A new process for extracting lithium from brine by utilizing temperature difference

Abstract

A new process for extracting lithium from brine using temperature difference. The method prepares a composite lithium extraction adsorbent with high lithium selectivity by high-temperature calcination, lithium removal, and heat effect material loading of raw materials, and extracts lithium from salt lake brine using natural temperature difference. The process is simple, has high resource utilization rate, is suitable for lithium extraction from salt lake brine in high-altitude areas with large daily temperature difference, and has good economic benefits. The method is expected to alleviate the current situation of lithium resource shortage caused by the rapid development of lithium battery industry.

Description

Technical Field

[0001] This application relates to the field of lithium extraction technology from salt lakes, and more specifically, to a process for extracting lithium from salt lake brine using temperature differences. Background Technology

[0002] Lithium, the lightest metallic element in the periodic table, is one of the 24 strategic minerals listed by the state. Due to its excellent properties, it is widely used in nuclear industry, new energy, new materials, and pharmaceuticals. In recent years, with the gradual depletion of global fossil fuels, leading to rising oil prices and strong promotion and support for new energy industries, especially electric vehicles, by various countries, global lithium consumption is currently growing at a rate of 15% to 20% annually. This still cannot meet future market demand, resulting in a continuous rise in the price of lithium carbonate, a midstream product in the lithium industry chain, causing market supply shortages and potentially impacting national strategic security. my country's new energy industry is developing rapidly. In 2023, my country's new energy power battery production capacity accounted for 60% of the world's total, and its new energy vehicle production capacity reached half of the world's total, essentially achieving the national strategy of leapfrogging development in the new energy vehicle industry.

[0003] Currently, my country's existing lithium extraction technology from salt lakes mainly relies on adsorption-coupled membrane processes. However, mainstream aluminum-based adsorbents suffer from low adsorption capacity, limited selectivity, and are only applicable to lithium extraction from old brine, thus limiting their production capacity. Therefore, to support the national new energy development strategy, lithium extraction from salt lakes requires new technological breakthroughs, particularly in the technology and processes for lithium extraction from raw brine. Furthermore, most salt lakes in the Qinghai-Tibet Plateau region of China are located at high altitudes, with harsh natural conditions and a weak industrial base. Therefore, developing and utilizing natural energy for large-scale lithium extraction is the main direction for the large-scale deployment of lithium extraction technology from salt lakes.

[0004] Thermal energy, as one of the most widely available renewable energy sources, has enormous application potential. It is also a natural energy source that is easily overlooked. The temperature difference in high-altitude salt lake areas varies greatly throughout the day. If the temperature difference is used as energy to drive lithium extraction from salt lakes, it will be of great significance for lithium extraction in salt lake areas with harsh natural environments and limited industrial capabilities.

[0005] This invention utilizes temperature variations occurring in a salt lake over different time periods to induce spontaneous polarization in thermally active materials, thereby enabling lithium extraction from salt lake brine using natural temperature differences. This method is low-cost, offers significant environmental and economic benefits, and is of great practical importance for the development of lithium resources in high-altitude, difficult-to-mine salt lakes in my country and for safeguarding the national strategy of new energy lithium resources. Summary of the Invention

[0006] This invention provides a process for lithium extraction from brine using temperature differences. A novel lithium adsorbent with high lithium selectivity is prepared by mixing a lithium source, functional raw materials, and framework raw materials, followed by high-temperature calcination, delithiation, and loading with thermally effective materials. This process cleverly utilizes temperature differences to extract lithium resources from salt lake brine. The method is simple, has high resource utilization, and is suitable for lithium extraction from salt lake brine in high-altitude areas with large daily temperature differences. It offers good economic benefits and is expected to solve the problem of lithium extraction from salt lake brine in areas with harsh natural conditions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A process for extracting lithium from brine using temperature difference includes the following steps: I. After mixing lithium source, functional raw material A and framework raw material B in a certain mass ratio, the mixture is calcined to obtain a precursor. The precursor is ground and added to deionized water, and then stirred and ultrasonically dispersed at room temperature to obtain slurry I. II. Add the thermal effect material to slurry I, mix evenly and transfer to a reaction vessel for hydrothermal reaction. Separate the resulting mixture into solid and liquid, dry and grind to obtain solid powder I, and calcine solid powder I to obtain the adsorption precursor. III. The adsorption precursor from step II is ground and added to the eluent. After delithiation, the precipitate is washed and dried to obtain solid II, which is suitable for selective adsorption of lithium ions. IV. After uniformly mixing the solid II from step III with the conductive agent and binder in a solvent at a certain mass ratio, the mixture is coated onto a heat capture plate. The capture plate is then placed in the brine of a salt lake, thus enabling lithium extraction from the brine by utilizing the temperature difference.

