Preparation method of medicinal lithium carbonate

Abstract

The invention belongs to the technical field of lithium carbonate preparation, and particularly relates to a preparation method of medicinal lithium carbonate. The preparation method comprises the following steps: adding industrial lithium carbonate slurry into a supergravity rotating bed filled with a functional filler, introducing carbon dioxide gas under stirring to carry out a hydrocarbon reaction, and carrying out solid-liquid separation on the obtained feed liquid to obtain a lithium bicarbonate solution; the functional filler is polyethyleneimine modified filler or ordered mesoporous activated carbon; and under an inert atmosphere, heating the lithium bicarbonate solution for decomposition reaction, carrying out solid-liquid separation on the obtained decomposed feed liquid, and drying the solid to obtain the medicinal lithium carbonate. The functional filler is adopted, the mass transfer performance of the functional filler can be improved, the reaction efficiency is improved, the hydrocarbon reaction conversion rate is high (can reach 99.3%), the prepared medicinal lithium carbonate is high in purity and yield, the particle size meets the medicinal requirement, and further crushing is not needed.

Description

Technical Field

[0001] This invention belongs to the field of lithium carbonate preparation technology, and specifically relates to a method for preparing pharmaceutical-grade lithium carbonate. Background Technology

[0002] Lithium carbonate is a white crystalline inorganic carbonate drug that is slightly soluble in water (slightly more soluble in cold water, and less soluble in hot water) but soluble in dilute acids. Its main pharmacological action is due to lithium ions. Initially used only to treat mania, a neurological disorder, lithium carbonate has been increasingly applied as a mood stabilizer in the treatment of other mental illnesses, such as bipolar disorder and depression, with in-depth clinical research. In particular, the combined use of antipsychotic drugs with low doses of lithium carbonate can reduce the incidence of adverse reactions to antipsychotic drugs. In recent years, the application of lithium carbonate has expanded again. Studies have shown that in the treatment of hyperthyroidism, when patients receive... 121 The combined use of low-dose lithium carbonate for three weeks before and after I-treatment can reduce [the risk of infection]. 121 Lithium carbonate improves treatment conditions, reduces patient discomfort, and enhances efficacy. This provides a more economical, rapid, simple, and effective treatment method for hyperthyroidism. Furthermore, the combined use of lithium carbonate and anti-tumor drugs can not only reduce the degree of genetic damage in cancer patients but also improve bone marrow suppression caused by radiotherapy and chemotherapy. All of these demonstrate the excellent therapeutic potential of lithium carbonate.

[0003] As a pharmaceutical grade lithium carbonate, it not only requires high purity (99.5% or higher) and to be a crystalline powder, but also has certain particle size requirements (D10 controlled at 4~12μm, D50 controlled at 20~40μm, and D90 controlled at 60~100μm) to meet the needs of the formulation.

[0004] Currently, the main methods for preparing pharmaceutical-grade lithium carbonate include: the LiOH solution CO2 precipitation method and the method for producing high-purity pharmaceutical-grade lithium carbonate from industrial lithium carbonate. The LiOH solution CO2 precipitation method has a long calcium removal process and requires expensive LiOH, making the use of industrial lithium carbonate as a more economical method. The production of high-purity lithium carbonate from industrial lithium carbonate is further divided into the Li2CO3 recrystallization method, the hydrocarbonation decomposition method, and the hydrocarbonation precipitation method. The Li2CO3 recrystallization method has high energy consumption and a long production cycle; the Li2CO3 produced by the hydrocarbonation precipitation method still has a high impurity content; and the sodium carbonate chemical precipitation method does not completely remove calcium and also introduces impurities such as Na. + The hydrocarbonation decomposition method mainly utilizes the fact that Li2CO3 can be hydrocarbonated to generate LiHCO3, which has a much higher solubility, while most other impurities are not hydrogenated. Insoluble carbonates can be removed by filtration, making the method simple. However, the current method of preparing lithium carbonate using the hydrocarbonation decomposition method suffers from the problem of low yield. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for preparing pharmaceutical-grade lithium carbonate. The preparation method provided by the present invention yields lithium carbonate with high purity and high yield.

[0006] This invention provides a method for preparing pharmaceutical-grade lithium carbonate, comprising the following steps: A slurry of industrial lithium carbonate is added to a rotating bed filled with functional filler material, and carbon dioxide is introduced to carry out a hydrocarbonation reaction. The resulting liquid-solid mixture is then separated to obtain a lithium bicarbonate solution. The functional filler material is a polyethyleneimine-modified filler material or ordered mesoporous activated carbon. The purity of the industrial lithium carbonate is 98.5% to 99.4%. Under an inert atmosphere, the lithium bicarbonate solution is heated to carry out a decomposition reaction. The resulting decomposition liquid is separated into solid and liquid components, and the obtained solid is dried to obtain pharmaceutical grade lithium carbonate. The purity of the pharmaceutical grade lithium carbonate is above 99.5%, and the particle size is: D10 is 4~12μm, D50 is 20~40μm, and D90 is 60~100μm.

