Method for producing and working silicon carbide micro-channel chip reactor for rapid lithium extraction from brine

Abstract

The present application relates to the quick lithium extraction of brine silicon carbide micro-channel chip reactor and its manufacturing and working method, the reactor includes the glass packaging unit provided with brine inlet and brine outlet, glass packaging unit is provided with two or more silicon carbide micro-channel chip working pole, silicon carbide micro-channel chip working pole is staggered and is spaced apart to form micro-channel, micro-channel is connected with quartz glass tube through connecting port, quartz glass tube is provided with stainless steel pestle, stainless steel pestle is provided with stainless steel pestle wire, stainless steel pestle wire extends to the outside of quartz glass tube, silicon carbide micro-channel chip working pole is provided with silicon carbide micro-channel chip wire, silicon carbide micro-channel chip wire extends to the outside of glass packaging unit.The present application realizes the large adsorption of lithium element through the design of silicon carbide adsorption material, the design of micro-channel chip reactor breaks through the mass transfer limitation of traditional macroscopic reactor, and the lithium enrichment speed is improved.

Description

Technical Field

[0001] This invention relates to a silicon carbide microchannel chip reactor and its fabrication method for rapidly concentrating and purifying lithium in the liquid phase, belonging to the field of microreactors in the hydrometallurgical industry. Background Technology

[0002] Hydrometallurgical lithium extraction is a metallurgical technique for extracting lithium from lithium-containing salt lake brines or concentrated brine from salt fields. my country has abundant lithium-rich salt lake brines, and in recent years, various hydrometallurgical technologies, such as physical combined membrane methods, physicochemical adsorption-desorption methods, ion exchange methods, chemical precipitation methods, and electrochemical electrodialysis methods, have received widespread attention and development in my country. Among these technologies, directional adsorption-desorption has advantages such as high directional adsorption capacity for lithium and simple operation, making it the most promising brine lithium extraction technology. However, current adsorbents generally suffer from complex regeneration processes and aging and shortened lifespan due to contamination by other cations. These drawbacks severely restrict the application of directional adsorption-desorption technology. Therefore, finding adsorbents with high directional adsorption equivalent, easy regeneration, and long service life has become an urgent problem to be solved.

[0003] From a reactor perspective, directional adsorption-desorption technology commonly utilizes various macroscopic reactors such as batch reactors and cross-flow reactors to extract lithium from brine. However, macroscopic reactors have significant drawbacks: First, lithium extraction often takes several hours or even days, greatly increasing the time cost of adsorption-desorption. This is primarily due to the low lithium concentration in Chinese brine (0.1–2.2 mg / ml), where the mass transfer process between the adsorbent and lithium ions in the brine is the main constraint on rapid lithium extraction in large-scale reactors. Second, during operation, backflushing, and activation, the instantaneous Reynolds number increases as the mobile phase (lithium-containing brine) passes through the stationary phase (adsorbent). The mobile phase passing through the adsorbent layer does not contact the stationary phase in a laminar or horizontal flow, but rather exhibits predominantly localized turbulence and other fluid states. This widespread localized turbulence and turbulence leads to physical wear on the materials, reducing the lifespan of the adsorbent and also increasing the economic cost of the lithium extraction process. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a silicon carbide microchannel chip reactor for rapid lithium extraction from brine and its fabrication method. This invention achieves high lithium adsorption capacity through the design of silicon carbide adsorbent materials; the microchannel chip reactor design overcomes the mass transfer limitations of traditional macroscopic reactors, thereby improving the lithium enrichment rate.

[0005] The technical solution of the present invention is as follows:

[0006] A silicon carbide microchannel chip reactor for rapid lithium extraction from brine includes a glass encapsulation unit with a brine inlet and a brine outlet. The glass encapsulation unit contains two or more silicon carbide microchannel chip working rods, which are staggered to form microchannels. The microchannels are connected to a quartz glass tube via connectors. A stainless steel pestle is placed inside the quartz glass tube, and the pestle is equipped with stainless steel pestle wires extending to the outside of the quartz glass tube. The silicon carbide microchannel chip working rods are equipped with silicon carbide microchannel chip wires extending to the outside of the glass encapsulation unit.

[0007] According to the present invention, preferably, the silicon carbide microchannel chip has 9 working rods; preferably, the spacing between adjacent silicon carbide microchannel chips is 1.5-2.0 mm.

[0008] According to the present invention, preferably, both the silicon carbide microchannel chip wire and the stainless steel rod wire are copper wires; more preferably, the diameter of the copper wire is 0.25 mm.

[0009] According to the present invention, preferably, the silicon carbide microchannel chip working rod is cuboid in shape; preferably, the stainless steel rod is cylindrical in shape; more preferably, the dimensions of the silicon carbide microchannel chip working rod are length × width × height = (98-99) mm × 1.5 mm × 1.5 mm.

[0010] According to the present invention, preferably, the silicon carbide microchannel chip is made of a composite material composed of tetravalent active Ti oxide groups, tetravalent active Mn oxides and silicon carbide.

[0011] Preferably, the tetravalent active Mn oxide is MnO2·0.5H2O or / and λ-MnO2, and the tetravalent active Ti oxide group is [H / Li]4Mn5O. 12 [H / Li]4Ti5O 12 Or / and [H / Li]2TiO3;

[0012] In the composite material, silicon carbide acts as a carrier and conductor, playing a supporting and anode role; the tetravalent active Mn oxide plays an adsorption role on Li, and the tetravalent active Ti oxide group plays an ion exchange role on Li.

[0013] According to the present invention, preferably, the silicon carbide microchannel chip working rod is prepared by the following method:

[0014] ① Prepare a mixed solvent by mixing anhydrous ethylene glycol and DMF at a volume ratio of 9-10:1. Then, add manganese alkydate and titanate salt as solutes to the mixed solvent at a molar ratio of Mn:Ti of 1-2:1, and control the concentration of Mn+Ti in the solution to be 0.8-1.0 mol / L. Melt the solution completely in an oil bath shaker at 120-125℃. When the solution is free of impurities and shows obvious Tyndall effect, the mother liquor A is obtained.

[0015] ② Keep the temperature of mother liquor A at 80-85℃, add silicon carbide to mother liquor A at a ratio of 250-300g / L; then use a 0.05-0.07mol / L LiCl aqueous solution as a guiding agent, and add the guiding agent at a volume ratio of guiding agent to mother liquor A of 1:20, and continue stirring for no less than 12h to obtain slurry B;

[0016] ③Aging slurry B at a constant temperature of 175℃ for more than 24 hours yields casting liquid C;

[0017] ④ Pour the casting liquid C into the ashless paper precast mold, then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①; Insert a wire into the ashless paper precast mold, with the wire 5mm away from the bottom.

[0018] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0019] ⑥ Transfer the ashless paper preform mold filled with precursor D directly into a sintering furnace with continuously supplied dry air, according to...

[0020] Lift

[0021] The temperature is increased to 580-600℃ at a rate of 2-3K / min, then held at that temperature for 3 hours. Dry air is then continuously introduced, and the temperature is reduced to room temperature at a rate of 2-3K / min to obtain the silicon carbide microchannel chip working rod.

[0022] According to the present invention, the preferred embodiment of the fabrication process of the silicon carbide microchannel chip working rod is as follows:

[0023] In step ①, the mixed solvent is prepared by mixing anhydrous ethylene glycol and DMF in a volume ratio of 10:1;

[0024] Preferably, the manganese alkyd and titanate salts are selected as manganese acetate (Mn(CH3COO)2) and tri-n-butyl titanate (Ti(OC4H9)4), respectively, and are added to a mixed solvent at a molar ratio of Mn:Ti of 1.5:1, with the Mn+Ti concentration in the solution controlled at 1.0 mol / L; and are fully melted in an oil bath shaker at 125°C.