[0008] In the process described above for extracting lithium from brine using temperature difference, preferably, the lithium source in step I is one or a mixture of two or more of lithium chloride, lithium carbonate, lithium bicarbonate, lithium phosphate, lithium acetate, lithium oxalate, or lithium hydroxide.

[0009] In the process of lithium extraction from brine using temperature difference as described above, preferably, the functional raw material A in step I is one or a mixture of two or more of the following: titanium chloride, manganese chloride, ferric chloride, cobalt chloride, nickel chloride, zirconium chloride, titanium dioxide, manganese oxide, nickel oxide, zirconium oxide, bismuth oxide, ferrous hydroxide, ferric hydroxide, ferric nitrate, titanium nitrate, manganese nitrate, titanium sulfate, manganese sulfate, and cobalt sulfate.

[0010] In the process described above for extracting lithium from brine using temperature difference, preferably, the skeletal raw material B in step I is one or a mixture of two or more of the following: silicon dioxide, lithium silicate, sodium silicate, lithium phosphate, lithium sulfide, sodium phosphate, and sodium sulfide.

[0011] In the process of lithium extraction in brine using temperature difference as described above, preferably, in step I, the mass ratio of lithium source, structural raw material A, and structural raw material B is 1:(0.5~3):(1~3.5), the calcination temperature is 300~750℃, and the calcination time is 2~16h.

[0012] In the process of extracting lithium from brine using temperature difference as described above, preferably, the thermal effect material in step II is barium strontium titanate, barium titanate, polyvinylidene fluoride, polyvinylidene fluoride, lithium tantalate, barium strontium niobate, zinc oxide, or tourmaline.

[0013] In the process of lithium extraction from brine using temperature difference as described above, preferably, the hydrothermal reaction temperature in step II is 90~240℃, and the reaction time is 1.5~16h; the calcination temperature is 200~600℃, and the reaction time is 1~12h.

[0014] In the process of lithium extraction from brine using temperature difference as described above, preferably, the eluent used in step III is one or a mixture of two or more of the following: citric acid, acetic acid, oxalic acid, hydrochloric acid, boric acid, phosphoric acid, hydrogen peroxide, sodium hypochlorite, sodium persulfate, and potassium persulfate, wherein the concentration of the solution reagent is 0.1–0.8 mol / L.

[0015] In the process of lithium extraction from brine using temperature difference as described above, preferably, in step IV, the conductive agent is at least one of conductive graphite, carbon fiber, and carbon nanotubes; the binder is at least one of polyvinylidene fluoride, polyurethane, epoxy resin, acrylate, polyvinyl alcohol, vinyl acetate, chlorinated rubber, styrene-butadiene rubber, or carboxymethyl cellulose; the solvent is at least one of N-methylpyrrolidone, dimethylacetamide, N,N-dimethylformamide, or dimethyl sulfoxide; the heat capture plate is made of one or more of aluminum, silver, copper, indium tin oxide, graphene, and carbon nanotubes; wherein the mass ratio of solid I, conductive agent, and binder is (1~5):(1~7.8):0.1.

[0016] In the process described above for extracting lithium from brine using temperature difference, preferably, the temperature difference between the two sides of the heat capture plate is 5~50℃.

[0017] In the process of lithium extraction from brine using temperature difference as described above, preferably, the adsorbent after lithium extraction by temperature difference can be delithiated in step III and recycled.

[0018] The present invention has the following advantages: The beneficial effects of this invention are that the method uses hydrothermal method, sintering method and acid leaching method to prepare high-quality composite lithium extraction adsorbent that can respond to temperature difference. It can efficiently utilize temperature difference to adsorb lithium resources in salt lake brine, is suitable for relatively harsh salt lake environment, and has good economic benefits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the coating process for a heat capture plate.