[0007] Preferably, the polyethyleneimine modified filler includes one or more of the following: polyethyleneimine modified activated carbon, polyethyleneimine modified molecular sieve, polyethyleneimine modified silica, polyethyleneimine modified resin, polyethyleneimine modified alumina, polyethyleneimine modified ferrous material, and polyethyleneimine modified ordered mesoporous activated carbon.

[0008] Preferably, the preparation method of the polyethyleneimine modified filler includes: impregnating the filler in a methanol solution of polyethyleneimine and drying it to obtain the polyethyleneimine modified filler; the filler includes one or more of activated carbon, molecular sieve, silica, resin, alumina, ferrous materials and ordered mesoporous activated carbon.

[0009] Preferably, the methanol solution of polyethyleneimine is obtained by mixing polyethyleneimine and methanol, and the mass ratio of polyethyleneimine, methanol and filler is 1:2~20:1~5.

[0010] Preferably, the ordered mesoporous activated carbon is prepared by solvent evaporation-induced self-assembly.

[0011] Preferably, the industrial lithium carbonate slurry is obtained by mixing industrial lithium carbonate and water, wherein the mass ratio of industrial lithium carbonate to water is 1:10~40.

[0012] Preferably, the mass ratio of industrial lithium carbonate to carbon dioxide is 1:0.6~1.0.

[0013] Preferably, the slurry of industrial lithium carbonate is added at a rate of 30-100 mL / min; the flow rate of carbon dioxide is 0.01-1.0 m / min. 3 / h.

[0014] Preferably, the inert atmosphere gas is nitrogen or argon.

[0015] Preferably, the decomposition reaction is carried out at a temperature of 40~120℃ for 1~3 hours.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for preparing pharmaceutical-grade lithium carbonate, comprising the following steps: mixing industrial lithium carbonate slurry, functional filler, and carbon dioxide to carry out a hydrocracking reaction; separating the resulting liquid from the solid to obtain a lithium bicarbonate solution; wherein the functional filler is a polyethyleneimine-modified filler or ordered mesoporous activated carbon; the purity of the industrial lithium carbonate is 98.5-99.4%; under an inert atmosphere, heating the lithium bicarbonate solution to carry out a decomposition reaction; separating the resulting decomposition liquid from the solid; drying the obtained solid to obtain pharmaceutical-grade lithium carbonate; wherein the purity of the pharmaceutical-grade lithium carbonate is above 99.5%, and the particle size is: D10 4-12 μm, D50 20-40 μm, and D90 60-100 μm.

[0017] This invention employs industrial lithium carbonate and carbon dioxide with the addition of functional fillers (polyethyleneimine-modified fillers or ordered mesoporous activated carbon) for a hydrocarbonation reaction. The functional fillers possess strong carbon dioxide adsorption capacity and strong hydrophobicity, enhancing mass transfer performance and reaction efficiency. The hydrocarbonation conversion rate is high (up to 99.3%). Insoluble impurities are removed during solid-liquid separation, resulting in pharmaceutical-grade lithium carbonate with high purity and yield. This invention utilizes an inert atmosphere for the decomposition reaction, continuously introducing inert gas to keep the precipitated material in motion, preventing agglomeration and the formation of large particles. The particle size is regularly distributed within a certain range, and impurities are not trapped, further improving product purity. Example data shows that the pharmaceutical-grade lithium carbonate prepared by this invention has a purity of over 99.5% and a uniform particle size distribution: D10 is 4-12 μm, D50 is 20-40 μm, and D90 is 60-100 μm. The lithium carbonate obtained by this invention does not require pulverization to meet the requirements for pharmaceutical-grade lithium carbonate.

[0018] This invention uses industrial lithium carbonate, carbon dioxide, and water as raw materials, and then purifies the industrial lithium carbonate through a metathesis reaction to prepare pharmaceutical-grade lithium carbonate. Industrial lithium carbonate and carbon dioxide are abundant and have low raw material costs.

[0019] Furthermore, the present invention uses a rotating packed bed as the reaction equipment, which has the characteristics of small equipment size, short reaction time, high conversion rate and low operating cost.

