Method for extracting lithium, rubidium and cesium from pegmatite lithium concentrate

Abstract

The application discloses a method for extracting lithium, cesium and rubidium from pegmatite lithium concentrate, comprising the following steps: step 1, uniformly mixing mixed roasting additives with pegmatite lithium concentrate to obtain a mixture; step 2, performing alkali roasting on the mixture to obtain a calcine containing lithium, rubidium and cesium; step 3, finely grinding the calcine containing lithium, rubidium and cesium, and then adding a leaching agent to leach the calcine to obtain a solution containing lithium, rubidium and cesium; and step 4, extracting lithium, rubidium and cesium from the solution containing lithium, rubidium and cesium. By adding mixed roasting additives to the pegmatite lithium concentrate raw material, low-temperature alkali roasting can be realized. In addition, the method provided by the application can be used for large-scale industrial production, is energy-saving and environment-friendly, low in cost, and has a wide popularization prospect.

Description

Technical Field

[0001] This invention relates to the field of ore extraction, and in particular to a method for extracting lithium, rubidium, and cesium from pegmatite lithium concentrate. Background Technology

[0002] Currently, the largest consumer of lithium products is the lithium battery industry, accounting for approximately 71% of total consumption. In recent years, with the rapid development of the new energy battery industry, the supply of lithium battery raw materials has fallen short of demand. This supply-demand imbalance has led to a continuous rise in the prices of lithium carbonate and lithium hydroxide since the end of 2020. Rubidium and cesium, due to their excellent photoelectric properties and unique chemical properties, are finding increasingly widespread applications in high-tech and emerging fields such as the national economy and national defense. Naturally abundant and easily exploitable lithium ore resources, such as spodumene, lepidolite, and lithium mica, are all pegmatite-type minerals. Mica-type lithium ores also contain rare metal elements such as rubidium and cesium, making them important resources for extracting rubidium and cesium. Lithium iron ore contains approximately 1.30% lithium and small amounts of rubidium and cesium; lepidolite contains 1.36-3.6% lithium and about 1% rubidium, making it an important resource for extracting lithium, rubidium, and cesium, and one of the main lithium and rubidium ore resources currently being mined. Spodumene contains 3.7% lithium and is currently the most widely mined lithium ore resource. The comprehensive development and utilization of lithium, rubidium, and cesium resources in pegmatite-type minerals has extremely high economic and strategic value.

[0003] Currently, the main industrial methods for lithium extraction from pegmatite lithium ore include sulfate roasting, sulfuric acid ripening, and chlorination roasting. Sulfate roasting, with a roasting temperature of 850℃, has a relatively short process flow but high cost and is mainly used for lithium extraction from lepidolite. Sulfuric acid ripening involves heating at approximately 200℃, but concentrated sulfuric acid and hydrogen fluoride volatilize during heating, causing severe corrosion to equipment, and the subsequent purification process is also complex. Chlorination roasting, with a roasting temperature of 850℃, also suffers from equipment corrosion problems and is currently less commonly used. In addition, although the lithium leaching rate of sulfuric acid roasting and sulfate roasting can reach over 95%, the leaching rate of rubidium and cesium is very low, only 20-30%, and the comprehensive utilization rate of mica-based lithium ore is low. Although the leaching rate of lithium, rubidium, and cesium in lepidolite concentrate is relatively high, reaching 97%, the use of chloride salts as roasting additives causes corrosion of equipment due to the high chloride ion content in the mother liquor. Alkali roasting requires high-pressure cooking and is not suitable for large-scale production, so it can only be used for experimental research.

[0004] It is evident that existing processes suffer from problems such as high roasting temperatures, high energy consumption, equipment corrosion, and limitations in large-scale scalability. Therefore, in the technical field of lithium ore roasting for lithium, rubidium, and cesium extraction, there is an urgent need for a highly efficient, energy-saving, and scalable method for extracting lithium, rubidium, and cesium. Summary of the Invention

[0005] To address the above problems, this invention provides a method for extracting lithium, rubidium, and cesium from pegmatite lithium concentrate, comprising the following steps:

[0006] Step 1: Mix the mixed roasting additive with pegmatite lithium concentrate evenly to obtain a mixture;

[0007] Step 2: The mixture is subjected to alkaline calcination to obtain calcined sand containing lithium, rubidium, and cesium;

[0008] Step 3: Grind the calcined sand containing lithium, rubidium, and cesium into a fine powder, then add a leaching agent to leach it to obtain a solution containing lithium, rubidium, and cesium.

