifically, the concentration of Formula 1a in the extraction system is 0.3M and the concentration of Formula 2a is 0.5M; the O. / A ratio in the extraction stage is 2:1.

[0107] In addition, the extraction conditions in step 3 are changed, specifically, the concentration of formula 3a in the extraction system is 0.8M; and the O. / A ratio in the extraction stage is 2:1.

[0108] All other operations and parameters are the same as in Example 1.

[0109] The result is: In step 2, the separation coefficient β Li / Na β Li / K β Li / Rb β Li / Cs The values ​​are 321, 881, 4620, and 4670, respectively, indicating that lithium has a good separation effect from other alkali metal ions.

[0110] In step 3, the separation coefficients β(Rb+Cs) / Na and β(Rb+Cs) / K are 432 and 30, respectively, indicating good separation of rubidium and cesium from sodium and potassium.

[0111] Example 4

[0112] Compared with Example 2, the only difference is that in step 3, formula 3b is used. Replace Equation 3a with an equal amount, and perform the same operations and parameters as in Example 2.

[0113] The result is: In step 3, the separation coefficient β (Rb+Cs) / Na β (Rb+Cs) / K They are 305 and 15 respectively.

[0114] Comparative Example 1

[0115] Compared with Example 2, the only difference is that in step 2, formula 2a is missing from the extraction system, and the content of the remaining active extractant and other operations and parameters are the same as in Example 2.

[0116] The result is: In step 2, the separation coefficient β Li / Na β Li / K β Li / Rb β Li / Cs The numbers are 287, 193, 433, and 308 respectively.

[0117] Comparative Example 2

[0118] Compared with Example 2, the only difference is that in step 2, Formula 1a is missing from the extraction volume, and the content of the remaining active ingredient and other operations and parameters are the same as in Example 2.

[0119] The result is: In step 2, the separation coefficient βLi / Na β Li / K β Li / Rb β Li / Cs The figures are 7.96, 3.57, 10.70, and 12.66, respectively.

[0120] As can be seen from Example 2 and Comparative Examples 1-2, under the ultra-high alkalinity, the combined extraction system described in this invention can significantly optimize the extraction effect and selectivity of lithium.

Claims

1. A method for recovering lithium, rubidium and cesium elements from lepidolite, characterized by the steps of Comprising: Step (1): Circulating alkali leaching Step (1a): Pressure alkali leaching The mixture of lithium mica, inhibitor, alkali solution and dispersant is placed in a sealed container and pressure alkali leached at a temperature of 200℃ or higher, followed by solid-liquid separation to obtain a leaching solution; Step (1b): Impurity removal The leaching solution is added to the impurity removal agent to remove aluminum silicon fluoride to obtain a purified solution; Step (1c): Circulation The purified solution is recycled as an alkali solution to step (1a) and participates in the pressure alkali leaching step to obtain a lithium-rich rubidium cesium leaching solution; wherein the molar concentration of sodium hydroxide in the lithium-rich rubidium cesium leaching solution is 4-8M; Step (2): Recovery of lithium: The lithium-rich rubidium cesium leaching solution is extracted with organic phase A to obtain lithium extraction raffinate and lithium-loaded organic phase; The organic phase A comprises component a, component b and hydrophobic diluent; The component a is a compound with formula 1 Formula 1 R1, R2, R3 are C4-C8 alkyl; The component b is a compound with formula 2; Formula 2 R4is C1- C 12 alkyl; Step (3): Recovery of rubidium cesium: The lithium extraction raffinate is extracted with organic phase B to obtain rubidium cesium extraction raffinate and rubidium cesium-loaded organic phase; The organic phase B comprises component c and hydrophobic diluent; the component C is a compound with formula 3; Formula 3 R5 is C1-C6 alkyl, and R6 is H or C1-C6 alkyl; The rubidium cesium extraction raffinate is recycled as an alkali solution to step (1a).

2. The method of recovering lithium, rubidium, and cesium elements from lepidolite according to claim 1, wherein In step (1a), the inhibitor is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

3. The method of recovering lithium, rubidium, and cesium elements from lepidolite according to claim 2, wherein In step (1a), the amount of inhibitor added is 10%-80% of the weight of lithium mica.

4. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 2, wherein In step (1a), the basic solute in the alkali solution includes at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

5. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 4, wherein In step (1a), the concentration of basic solute in the alkali solution is controlled at 5-10M.

6. The method for recovering lithium, rubidium and cesium elements from lepidolite according to any one of claims 2 to 5, wherein the lepidolite is lepidolite containing 0.1% or more of potassium. The temperature of the pressure alkali leaching stage is 200-280℃.

7. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 6, wherein The time of pressure alkali leaching is 1-8h.

8. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 6, wherein The liquid-solid ratio of the pressure alkali leaching stage is 5 / 1-50 / 1.

9. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein In step (1b), the impurity removal agent is at least one of calcium oxide, calcium hydroxide, calcium sulfate, magnesium oxide, magnesium hydroxide, and magnesium sulfate.

10. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 9, wherein In step (1b), the amount of impurity removal agent added is 5-30g / L.

11. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein In step (1b), the temperature of the impurity removal stage is 25℃-90℃.

12. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein In step (1b), the time of impurity removal is 1-8h.

13. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein In step (1b), the concentration of lithium in the leaching solution is 1-5g / L.

14. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein In step (2), the hydrophobic diluent in the organic phase A includes at least one of sulfonated kerosene, xylene, cyclohexane, and diethylbenzene.

15. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 14, wherein In step (2), the content of component a in the organic phase A is 5-30v%, and the volume fraction of component b is 5-30v%.

16. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein In step (2), the concentration of basic components in the aqueous phase of the extraction stage is 4-8M.

17. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 16, wherein The O / A of the extraction stage is 5 / 1-1 / 10.

18. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein The lithium-loaded organic phase is washed and then stripped to obtain a lithium-rich stripping solution.

19. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 18, wherein The washing solution is pure water or an acid solution with a concentration of 5-20g / L.

20. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 18, wherein The O / A volume ratio of the washing stage is 5 / 1-50 / 1.

21. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 18, wherein The washing solution is a solution containing at least one acidic solute selected from sulfuric acid, hydrochloric acid and phosphoric acid, and the concentration of the acidic solute is 100-900 g / L.

22. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 21, wherein The O / A volume ratio in the stripping stage is 5 / 1-50 / 1.

23. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein The concentration of the component c in the organic phase B is 0.5-3 mol / L.

24. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein The O / A volume ratio in the extraction is 5 / 1-1 / 5.

25. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 1, wherein The rubidium-loaded cesium organic phase is washed and then subjected to stripping to obtain a rubidium-rich cesium stripping solution.

26. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 25, wherein The washing solution is pure water.

27. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica according to claim 25, wherein The O / A volume ratio in the washing stage is 5 / 1-10 / 1.

28. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica of claim 25, wherein, The stripping solution is a solution containing at least one acidic solute selected from sulfuric acid and hydrochloric acid, and the concentration of the acidic solute is 50-400 g / L.

29. The method of recovering lithium, rubidium, and cesium elements from lepidolite mica of claim 25, wherein, The O / A volume ratio in the stripping stage is 2 / 1-50 / 1.

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