[0020] The carbon dioxide used in this invention is small, and the carbon dioxide produced by thermal decomposition can be recycled in lithium carbonate mother liquor (the liquid after solid-liquid separation of the decomposed feed liquid), which not only saves production costs but is also low-carbon and environmentally friendly. The lithium carbonate mother liquor of this invention can be recycled, which improves the yield of pharmaceutical lithium carbonate and reduces the discharge of waste liquid, thus alleviating environmental pressure. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The image shows the particle size distribution of lithium carbonate prepared in Example 1. Figure 2 The image shows the particle size distribution of lithium carbonate prepared in Example 3. Figure 3 The image shows the particle size distribution of lithium carbonate prepared in Example 6. Figure 4 The image shows the particle size distribution of lithium carbonate prepared in Example 7. Figure 5 The particle size distribution diagram shows the lithium carbonate prepared in Comparative Example 1. Figure 6 The particle size distribution diagram shows the lithium carbonate prepared in Comparative Example 3. Figure 7 The infrared spectrum of lithium carbonate prepared in Example 1; Figure 8 The image shows the XRD pattern of lithium carbonate prepared in Example 1. Detailed Implementation

[0023] This invention provides a method for preparing pharmaceutical-grade lithium carbonate, comprising the following steps: A slurry of industrial lithium carbonate is added to a rotating bed filled with functional filler material, and carbon dioxide is introduced to carry out a hydrocarbonation reaction. The resulting liquid-solid mixture is then separated to obtain a lithium bicarbonate solution. The functional filler material is a polyethyleneimine-modified filler material or ordered mesoporous activated carbon. The purity of the industrial lithium carbonate is 98.5% to 99.4%. Under an inert atmosphere, the lithium bicarbonate solution is heated to carry out a decomposition reaction. After solid-liquid separation of the resulting decomposition liquid, the obtained solid is dried to obtain pharmaceutical grade lithium carbonate. The purity of the pharmaceutical grade lithium carbonate is above 99.5%, and the particle size is: D10 is 4~12μm, D50 is 20~40μm, and D90 is 60~100μm.

[0024] Unless otherwise specified, all materials and equipment used in this invention are commercially available products in the field.

[0025] This invention involves adding an industrial lithium carbonate slurry to a high-gravity rotating bed filled with functional fillers, introducing carbon dioxide to carry out a hydrocarbon reaction, and separating the resulting liquid from the solid to obtain a lithium bicarbonate solution; the functional filler is a polyethyleneimine modified filler or ordered mesoporous activated carbon; the purity of the industrial lithium carbonate is 98.5~99.4%.

[0026] In this invention, the industrial lithium carbonate slurry is preferably obtained by mixing industrial lithium carbonate and water; the purity of the industrial lithium carbonate is 98.5-99.4%, specifically 99.1%; the water is preferably purified water; the mass ratio of industrial lithium carbonate to water is preferably 1:10-40, more preferably 1:15-25, specifically 1:20; the concentration of the industrial lithium carbonate slurry is preferably 50-60 g / L; the mixing is preferably by stirring, the stirring temperature is preferably 15-20°C, and the stirring time is preferably 30 min.

[0027] In this invention, the preferred method for preparing the polyethyleneimine modified filler includes: impregnating the filler in a methanol solution of polyethyleneimine and drying it to obtain the polyethyleneimine modified filler; the filler preferably includes one or more of activated carbon, molecular sieve, silica (white carbon black), resin, alumina, ferrous materials, and ordered mesoporous activated carbon, the molecular sieve preferably includes a 3Å molecular sieve, the resin preferably includes an ion exchange resin, and the ion exchange resin is preferably a macroporous weakly acidic cation exchange resin. The methanol solution of polyethyleneimine is obtained by mixing polyethyleneimine and methanol, and the mass ratio of polyethyleneimine (PEI), methanol, and filler is preferably 1:2~20:1~5, more preferably 1:5~10:1~3, and specifically 1:8:1.5; the mixing of polyethyleneimine and methanol is preferably carried out under stirring, the temperature is preferably 40~42℃, and the time is preferably 10 min. The impregnation temperature is preferably 40-42°C, and the impregnation is preferably accompanied by stirring or ultrasound. The stirring time is preferably 20 minutes, and the ultrasound time is preferably 10 minutes. This invention loads polyethyleneimine (PEI) onto the filler through impregnation. The drying temperature is preferably 70-100°C, more preferably 70-80°C, specifically 75°C, and the drying time is preferably 10-20 hours, more preferably 10-15 hours, specifically 12 hours.

[0028] In this invention, the polyethyleneimine-modified filler preferably comprises one or more of the following: polyethyleneimine-modified activated carbon, polyethyleneimine-modified molecular sieve, polyethyleneimine-modified silica (white carbon black), polyethyleneimine-modified resin, polyethyleneimine-modified alumina, polyethyleneimine-modified ferrous materials, and polyethyleneimine-modified ordered mesoporous activated carbon. The polyethyleneimine-modified filler of this invention exhibits strong adsorption capacity for carbon dioxide, with an adsorption capacity of 0.89~5.1 mmol / g, and its hydrophobicity is nearly doubled compared to that before modification.