[0025] In step ②, the temperature of mother liquor A is 85℃;

[0026] Preferably, the silicon carbide is oven-dried silicon carbide with a purity of 98% or higher and a mesh size of 10,000 (1.3 μm). The silicon carbide is added to the mother liquor A in 10 portions at a ratio of 250 g / L. Subsequently, a 0.06 mol / L LiCl aqueous solution is used as a guiding agent. After adding the guiding agent, the mixture is stirred continuously for 24 hours to obtain slurry B.

[0027] In step ④, the dimensions of the ashless paper prefabrication mold are length: width: height = 98-99mm: 1.5mm: 1.5mm; preferably, the wire is a copper wire with a diameter of 0.25mm and a length of 100mm;

[0028] In step ⑥, the ashless paper preform mold filled with precursor D is heated to 600℃ at a rate of 2K / min, then kept at that temperature for 3 hours, and then continuously circulated with dry air and cooled to room temperature at a rate of 2K / min.

[0029] According to the present invention, the silicon carbide microchannel chip is the smallest working unit of the silicon carbide microchannel chip reactor and also the core reaction site for rapid lithium extraction from brine. A stainless steel pestle and the silicon carbide microchannel chip form a DC loop regeneration circuit, which is essentially an electrolytic cell. The working rod of the silicon carbide microchannel chip serves as the anode of the electrolytic cell, connected to the positive terminal of the DC power supply; the stainless steel pestle, sealed in a quartz glass tube, serves as the cathode, connected to the negative terminal of the DC power supply; and the brine serves as the electrolyte. The DC loop regeneration circuit is used to maintain the activation and regeneration of the silicon carbide microchannel chip.

[0030] According to the present invention, a method for preparing the silicon carbide microchannel chip reactor for rapid lithium extraction from brine is also provided, comprising the following steps:

[0031] (1) Apply silane coupling agent to the upper and lower sides of the silicon carbide microchannel chip working rod, with the side of the silicon carbide microchannel chip working rod with the exposed wire facing outward, and arrange them in an alternating manner between the upper and lower quartz glass layers; press the two quartz glass layers to maintain the adhesion between the silicon carbide microchannel chip working rod and the upper and lower quartz glass layers; then perform heat curing treatment at 150℃ to obtain the silicon carbide microchannel chip unit.

[0032] (2) Apply epoxy resin evenly around the silicon carbide microchannel chip unit, leaving a brine inlet and a brine outlet. The coating thickness is 1-1.5 mm. Place it in a dry and ventilated place to cure, and obtain a glass encapsulation unit containing a silicon carbide microchannel chip.

[0033] (3) Place the stainless steel pestle with the stainless steel pestle wire in the quartz glass tube, use a heat source to heat and soften the wall of the quartz glass tube, let the stainless steel pestle wire pass through the wall of the quartz glass tube, and bend the two ends of the quartz glass tube to obtain the two-end connection.

[0034] (4) At the lower end of the silicon carbide microchannel chip unit, a microchannel opening is located between the silicon carbide microchannel chips, and at the same time, a corresponding opening is made in the quartz glass tube on which the stainless steel pestle is placed; then the opening of the quartz glass tube corresponds one-to-one with the opening at the lower end of the silicon carbide microchannel chip unit and is sealed and connected to obtain the silicon carbide microchannel chip reactor for rapid lithium extraction from brine.

[0035] Use an injection pump to inject 20 kPa of clean water through the brine inlet. Once the silicon carbide microchannel chip unit and the quartz glass tube containing the stainless steel pestle are completely filled with clean water, seal the brine outlet and further increase the water pressure to 30 kPa and maintain it for 1 hour. If the pressure does not drop, the seal is complete.

[0036] According to the present invention, the silicon carbide microchannel chip reactor for rapid lithium extraction from brine can be used individually or in combination by connecting multiple silicon carbide microchannel chip reactors in parallel.

[0037] According to the present invention, the working process of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine is as follows:

[0038] ① Initial activation: Inject the silicon carbide microchannel chip reactor into a 0.1 mol / L LiCl solution with pH=6 for sealing and storage. Keep the silicon carbide microchannel chip reactor in a closed state. Connect the silicon carbide microchannel chip wire to the positive terminal of the power supply and the stainless steel rod wire to the negative terminal of the power supply. Activate the DC ring regeneration circuit with a power supply voltage of 2.0-2.2V and a current intensity of 50-60mA. When obvious bubbles appear in the silicon carbide microchannel chip, turn off the DC ring regeneration circuit.

[0039] ② The working process is divided into an adsorption process and a desorption process. The specific process is as follows: A pre-filtered lithium-containing brine is introduced into the silicon carbide microchannel chip reactor through the brine inlet using an injection pump, with a flow rate controlled at 5-10 mm / s. The residence time of the brine in the silicon carbide microchannel chip reactor is 80-160 s. After continuous operation for 80-160 minutes until Li concentration saturation is reached, the backflushing desorption process begins. At this time, clean water is introduced into the silicon carbide microchannel chip reactor through the brine outlet using an injection pump, with a flow rate controlled at 5-10 mm / s. The residence time of the clean water in the silicon carbide microchannel chip reactor is 80-160 s. After continuous operation for 8-16 minutes, the adsorption process begins again. One adsorption-desorption cycle includes 60 lithium adsorption cycles and 6 lithium desorption cycles, with one cycle lasting 88-176 minutes.

[0040] ③ After 3-5 consecutive cycles, the regeneration process begins. At this time, a syringe pump is used to inject lithium-containing brine as the electrolyte through the brine inlet, and the flow rate is set to 1.25 mm / s. The DC ring regeneration circuit is activated, and the power supply voltage is adjusted to 2.0-2.2V and the current intensity to 50-60mA. After 720s, the DC ring regeneration circuit is turned off to complete the activation, and then the working process begins.

[0041] According to the present invention, the preferred embodiment of the working process of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine is as follows:

[0042] ① Initial activation: Inject the silicon carbide microchannel chip reactor into a LiCl solution with pH=6 and a concentration of 0.1mol / L for sealing and storage. Keep the silicon carbide microchannel chip reactor in a closed state. Connect the silicon carbide microchannel chip wire to the positive terminal of the power supply and the stainless steel rod wire to the negative terminal of the power supply. Activate the DC ring regeneration circuit. The power supply voltage is 2.2V and the current intensity is 55mA. When obvious bubbles appear in the silicon carbide microchannel chip, turn off the DC ring regeneration circuit.

[0043] ② The working process is divided into an adsorption process and a desorption process. The specific process is as follows: The pre-filtered lithium-containing brine is introduced into the silicon carbide microchannel chip reactor through the brine inlet using an injection pump, and the flow rate is controlled at 5 mm / s. At this time, the residence time of the brine in the silicon carbide microchannel chip reactor is 160s. After continuous operation for 160 minutes to complete one adsorption process, the backwash desorption process begins. At this time, the clean water is introduced into the silicon carbide microchannel chip reactor through the brine outlet using an injection pump, and the flow rate is controlled at 8 mm / s. At this time, the residence time of the clean water in the silicon carbide microchannel chip reactor is 100s. After continuous operation for 10 minutes, the adsorption process begins again. One adsorption-desorption cycle includes 60 lithium adsorption cycles and 6 lithium desorption cycles, and one cycle is 170 minutes.

