Method for improving dissolution rate of lithium in bauxite

Abstract

The invention relates to a method for improving the dissolution rate of lithium in bauxite, and belongs to the technical field of aluminum oxide industry. The method comprises the following steps: obtaining lithium-containing bauxite; mixing the lithium-containing bauxite, calcium ferrite and circulating mother liquor to obtain a mixture; wherein the mass of the calcium ferrite is 1%-8% of the mass of the lithium-containing bauxite; the mixture is subjected to ball milling, and raw ore pulp is obtained; the raw ore pulp is sequentially subjected to pre-desilicication and dissolution treatment, and dissolution ore pulp is obtained; carrying out solid-liquid separation on the dissolved-out ore pulp to obtain a lithium-containing sodium aluminate solution; and lithium ions in the lithium-containing sodium aluminate solution are sequentially enriched and precipitated, so that the lithium ions in the lithium-containing sodium aluminate solution are separated. According to the method, calcium ferrite is added in the ball milling process, and then pre-desiliconization and dissolution treatment are carried out, so that the effect of improving the dissolution rate of lithium is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of alumina industry, and in particular to a method for increasing the lithium dissolution rate in bauxite. Background Art

[0002] Lithium, a key strategic metal, is increasingly used in new energy, defense, and military applications, playing a crucial role in the national economy and national security. On the one hand, high-quality lithium ore resources are scarce, making it difficult to meet the growing demand for lithium. On the other hand, the technical challenges of separating magnesium from lithium in high-magnesium brines in China's salt lakes remain unresolved, resulting in the inability to effectively extract a significant amount of lithium resources. Furthermore, limited capacity expansion by international lithium giants has further exacerbated the global lithium supply shortage. In the long term, relying solely on lithium resources from minerals and brines will not be enough to meet the needs of sustainable development.

[0003] Against this backdrop, finding new sources of lithium resources is crucial. my country's bauxite is rich in lithium, particularly in central China, where the lithium content is high. This offers new avenues for lithium resource development. However, during alumina production, lithium from the bauxite dissolves into the sodium aluminate solution and subsequently precipitates into aluminum hydroxide during seed crystal decomposition, impacting the quality of the alumina product. Therefore, efficiently removing lithium from the alumina production process—both to improve product quality and maximize lithium resource utilization—has become a pressing issue.

[0004] Currently, technologies for extracting lithium from bauxite primarily focus on Bayer process production, such as adsorption and extraction. However, these methods do not address how to increase the lithium dissolution rate from bauxite during alumina production. Therefore, developing a technology that can effectively increase the lithium dissolution rate from bauxite is crucial for alleviating the imbalance between lithium supply and demand in my country and promoting the development of the new energy industry. Summary of the Invention

[0005] The present application provides a method for increasing the dissolution rate of lithium in bauxite to solve the following technical problem: how to increase the dissolution rate of lithium in bauxite.

[0006] The present invention provides a method for increasing the lithium dissolution rate in bauxite, the method comprising:

[0007] Obtaining lithium-containing bauxite;

[0008] The lithium-containing bauxite, calcium ferrite and circulating mother liquor are mixed to obtain a mixture; wherein the mass of the calcium ferrite is 1% to 8% of the mass of the lithium-containing bauxite;

[0009] ball milling the mixture to obtain raw ore slurry;

[0010] The raw ore pulp is subjected to pre-desiliconization and dissolution treatment in sequence to obtain dissolution ore pulp;

[0011] performing solid-liquid separation on the dissolved slurry to obtain a lithium-containing sodium aluminate solution;

[0012] The lithium ions in the lithium-containing sodium aluminate solution are sequentially enriched and precipitated to separate the lithium ions in the lithium-containing sodium aluminate solution.

[0013] Optionally, the lithium-containing bauxite is diaspore-type bauxite, and the lithium in the lithium-containing bauxite exists in the form of lithium chlorite.

[0014] Optionally, the solid content of the raw ore slurry is 300g / L to 350g / L.

[0015] Optionally, the mass concentration of caustic soda in the circulating mother liquor is not less than 230 g / L.

[0016] Optionally, the mass of the raw ore pulp with a particle size of less than 65 μm is 72% to 75% of the total mass of the raw ore pulp.