[0009] Step 4: Extract lithium, rubidium and cesium from the solution containing lithium, rubidium and cesium.

[0010] Preferably, the mixed calcination additive is calcium oxide and sodium hydroxide.

[0011] Preferably, the mass ratio of sodium hydroxide to calcium oxide in the mixed roasting additive is 1-2:0.3-0.5.

[0012] Preferably, the mass ratio of the pegmatite lithium concentrate to the mixed roasting additive is 1:1.0 to 2.5.

[0013] Preferably, the calcination temperature of the alkali fusion calcination is 500–700°C.

[0014] Preferably, the holding time for the alkali fusion roasting is 60 to 240 minutes.

[0015] Preferably, the leaching agent is water.

[0016] Preferably, in step 3, the liquid-to-solid ratio of the leaching agent and the calcined sand containing lithium, rubidium, and cesium is 2 to 4:1.

[0017] Preferably, the leaching temperature is 60–90°C.

[0018] Preferably, the leaching time is 60 to 90 minutes.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention discloses a method for extracting lithium, cesium, and rubidium from pegmatite lithium concentrate, comprising the following steps: Step 1: Mixing a mixed roasting additive with pegmatite lithium concentrate uniformly to obtain a mixture; Step 2: Alkali-fusible roasting of the mixture to obtain roasted sand containing lithium, rubidium, and cesium; Step 3: Grinding the roasted sand containing lithium, rubidium, and cesium into a fine powder, and then adding a leaching agent for leaching to obtain a solution containing lithium, rubidium, and cesium; Step 4: Extracting lithium, rubidium, and cesium from the solution containing lithium, rubidium, and cesium. This invention achieves low-temperature alkali-fusible roasting by adding a mixed roasting additive to pegmatite lithium concentrate raw material. Furthermore, the method provided by this invention can be used for large-scale industrial production, and is energy-saving, environmentally friendly, and low-cost, with broad prospects for promotion.

[0021] This invention utilizes the synergistic effect of mixed roasting additives added to pegmatite lithium concentrate raw materials to disrupt the structure of the lithium concentrate at a lower roasting temperature, effectively decomposing the lithium concentrate and efficiently extracting valuable metals such as lithium, rubidium, and cesium from pegmatite lithium concentrate at low temperatures. The method provided by this invention achieves low-temperature alkali fusion roasting, thus offering advantages such as low energy consumption, energy saving and environmental protection, low cost, and high efficiency (high leaching rate). Furthermore, the reaction conditions in the method provided by this invention are mild (under normal pressure), making it suitable for large-scale industrial production and possessing broad prospects for widespread application. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating a method for extracting lithium, rubidium, and cesium from pegmatite lithium concentrate according to an embodiment of the present invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the examples, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0024] This invention provides a method for extracting lithium, rubidium, and cesium from pegmatite lithium concentrate, comprising the following steps:

[0025] S101, the mixed roasting additives are mixed evenly with pegmatite lithium concentrate to obtain a mixture;

[0026] S102, the mixture is subjected to alkaline calcination to obtain calcined sand containing lithium, rubidium, and cesium;

[0027] S103, the calcined sand containing lithium, rubidium, and cesium is ground into a fine powder, and then a leaching agent is added for leaching to obtain a solution containing lithium, rubidium, and cesium.

[0028] S104, extracting lithium, rubidium and cesium from the solution containing lithium, rubidium and cesium.

[0029] In this embodiment of the invention, calcined sand containing lithium, rubidium and cesium can be obtained at a lower calcination temperature, thereby making it easier to extract valuable metals such as lithium, rubidium and cesium from the calcined sand.

[0030] This invention utilizes the synergistic effect of mixed roasting additives added to pegmatite lithium concentrate raw materials to disrupt the structure of the lithium concentrate at a lower roasting temperature, effectively decomposing the lithium concentrate and efficiently extracting valuable metals such as lithium, rubidium, and cesium from pegmatite lithium concentrate at low temperatures. The method provided by this invention achieves low-temperature alkali fusion roasting, thus offering advantages such as low energy consumption, energy saving and environmental protection, low cost, and high efficiency (high leaching rate). Furthermore, the reaction conditions in the method provided by this invention are mild (under normal pressure), making it suitable for large-scale industrial production and possessing broad prospects for widespread application.