[0044] ③ After several cycles, the regeneration process begins. At this time, a syringe pump is used to inject lithium-containing brine as the electrolyte through the brine inlet and the flow rate is set to 1.25 mm / s. The DC ring regeneration circuit is activated and the power supply voltage is adjusted to 2.2V and the current intensity to 55mA. After 720s, the DC ring regeneration circuit is turned off to complete the activation and then the working process begins.

[0045] The principle of this invention:

[0046] The silicon carbide microchannel chip reactor of this invention enables rapid lithium extraction from brine through a process of directional adsorption-desorption of lithium ions present in the liquid phase. The specific mechanism is as follows:

[0047] (1) Preparation mechanism of Li element adsorbent: The supporting material of the working rod of silicon carbide microchannel chip is SiC as carrier and conductor. The substances that enrich Li in the working rod of silicon carbide microchannel chip are divided into two categories: tetravalent active Mn oxides such as MnO2·0.5H2O and λ-MnO2 that adsorb Li, and tetravalent active Ti oxide groups such as [H / Li]4Mn5O that exchange ions with Li. 12 [H / Li]4Ti5O 12 Substances such as [H / Li]₂TiO₃ are involved. These substances are formed via a sol-gel method (i.e., gel-solution method) to create an amorphous hydroxide intermediate. Subsequently, they form a stable intermediate @silicon carbide through chemical bonds with silicon carbide, which has a large specific surface area and strong hydroxyl binding capacity. Under thermally guided conditions at a programmed temperature of 580-600℃, the intermediate @silicon carbide undergoes dehydroxylation, i.e., (-OH + -OH → = O + H₂O), forming Mn oxide and Ti oxide groups. It is important to emphasize that the LiCl aqueous solution added during the preparation of the intermediate @silicon carbide acts as a guide agent, forming a Li ion intercalation and guiding the "memory effect" of the Ti oxide adsorbent. This is also the main factor contributing to the relatively high Li adsorption capacity of this invention.

[0048] (2) Excitation and regeneration of the adsorbent by the DC loop circuit: Since silicon carbide itself is a third-generation semiconductor material with a certain conductivity, the working rod of the silicon carbide microchannel chip is connected to the positive terminal (i.e., positive voltage) of the external power supply in the DC loop circuit to act as the anode of the electrolytic cell; the stainless steel rod is connected to the negative terminal (negative voltage) of the external power supply in the DC loop circuit to act as the cathode of the electrolytic cell; the brine acts as the electrolyte due to its conductivity. When the DC circuit is turned on, oxidation occurs at the anode. The hydroxyl radicals generated not only clean the silicon carbide microchannel chip in the early stage, but the oxygen generated also further flushes the working rod of the silicon carbide microchannel chip. At the same time, the overflow of oxygen reduces the pH of the microenvironment around the working rod of the silicon carbide microchannel chip, and the excess H enters the active Ti oxide group to replace the impurity M metal (including but not limited to Na, K, Ca and Mg) in [H / M], thus restoring it to the initial state.

[0049] (3) Microchannel chip reactor: The microchannel chip reactor has a small channel diameter, and due to the size effect, the brine flows in a laminar manner (Reynolds number R < 20). Therefore, it avoids the loss of adsorbent material caused by local turbulence or turbulence in traditional macro reactors. In addition, the microchannels greatly enhance the mass transfer effect of Li ions. This is the main factor that the microchannel chip reactor can shorten the reaction time.

[0050] The beneficial effects of this invention are:

[0051] 1. This invention achieves the adsorption of large amounts of lithium through the design of silicon carbide adsorption materials; the design of microchannel chip reactor breaks through the mass transfer limitations of traditional macroscopic reactors and improves the lithium enrichment rate.

[0052] 2. Based on the semiconductor characteristics of silicon carbide material, this invention simplifies the regeneration and activation process of the adsorbent material, effectively reducing regeneration and maintenance time. This achieves the overall goal of reducing the time, economic, and labor costs of lithium extraction from brine. This invention is not only applicable to extracting primary lithium-enriched solutions from lithium-containing salt lake brine or concentrated brine from salt fields, but also enables secondary concentration, purification, and refining of the extracted primary lithium-enriched solutions.

[0053] 3. The device of the present invention has the characteristics of compact structure, simple operation, good effect on lithium extraction from brine, short extraction time, simple regeneration and low maintenance cost. Furthermore, the structural design of silicon carbide microchannels overcomes the shortcomings of existing macroscopic reactors in terms of fluid, and has significant advantages in fluid mass transfer. Attached Figure Description

[0054] Figure 1 This is a top view of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to the present invention.

[0055] Figure 2This is a cross-sectional view along the AA direction of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to the present invention.

[0056] Figure 3 This is a schematic diagram of the adsorption process of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to the present invention.

[0057] Figure 4 This is a schematic diagram of the backflushing and desorption process of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to the present invention.

[0058] Figure 5 This is a SEM image of the silicon carbide microchannel chip preparation material for rapid lithium extraction from brine in Example 2 of the present invention.

[0059] Figure 6 This is a TEM image of the silicon carbide microchannel chip preparation material for rapid lithium extraction from brine in Example 2 of the present invention.

[0060] Figure 7 This is the TG-DTG curve of the casting liquid C in Example 2 of the present invention.

[0061] The components are: 1. Silicon carbide microchannel chip wire, 2. Silicon carbide microchannel chip working rod, 3. Brine outlet, 4. Glass encapsulation unit, 5. Brine inlet, 6. Stainless steel pestle wire, 7. Stainless steel pestle, 8. Connector, 9. Quartz glass tube, 10. Microchannel. Detailed implementation method:

[0062] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings, but this is not intended to limit the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of the present invention.

[0063] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0064] Example 1:

[0065] like Figure 1-2As shown, a silicon carbide microchannel chip reactor for rapid lithium extraction from brine includes a glass encapsulation unit 4 with a brine inlet 5 and a brine outlet 3. The glass encapsulation unit 4 contains two or more silicon carbide microchannel chip working rods 2, which are staggered to form microchannels 10. The microchannels 10 are connected to a quartz glass tube 9 via a connector 8. A stainless steel pestle 7 is placed inside the quartz glass tube 9, and the stainless steel pestle 7 is equipped with a stainless steel pestle wire 6 extending to the outside of the quartz glass tube 9. The silicon carbide microchannel chip working rods 2 are equipped with silicon carbide microchannel chip wires 1 extending to the outside of the glass encapsulation unit 4.

[0066] In this embodiment, there are nine silicon carbide microchannel chip working rods 2, and the spacing between adjacent silicon carbide microchannel chip working rods 2 is 1.5-2.0 mm. Both the silicon carbide microchannel chip wire 1 and the stainless steel rod wire 6 are copper wires with a diameter of 0.25 mm. The silicon carbide microchannel chip working rod 2 is cuboid in shape, and the stainless steel rod 7 is cylindrical. The dimensions of the silicon carbide microchannel chip working rod 2 are length × width × height = (98-99) mm × 1.5 mm × 1.5 mm.

[0067] In this embodiment, the silicon carbide microchannel chip working rod 2 is made of a composite material composed of tetravalent active Ti oxide groups, tetravalent active Mn oxides and silicon carbide.

[0068] The tetravalent active Mn oxide is MnO2·0.5H2O or / and λ-MnO2, and the tetravalent active Ti oxide group is [H / Li]4Mn5O. 12 [H / Li]4Ti5O 12 Or / and [H / Li]2TiO3;

[0069] In the composite material, silicon carbide acts as a support, while the tetravalent active Mn oxide adsorbs Li and the tetravalent active Ti oxide groups exchange ions with Li.