[0017] Optionally, the pre-desiliconization temperature is 95°C to 105°C.

[0018] Optionally, the pre-desiliconization time is 4 hours to 8 hours.

[0019] Optionally, the dissolution treatment time is not less than 45 minutes.

[0020] Optionally, the temperature of the dissolution treatment is not lower than 260°C.

[0021] Optionally, the mass concentration of suspended matter in the lithium-containing sodium aluminate solution is less than 0.25 g / L.

[0022] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0023] The present invention provides a method for increasing the lithium dissolution rate in bauxite, comprising: obtaining lithium-containing bauxite; mixing the lithium-containing bauxite, calcium ferrite, and a circulating mother liquor to obtain a mixture; wherein the mass of the calcium ferrite is 1% to 8% of the mass of the lithium-containing bauxite; ball milling the mixture to obtain a raw ore slurry; sequentially performing pre-desiliconization and dissolution treatments on the raw ore slurry to obtain a dissolution slurry; performing solid-liquid separation on the dissolution slurry to obtain a lithium-containing sodium aluminate solution; and sequentially enriching and precipitating the lithium ions in the lithium-containing sodium aluminate solution to separate the lithium ions in the lithium-containing sodium aluminate solution. By adding calcium ferrite as an additive to the bauxite during the ball milling process, on the one hand, it can effectively promote the destruction of the layered structure of lithium chlorite, making it easier to dissolve lithium under high temperature and strong alkaline conditions. On the other hand, in the sodium aluminate solution, lithium ions easily react with aluminate ions to form lithium aluminate, resulting in a reduced lithium dissolution rate. The ferrite ions in calcium ferrite can form stable compounds with lithium ions, thereby inhibiting the entry of lithium into red mud and increasing the dissolution rate of lithium. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0026] Figure 1 A schematic flow chart of a method for increasing the lithium dissolution rate in bauxite provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] The range descriptions described in this article, such as numerical ranges, ratio ranges, etc., include all possible sub-ranges and single numerical values ​​within the range. For example, the range description of "1 to 6" or "1~6" covers all sub-ranges from 1 to 6 (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6). Unless otherwise specified, the terms "including", "comprising", etc. used in this article mean "including but not limited to"; relational terms such as "first" and "second" are only used to distinguish different entities or operations, and do not imply an actual sequence or association relationship; "and / or" means that multiple situations can exist alone or at the same time; expressions such as "at least one", "multiple", and "at least one" refer to any combination of corresponding objects, including a combination of single or multiple objects. The proportional relationships involved in the article, such as mass ratios, molar ratios, etc., should be understood as the corresponding relationship between the first and second terms of the proportional formula in the order of description. The raw materials, reagents, instruments and equipment used in this article can be purchased on the market or prepared by existing methods.

[0029] Figure 1 A schematic flow chart of a method for increasing the lithium dissolution rate in bauxite provided in an embodiment of the present application.

[0030] See Figure 1 , the embodiment of the present application provides a method for increasing the lithium dissolution rate in bauxite, the method comprising:

[0031] S1, obtaining lithium-containing bauxite;

[0032] In some embodiments, the lithium-containing bauxite is a diaspore-type bauxite, and the lithium in the lithium-containing bauxite exists in the form of lithium chlorite.

[0033] Lithium-containing bauxite is a diaspore-type bauxite, the main mineral component of which is diaspore (AlO(OH)), which belongs to the gibbsite family of minerals. This type of ore is characterized by high aluminum and low silicon, and the associated lithium element is lithium chlorite (LiAl4(Si3Al)O 10 (OH)8) exists as an independent mineral form within the ore structure. Lithium chlorite is a layered aluminum silicate mineral with a crystal structure between dioctahedron and trioctahedron. During the dissolution process of the present invention, calcium ferrite destroys its layered structure to release lithium. The behavior of lithium chlorite during the dissolution process is as follows:

[0034] The addition of calcium ferrite (CaO·Fe2O3) can promote the destruction of its layered structure and release lithium ions. The reaction formula is: 2LiAl4(Si3Al)O 10 (OH)8+3(3CaO·Fe2O3·6H2O)+8OH - →3(3CaO·Fe2O3·2SiO2·2H2O)+2Li+ +10Al(OH)4 - +4H2O.