[0031] Preferably, the mixed calcination additive is calcium oxide and sodium hydroxide.

[0032] In this embodiment of the invention, a mixture of calcium oxide and sodium hydroxide is used as a roasting additive. Utilizing their synergistic effect, the roasting temperature is reduced from the previous 850℃ to below 700℃. Specifically, the synergistic effect is as follows: (1) As the roasting temperature gradually increases, molten NaOH provides a molten environment for the reaction of CaO. The reaction between lithium concentrate soaked in molten NaOH and CaO is more complete, which is more conducive to ion diffusion; (2) NaOH and CaO react with different structures in the lithium concentrate, making the lithium concentrate decompose more thoroughly, which is beneficial for the subsequent leaching of lithium, rubidium, and cesium. This invention uses a mixture of two roasting additives as a roasting additive, enabling the lithium concentrate to decompose effectively during roasting.

[0033] Preferably, the mass ratio of sodium hydroxide to calcium oxide in the mixed roasting additive is 1-2:0.3-0.5.

[0034] Preferably, the mass ratio of the pegmatite lithium concentrate to the mixed roasting additive is 1:1.0 to 2.5.

[0035] Preferably, the calcination temperature of the alkali fusion calcination is 500–700°C.

[0036] In this embodiment of the invention, as the calcination temperature gradually increases, NaOH changes from a solid state to a molten state (near-liquid fluid). The molten NaOH reacts with the [Al-O] structure in the lithium concentrate to generate NaAlO2 and H2O, thereby destroying the [Al-O] structure in the lithium concentrate. CaO reacts with the [Si-O] structure in the lithium concentrate to generate Na4SiO4, Ca2SiO4, and H2O, further destroying the [Si-O] structure in the lithium concentrate. In addition, the molten NaOH in the early stage provides conditions (molten environment) for the later reaction (structural destruction) of CaO. The lithium concentrate and CaO are immersed in the molten NaOH, which is conducive to ion diffusion and makes the reaction more complete.

[0037] This invention utilizes the synergistic effect of NaOH and CaO (the two points mentioned above) to cause more severe damage to the structure of lithium concentrate, resulting in complete decomposition of the lithium concentrate, thus not affecting the subsequent leaching of lithium, cesium, and rubidium.

[0038] Preferably, the holding time for the alkali fusion roasting is 60 to 240 minutes.

[0039] Preferably, the leaching agent is water.

[0040] In this embodiment of the invention, water is chosen as the leaching agent for the following two reasons: (1) According to the properties of the material to be leached in this invention, water has the best leaching effect; (2) It is convenient, inexpensive and non-toxic.

[0041] Preferably, in step 3, the liquid-to-solid ratio of the leaching agent and the calcined sand containing lithium, rubidium, and cesium is 2 to 4:1.

[0042] Preferably, the leaching temperature is 60–90°C.

[0043] Preferably, the leaching time is 60 to 90 minutes.

[0044] In this embodiment of the invention, lithium in the calcined calcined sand exists in the form of lithium hydroxide, while rubidium and cesium in the calcined sand exist primarily in the form of oxides. After the calcined sand is finely ground, a certain amount of leaching agent is added for cyclic leaching. The leaching solution from the first leaching, containing lithium, rubidium, and cesium, is used as the leaching agent for the next batch of calcined sand, and the process is repeated three times. Through this circulating water leaching process, lithium, rubidium, and cesium from lithium hydroxide, rubidium oxide, and cesium oxide are selectively leached into the solution, resulting in a leaching solution rich in lithium, rubidium, and cesium. Impurities such as silicon and aluminum remain in the leaching residue. Since lithium hydroxide is hygroscopic, its dissolution in water is more conducive to subsequent water leaching.

[0045] In this embodiment of the invention, alkaline roasting is used to effectively decompose lithium concentrate, allowing lithium, rubidium, and cesium to dissolve well during water leaching for extraction. Because the synergistic effect of NaOH and CaO during alkaline roasting effectively and completely decomposes the lithium concentrate, combined with a circulating water leaching process, the leaching rate of lithium can reach 91.7%, rubidium 98.8%, and cesium 98.2%.

[0046] To enable those skilled in the art to better understand the present invention, experiments were conducted using refractory metal raw materials of different shapes, resulting in multiple specific embodiments, which illustrate the method provided by the present invention.

[0047] In Examples 1-7, lithium iron ore mica concentrate was selected from pegmatite lithium concentrate.