[0070] In this embodiment, the silicon carbide microchannel chip working rod 2 is prepared by the following method:

[0071] ① Prepare a mixed solvent by mixing anhydrous ethylene glycol and DMF at a volume ratio of 9-10:1. Then, add manganese alkydate and titanate salt as solutes to the mixed solvent at a molar ratio of Mn:Ti of 1-2:1, and control the concentration of Mn+Ti in the solution to be 0.8-1.0 mol / L. Melt the solution completely in an oil bath shaker at 120-125℃. When the solution is free of impurities and shows obvious Tyndall effect, the mother liquor A is obtained.

[0072] ② Keep the temperature of mother liquor A at 80-85℃, add silicon carbide to mother liquor A at a ratio of 250-300g / L; then use a 0.05-0.07mol / L LiCl aqueous solution as a guiding agent, and add the guiding agent at a volume ratio of guiding agent to mother liquor A of 1:20, and continue stirring for no less than 12h to obtain slurry B;

[0073] ③Aging slurry B at a constant temperature of 175℃ for more than 24 hours yields casting liquid C;

[0074] ④ Pour the casting liquid C into the ashless paper precast mold, then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①; Insert a wire into the ashless paper precast mold, with the wire 5mm away from the bottom.

[0075] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0076] ⑥ Transfer the ashless paper preform mold filled with precursor D directly to a sintering furnace with continuous dry air supply. Heat the mold to 580-600℃ at a heating rate of 2-3K / min, then hold it at that temperature for 3 hours. Then, continue to supply dry air and cool the mold to room temperature at a cooling rate of 2-3K / min to obtain the silicon carbide microchannel chip working rod 2.

[0077] Example 2:

[0078] The silicon carbide microchannel chip reactor for rapid lithium extraction from brine as described in Example 1 differs in that:

[0079] The raw material preparation ratios for the silicon carbide microchannel chip working rod 2 vary, and the specific preparation methods are as follows:

[0080] ① Mother liquor A: In a polytetrafluoroethylene bottle, anhydrous ethylene glycol and DMF are mixed in a volume ratio of 10:1. Then, manganese alkydate and titanate salt are added to the mixed solvent in a molar ratio of Mn:Ti of 1.5:1, while controlling the concentration of Mn+Ti in the solution to 1.0 mol / L. The polytetrafluoroethylene bottle is then sealed and fully melted in an oil bath shaker at 125°C. When the mixture is free of impurities and shows obvious Tyndall effect, metal mother liquor A is obtained.

[0081] ② Slurry B: While keeping mother liquor A in a closed mechanical stirrer and maintaining the temperature at 85℃, add oven-dried silicon carbide with a purity of 98% or higher and a mesh size of 10,000 (1.3μm) in 10 portions at a ratio of 250g / L to mother liquor A; then use a 0.06mol / L LiCl aqueous solution as a guiding agent and add it at a volume ratio of guiding agent to mother liquor A of 1:20. After adding the guiding agent, continue stirring for 24 hours to obtain slurry B.

[0082] ③ Casting liquid C: Seal slurry B in a tetrafluoroethylene bottle and transfer it to a constant temperature aging furnace at 175℃ for more than 24 hours to obtain casting liquid C.

[0083] ④ Pour the casting liquid C into a ashless paper precast mold with internal dimensions of length:width:height = 98.5mm:1.5mm:1.5mm. Then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①. At this time, insert a copper wire with a diameter of 0.25mm and a length of 98.5mm into the ashless paper precast mold, with the copper wire 10mm away from the bottom.

[0084] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0085] ⑥ The ashless paper preform mold filled with precursor D is directly transferred to a sintering furnace with continuous dry air supply. The temperature is increased to 600℃ at a heating rate of 2K / min, and then held for 3 hours. After that, dry air is continuously supplied, and the temperature is decreased to room temperature at a cooling rate of 2K / min. At this time, the silicon carbide microchannel chip working rod 2 is obtained.

[0086] ⑦ Use dry air to thoroughly blow away the residual ash from the burn-off of the ashless paper preform mold. Apply silane coupling agent to the upper and lower sides of the silicon carbide microchannel chip working rod 2, with the side of the silicon carbide microchannel chip working rod 2 with the exposed wires facing outwards. Arrange the two quartz glass layers in an alternating pattern. Press the two quartz glass layers to maintain the adhesion between the silicon carbide microchannel chip working rod 2 and the two quartz glass layers. Blow again with dry air at 45°C, and then heat-cur at 150°C to obtain the silicon carbide microchannel chip unit.

[0087] SEM and TEM images of the silicon carbide microchannel chip material prepared in this embodiment were tested, such as... Figure 5 , Figure 6 As shown. Figure 5 The corresponding SEM image shows the working layer of the silicon carbide microchannel chip. Observation reveals that the working layer of the silicon carbide microchannel chip material is dense, exhibiting excellent performance. Figure 6This is a TEM image of the silicon carbide microchannel chip during operation. The image shows that the extracted material is uniformly adsorbed on the silicon carbide microchannel chip.

[0088] The TG-DTG curve of the casting fluid C in this embodiment was tested, as shown in the figure. Figure 7 As shown.

[0089] Depend on Figure 7 It can be seen that the thermal analysis curves (TG-DTG) obtained at a heating rate β = 2 K / min show a weight loss of less than 0.32% before 400 K in the TG curve, while a slight weight loss peak appears in the DTG curve. The silicon carbide microchannel chip material exhibits slight weight loss due to the evaporation of absorbed water, which is caused by the strong hydroxyl affinity of the silicon carbide micromaterials themselves in the casting solution C. The main reaction zone occurs within the operating temperature range of 349 K to 673 K. The TG curve shows a significant weight loss (~22.5%). The DTG curve shows more precise details because two distinct DTG peaks appear sequentially and are connected by a shoulder, indicating that two reactions occur in this region. The partial overlap at the shoulder point indicates that two dehydration reactions occur in this weight loss region: evaporation of water of crystallization and dehydroxylation of -OH groups. This confirms that the active substances produced by heat treatment of Mn and Ti in the casting solution C exist in the form of metal oxides.

[0090] Example 3:

[0091] The preparation method of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine as described in Example 1 includes the following steps:

[0092] (1) Apply silane coupling agent to the upper and lower sides of the silicon carbide microchannel chip working rod 2, with the side of the silicon carbide microchannel chip working rod 2 with the exposed wire facing outward, and arrange them in an alternating manner between the upper and lower quartz glass layers; press the two quartz glass layers to maintain the adhesion between the silicon carbide microchannel chip working rod 2 and the upper and lower quartz glass layers; then perform heat curing treatment at 150℃ to obtain the silicon carbide microchannel chip unit;

[0093] (2) Epoxy resin is evenly coated around the silicon carbide microchannel chip unit, with brine inlet 5 and brine outlet 3 left. The coating thickness is 1-1.5 mm. The coating is then placed in a dry and ventilated place to cure, resulting in a glass encapsulation unit 4 encapsulating the silicon carbide microchannel chip working rod 2.

[0094] (3) Place the stainless steel pestle 7 with the stainless steel pestle wire 6 in the quartz glass tube 9, use a heat source to heat and soften the tube wall of the quartz glass tube 9, let the stainless steel pestle wire 6 pass through the quartz glass tube wall, and bend the two ends of the quartz glass tube 9 to obtain the two-end connection port 8.

[0095] (4) At the lower end of the silicon carbide microchannel chip unit, the microchannel 10 between the working rods 2 of the silicon carbide microchannel chip is opened, and at the same time, the corresponding position of the quartz glass tube 9 on which the stainless steel pestle 7 is placed is opened; then the opening of the quartz glass tube 9 corresponds one-to-one with the opening at the lower end of the silicon carbide microchannel chip unit and is closed and connected to obtain the silicon carbide microchannel chip reactor for rapid lithium extraction from brine.

