Process for extracting rubidium from a sedimentary type grey-green salt lake clay

Abstract

This invention relates to the field of metal extraction technology, and more particularly to a process for extracting rubidium from sedimentary gray-green salt lake clay. The process includes the following steps: crushing and sieving the sedimentary gray-green salt lake clay, then impregnating the fine particles in a leaching agent, and filtering to obtain a leachate containing rubidium. The leaching agent is prepared from concentrated hydrochloric acid, low-mineralized water, and sodium sulfate, with the concentrated hydrochloric acid having a volume fraction of 30%–50%, and the liquid-to-solid ratio of low-mineralized water to sodium sulfate being 30 mL:1 g. The low-mineralized water is natural water from the Mahai Basin. This invention uses a composite leaching agent of low-mineralized water, concentrated hydrochloric acid, and sodium sulfate to extract rubidium. Rubidium ions are released through acid hydrolysis and ion exchange, directly extracting rubidium from sedimentary gray-green salt lake clay. A process method and key parameters for extracting rubidium from this type of clay in the Mahai area of ​​Qinghai Province have been established.

Description

Technical Field

[0001] This invention relates to the field of metal extraction technology, and in particular to a process for extracting rubidium from sedimentary gray-green salt lake clay. Background Technology

[0002] Sedimentary saline lake clay refers to fine-grained clay sediments formed in closed or semi-closed saline lake environments in arid to semi-arid regions. They are widely distributed in inland basins such as the Qaidam Basin in China, the Great Salt Lake in the United States, and the Dead Sea in the Middle East. Their formation is primarily due to the transport of weathering products (clay minerals and debris) from surrounding rocks into the lake. Under conditions of intense evaporation and concentration, high salinity (high mineralization), and high pH, ​​these materials are co-deposited with precipitated evaporative salt minerals (such as gypsum, halite, and mirabilite).

[0003] The Balunmahai area is located in the northwestern part of the Qaidam Basin in Qinghai Province. Its salt lake clay minerals mainly include kaolinite, illite, montmorillonite, and chlorite. The closed topography of the basin causes clay minerals weathered from the surrounding areas to be transported here by water and wind. Extreme drought leads to strong evaporation that far exceeds precipitation, resulting in continuous concentration of lake water and extremely high salinity. This high-salinity, still water environment inhibits hydrodynamics, facilitating the settling of even the finest clay particles. Furthermore, the abundant electrolytes in the water neutralize the surface charge of the clay particles through flocculation, causing them to rapidly aggregate and accelerate deposition. Ultimately, this forms a sedimentary saline clay layer at the bottom of the lake basin. Through long-term sedimentation and diagenesis, this clay layer often appears in specific strata within the saline lake sedimentary sequence: the upper part is an evaporite layer, which can be divided into clay with high halite content (referred to as halite clay) and clay with high silt content (referred to as silt clay); the lower part consists of grayish-brown clay (shallow strata, oxidizing environment, containing brown minerals such as hematite) and grayish-green clay (deep strata, reducing environment, containing grayish-green minerals such as siderite), rich in illite and chlorite. Among them, the gray-green clay was formed in the relatively moist deep-water reducing environment of the early salt lake. The low salinity of the water allowed clay minerals (such as illite) to be fully dispersed and efficiently adsorb rubidium ions from the lake water. After long-term burial, rubidium was stably fixed in the clay lattice, avoiding leaching and loss by the high-salinity brine later. Furthermore, the pure clay texture (almost free of halite and silt impurities) significantly reduced the interference of impurities from salt dissolution on rubidium extraction. At the same time, the organic matter preserved in the reducing environment often has a symbiotic relationship with rubidium; the humic acid produced by the decomposition of organic matter can enhance the complexation and adsorption of rubidium, further enriching the rubidium element. Therefore, the gray-green clay has the highest rubidium enrichment grade and superior extraction economics, making it the best choice for rubidium extraction from sedimentary salt lake clay in the Mahai area.

[0004] It is worth noting that rubidium, as a rare alkali metal, has irreplaceable application value in many cutting-edge fields due to its high electropositivity, low ionization energy, and excellent photosensitivity.

[0005] With the surge in global demand for new energy, quantum computing, and deep space exploration technologies, the supply and demand imbalance of rubidium resources is becoming increasingly prominent.