[0029] In this invention, the ordered mesoporous activated carbon is preferably prepared by solvent evaporation-induced self-assembly. The solvent evaporation-induced self-assembly method preferably includes the following steps: mixing phenol, formaldehyde, sodium hydroxide, and water to obtain a Resol-type phenolic resin; mixing the Resol-type phenolic resin, F127-type phenolic resin, and ethanol, then evaporating the solvent to induce self-assembly, followed by carbonization to obtain ordered mesoporous activated carbon. The molar ratio of phenol, formaldehyde, sodium hydroxide, and F127-type phenolic resin is preferably 1:0.2:0.1:0.01~0.02, more preferably 1:0.2:0.1:0.012~0.013; the carbonization temperature is preferably 600~900℃, more preferably 600~800℃, and the holding time is preferably 3 hours. In this embodiment of the invention, the preparation steps of the ordered mesoporous activated carbon are as follows: In a 1000mL reaction flask, 244g of phenol is added, followed by 52g of 20wt% sodium hydroxide solution under stirring. The temperature is raised to 40-42℃ and stirred for 10min. Then, 420g of 37wt% formaldehyde solution is added, and stirring continues for 20min. The temperature is then raised to 75℃ and stirred for 2h. After cooling to room temperature, the solution is adjusted to neutral with 0.6M hydrochloric acid and evaporated at 45℃ for 24h to obtain Resol-type phenolic resin. In a 10L reaction vessel, 5L of ethanol is added, followed by the above phenolic resin under stirring. After 10min, 408.8g of [unspecified substance] is added. F127 resin was stirred for 10 minutes, then the alcohol was collected to a suitable amount and transferred to an open stainless steel basin. It was allowed to evaporate naturally until dry, and then dried in an oven at 100°C for 24 hours to obtain a soft film. The film was cut into pieces and then calcined at 800°C for 3 hours under nitrogen protection in a vacuum tube furnace. The material was then discharged and pulverized into powder. 4000g of 48wt% sulfuric acid was added to a 10L reactor, and the powder obtained above was added while stirring. The temperature was raised to 95°C and the reaction was controlled for 24 hours. The temperature was then lowered, filtered, washed with water and ethanol, discharged, and dried at 75°C for 12 hours to obtain ordered mesoporous activated carbon.

[0030] In this invention, the preferred mass ratio of industrial lithium carbonate to carbon dioxide is 1:0.6~1.0, more preferably 1:0.6~0.8, and specifically 1:0.7. This invention controls the amount of carbon dioxide used, thereby reducing carbon dioxide emissions and making the production process green and environmentally friendly.

[0031] In this invention, the temperature of the hydrocracking reaction is preferably 10~30℃, more preferably 15~20℃; the time is preferably 0.3~5h, more preferably 0.5~1.5h. The endpoint of the hydrocracking reaction is that the pH value of the resulting solution is 7~9, specifically 8. The reaction formula for the hydrocracking reaction is shown below: .

[0032] In this invention, the centrifugal rotating bed is preferably a baffle-type centrifugal rotating packed bed, specifically a DN200 type; the industrial lithium carbonate slurry is preferably pumped in using a micro-pump, and the addition rate of the industrial lithium carbonate slurry is preferably 30~100mL / min, specifically 50mL / min; the carbon dioxide is preferably continuously introduced using a gas circulation pump, and the flow rate of the carbon dioxide is preferably 0.01~1.0m. 3 / h, more preferably 0.04~0.4m 3 The flow rate is 2 L / h, specifically 2 L / min. The packing material is preferably bulk packing or structured packing, more preferably structured packing. The rotational speed C of the high-gravity rotating bed is preferably 50 Hz.

[0033] In this invention, the working principle of the baffled high-gravity rotating packed bed is as follows: Driven by a motor, the packing material inside the rotor rotates at high speed. Industrial lithium carbonate slurry, propelled by a peristaltic pump, enters the rotor cavity through the liquid inlet. The immense shear force generated by the high-speed rotation cuts the added liquid into thin liquid films and smaller droplets, causing the liquid to exist in the packing as liquid films, filaments, and droplets. The resulting centrifugal force pushes it towards the outer edge of the rotor. Gas enters the outer edge of the rotor tangentially through the gas inlet via a circulating pump, and then enters the packing. When the gas enters the rotor and comes into contact with the highly dispersed, highly turbulent, strongly mixed, and rapidly renewing liquid micro-elements, the gas-liquid interface area increases and the interface renewal frequency accelerates, significantly enhancing gas-liquid mass transfer. This results in a 2-8 times higher liquid-phase mass transfer coefficient in the rotating packed bed compared to traditional tower equipment. Afterward, the liquid is thrown by the rotor to the outer shell, collects, and is discharged through the liquid outlet. The gas leaves the rotor from the center, completing the entire reaction process.

[0034] In this invention, the solid-liquid separation is preferably achieved through filtration, which removes insoluble impurities.

[0035] After obtaining the lithium bicarbonate solution, the present invention heats the lithium bicarbonate solution under an inert atmosphere to carry out a decomposition reaction. After solid-liquid separation of the obtained decomposition liquid (lithium carbonate slurry), the obtained solid is dried to obtain pharmaceutical grade lithium carbonate. The purity of the pharmaceutical grade lithium carbonate is above 99.5%, and the particle size is: D10 is 4~12μm, D50 is 20~40μm, and D90 is 60~100μm.