[0096] Example 4:

[0097] like Figure 3-4 As shown, the working process of the silicon carbide microchannel chip reactor for rapid lithium extraction from brine prepared in Example 3 is as follows:

[0098] ① Initial activation: Inject the silicon carbide microchannel chip reactor into a LiCl solution with pH=6 and a concentration of 0.1mol / L for sealing and storage. Keep the silicon carbide microchannel chip reactor in a closed state. Connect the silicon carbide microchannel chip wire 1 to the positive terminal of the power supply and the stainless steel rod wire 6 to the negative terminal of the power supply. Activate the DC ring regeneration circuit. The power supply voltage is 2.2V and the current intensity is 55mA. When obvious bubbles appear on the silicon carbide microchannel chip working rod 2, turn off the DC ring regeneration circuit.

[0099] ② The working process is divided into an adsorption process and a desorption process. The specific process is as follows: The pre-filtered lithium-containing brine is introduced into the silicon carbide microchannel chip reactor through brine inlet 5 using an injection pump, and the flow rate is controlled at 5 mm / s. At this time, the residence time of the brine in the silicon carbide microchannel chip reactor is 160s. After continuous operation for 160 minutes to reach Li concentration saturation, the backflushing desorption process begins. At this time, the purified water is introduced into the silicon carbide microchannel chip reactor through brine outlet 3 using an injection pump, and the flow rate is controlled at 8 mm / s. At this time, the residence time of the purified water in the silicon carbide microchannel chip reactor is 100s. After continuous operation for 10 minutes, the adsorption process begins again. One adsorption-desorption cycle includes 60 lithium adsorption cycles and 6 lithium desorption cycles, and one cycle is 170 minutes.

[0100] ③ After three consecutive cycles, the regeneration process begins. At this time, a syringe pump is used to inject lithium-containing brine as the electrolyte through the brine inlet 5, and the flow rate is set to 1.25 mm / s. The DC ring regeneration circuit is activated, and the power supply voltage is adjusted to 2.2V and the current intensity to 55mA. After 720s, the DC ring regeneration circuit is turned off to complete the activation, and then the working process begins.

[0101] Performance Testing: Based on the conditions of the Qarhan Salt Lake in my country, a water sample with a lithium content of 0.29 g / L and a Mg:Li ratio of 280:1 was prepared to simulate the brine of the Qarhan Salt Lake. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine prepared in Example 3 was used to test the lithium extraction from the simulated brine. The theoretical lithium extraction yield was 41 mg Li / g Ads. Under these conditions, the lithium extraction concentration of the silicon carbide microchannel chip reactor was 28.83 mg Li / g Ads, and the lithium extraction workload was 70.31% of the theoretical lithium extraction yield.

[0102] Example 5:

[0103] The silicon carbide microchannel chip reactor for rapid lithium extraction from brine as described in Example 2 differs in that:

[0104] The raw material preparation ratios for the silicon carbide microchannel chip working rod 2 vary, and the specific preparation methods are as follows:

[0105] ① Mother liquor A: In a polytetrafluoroethylene bottle, anhydrous ethylene glycol and DMF are mixed in a volume ratio of 9:1. Then, manganese alkydate and titanate salt are added to the mixed solvent in a molar ratio of Mn:Ti of 2:1, while controlling the concentration of Mn+Ti in the solution to 1.0 mol / L. The polytetrafluoroethylene bottle is then sealed and fully melted in an oil bath shaker at 125°C. When the mixture is free of impurities and shows obvious Tyndall effect, metal mother liquor A is obtained.

[0106] ② Slurry B: While keeping mother liquor A in a closed mechanical stirrer and maintaining the temperature at 85℃, add oven-dried silicon carbide with a purity of 98% or higher and a mesh size of 10,000 (1.3μm) in 10 portions at a ratio of 250g / L to mother liquor A; then use a 0.06mol / L LiCl aqueous solution as a guiding agent and add it at a volume ratio of guiding agent to mother liquor A of 1:20. After adding the guiding agent, continue stirring for 24 hours to obtain slurry B.

[0107] ③ Casting liquid C: Seal slurry B in a tetrafluoroethylene bottle and transfer it to a constant temperature aging furnace at 175℃ for more than 24 hours to obtain casting liquid C.

[0108] ④ Pour the casting liquid C into a ashless paper precast mold with internal dimensions of length:width:height = 98.5mm:1.5mm:1.5mm. Then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①. At this time, insert a copper wire with a diameter of 0.25mm and a length of 98.5mm into the ashless paper precast mold, with the copper wire 10mm away from the bottom.

[0109] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0110] ⑥ The ashless paper preform mold filled with precursor D is directly transferred to a sintering furnace with continuous dry air supply. The temperature is increased to 600℃ at a heating rate of 2K / min, and then held for 3 hours. After that, dry air is continuously supplied, and the temperature is reduced to room temperature at a cooling rate of 2-3K / min. At this time, the silicon carbide microchannel chip working rod 2 is obtained.

[0111] ⑦ Thoroughly blow dry air onto the working rod E to remove residual ash from the burn-off of the ashless paper preform mold; apply silane coupling agent to the upper and lower sides of the silicon carbide microchannel chip working rod 2, with the side of the silicon carbide microchannel chip working rod 2 exposing the wires facing outwards, and arrange them in an alternating pattern between the upper and lower quartz glass layers, maintaining a lateral distance of 2.0 mm between the silicon carbide microchannel chip working rods 2, according to... Figure 1 The arrangement involves arranging the silicon carbide microchannel chip working rods 2 between two layers of quartz glass; using an elastic molding machine for initial pressing to maintain the adhesion between the silicon carbide microchannel chip working rods 2 and the two layers of quartz glass; then purging with dry air at 45-50℃, and then placing it in a vacuum drying oven at 150℃ for heat curing treatment, at which point the silicon carbide microchannel chip unit is obtained.

[0112] A silicon carbide microchannel chip reactor for rapid lithium extraction from brine was prepared according to the method in Example 3.

[0113] The specific working method of the silicon carbide microchannel chip reactor is as follows:

[0114] ① Initial activation: Keep the silicon carbide microchannel chip reactor in a closed state, activate the DC ring regeneration circuit and adjust the positive voltage of the silicon carbide microchannel chip working rod 2 to 2.2V and the current intensity to 55mA. When obvious bubbles appear on the silicon carbide microchannel chip working rod 2, turn off the DC ring regeneration circuit.

[0115] ② The adsorption process is as follows: the brine flow rate is controlled at 5 mm / s, the residence time is 160 s, and continuous operation for 160 min completes one adsorption process. The backflushing desorption process controls the flow rate at 8.0 mm / s, during which the brine residence time in the silicon carbide microchannel chip reactor is 100 s. After 10 min of continuous operation, the adsorption process resumes. One adsorption-desorption cycle consists of 60 lithium adsorption cycles and 6 lithium desorption cycles. One cycle is 170 min.

[0116] ③ After three consecutive cycles, the regeneration process begins. A DC ring regeneration circuit is used, and the connection voltage of the silicon carbide microchannel chip's working rod 2 is adjusted to 2.2V; the current intensity is 55mA.