[0006] Existing rubidium extraction technologies mainly include: calcination-leaching, a mature process adapted to complex mineral structures, which uses high-temperature calcination to break down the clay mineral structure, causing rubidium to dissociate from the silicate lattice and release the element into the liquid phase through leaching; however, this method requires continuous optimization of the calcination temperature and has high energy consumption; direct microextraction (CRME) can directly extract rubidium from solid clay minerals, utilizing the Ostwald ripening phenomenon, by contacting KCl salts in the clay with an oil-phase extractant (such as crown ether reagents), constructing ion diffusion channels through a saturated solution, and releasing rubidium ions encapsulated in the clay particles; this method is low-carbon and low-energy, but costly, and the byproducts generated during extraction are difficult to handle; and ion exchange, which uses modified clay minerals or synthetic adsorbents to selectively enrich rubidium. This method has high selectivity and is green and low-carbon, but research and development costs are huge, adsorbent loss is high, and it is difficult to reuse, making it difficult to promote on a large scale for industrial production. Although the above-mentioned processes can extract rubidium from potash ore, each has its own advantages and disadvantages. When adopting different methods, the specific conditions of the production site should be taken into account to maximize industrial value under controllable costs.

[0007] In recent years, geological exploration results in the Mahai Basin of Qinghai Province have revealed that rubidium is abundant and its reserves are enormous in saline lake clay. As a novel carrier of rubidium resources, saline lake clay, due to its vast reserves and comprehensive development potential, has become an important direction for solving the resource dilemma. However, rubidium is often adsorbed in ionic form within the crystal lattice of clay minerals (such as illite), or forms complex salt solid solutions with alkali metals such as potassium and cesium, leading to the failure of physical separation and necessitating chemical leaching or ion exchange technologies, which are costly. Existing rubidium extraction processes are typically energy-intensive, highly polluting, and mostly designed for brine, resulting in low leaching rates and selectivity for clay solid phase resources. Therefore, conducting research on rubidium extraction from sedimentary saline lake clay in the Mahai area has significant practical implications. Summary of the Invention

[0008] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a rubidium extraction process from sedimentary gray-green salt lake clay.

[0009] The purpose of this invention is to provide a process for extracting rubidium from sedimentary gray-green salt lake clay, comprising the following steps: crushing and sieving the sedimentary gray-green salt lake clay, then impregnating the fine particles in a leaching agent, and filtering to obtain a leachate containing rubidium; wherein the leaching agent is prepared by mixing concentrated hydrochloric acid, low-mineralized water and sodium sulfate, the volume fraction of concentrated hydrochloric acid is 30%~50%, and the liquid-to-solid ratio of low-mineralized water to sodium sulfate is 30 mL:1 g; the low-mineralized water is natural water from the Mahai Basin.

[0010] Furthermore, the leaching temperature is 25℃~55℃.

[0011] Furthermore, the leaching temperature is 40℃~55℃.

[0012] Furthermore, the soaking time is 15 min to 60 min.

[0013] Furthermore, the soaking time is 35 min to 45 min.

[0014] Furthermore, the liquid-to-solid ratio of the leaching agent and the sedimentary gray-green salt lake clay is 3-6:1.

[0015] Furthermore, the leaching temperature is 40℃~55℃, the leaching time is 35min~45min, the liquid-solid ratio of the leaching agent and the sedimentary gray-green salt lake clay is 3-5:1, and the volume ratio of concentrated hydrochloric acid and low-mineralized water is 40%~50%.

[0016] Furthermore, ultrasonic treatment is used to assist impregnation under constant temperature conditions.

[0017] Furthermore, the particle size of the fine particles is 80-400 mesh.

[0018] This invention addresses the challenges of scarce freshwater resources and high clay salinity by proposing an environmentally friendly and efficient rubidium extraction process. It utilizes low-mineralized water from the Mahai Basin, local mirabilite resources, and a composite leaching agent prepared with concentrated hydrochloric acid. The key mechanism is as shown in Tables 2 and 3: after the concentrated hydrochloric acid, low-mineralized water, and mirabilite are combined, the low-mineralized water acts as a dilution medium for the leaching agent, significantly reducing the concentration of impurity ions in the initial leaching system. Simultaneously, the low-mineralized water reacts with the Na+ in the mirabilite. + Rubidium leaching rate can be improved by participating in competitive exchange during subsequent leaching processes. Additionally, when preparing leaching agents, the Ca²⁺ content in low-mineralized water... + The cations will react with Glauber's salt to produce SO4²⁻ - The combination of these ions into precipitates significantly reduces their concentration in the compound leaching agent. This mitigates the negative impact of these ions competing with rubidium ions for adsorption sites during the leaching stage, thereby improving the rubidium leaching effect. Simultaneously, careful control of the amount of sodium sulfate added is maintained at a low level to avoid excessive sulfate ions forming large amounts of precipitate with impurity ions, which would negatively impact the leaching effect. The amount of sodium sulfate added is determined based on the precipitation-dissolution equilibrium principle and calculated according to the calcium ion content in low-mineralized water.