[0035] Lithium ions entering the sodium aluminate solution easily react with the sodium aluminate solution to form lithium aluminate LiAl2(OH)7·2H2O, which then enters the red mud, causing the lithium dissolution rate to decrease, while the ferrite ions (FeO2 - ) can inhibit the reaction of lithium ions with aluminate to form lithium aluminate (LiAl v (OH)7·2H v O), to prevent lithium from re-entering the red mud. The reaction formula is: LiAl2(OH)7·2H2O+FeO2 - →Li + +2Al(OH)4 - +Fe(OH)3.

[0036] During the dissolution process, calcium ferrite can also form ferrohydrite garnet [3CaO·Fe2O3·nSiO2·(6-2n)H2O, n=1.5-2.6]. This compound will enter the red mud. This process helps to improve the recovery rate of alumina and reduce the alkali consumption during the dissolution process, thereby improving the economy and environmental protection of the overall process.

[0037] S2. Mixing the lithium-containing bauxite, calcium ferrite, and circulating mother liquor to obtain a mixture; wherein the mass of the calcium ferrite is 1% to 8% of the mass of the lithium-containing bauxite;

[0038] Calcium ferrite can play a catalytic role in the dissolution process of bauxite, especially in promoting the 10 (OH)8) has a significant effect on the dissolution reaction of lithium chlorite. Lithium chlorite is the main form of lithium in bauxite, and its structure is stable and not easily dissolved by conventional methods. However, under the action of calcium ferrite, the layered structure of lithium chlorite is more easily destroyed, making lithium ions more easily released, thereby significantly improving the dissolution rate of lithium. Excessive addition of calcium ferrite (the mass of calcium ferrite is greater than 8% of the mass of lithium-containing bauxite) will cause calcium ferrite to cover the surface of the mineral and hinder the reaction interface. In the embodiment of the present application, the mass of calcium ferrite is 1% to 8% of the mass of lithium-containing bauxite, which is a balance point. If the mass of calcium ferrite is less than 1% of the mass of lithium-containing bauxite, it may not be able to fully exert its promoting effect, and if the mass of calcium ferrite is greater than 8% of the mass of lithium-containing bauxite, it may cause waste of resources and even have an adverse effect on the dissolution process. Therefore, the mass of calcium ferrite is 1% to 8% of the mass of lithium-containing bauxite, which not only ensures the dissolution effect, but also reduces production costs. Illustratively, the mass of the calcium ferrite may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc., of the mass of the lithium-containing bauxite.

[0039] In the embodiments of the present application, the circulating mother liquor is a commonly used raw material in the Bayer process for producing alumina. It has strong alkalinity and can dissolve aluminum compounds in bauxite to form a sodium aluminate solution. After the sodium aluminate solution is treated to precipitate aluminum hydroxide, the remaining liquid phase can be recycled after treatment such as evaporation and concentration, and can be used again to dissolve aluminum compounds in the aluminum ore. Therefore, it is called the circulating mother liquor.

[0040] In some embodiments, the mass concentration of caustic soda in the circulating mother liquor is not less than 230 g / L.

[0041] Lithium chlorite is the main form of lithium in bauxite. Its structure is stable and not easily dissolved by conventional methods. However, under the action of a circulating mother liquor with a high caustic alkali concentration (≥230g / L), the dissolution reaction of lithium chlorite can be effectively promoted. Caustic alkali can destroy the layered structure of lithium chlorite, making it easier for lithium ions to be released, thereby increasing the dissolution rate of lithium. A mass concentration of caustic alkali ≥230g / L helps maintain a strong alkaline environment during the dissolution process, which is also beneficial for the dissolution of other aluminum-containing compounds in bauxite. Under strong alkaline conditions, aluminosilicate minerals in bauxite can react more effectively with alkali to form soluble sodium aluminate, thereby improving the overall dissolution effect. A mass concentration of caustic alkali ≥230g / L in the circulating mother liquor can also provide more flexible process conditions for the dissolution process. For example, under the condition of a mass concentration of caustic alkali ≥230g / L, the dissolution temperature and time can be optimized to a certain extent, thereby reducing energy consumption and production costs while ensuring the dissolution effect. For example, the mass concentration of caustic soda in the circulating mother liquor can be 230 g / L, 232 g / L, 234 g / L, 236 g / L, 238 g / L, 240 g / L, etc.