[0036] In this invention, the inert atmosphere gas is preferably nitrogen or argon, more preferably nitrogen.

[0037] In this invention, the preferred temperature for the decomposition reaction is 40~120℃, more preferably 60~100℃; the preferred time is 1~3h; the decomposition reaction is preferably carried out under continuous nitrogen gas purging; the reaction temperature and conditions described in this invention can control the decomposition rate, preventing lithium carbonate from agglomerating into large particles, and ensuring that the particle size is regularly distributed within a certain range; the reaction formula is shown below: .

[0038] In this invention, the carbon dioxide gas produced by the decomposition reaction can be passed into the lithium carbonate mother liquor for reuse, while reducing carbon dioxide emissions.

[0039] In this invention, the solid-liquid separation is preferably centrifugation; the drying temperature is preferably 70~100℃, more preferably 70~80℃, specifically 75℃ or 95℃, and the time is preferably 10~20h, more preferably 10~15h, specifically 8h or 12h.

[0040] The pharmaceutical-grade lithium carbonate prepared by this invention has a purity of over 99.5% and a uniform particle size distribution, with D10 controlled at 4-12 μm, D50 at 20-40 μm, and D90 at 60-100 μm. The pharmaceutical-grade lithium carbonate prepared by this invention meets the requirements for lithium carbonate formulations.

[0041] This invention prepares pharmaceutical-grade lithium carbonate from industrial lithium carbonate as raw material via lithium bicarbonate intermediate. The specific steps are as follows: industrial lithium carbonate and water are mixed to form a slurry of a certain concentration and reacted with carbon dioxide in a rotating packed bed to generate lithium bicarbonate. After filtration to remove impurities, the lithium bicarbonate is decomposed under heating and nitrogen gas to generate pharmaceutical-grade lithium carbonate.

[0042] To further illustrate the present invention, the preparation method of pharmaceutical-grade lithium carbonate provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0043] In the embodiments or comparative examples of this invention, the industrial lithium carbonate used has a purity of 99.1%.

[0044] Preparation Example 1: Preparation of Modified Filler (1) Preparation of modified activated carbon: In a 500mL reaction flask, add 320g of methanol, add 40g of polyethyleneimine (PEI) while stirring, heat to 40~42℃ and stir for 10min, then add 60g of activated carbon, continue stirring for 20min, then sonicate for 10min, filter, discharge, dry at 75℃ for 12h, collect, bag, and use for later use.

[0045] Referring to the method in (1), modified 3Å molecular sieve, modified silica (white carbon black), modified silica gel, and modified macroporous weak acid cation exchange resin can be prepared.

[0046] (2) Preparation of ordered mesoporous activated carbon: 244g of phenol was added to a 1000mL reaction flask, and 52g of 20wt% sodium hydroxide solution was added under stirring. The temperature was raised to 40~42℃ and stirred for 10min. Then 420g of 37wt% formaldehyde solution was added and stirred for 20min. The temperature was raised to 75℃ and stirred for 2h. Then the temperature was cooled to room temperature and adjusted to neutral with 0.6M hydrochloric acid. The solution was evaporated at 45℃ for 24h to obtain Resol type phenolic resin. 5L of ethanol was added to a 10L reactor and the above phenolic resin was added under stirring. After 10min, 408.8g of F127 type resin was added and stirred for 10min. The alcohol was collected to an appropriate amount and transferred to an open stainless steel basin. The solution was allowed to evaporate naturally to dryness and then dried in an oven at 100℃ for 24h to obtain a soft film. The film was cut into pieces and then calcined at 800℃ for 3h under nitrogen protection in a vacuum tube furnace. The material was discharged and pulverized into powder. Add 4000g of 48wt% sulfuric acid to a 10L reactor, add the powder obtained above while stirring, heat to 95℃ and react for 24h, then cool down, filter, wash with water and ethanol, discharge, dry at 75℃ for 12h, collect, bag and store for later use.

[0047] (3) Preparation of modified ordered mesoporous activated carbon: In a 500mL reaction flask, add 320g of methanol, add 40g of polyethyleneimine (PEI) while stirring, heat to 40~42℃ and stir for 10min, then add 60g of ordered mesoporous activated carbon, continue stirring for 20min, then sonicate for 10min, filter, discharge, dry at 75℃ for 12h, collect, bag and use for later use.

[0048] In the following examples or comparative examples, the DN200 type ultragravity rotating packing bed used has a diameter of 200mm, two layers, a packing column length of 160mm, a packing column diameter of 30mm, and a packing amount of approximately 64g.