[0019] Rubidium was extracted using a composite leaching agent of low-mineralized water, concentrated hydrochloric acid, and sodium sulfate, releasing rubidium ions through acid hydrolysis and ion exchange. On one hand, concentrated hydrochloric acid, as a strong acid, releases H+ ions... + This disrupts the crystal structure of clay minerals, causing rubidium (Rb) to be released from silicate, aluminate, and other minerals, while Cl...- Can be replaced by Rb + They combine to form the soluble salt RbCl, which has extremely high solubility, far exceeding that of other rubidium salts (such as sulfates), and can bind Rb... + It exists stably in the leachate and prevents re-adsorption or precipitation; on the other hand, clay minerals (such as montmorillonite and illite) have a layered structure and cation exchange capacity, naturally adsorbed Rb + Through H + Na + Competition for rubidium into the solution via exchange, thereby enabling the extraction of rubidium (e.g., through the exchange of rubidium with other molecules). Figure 2 ).

[0020] In summary, this study proposes a novel process for directly extracting rubidium from sedimentary gray-green saline lake clay. Through orthogonal leaching experiments to optimize extraction conditions, a novel extraction process and key parameters suitable for this type of clay in the Mahai area of ​​Qinghai Province were established for the first time. The heat of reaction during the preparation of the leaching agent was innovatively utilized to enhance the subsequent leaching process, thereby improving the rubidium leaching efficiency and achieving cascaded energy utilization. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention;

[0022] Figure 2 This is a schematic diagram of ion exchange. Detailed Implementation

[0023] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0024] Clay sample preparation

[0025] Random sampling was used to collect samples of gray-green salt lake clay from different sampling points. The required number of samples were selected using a random sampling table. The collected samples were then spread out, mixed, and thoroughly dried before being stored for later use. The clay samples were coarsely crushed in a jaw crusher, then finely crushed using a mortar and pestle, and finally passed through a 200-mesh standard sieve. The resulting clay was used as the leaching sample.

[0026] Table 1 Relationship between sample particle size and Rb content

[0027]

[0028] As shown in Table 1, the smaller the sample particle size, the higher the Rb content. This is especially true in the particle size range below 200 mesh, where the Rb content increases significantly, indicating that fine particles have a more pronounced enrichment effect on Rb. Optimizing the sample particle size can effectively improve the Rb leaching efficiency, laying the foundation for subsequent leaching processes.

[0029] Preparation of leaching agent

[0030] According to experimental requirements, a compound leaching agent consisting of concentrated hydrochloric acid (37%), low-mineralized water, and Glauber's salt was prepared. The liquid-to-solid ratio of low-mineralized water to Glauber's salt was 30 mL:1 g. Therefore, when the volume fraction of concentrated hydrochloric acid in the leaching agent was 20%, 30%, 40%, and 50%, the corresponding Glauber's salt dosages were 26.67 g / L, 23.33 g / L, 20 g / L, and 16.67 g / L, respectively. Taking the preparation of a compound leaching agent with a volume fraction of 20% concentrated hydrochloric acid as an example:

[0031] Take 2000 mL of low-mineralization water in a volumetric flask, add 66.67 g of sodium sulfate, and then slowly add a total of 500 mL of concentrated hydrochloric acid in several portions to the volumetric flask to obtain the leaching solvent required for acid leaching. The solution temperature was measured to be 51℃ at this point. Since temperature promotes the leaching effect during the leaching process, the heat generated during the preparation of the leaching solvent can be used for subsequent leaching, improving energy utilization and saving costs.

[0032] Table 2. Composition and content of low-mineralized water

[0033]

[0034] According to the data in Tables 2 and 3, the rubidium content in the leaching solution decreased after adding concentrated hydrochloric acid and sodium sulfate to low-mineralized water to prepare a compound leaching agent, and the decrease trend was increasing with the increase of hydrochloric acid concentration. This indicates that the addition of concentrated hydrochloric acid can reduce the initial rubidium content in low-mineralized water to a certain extent, thereby reducing its interference with the subsequent leaching process.