[0048] Example 1

[0049] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.5, placed in a crucible, and subjected to alkaline fusion roasting in a furnace at a temperature of 650℃ for 90 minutes. After the holding time, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium, with leaching rates of 87.9%, 98.8%, and 84.4%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0050] Example 2

[0051] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.5, placed in a crucible, and subjected to alkaline fusion roasting in a furnace at a temperature of 550℃ for 90 minutes. After the holding time, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium, with leaching rates of 77.5%, 97.9%, and 63.8%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0052] Example 3

[0053] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.5, placed in a crucible, and subjected to alkaline fusion roasting in a heating furnace at a temperature of 700℃ for 90 minutes. After the holding time, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely, and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium, with leaching rates of 76.9%, 98.7%, and 65.2%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0054] Example 4

[0055] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.5 and placed in a crucible. The crucible was then placed in a furnace for alkaline fusion roasting at 650℃ for 60 minutes. After the roasting was completed, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed as it cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium. The leaching rates of lithium, rubidium, and cesium were 75.5%, 98.8%, and 75.5%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0056] Example 5

[0057] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2.2:0.4 and placed in a crucible. The crucible was then placed in a furnace for alkaline fusion roasting at 650℃ for 90 minutes. After the roasting was completed, the heating device was turned off, and the calcined sand containing lithium, rubidium, and cesium was removed and cooled to room temperature. The calcined sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium. The leaching rates of lithium, rubidium, and cesium were 78.8%, 98.6%, and 84.3%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0058] Example 6

[0059] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:1:0.4, placed in a crucible, and subjected to alkaline fusion roasting in a heating furnace at a temperature of 650℃ for 90 minutes. After the roasting was completed, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium, with leaching rates of 25.0%, 98.8%, and 44.6%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0060] Example 7

[0061] Lithium-iron mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.3 and placed in a crucible. The crucible was then placed in a heating furnace for alkaline fusion roasting at 650℃ for 90 minutes. After the roasting was completed, the heating device was turned off, and the calcined sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The calcined sand containing lithium, rubidium, and cesium was then ground into a fine powder and water (as a leaching agent) was added at a solid-liquid ratio of 1:2. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium. The leaching rates of lithium, rubidium, and cesium were 71.3%, 98.6%, and 68.2%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0062] In Examples 8-10, lithium concentrate from pegmatite was selected from lepidolite concentrate.

[0063] Example 8

[0064] Lithium mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.5 and placed in a crucible. The crucible was then placed in a heating furnace for alkaline fusion roasting at 650℃ for 90 minutes. After the roasting was completed, the heating device was turned off, and the calcined sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The calcined sand containing lithium, rubidium, and cesium was then ground into a fine powder and water (as a leaching agent) was added at a solid-liquid ratio of 1:4. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium. The leaching rates of lithium, rubidium, and cesium were 90.8%, 98.6%, and 98.2%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0065] Example 9

[0066] Lithium mica concentrate was mixed with NaOH and CaO (as mixed roasting additives) in a mass ratio of 1:2:0.5 and placed in a crucible for alkaline fusion roasting in a furnace at a temperature of 550℃ for 90 minutes. After the roasting was completed, the heating device was turned off and the furnace was cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then removed. The roasted sand containing lithium, rubidium, and cesium was ground into a fine powder and water (as a leaching agent) was added at a solid-liquid ratio of 1:4. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium. The leaching rates of lithium, rubidium, and cesium were 74.2%, 98.0%, and 92.2%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0067] Example 10

[0068] Lithium mica concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.5, placed in a crucible, and subjected to alkaline fusion roasting in a heating furnace at a temperature of 700℃ for 90 minutes. After the holding time, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:4. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a solution rich in lithium, rubidium, and cesium, with leaching rates of 76.1%, 98.5%, and 75.5%, respectively. Finally, lithium, rubidium, and cesium were easily extracted from the solution containing lithium, rubidium, and cesium.

[0069] In Examples 11-13, the pegmatite lithium concentrate used was spodumene concentrate. Since spodumene concentrate does not contain rubidium and cesium, only lithium was leached in Examples 11-13.

[0070] Example 11

[0071] Lithium spodumene concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.4, placed in a crucible, and subjected to alkaline fusion roasting in a heating furnace at a temperature of 650℃ for 90 minutes. After the holding time, the heating device was turned off, and the lithium-containing roasted sand was removed when the furnace cooled to room temperature. The roasted sand was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:4. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a lithium-rich solution with a lithium leaching rate of 91.7%. Lithium was then easily extracted from the lithium-containing solution.