[0049] Example 1: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 50 g / L, modified ordered mesoporous activated carbon filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0050] Start the DN200 type high-gravity rotating packed bed (rotation speed C=50Hz), add the above slurry into the rotating packed bed at a rate of 50mL / min using a micro pump, turn on the gas circulation pump, and introduce carbon dioxide gas at a rate of 2L / min. React at 15~20℃ for 0.5h, take a sample to measure the pH value, the pH value is about 8, the reaction endpoint has been reached, discharge and filter, dry, the dried filter cake is 0.28g, the hydrocarbon conversion rate is 99.3%. The hydrocarbon conversion rate is calculated by the formula: (batch amount of industrial lithium carbonate - weight of dried filter cake) ÷ batch amount of industrial lithium carbonate × 100%.

[0051] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were introduced into the pretreated lithium carbonate mother liquor (for further impurity removal using pretreatment).

[0052] After decomposition, the mixture was filtered, dried under vacuum, and then dried (95℃, 8h) to obtain 34g of lithium carbonate, with a yield of 85% and a lithium carbonate content of 99.81%. Particle sizes: D10 10.17μm, D50 36.78μm, D90 85.85μm, etc. Figure 1 As shown.

[0053] Example 2: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 50 g / L, ordered mesoporous activated carbon filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0054] The DN200 type high-gravity rotating packed bed was started (rotation speed C=50Hz). The above slurry was added to the rotating packed bed at a rate of 50mL / min using a micro pump. The gas circulation pump was turned on, and carbon dioxide gas was introduced at a rate of 2L / min. The reaction was carried out at 15~20℃ for 0.5h. The pH value was measured and found to be approximately 8, indicating that the reaction had reached its endpoint. The material was discharged, filtered, and dried. The filter cake yielded 1.88g, with a hydrocarbon conversion rate of 95.3%.

[0055] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0056] After decomposition, the sample was filtered, dried under vacuum, and dried to obtain 33.2 g of lithium carbonate, with a yield of 83% and a lithium carbonate content of 99.79%. Particle sizes: D10 9.785 μm, D50 33.08 μm, D90 80.08 μm.

[0057] Example 3: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 50 g / L, modified 3 Å molecular sieve packing) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0058] The DN200 type high-gravity rotating packed bed was started (rotation speed C=50Hz). The above slurry was added to the rotating packed bed at a rate of 50mL / min using a micro pump. The gas circulation pump was turned on, and carbon dioxide gas was introduced at a rate of 2L / min. The reaction was carried out at 15~20℃ for 0.5h. A sample was taken to measure the pH value. The pH value was about 8, which indicated that the reaction had reached the endpoint. The material was discharged, filtered, and dried. The filter cake was dried to obtain 3.08g, and the hydrocarbon conversion rate was 92.3%.

[0059] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0060] After decomposition, the sample was filtered, dried under vacuum, and then dried again to obtain 32.4 g of lithium carbonate, with a yield of 81% and a lithium carbonate content of 99.83%. Particle sizes: D10 8.516 μm, D50 33.13 μm, D90 8174 μm, etc. Figure 2 As shown.

[0061] Example 4: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 50 g / L, modified white carbon black filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0062] Start the DN200 type high-gravity rotating packed bed (rotation speed C=50Hz), add the above slurry into the rotating packed bed at a rate of 50mL / min using a micro pump, turn on the gas circulation pump, and introduce carbon dioxide gas at a rate of 2L / min. React at 15~20℃ for 0.5h, take a sample to measure the pH value, the pH value is about 8, the reaction endpoint has been reached, discharge and filter, dry, and the filter cake is dried to obtain 2g, the hydrocarbon conversion rate is 95%.

[0063] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0064] After decomposition, the sample was filtered, dried under vacuum, and dried to obtain 33.2 g of lithium carbonate, with a yield of 83% and a lithium carbonate content of 99.78%. Particle sizes: D10 10.68 μm, D50 38.60 μm, D90 88.82 μm.

[0065] Example 5: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 50 g / L, modified macroporous weakly acidic cation exchange resin filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0066] The DN200 high-gravity rotating packed bed (rotation speed C=50Hz) was started, and the above slurry was added to the rotating packed bed at a rate of 50mL / min using a micro pump. The gas circulation pump was turned on, and carbon dioxide gas was introduced at a rate of 2L / min. The reaction was carried out at 15~20℃ for 0.5h. A sample was taken to measure the pH value, which was about 8, indicating that the reaction had reached the endpoint. The material was discharged, filtered, and dried. The filter cake was dried to obtain 3.36g, and the hydrocarbon conversion rate was 91.6%.

[0067] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0068] After decomposition, the mixture was filtered, dried under vacuum, and dried to obtain 32g of lithium carbonate, with a yield of 80% and a lithium carbonate content of 99.85%. Particle sizes: D10 12.20μm, D50 38.90μm, D90 87.39μm.

[0069] Example 6: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 60 g / L, modified ordered mesoporous activated carbon filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 48g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0070] Start the DN200 type high-gravity rotating packed bed (rotation speed C=50Hz), add the above slurry into the rotating packed bed at a rate of 50mL / min using a micro pump, turn on the gas circulation pump, and introduce carbon dioxide gas at a rate of 2L / min. React at 15~20℃ for 0.5h, take a sample to measure the pH value, the pH value is about 8, the reaction endpoint has been reached, discharge and filter, dry, the filter cake is dried to obtain 0.62g, the hydrocarbon conversion rate is 98.7%.