[0035] Table 3. Elemental composition and content of the solution after mixing concentrated hydrochloric acid, low-mineralized water, and Glauber's salt.

[0036]

[0037] Content detection:

[0038] Based on the testing requirements, rubidium in the leachate and leachate residue were tested separately. The laboratory developed corresponding analytical method protocols based on the sample properties and the requirements of the "Geological and Mineral Resources Laboratory Testing Quality Management Standard (DZ / T 0130-2006)" (hereinafter referred to as the "Standard").

[0039] 1) Standards and methods for testing immersion solutions:

[0040] Table 4. Analysis methods and standards for liquid samples

[0041]

[0042] Brief flowchart of the analysis method:

[0043] Accurately pipette 2.5 mL of the leachate sample into a 30 mL polytetrafluoroethylene crucible, place it on a constant temperature hot plate to heat and remove sulfuric acid, extract with HCl, and dilute to 100 mL in a volumetric flask. Plot a standard curve in 10% HCl medium using a mixed standard solution, determine Rb by ICP-MS, and automatically correct for matrix and spectral interferences by computer.

[0044] 2) Standards and methods for testing leaching residue:

[0045] Table 5. Analytical Methods and Standards for Solid Samples

[0046]

[0047] Brief flowchart of the analysis method:

[0048] Weigh 0.1000 g of sample, add 0.1000 g of buffer, grind evenly in a mortar, load into the electrode, use germanium as internal standard, and perform AC vertical polarity spectroscopy on the electrode. Use a CCD-I type powder solid sample arc emission spectrometer with automatic background removal to determine Rb.

[0049] Leaching conditions

[0050] Rubidium was extracted from halite clay, silty clay, grayish-brown clay, and grayish-green clay using a prepared leaching solution. An orthogonal experiment was conducted, selecting four factors: leaching temperature, leaching time, hydrochloric acid concentration, and liquid-to-solid ratio. Each factor had four levels, resulting in sixteen orthogonal experiments. The factor levels are shown in Table 6. The leaching products were analyzed, the leaching rate was calculated, and the optimal experimental ratio was selected. The liquid-to-solid ratio represents the ratio of the leachate volume to the clay sample mass; for example, 3:1 means leaching 100 g of sample with 300 mL of leachate.

[0051] Table 6. Factor Level Table for Orthogonal Experiment

[0052]

[0053] Leaching Experiment Procedure

[0054] like Figure 1 As shown, accurately weigh 100.00 g of dry clay sample into a 1 L beaker; add the leaching agent to the beaker while stirring; place the beaker in a heated ultrasonic cleaner, set the temperature and time conditions, and turn on the top-mounted stirrer to perform stirring and leaching. After the reaction is complete, immediately remove the beaker and use a circulating water vacuum pump to filter the leached suspension to separate the leachate from the leaching residue.

[0055] Leaching rate calculation

[0056]

[0057] Examples and Comparative Examples

[0058] To compare the leaching effects of different solvents, orthogonal leaching experiments were conducted on gray-green salt lake clay using three solvents: low-mineralized water, concentrated hydrochloric acid plus fresh water, and concentrated hydrochloric acid plus low-mineralized water plus Glauber's salt, with the type of solvent as the variable. The aim was to investigate the influence of the solvent on the final leaching effect of the rubidium extraction process. The leaching results are as follows: L represents low-mineralized water, M represents Glauber's salt, D represents fresh water, SY represents halite layer clay, FS represents silty sand layer clay, HH represents gray-brown clay, HL represents gray-green clay, and C represents hydrochloric acid. For example, LM-HL-C represents a series of orthogonal experiments conducted using a mixture of hydrochloric acid, low-mineralized water, and Glauber's salt as the solvent for leaching gray-green clay.

[0059] Case 1:

[0060] Table 7. Orthogonal experimental results of water-soluble gray-green clay with low mineralization

[0061]

[0062] As can be seen from the data in Table 7, the leaching rates of the 16 orthogonal experiments were all relatively low, with a maximum of 5.41% and an average of 2.79%. Changes in experimental conditions had little impact on the leaching rate, and rubidium in the leachate may have been adsorbed onto the leaching residue, leading to the low leaching rate. Therefore, using only low-mineralized water as a solvent to extract rubidium from gray-green salt lake clay is ineffective.

[0063] Case 2:

[0064] Table 8. Results of orthogonal experiments on the dissolution of gray-green clay with concentrated hydrochloric acid and fresh water.