[0072] Example 12

[0073] Lithium spodumene concentrate, mixed additives NaOH and CaO (as mixed roasting additives) were mixed evenly in a mass ratio of 1:2:0.4, placed in a crucible, and subjected to alkaline fusion roasting in a heating furnace at a temperature of 500℃ for 90 minutes. After the holding time, the heating device was turned off, and the calcined sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The calcined sand containing lithium, rubidium, and cesium was then ground into a fine powder and water (as a leaching agent) was added at a solid-liquid ratio of 1:4. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a lithium-rich solution with a lithium leaching rate of 82.2%. Finally, lithium was easily extracted from the solution containing lithium, rubidium, and cesium.

[0074] Example 13

[0075] Lithium spodumene concentrate, NaOH, and CaO (as a mixed roasting additive) were mixed evenly in a mass ratio of 1:2:0.4, placed in a crucible, and subjected to alkaline fusion roasting in a furnace at a temperature of 700℃ for 60 minutes. After the holding time, the heating device was turned off, and the roasted sand containing lithium, rubidium, and cesium was removed when the furnace cooled to room temperature. The roasted sand containing lithium, rubidium, and cesium was then ground finely and water (as a leaching agent) was added at a solid-liquid ratio of 1:4. Leaching was carried out at a leaching temperature of 90℃ for 60 minutes to obtain a lithium-rich solution with a lithium leaching rate of 86.5%. Finally, lithium was easily extracted from the lithium, rubidium, and cesium-containing solution.

[0076] The leaching rates of lithium, cesium, and rubidium after low-temperature roasting of the pegmatite lithium concentrate in the above embodiments are shown in Table 1 below.

[0077] Table 1. Comparison of experimental conditions and leaching rates of lithium, cesium, and rubidium in various embodiments.

[0078]

[0079]

[0080] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0081] The above provides a detailed description of a method for extracting lithium, rubidium, and cesium from pegmatite lithium concentrate. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the invention. At the same time, those skilled in the art will recognize that, based on the ideas of the invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the invention.

Claims

1. A method for extracting lithium, rubidium, and cesium from pegmatite lithium concentrate, characterized in that, Includes the following steps: Step 1: The mixed roasting additive is directly mixed evenly with pegmatite lithium concentrate to obtain a mixture. The mixed roasting additive is calcium oxide and sodium hydroxide. The molten sodium hydroxide reacts with the [Al-O] structure in the lithium concentrate to generate NaAlO2 and H2O, thus destroying the [Al-O] structure. The calcium oxide reacts with the [Si-O] structure in the lithium concentrate to generate Na4SiO4, Ca2SiO4, and H2O, thus disrupting the [Si-O] structure. The mass ratio of the pegmatite lithium concentrate to the mixed roasting additive is 1:1.0~2.

5. The mass ratio of sodium hydroxide to calcium oxide in the mixed roasting additive is 1~2:0.3~0.

5. The roasting temperature for alkali fusion roasting is 550℃ or 650℃. The holding time for alkali fusion roasting is 60~240 min. Step 2: The mixture is subjected to alkaline fusion roasting, whereby the molten sodium hydroxide provides a molten environment for the reaction of the calcium oxide, resulting in roasted slag containing lithium, rubidium, and cesium; Step 3: Grind the calcined sand containing lithium, rubidium, and cesium into fine powder. After grinding, add a certain amount of leaching agent for leaching. The first leaching solution, which is the leaching solution containing lithium, rubidium, and cesium, is used as the leaching agent for a new batch of calcined sand. The process is repeated three times to obtain a solution containing lithium, rubidium, and cesium. Step 4: Extract lithium, rubidium and cesium from the solution containing lithium, rubidium and cesium; wherein the leaching rate of lithium is 91.7%, the leaching rate of rubidium is 98.8% and the leaching rate of cesium is 98.2%.

2. The method according to claim 1, characterized in that, The leaching agent is water.

3. The method according to claim 1, characterized in that, In step 3, the liquid-to-solid ratio of the leaching agent and the calcined sand containing lithium, rubidium, and cesium is 2 to 4:

1.

4. The method according to claim 1, characterized in that, The leaching temperature is 60~90℃.

5. The method according to claim 1, characterized in that, The leaching time is 60-90 minutes.

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