[0117] Performance Testing: Based on the conditions of Taijinaier Salt Lake in my country, a water sample with a lithium content of 3.2 g / L and a Mg:Li ratio of 160:1 was prepared to simulate the brine of Taijinaier Salt Lake. A silicon carbide microchannel chip reactor for rapid lithium extraction from brine was used to test lithium extraction from the simulated brine. The theoretical lithium extraction yield was 42 mg Li / g Ads. Under these conditions, the lithium extraction concentration was 28.40 mg Li / g Ads, and the lithium extraction workload was 67.62% of the theoretical lithium extraction yield.

[0118] Example 6:

[0119] The silicon carbide microchannel chip reactor for rapid lithium extraction from brine as described in Example 5 differs in that:

[0120] The raw material preparation ratios for the silicon carbide microchannel chip working rod 2 vary, and the specific preparation methods are as follows:

[0121] ① Mother liquor A: In a polytetrafluoroethylene bottle, anhydrous ethylene glycol and DMF are mixed in a volume ratio of 10:1. Then, manganese alkyd salt and titanate salt are added to the mixed solvent in a molar ratio of Mn:Ti of 1.5:1, while controlling the concentration of Mn+Ti in the solution to 1.0 mol / L. The polytetrafluoroethylene bottle is then sealed and fully melted in an oil bath shaker at 125°C. When the mixture is free of impurities and shows obvious Tyndall effect, metal mother liquor A is obtained.

[0122] ② Slurry B: While keeping mother liquor A in a closed mechanical stirrer and maintaining the temperature at 85℃, add oven-dried silicon carbide with a purity of 98% or higher and a mesh size of 10,000 (1.3μm) in 10 portions at a ratio of 250g / L to mother liquor A; then use a 0.06mol / L LiCl aqueous solution as a guiding agent and add it at a volume ratio of guiding agent to mother liquor A of 1:20. After adding the guiding agent, continue stirring for 24 hours to obtain slurry B.

[0123] ③ Casting liquid C: Seal slurry B in a tetrafluoroethylene bottle and transfer it to a constant temperature aging furnace at 175℃ for more than 24 hours to obtain casting liquid C.

[0124] ④ Pour the casting liquid C into a ashless paper precast mold with internal dimensions of length:width:height = 98.5mm:1.5mm:1.5mm. Then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①. At this time, insert a copper wire with a diameter of 0.25mm and a length of 98.5mm into the ashless paper precast mold, with the copper wire 10mm away from the bottom.

[0125] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0126] ⑥ The ashless paper preform mold filled with precursor D is directly transferred to a sintering furnace with continuous dry air supply. The temperature is increased to 600℃ at a heating rate of 2K / min, and then held for 3 hours. After that, dry air is continuously supplied, and the temperature is reduced to room temperature at a cooling rate of 2-3K / min. At this time, the silicon carbide microchannel chip working rod 2 is obtained.

[0127] ⑦ Thoroughly purge the silicon carbide microchannel chip working rod 2 with dry air to remove residual ash from the burn-off of the ashless paper preform mold; apply silane coupling agent to both the upper and lower sides of the silicon carbide microchannel chip working rod 2, with the side of the silicon carbide microchannel chip working rod 2 exposing the wires facing outwards, and arrange them in an alternating pattern between the upper and lower quartz glass layers, maintaining a lateral distance of 2.0 mm between the silicon carbide microchannel chip working rods 2, according to... Figure 1 The arrangement involves arranging the silicon carbide microchannel chip working rods 2 between two layers of quartz glass; using an elastic molding machine for initial pressing to maintain the adhesion between the silicon carbide microchannel chip working rods 2 and the two layers of quartz glass; then purging with dry air at 45-50℃, and then placing it in a vacuum drying oven at 150℃ for heat curing treatment, at which point the silicon carbide microchannel chip unit is obtained.

[0128] A silicon carbide microchannel chip reactor for rapid lithium extraction from brine was prepared according to the method in Example 3.

[0129] The specific working method of the silicon carbide microchannel chip reactor is as follows:

[0130] ① Initial activation: Keep the silicon carbide microchannel chip reactor in a closed state, activate the DC ring regeneration circuit and adjust the positive voltage of the silicon carbide microchannel chip working rod 2 to 2.2V and the current intensity to 55mA. When obvious bubbles appear on the silicon carbide microchannel chip working rod 2, turn off the DC ring regeneration circuit.

[0131] ② The adsorption process is as follows: the brine flow rate is controlled at 6.4 mm / s, the residence time is 125 s, and continuous operation for 125 min completes one adsorption process. The backflushing desorption process controls the flow rate at 8 mm / s, during which the brine residence time in the silicon carbide microchannel chip reactor is 100 s. After 10 min of continuous operation, the adsorption process resumes. One adsorption-desorption cycle consists of 60 lithium adsorption cycles and 6 lithium desorption cycles. One cycle is 135 min.

[0132] ③ After three consecutive cycles, the regeneration process begins. A DC ring regeneration circuit is used, and the connection voltage of the silicon carbide microchannel chip's working rod 2 is adjusted to 2.2V; the current intensity is 55mA.

[0133] Performance Testing: Based on the conditions of Da Qaidam Salt Lake in my country, a water sample with a lithium content of 0.6 g / L and a Mg:Li ratio of 500:1 was prepared to simulate the brine of Da Qaidam Salt Lake. Using the silicon carbide microchannel chip reactor for rapid lithium extraction from brine prepared in this embodiment, lithium extraction tests were conducted on the simulated brine. The theoretical lithium extraction yield was 43.2 mg-Li / g-Ads. Under these conditions, the lithium extraction concentration was 31.11 mg-Li / g-Ads, and the lithium extraction workload was 72.01% of the theoretical lithium extraction yield.

[0134] Example 7:

[0135] The silicon carbide microchannel chip reactor for rapid lithium extraction from brine as described in Example 5 differs in that:

[0136] The raw material preparation ratios for the silicon carbide microchannel chip working rod 2 vary, and the specific preparation methods are as follows:

[0137] ① In a polytetrafluoroethylene bottle, anhydrous ethylene glycol and DMF are mixed in a volume ratio of 10:1. Then, manganese alkyd and titanate salts are added to the mixed solvent in a molar ratio of Mn:Ti of 1.5:1, while controlling the concentration of Mn+Ti in the solution to 1.0 mol / L. The polytetrafluoroethylene bottle is then sealed and fully melted in an oil bath shaker at 125°C. Metal mother liquor A is obtained when the mixture is free of impurities and exhibits a clear Tyndall effect.

[0138] ② While keeping the mother liquor A in a closed mechanical stirrer and maintaining the temperature at 85℃, add oven-dried silicon carbide with a purity of 98% or higher and a mesh size of 10,000 (1.3μm) in 10 portions at a ratio of 250g / L to mother liquor A; then use a 0.06mol / L LiCl aqueous solution as a guiding agent and add it at a volume ratio of guiding agent to mother liquor A of 1:20. After adding the guiding agent, continue stirring for 24 hours to obtain slurry B.

[0139] ③ Seal slurry B in a tetrafluoroethylene bottle and transfer it to a constant temperature aging furnace at 175℃ for more than 24 hours to obtain casting liquid C.

[0140] ④ Pour the casting liquid C into a ashless paper precast mold with internal dimensions of length:width:height = 98.5mm:1.5mm:1.5mm. Then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①. At this time, insert a copper wire with a diameter of 0.25mm and a length of 98.5mm into the ashless paper precast mold, with the copper wire 10mm away from the bottom.

[0141] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0142] ⑥ The ashless paper preform mold filled with precursor D is directly transferred to a sintering furnace with continuous dry air supply. The temperature is increased to 600℃ at a heating rate of 2K / min, and then held for 3 hours. After that, dry air is continuously supplied, and the temperature is reduced to room temperature at a cooling rate of 2-3K / min. At this time, the silicon carbide microchannel chip working rod 2 is obtained.