[0065]

[0066] Table 8 shows the results of an orthogonal experiment using concentrated hydrochloric acid and fresh water as the leaching solvent. The table shows that the highest leaching rate for rubidium was 11.95%, with an average leaching rate of 8.30%. Comparison with Case 1 reveals that the addition of concentrated hydrochloric acid enhances the leaching effect of rubidium, indicating that strong acids can release H₂O. + This disrupts the crystal structure of clay minerals, releasing rubidium from silicates, aluminates, or other minerals, while Cl... - Can be replaced by Rb + Combined to form the soluble salt RbCl, making Rb + It exists stably in the leachate and prevents re-adsorption or precipitation, thereby improving the leaching rate.

[0067] Case 3:

[0068] Orthogonal leaching experiments were conducted on gray-green clay using a compound leaching agent of concentrated hydrochloric acid, low-mineralized water, and Glauber's salt. Under different volume fractions of concentrated hydrochloric acid (20%, 30%, 40%, and 50%), the corresponding Glauber's salt dosages were 26.67 g / L, 23.33 g / L, 20 g / L, and 16.67 g / L, respectively.

[0069] Table 9. Results of orthogonal experiments on the leaching of gray-green clay with concentrated hydrochloric acid, low-mineralized water, and sodium sulfate.

[0070]

[0071] Table 9 shows that rubidium had the highest leaching rate at 18.89%, with an average leaching rate of 14.06%. A comparison of Case 1 and Case 2 reveals that the overall leaching effect was improved when concentrated hydrochloric acid, sodium sulfate, and low-mineralized water were used simultaneously, with the average leaching rate increasing from 2.79% to 14.06%. This indicates that the sodium sulfate in the low-mineralized water and sodium sulfate... + Rb can be naturally adsorbed through competitive exchange. + It can enter the leachate, promoting the extraction of rubidium; and the SO4²⁻ in Glauber's salt - It can react with Ca in low-mineralized water 2+ The formation of precipitates by cations prevents these ions from affecting the H+ ions during the leaching process. + Na + The competitive exchange process of rubidium, etc., can increase the leaching rate of rubidium.

[0072] The data comparison of the above cases shows that different leaching conditions have a significant impact on the leaching rate of rubidium. Among them, Case 3 (using a leaching agent composed of concentrated hydrochloric acid, low-mineralized water, and sodium sulfate) exhibits the best leaching effect. Based on the successful experience of Case 3, this invention further selects this leaching agent (concentrated hydrochloric acid, low-mineralized water, and sodium sulfate) and conducts orthogonal experimental analysis on clays of different layers, aiming to systematically explore the leaching effect of this leaching agent on rubidium in clays of different layers.

[0073] An Investigation into the Leaching Effects of a Composite Leaching Agent Combining Concentrated Hydrochloric Acid, Glauber's Salt, and Low-Mineralized Water on Different Clays

[0074] The leaching effects of halite clay, silty clay, and grayish-brown clay were studied and compared with the leaching results of grayish-green clay to explore the leaching effect of compound leaching agents on clays of different layers.

[0075] Case 4:

[0076] An orthogonal leaching experiment was conducted on halite clay using a compound leaching agent made of concentrated hydrochloric acid, low-mineralized water, and mirabilite. The amount of mirabilite used in this case was consistent with that in Case 3.

[0077] Table 10 Results of orthogonal experiments on halite layer clay

[0078]

[0079] Table 10 presents the orthogonal experimental results of leaching halite clay using a compound solvent of concentrated hydrochloric acid, sodium sulfate, and low-mineralization water. The data shows that the average Rb content in the leaching residue was 96.81 μg / g, while the average Rb content in the leachate was 2.77 μg / mL. The highest rubidium leaching rate was 15.85%, and the average leaching rate was 11.10%. This indicates that the compound solvent of hydrochloric acid, low-mineralization water, and sodium sulfate can effectively extract rubidium from halite clay. However, its overall leaching effect is slightly worse than that of gray-green clay, presumably because the halite clay contains a higher content of other salt minerals, which hinders the leaching of rubidium during the leaching process.

[0080] Case 5:

[0081] An orthogonal leaching experiment was conducted on silty clay layers using a compound leaching agent made of concentrated hydrochloric acid, low-mineralized water, and sodium sulfate. The amount of sodium sulfate used in this case was consistent with that in Case 3.