[0020] Figure 2 This is a process flow diagram for lithium extraction adsorbents.

[0021] Figure 3 The image shows the X-ray powder diffraction pattern of the lithium extraction adsorbent prepared in Example 1.

[0022] Figure 4 The image shows the X-ray powder diffraction pattern of the lithium extraction adsorbent prepared in Example 2.

[0023] Figure 5 The image shows the X-ray powder diffraction pattern of the lithium extraction adsorbent prepared in Example 3. Detailed Implementation

[0024] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Example

[0025] Lithium carbonate, ferric chloride, and sodium phosphate were mixed uniformly at a mass ratio of 1:2.0:1.5 and calcined at 500℃ for 5 hours to obtain a precursor. The precursor was ground and added to deionized water, and then stirred and ultrasonically dispersed at room temperature for 6 hours. Lithium tantalate was then added, and the uniformly mixed slurry was hydrothermally reacted at 90℃ for 2 hours. After solid-liquid separation and drying, it was calcined at 200℃ for 1.5 hours. After calcination, 30 mL of sodium persulfate was added for delithiation, thus preparing a lithium extraction material with selective adsorption. This material was then mixed uniformly with carbon fiber and polyvinylidene fluoride at a mass ratio of 3:2.8:0.1 in dimethyl sulfoxide, and finally coated onto a graphene film to obtain a lithium extraction material that can be directly applied to lithium extraction from raw brine using temperature changes. When this material was placed in salt lake brine, the adsorption capacity reached 24.32 mg / g after 5 days. This example used raw brine from Dongtai Jinaier Salt Lake, and its chemical composition analysis results are shown in Table 1.

[0026]

[0027] Example 2 Lithium chloride, manganese oxide, and lithium silicate were mixed uniformly at a mass ratio of 1:1.5:1.2 and calcined at 600℃ for 4 hours to obtain a precursor. The precursor was ground and added to deionized water, and then stirred and ultrasonically dispersed at room temperature for 4 hours. Zinc oxide and barium titanate composite materials were then added, and the uniformly mixed slurry was hydrothermally reacted at 120℃ for 2.5 hours. After solid-liquid separation and drying, it was calcined at 200℃ for 2 hours. After calcination, 60 mL of hydrochloric acid solution was added for delithiation, thus preparing a lithium extraction material with selective adsorption. This material was then mixed uniformly with carbon fiber and graphene composite materials and carboxymethyl cellulose at a mass ratio of 1:4:0.1 in N,N-dimethylformamide, and finally coated onto an indium tin oxide film to obtain a lithium extraction material that can be directly applied to lithium extraction from raw brine using temperature changes. When this material was placed in salt lake brine, the adsorption capacity reached 28.24 mg / g after 5 days. This example used raw brine from Zabuye Salt Lake, and its chemical composition analysis results are shown in Table 2.

[0028]

[0029] Example 3 Lithium bicarbonate, titanium sulfate, and lithium phosphate were mixed uniformly at a mass ratio of 1:1:2 and calcined at 400℃ for 6 hours to obtain a precursor. The precursor was ground and added to deionized water, and then stirred and ultrasonically dispersed at room temperature for 4 hours. Strontium barium titanate was then added, and the uniformly mixed slurry was hydrothermally reacted at 100℃ for 1.5 hours. After solid-liquid separation and drying, it was calcined at 200℃ for 3 hours. After calcination, 40 mL of hydrogen peroxide was added for delithiation, thus preparing a lithium extraction material with selective adsorption. This material was then mixed uniformly with conductive graphite and polyvinylidene fluoride at a mass ratio of 2:3.8:0.1 in N,N-dimethylformamide, and finally coated onto a carbon nanotube film to obtain a lithium extraction material that can be directly applied to lithium extraction from raw brine using temperature changes. When this material was placed in salt lake brine, the adsorption capacity reached 27.44 mg / g after 6 days. This example used raw brine from Yiliping Salt Lake, and its chemical composition analysis results are shown in Table 3.