[0143] ⑦ Thoroughly purge the silicon carbide microchannel chip working rod 2 with dry air to remove residual ash from the burn-off of the ashless paper preform mold; apply silane coupling agent to both the upper and lower sides of the silicon carbide microchannel chip working rod 2, with the side of the silicon carbide microchannel chip working rod 2 exposing the wires facing outwards, and arrange them in an alternating pattern between the upper and lower quartz glass layers, maintaining a lateral distance of 2.0 mm between the silicon carbide microchannel chip working rods 2, according to... Figure 1 The arrangement involves arranging the silicon carbide microchannel chip working rods 2 between two layers of quartz glass; initial pressing is performed using an elastic molding machine to maintain the adhesion between the silicon carbide microchannel chip working rods 2 and the two layers of quartz glass; then, it is purged again with dry air at 45-50℃, and subsequently placed in a vacuum drying oven at 150℃ for thermosetting. This yields the silicon carbide microchannel chip unit.

[0144] A silicon carbide microchannel chip reactor for rapid lithium extraction from brine was prepared according to the method in Example 3.

[0145] The specific working method of the silicon carbide microchannel chip reactor is as follows:

[0146] ① Initial activation: Keep the silicon carbide microchannel chip reactor in a closed state, activate the DC ring regeneration circuit and adjust the positive voltage of the silicon carbide microchannel chip working rod 2 to 2.2V and the current intensity to 55mA. When obvious bubbles appear on the silicon carbide microchannel chip working rod 2, turn off the DC ring regeneration circuit.

[0147] ② The adsorption process is as follows: the brine flow rate is controlled at 8 mm / s, the residence time is 100 s, and continuous operation for 100 min completes one adsorption process. The backflushing desorption process is controlled at a flow rate of 8 mm / s, during which the brine residence time in the silicon carbide microchannel chip reactor is 100 s. After 10 min of continuous operation, the adsorption process resumes. One adsorption-desorption cycle consists of 60 lithium adsorption cycles and 6 lithium desorption cycles. One cycle is 110 min.

[0148] ③ After three consecutive cycles, the regeneration process begins. A DC ring regeneration circuit is used, and the connection voltage of the silicon carbide microchannel chip's working rod 2 is adjusted to 2.2V; the current intensity is 55mA.

[0149] Performance Testing: Based on the conditions of Zabuye Lake in my country, a water sample was prepared to simulate the brine of Zabuye Lake, with a lithium content of 1.12 g / L and a Mg:Li ratio of 0.024:1. Using the silicon carbide microchannel chip reactor for rapid lithium extraction from brine prepared in this embodiment, lithium extraction tests were conducted on the simulated brine. The theoretical lithium extraction yield was 42.5 mg-Li / g-Ads. Under these conditions, the lithium extraction concentration was 31.58 mg-Li / g-Ads, and the lithium extraction workload was 74.31% of the theoretical lithium extraction yield.

[0150] Example 8:

[0151] The silicon carbide microchannel chip reactor for rapid lithium extraction from brine as described in Example 5 differs in that:

[0152] The raw material preparation ratios for the silicon carbide microchannel chip working rod 2 vary, and the specific preparation methods are as follows:

[0153] ① In a polytetrafluoroethylene bottle, anhydrous ethylene glycol and DMF are mixed in a volume ratio of 10:1. Then, manganese alkyd and titanate salts are added to the mixed solvent in a molar ratio of Mn:Ti of 1.5:1, while controlling the concentration of Mn+Ti in the solution to 1.0 mol / L. The polytetrafluoroethylene bottle is then sealed and fully melted in an oil bath shaker at 125°C. Metal mother liquor A is obtained when the mixture is free of impurities and exhibits a clear Tyndall effect.

[0154] ② While keeping the mother liquor A in a closed mechanical stirrer and maintaining the temperature at 85℃, add oven-dried silicon carbide with a purity of 98% or higher and a mesh size of 10,000 (1.3μm) in 10 portions at a ratio of 250g / L to mother liquor A; then use a 0.06mol / L LiCl aqueous solution as a guiding agent and add it at a volume ratio of guiding agent to mother liquor A of 1:20. After adding the guiding agent, continue stirring for 24 hours to obtain slurry B.

[0155] ③ Seal slurry B in a tetrafluoroethylene bottle and transfer it to a constant temperature aging furnace at 175℃ for more than 24 hours to obtain casting liquid C.

[0156] ④ Pour the casting liquid C into a ashless paper precast mold with internal dimensions of length:width:height = 98.5mm:1.5mm:1.5mm. Then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure gas. After compression and liquefaction, the condensable gas can be reused in step ①. At this time, insert a copper wire with a diameter of 0.25mm and a length of 98.5mm into the ashless paper precast mold, with the copper wire 10mm away from the bottom.

[0157] ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained;

[0158] ⑥ The ashless paper preform mold filled with precursor D is directly transferred to a sintering furnace with continuous dry air supply. The temperature is increased to 600℃ at a heating rate of 2K / min, and then held for 3 hours. After that, dry air is continuously supplied, and the temperature is reduced to room temperature at a cooling rate of 2-3K / min. At this time, the silicon carbide microchannel chip working rod 2 is obtained.

[0159] ⑦ Thoroughly purge the silicon carbide microchannel chip working rod 2 with dry air to remove residual ash from the burn-off of the ashless paper preform mold; apply silane coupling agent to both the upper and lower sides of the silicon carbide microchannel chip working rod 2, with the side of the silicon carbide microchannel chip working rod 2 exposing the wires facing outwards, and arrange them in an alternating pattern between the upper and lower quartz glass layers, maintaining a lateral distance of 2.0 mm between the silicon carbide microchannel chip working rods 2, according to... Figure 1 The arrangement involves arranging the silicon carbide microchannel chip working rods 2 between two layers of quartz glass; initial pressing is performed using an elastic molding machine to maintain the adhesion between the silicon carbide microchannel chip working rods 2 and the two layers of quartz glass; then, it is purged again with dry air at 45-50℃, and subsequently placed in a vacuum drying oven at 150℃ for thermosetting. This yields the silicon carbide microchannel chip unit.

[0160] A silicon carbide microchannel chip reactor for rapid lithium extraction from brine was prepared according to the method in Example 3.

[0161] The specific working method of the silicon carbide microchannel chip reactor is as follows:

[0162] ① Initial activation: Keep the silicon carbide microchannel chip reactor in a closed state, activate the DC ring regeneration circuit and adjust the positive voltage of the silicon carbide microchannel chip working rod 2 to 2.2V and the current intensity to 55mA. When obvious bubbles appear on the silicon carbide microchannel chip working rod 2, turn off the DC ring regeneration circuit.

[0163] ② The adsorption process is as follows: the brine flow rate is controlled at 10 mm / s, the residence time is 80 s, and continuous operation for 80 minutes completes one adsorption process. The backflushing desorption process controls the flow rate at 8 mm / s, during which the brine residence time within the chip is 100 s. After 10 minutes of continuous operation, the adsorption process resumes. One adsorption-desorption cycle consists of 60 lithium adsorption cycles and 6 lithium desorption cycles. One cycle is 90 minutes.

[0164] ③ After three consecutive cycles, the regeneration process begins. A DC ring regeneration circuit is used, and the connection voltage of the silicon carbide microchannel chip's working rod 2 is adjusted to 2.2V; the current intensity is 55mA.