[0082] Table 11 Results of orthogonal experiments on silty clay layers

[0083]

[0084] Table 11 shows the orthogonal experimental results of leaching silty clay layers using a compound solvent of concentrated hydrochloric acid, sodium sulfate, and low-mineralization water. The data shows that the average Rb content in the leaching residue was 105.77 μg / g, while the average Rb content in the leachate was 2.46 μg / mL. The highest rubidium leaching rate was 12.07%, and the average leaching rate was 8.97%. This indicates that the compound solvent of concentrated hydrochloric acid, low-mineralization water, and sodium sulfate can extract rubidium from clay minerals in silty clay layers. However, the overall leaching effect is worse than that of grayish-green clay, presumably because the silty layer, similar to the halite layer, contains a relatively high amount of silt and salt minerals, which hinder rubidium leaching.

[0085] Case Six:

[0086] An orthogonal leaching experiment was conducted on grayish-brown clay using a compound leaching agent made of concentrated hydrochloric acid, low-mineralized water, and sodium sulfate. The amount of sodium sulfate used in this case was consistent with that in Case 3.

[0087] Table 12 Results of orthogonal experiments on gray-brown clay

[0088]

[0089] Table 12 shows the orthogonal experimental results of leaching grayish-brown clay using a compound solvent of concentrated hydrochloric acid, sodium sulfate, and low-mineralization water. The data shows that the average Rb content in the leaching residue was 89.35 μg / g, while the average Rb content in the leachate was 2.21 μg / mL. The highest rubidium leaching rate was 17.11%, and the average leaching rate was 9.39%. This indicates that the compound solvent of hydrochloric acid, low-mineralization water, and sodium sulfate can extract rubidium from grayish-brown clay minerals. However, its overall leaching effect is worse than that of grayish-green clay, possibly because grayish-brown clay contains a higher content of hematite (Fe2O3), forming a "rubidium-iron mineral" complex that can block acid contact, thus reducing the rubidium leaching effect.

[0090] Comparative analysis of the orthogonal experimental data (Tables 10-12) and Table 9 of Case 3 shows that: rubidium in other layers of salt lake clay can be leached using a compound solvent of concentrated hydrochloric acid, sodium sulfate, and low-mineralization water, but the overall leaching effect is not as good as that of gray-green clay. Under the same leaching conditions, the rubidium leaching effect in gray-green clay is the best, with a leaching rate of up to 18.89%, which is 19.2%, 56.5%, and 10.4% higher than that in halite clay, silt clay, and gray-brown clay, respectively.

[0091] In summary, this study proposes a novel process for directly extracting rubidium from sedimentary gray-green saline lake clay. Through orthogonal leaching experiments to optimize extraction conditions, a novel extraction process and key parameters suitable for this type of clay in the Mahai area of ​​Qinghai Province were established for the first time. The heat of reaction during the preparation of the leaching agent was innovatively utilized to enhance the subsequent leaching process, thereby improving the rubidium leaching efficiency and achieving cascaded energy utilization. This process balances the needs of industrial production efficiency and environmental protection in the Mahai area, and has promising prospects for regional application.

[0092] For any points not covered above, existing technologies shall apply.

[0093] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for the recovery of rubidium from a sedimentary type of greyish-green salt lake clay, characterized in that, The process includes the following steps: crushing and sieving sedimentary gray-green salt lake clay, then impregnating the fine particles in a leaching agent, and filtering to obtain a leachate containing rubidium; wherein, the leaching agent is prepared by mixing concentrated hydrochloric acid, low-mineralized water and mirabilite, with the volume fraction of concentrated hydrochloric acid being 30%~50%, and the liquid-to-solid ratio of low-mineralized water to mirabilite being 30 mL:1 g; the low-mineralized water is natural water from the Mahai Basin.

2. A process for the recovery of rubidium from a sedimentary type of greyish-green salt lake clay as claimed in claim 1 wherein, Leaching temperature: 25℃~55℃.

3. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, Leaching temperature: 40℃~55℃.

4. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, Soaking time: 15 min to 60 min.

5. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, Soaking time: 35-45 minutes.

6. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, The liquid-solid ratio of the leaching agent to the sedimentary gray-green salt lake clay is 3-6:

1.

7. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, Leaching temperature: 40℃~55℃, immersion time: 35min~45min, liquid-solid ratio of leaching agent to sedimentary gray-green salt lake clay: 3-5:1, volume ratio of concentrated hydrochloric acid to low-mineralized water: 40%~50%.

8. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, Ultrasonic treatment was used to assist impregnation under constant temperature conditions.

9. The rubidium extraction process from sedimentary gray-green salt lake clay as described in claim 1, characterized in that, The particle size of the fine particles is 80-400 mesh.

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