[0071] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0072] After decomposition, the sample was filtered, dried under vacuum, and then dried again to obtain 40.85 g of lithium carbonate, with a yield of 85.1% and a lithium carbonate content of 99.89%. Particle sizes: D10 9.120 μm, D50 32.17 μm, D90 81.61 μm, etc. Figure 3 As shown.

[0073] Example 7: Preparation of Lithium Carbonate (using the mother liquor from Example 1 with an industrial lithium carbonate concentration of 50 g / L, and modified ordered mesoporous activated carbon filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, and add 720mL of lithium carbonate mother liquor, 80mL of purified water, and 34.8g of industrial lithium carbonate in sequence with stirring. Stir at 15~20℃ for 30 minutes and set aside.

[0074] The DN200 high-gravity rotating packed bed was started (rotation speed C=50Hz). The above slurry was added to the rotating packed bed at a rate of 50mL / min using a micro pump. The gas circulation pump was turned on, and carbon dioxide gas was introduced at a rate of 2L / min. The reaction was carried out at 15~20℃ for 0.5h. A sample was taken to measure the pH value. The pH value was about 8, which indicated that the reaction had reached the endpoint. The material was discharged, filtered, and dried. The filter cake was dried to obtain 0.72g, and the hydrocarbon conversion rate was 98.2%.

[0075] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0076] After decomposition, the sample was filtered, dried under vacuum, and then dried again to obtain 32.3 g of lithium carbonate, with a yield of 92.82% and a lithium carbonate content of 99.93%. Particle sizes: D10 11.26 μm, D50 37.26 μm, D90 86.28 μm, etc. Figure 4 As shown.

[0077] Comparative Example 1: Preparation of Lithium Carbonate (Industrial lithium carbonate concentration 50 g / L, activated carbon filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0078] The DN200 type high-gravity rotating packed bed was started (rotation speed C=50Hz). The above slurry was added to the rotating packed bed at a rate of 50mL / min using a micro pump. The gas circulation pump was turned on, and carbon dioxide gas was introduced at a rate of 2L / min. The reaction was carried out at 15~20℃ for 0.5h. A sample was taken to measure the pH value, which was about 9. The material was discharged, filtered, and dried. The filter cake was dried to obtain 6.2g, and the hydrocarbon conversion rate was 84.5%.

[0079] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0080] After decomposition, the sample was filtered, dried under vacuum, and then dried again to obtain 28.3 g of lithium carbonate, with a yield of 70.7% and a lithium carbonate content of 99.83%. Particle sizes: D10 11.32 μm, D50 37.04 μm, D90 87.00 μm, etc. Figure 5 As shown.

[0081] Comparative Example 2: Preparation of Lithium Carbonate (Industrial Lithium Carbonate Concentration 50 g / L, White Carbon Black Filler) Place a clean and dry 1L three-necked reaction flask in a cold bath, add 800mL of purified water and 40g of industrial lithium carbonate in sequence with stirring, and stir for 30 minutes at a controlled temperature of 15~20℃.

[0082] Start the DN200 type high-gravity rotating packed bed (rotation speed C=50Hz), add the above slurry into the rotating packed bed at a rate of 50mL / min using a micro pump, and at the same time turn on the gas circulation pump to introduce carbon dioxide gas at a rate of 2L / min. React at 15~20℃ for 0.5h, take a sample to measure the pH value, which is about 9, filter the discharged material, dry it, and dry the filter cake to obtain 5g, with a hydrocarbon conversion rate of 87.5%.

[0083] The filtrate was placed in a clean reaction flask, and nitrogen gas was uniformly introduced. The mixture was heated to decompose, and the timing was started when the internal temperature reached 60°C and continued until the internal temperature reached 100°C, which took 1 hour. During this period, the carbon dioxide and nitrogen gas released during decomposition were also introduced into the pretreated lithium carbonate mother liquor.

[0084] After decomposition, the sample was filtered, dried under vacuum, and dried to obtain 29g of lithium carbonate, with a yield of 72.7% and a lithium carbonate content of 99.84%. Particle sizes: D10 10.72μm, D50 36.78μm, D90 87.85μm.