[0030]

[0031] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A process for extracting lithium from brine using temperature difference, characterized in that, The method includes the following steps: I. A precursor is obtained by uniformly mixing a lithium source, functional raw material A, and framework raw material B in a certain mass ratio and then calcining the mixture. The precursor is then ground and added to deionized water, and stirred and ultrasonically dispersed at room temperature to obtain slurry I. The lithium source is one or a mixture of two or more of lithium bromide, lithium iodide, lithium chloride, lithium nitrate, lithium carbonate, lithium bicarbonate, lithium sulfate, lithium bisulfate, lithium phosphate, lithium dihydrogen phosphate, lithium acetate, lithium oxalate, or lithium hydroxide. Functional raw material A is manganese chloride, ferric chloride, ferrous chloride, nickel chloride, zirconium chloride, cobalt chloride, or bismuth chloride. The following are one or more of the following: titanium chloride, silver chloride, manganese oxide, iron oxide, ferrous oxide, nickel oxide, zirconium oxide, cobalt oxide, bismuth oxide, titanium dioxide, ferrous hydroxide, ferric hydroxide, nickel hydroxide, zirconium hydroxide, cobalt hydroxide, ferric nitrate, titanium nitrate, manganese nitrate, titanium sulfate, manganese sulfate, ferrous sulfate, ferric sulfate, cobalt sulfate, nickel sulfate, zirconium sulfate, bismuth sulfate, or tetrabutyl titanate; and the skeleton material B is one or more of the following: silicon dioxide, lithium silicate, sodium silicate, lithium phosphate, lithium sulfide, sodium phosphate, or sodium sulfide. II. The thermal effect material is added to slurry I, mixed evenly, and transferred to a reaction vessel for hydrothermal reaction. The resulting mixture is subjected to solid-liquid separation, dried, and ground to obtain solid powder I. Solid powder I is calcined to obtain the adsorption precursor. The thermal effect material is one or a mixture of two or more of the following: lead titanate, barium strontium titanate, barium titanate, lead zirconate titanate, lanthanum lead zirconate titanate, polyvinylidene fluoride, polyvinylidene fluoride, lithium tantalate, barium strontium niobate, zinc oxide, and tourmaline. III. The adsorption precursor from step II is ground and added to the eluent. After delithiation, the precipitate is washed and dried to obtain solid II. This solid is suitable for selective adsorption of lithium ions. The eluent is one or a mixture of two or more of the following: nitric acid, sulfuric acid, citric acid, acetic acid, oxalic acid, hydrochloric acid, boric acid, phosphoric acid, hydrogen peroxide, sodium hypochlorite solution, sodium persulfate solution, potassium persulfate solution, or ammonium persulfate solution. The concentration of the solution reagent is 0.1~1 mol / L. IV. After uniformly mixing the solid II, conductive agent, and binder from step III in a solvent at a certain mass ratio, the mixture is coated onto a heat capture plate. The capture plate is then placed in the brine of a salt lake, thus enabling lithium extraction from the brine by utilizing the temperature difference.

2. The process for extracting lithium from brine using temperature difference according to claim 1, characterized in that, In step I, the mass ratio of lithium source, functional raw material A and framework raw material B is 1:(0~4):(0~5), the calcination temperature is 100~1000℃, and the calcination time is 1~24h.

3. The process for extracting lithium from brine using temperature difference according to claim 1, characterized in that, In step II, the hydrothermal reaction temperature is 70~260℃ and the reaction time is 2~24h; the calcination temperature is 100~900℃ and the reaction time is 0.5~24h.

4. The process for extracting lithium from brine using temperature difference according to claim 1, characterized in that, In step IV, the conductive agent is at least one of carbon black, conductive graphite, carbon fiber, carbon nanotubes, and graphene; the binder is at least one of polyvinylidene fluoride, polyurethane, epoxy resin, acrylate, polyvinyl alcohol, shellac, vinyl acetate, chlorinated rubber, styrene-butadiene rubber, or carboxymethyl cellulose; the solvent is at least one of N-methylpyrrolidone, dimethylacetamide, N,N-dimethylformamide, triethyl phosphate, or dimethyl sulfoxide; the heat capture plate is made of one or more of aluminum, palladium, silver, copper, and indium tin oxide; and the mass ratio of solid II, conductive agent, and binder is (1~7):(1~10):0.

1.

5. The process for extracting lithium from brine using temperature difference according to claim 1, characterized in that, The temperature difference between the two sides of the heat capture plate is 3~75℃.

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