[0165] Performance Testing: Based on the conditions of Yiliping Salt Lake in my country, a water sample with a lithium content of 1.6 g / L and a Mg:Li ratio of 65:1 was prepared to simulate the brine of Yiliping Salt Lake. Using the silicon carbide microchannel chip reactor for rapid lithium extraction from brine prepared in this embodiment, lithium extraction tests were conducted on the simulated brine. The theoretical lithium extraction yield was 42 mg-Li / g-Ads. Under these conditions, the lithium extraction concentration was 30.38 mg-Li / g-Ads, and the lithium extraction workload was 72.34% of the theoretical lithium extraction yield.

Claims

1. A silicon carbide microchannel chip reactor for rapid lithium extraction from brine, characterized in that, The reactor includes a glass encapsulation unit with a brine inlet and a brine outlet. The glass encapsulation unit contains two or more silicon carbide microchannel chip working rods, which are staggered to form microchannels. The microchannels are connected to a quartz glass tube via connectors. A stainless steel pestle is placed inside the quartz glass tube, and the stainless steel pestle is equipped with stainless steel pestle wires that extend to the outside of the quartz glass tube. The silicon carbide microchannel chip working rods are equipped with silicon carbide microchannel chip wires that also extend to the outside of the glass encapsulation unit. The silicon carbide microchannel chip working rod is made of a composite material composed of tetravalent active Ti oxide groups, tetravalent active Mn oxides, and silicon carbide.

2. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to claim 1, characterized in that, The number of working rods in the silicon carbide microchannel chip is 3-9.

3. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to claim 1, characterized in that, The spacing between adjacent silicon carbide microchannel chip working rods is 1.5-2.0 mm.

4. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to claim 1, characterized in that, The silicon carbide microchannel chip wires and stainless steel rod wires are both copper wires.

5. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to claim 1, characterized in that, The silicon carbide microchannel chip working rod is rectangular, and the stainless steel pestle is cylindrical.

6. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to claim 1, characterized in that, The tetravalent active Mn oxide is MnO2·0.5H2O or / and λ-MnO2, and the tetravalent active Ti oxide group is [H / Li]4Mn5O. 12 [H / Li]4Ti5O 12 Or / and [H / Li]2 TiO3.

7. The silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to claim 6, characterized in that, The silicon carbide microchannel chip working rod is prepared by the following method: ① Prepare a mixed solvent using anhydrous ethylene glycol and DMF at a volume ratio of 9-10:1, followed by the addition of manganese alkyd and titanate salts. As a solute, add it to the mixed solvent at a molar ratio of Mn:Ti of 1-2:1, and control the concentration of Mn+Ti in the solution at 0.8-1.0 mol / L; melt the solution completely in an oil bath shaker at 120-125℃, and obtain mother liquor A when the solution is free of impurities and shows obvious Tyndall effect; ② Keep the temperature of mother liquor A at 80-85℃, and add silicon carbide to mother liquor A at a ratio of 250-300g / L; Follow Then, a LiCl aqueous solution with a concentration of 0.05-0.07 mol / L was used as a guiding agent, and the guiding agent was added at a volume ratio of 1:20 of the guiding agent to the mother liquor A. The mixture was stirred continuously for no less than 12 hours to obtain slurry B. ③Aging slurry B at a constant temperature of 175℃ for more than 24 hours yields casting liquid C; ④ Pour the casting liquid C into the ashless paper precast mold, then place it in a vacuum drying oven to dry under negative pressure and collect the negative pressure. The gas, after being compressed and liquefied, can be condensed and reused in step ①; insert a wire into the ashless paper prefabrication mold, with the wire 5mm away from the bottom end; ⑤ Repeat step ④ until the ashless paper precast mold can no longer be filled with casting liquid C, at which point the precursor D is obtained; ⑥ Transfer the ashless paper preform mold filled with precursor D directly into a sintering furnace with continuously supplied dry air, according to the lifting speed... The temperature is increased to 580-600℃ at a rate of 2-3K / min, then held at that temperature for 3 hours. Dry air is then continuously introduced, and the temperature is reduced to room temperature at a rate of 2-3K / min to obtain the silicon carbide microchannel chip working rod.

8. The method for preparing the silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to any one of claims 1-7, comprising the following steps: (1) Apply silane coupling agent to the upper and lower sides of the silicon carbide microchannel chip working rod, with the side of the silicon carbide microchannel chip working rod with the exposed wire facing outward, and arrange the silicon carbide microchannel chip working rod alternately between the upper and lower quartz glass layers; press the two quartz glass layers to maintain the adhesion between the silicon carbide microchannel chip working rod and the upper and lower quartz glass layers; then perform heat curing treatment at 150℃ to obtain the silicon carbide microchannel chip unit; (2) Apply epoxy resin evenly around the silicon carbide microchannel chip unit, leaving a brine inlet and a brine outlet. The coating thickness is 1-1.5 mm. Place it in a dry and ventilated place to cure, and obtain a glass encapsulation unit with a silicon carbide microchannel chip working rod. (3) Place the stainless steel pestle with the stainless steel pestle wire in the quartz glass tube, use a heat source to heat and soften the wall of the quartz glass tube, let the stainless steel pestle wire pass through the wall of the quartz glass tube, and bend the two ends of the quartz glass tube to obtain the two-end connection. (4) At the lower end of the silicon carbide microchannel chip unit, a microchannel opening is located between the working rods of the silicon carbide microchannel chip, and at the same time, a corresponding opening is made in the quartz glass tube on which the stainless steel pestle is placed; then the opening of the quartz glass tube corresponds one-to-one with the opening at the lower end of the silicon carbide microchannel chip unit and is closed and connected to obtain the silicon carbide microchannel chip reactor for rapid lithium extraction from brine.

9. The method of operating the silicon carbide microchannel chip reactor for rapid lithium extraction from brine according to any one of claims 1-7, comprising the following steps: ① Initial activation: Inject the silicon carbide microchannel chip reactor into a 0.1 mol / L LiCl solution with pH=6 for sealing and storage. Keep the silicon carbide microchannel chip reactor in a closed state. Connect the silicon carbide microchannel chip wire to the positive terminal of the power supply and the stainless steel rod wire to the negative terminal of the power supply. Activate the DC ring regeneration circuit with a power supply voltage of 2.0-2.2V and a current intensity of 50-60mA. When obvious bubbles appear in the silicon carbide microchannel chip, turn off the DC ring regeneration circuit. ② The working process is divided into an adsorption process and a desorption process. The specific process is as follows: A pre-filtered lithium-containing brine is introduced into the silicon carbide microchannel chip reactor through the brine inlet using an injection pump, with a flow rate controlled at 5-10 mm / s. The residence time of the brine in the silicon carbide microchannel chip reactor is 80-160 s. After continuous operation for 80-160 minutes until Li concentration saturation is reached, the backflushing desorption process begins. At this time, clean water is introduced into the silicon carbide microchannel chip reactor through the brine outlet using an injection pump, with a flow rate controlled at 5-10 mm / s. The residence time of the clean water in the silicon carbide microchannel chip reactor is 80-160 s. After continuous operation for 8-16 minutes, the adsorption process begins again. One adsorption-desorption cycle includes 60 lithium adsorption cycles and 6 lithium desorption cycles, with one cycle lasting 88-176 minutes. ③ After 3-5 consecutive cycles, the regeneration process begins. At this time, a syringe pump is used to inject lithium-containing brine as the electrolyte through the brine inlet, and the flow rate is set to 1.25 mm / s. The DC ring regeneration circuit is activated, and the power supply voltage is adjusted to 2.0-2.2V and the current intensity to 50-60mA. After 720s, the DC ring regeneration circuit is turned off to complete the activation, and then the working process begins.

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