[0085] Comparative Example 3: Preparation of Lithium Carbonate (LiOH·H2O method) Add 600 mL of purified water to a clean, dry 1 L three-necked flask, heat to 80 °C, and add 186 g of lithium hydroxide monohydrate in three portions while stirring. Maintain the temperature at 90-95 °C and stir for 30 min. Filter while hot. Transfer the filtrate to a clean 1 L three-necked flask, turn on the gas circulation pump, and introduce carbon dioxide gas at a rate of 2 L / min. React at 80-90 °C for 6 h. Take a sample to measure the pH value; the pH is approximately 8, indicating the reaction endpoint has been reached. Discharge, filter, and dry under vacuum. First, dry at 120 °C for 2 h, then heat to 140-145 °C and dry for another 2 h. Grind to obtain 153.4 g of lithium carbonate with particle sizes: D10 7.53 μm, D50 70.18 μm, D90 157.8 μm. Figure 6 As shown, it needs to be pulverized to reach pharmaceutical grade, and the particle size distribution is not uniform.

[0086] Figure 7 The infrared spectrum of lithium carbonate prepared in Example 1; Figure 8 The image shows the XRD pattern of lithium carbonate prepared in Example 1; the crystal form of lithium carbonate prepared in Example 1 is consistent with that of the reference formulation.

[0087] This invention provides a highly efficient, environmentally friendly, and economical method for preparing pharmaceutical-grade lithium carbonate. The invention utilizes a rotating packed bed (baffle type), where a motor drives the packing material inside the rotor to rotate at high speed. The resulting immense shear force cuts the liquid into thinner liquid films and smaller droplets, allowing the liquid to exist within the packing in the form of liquid films, liquid filaments, and droplets. When gas enters the rotor and comes into contact with the liquid micro-elements, the gas-liquid interface area increases and the interface renewal frequency accelerates, significantly enhancing gas-liquid mass transfer. This results in a 2-8 times higher gas-liquid mass transfer coefficient in the rotating packed bed compared to traditional tower equipment.

[0088] In this invention, industrial lithium carbonate and purified water are mixed to form a slurry, which is then reacted with carbon dioxide in a rotating packed bed to produce lithium bicarbonate. After filtration to remove impurities, the lithium bicarbonate is decomposed under heating and nitrogen purging to produce lithium carbonate. This invention uses a rotating packed bed as the reaction equipment and employs structured modified mesoporous packing material, achieving the advantages of small equipment size, short reaction time, high conversion rate (up to 99.3%), and low operating cost.

[0089] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing pharmaceutical-grade lithium carbonate, characterized in that, Includes the following steps: A slurry of industrial lithium carbonate is added to a rotating bed filled with functional filler material, and carbon dioxide is introduced to carry out a hydrocarbonation reaction. The resulting liquid-solid mixture is then separated to obtain a lithium bicarbonate solution. The functional filler material is a polyethyleneimine-modified filler material or ordered mesoporous activated carbon. The purity of the industrial lithium carbonate is 98.5% to 99.4%. Under an inert atmosphere, the lithium bicarbonate solution is heated to carry out a decomposition reaction. The resulting decomposition liquid is separated into solid and liquid components, and the obtained solid is dried to obtain pharmaceutical grade lithium carbonate. The purity of the pharmaceutical grade lithium carbonate is above 99.5%, and the particle size is: D10 is 4~12μm, D50 is 20~40μm, and D90 is 60~100μm.

2. The preparation method according to claim 1, characterized in that, The polyethyleneimine-modified filler includes one or more of the following: polyethyleneimine-modified activated carbon, polyethyleneimine-modified molecular sieve, polyethyleneimine-modified silica, polyethyleneimine-modified resin, polyethyleneimine-modified alumina, polyethyleneimine-modified ferrous materials, and polyethyleneimine-modified ordered mesoporous activated carbon.

3. The preparation method according to claim 1 or 2, characterized in that, The preparation method of the polyethyleneimine modified filler includes: impregnating the filler in a methanol solution of polyethyleneimine and drying it to obtain the polyethyleneimine modified filler; the filler includes one or more of activated carbon, molecular sieve, silica, resin, alumina, ferrous materials and ordered mesoporous activated carbon.

4. The preparation method according to claim 3, characterized in that, The methanol solution of polyethyleneimine is obtained by mixing polyethyleneimine and methanol, and the mass ratio of polyethyleneimine, methanol and filler is 1:2~20:1~5.

5. The preparation method according to claim 3, characterized in that, The ordered mesoporous activated carbon was prepared by solvent evaporation-induced self-assembly.

6. The preparation method according to claim 1, characterized in that, The industrial lithium carbonate slurry is obtained by mixing industrial lithium carbonate and water, wherein the mass ratio of industrial lithium carbonate to water is 1:10~40.

7. The preparation method according to claim 1 or 6, characterized in that, The mass ratio of industrial lithium carbonate to carbon dioxide is 1:0.6~1.

0.

8. The preparation method according to claim 1, characterized in that, The slurry of industrial lithium carbonate is added at a rate of 30-100 mL / min; the flow rate of carbon dioxide is 0.01-1.0 m / min. 3 / h.

9. The preparation method according to claim 1, characterized in that, The inert atmosphere is composed of nitrogen or argon.

10. The preparation method according to claim 1, characterized in that, The decomposition reaction is carried out at a temperature of 40~120℃ for 1~3 hours.

Images