[0042] S3, ball milling the mixture to obtain raw ore slurry;

[0043] In some embodiments, the solid content of the raw ore slurry is 300 g / L to 350 g / L.

[0044] A solids content of 300g / L to 350g / L ensures sufficient contact area between the solid particles in the raw ore slurry and the calcium ferrite and circulating mother liquor, thereby promoting the leaching reaction of lithium chlorite. A solids content below 300g / L may result in insufficient contact between the reactants and reduce reaction efficiency; a solids content above 350g / L may increase the viscosity of the raw ore slurry, hindering the reaction. During the pre-desiliconization and dissolution processes, a solids content of 300g / L to 350g / L helps maintain slurry stability and fluidity, allowing for more even distribution of heat and reactants, thereby improving lithium dissolution efficiency. Solids contents above or below 350g / L may impair dissolution and reduce lithium recovery. Furthermore, controlling the raw ore slurry solids content within the range of 300g / L to 350g / L can facilitate the subsequent solid-liquid separation process. Solid contents above 350 g / L may make separation difficult, increasing energy consumption and time costs; whereas solid contents below 300 g / L may result in excessive solution volume, increasing processing burden. A solid content between 300 g / L and 350 g / L allows for more efficient solid-liquid separation, yielding a higher-quality lithium-containing sodium aluminate solution. For example, the solid content of the raw ore slurry may be 300 g / L, 310 g / L, 320 g / L, 330 g / L, 340 g / L, 350 g / L, and so on.

[0045] In some embodiments, the mass of the raw ore pulp with a particle size of less than 65 μm accounts for 72% to 75% of the total mass of the raw ore pulp.

[0046] The mass of the raw ore pulp with a particle size of less than 65 μm accounts for 72% to 75% of the total mass of the raw ore pulp, which can increase the contact area between lithium chlorite and the circulating mother liquor and additives, and accelerate the lithium chlorite (LiAl4 (Si3Al) O 10 (OH)8) chemical reaction, thereby improving the dissolution efficiency of lithium. If the particle size of the raw ore pulp is too coarse (less than 65μm and less than 72%), some lithium chlorite may not be able to fully contact with the circulating mother liquor, resulting in incomplete dissolution. If the particle size of the raw ore pulp is too fine (less than 65μm and more than 75%), it will increase the difficulty of solid-liquid separation in the subsequent sedimentation or filtration process, resulting in poor red mud sedimentation performance, excessive liquid suspended matter and other problems. Exemplarily, the mass of the raw ore pulp with a particle size of less than 65μm can be 72%, 72.5%, 73%, 73.5%, 74%, 74.5%, 75%, etc. of the total mass of the raw ore pulp.

[0047] S4, sequentially performing pre-desiliconization and dissolution treatment on the raw ore pulp to obtain a dissolution slurry;

[0048] Pre-desiliconization is an important step in the bauxite processing process. Its main purpose is to remove silicon-containing minerals (such as kaolinite) in the slurry to prevent these minerals from forming scars in the subsequent dissolution process and affecting the dissolution effect.

[0049] In some embodiments, the pre-desiliconization temperature is 95°C to 105°C.

[0050] Controlling the pre-desiliconization temperature at 95°C to 105°C can effectively promote the reaction of kaolinite (mainly silicon-containing minerals) in bauxite with alkaline solution to generate hydrated sodium aluminosilicate (Na2O·Al2O3·nSiO2·mH2O) and enter the solid phase, thereby being removed from the slurry. This process can prevent silicon from forming scars in the subsequent high-temperature dissolution stage, reduce the risk of pipeline and equipment blockage, and ensure production continuity. When the temperature is lower than 95°C, the decomposition reaction rate of kaolinite is significantly reduced, resulting in an extension of the pre-desiliconization time; while above 105°C, steam consumption will increase, resulting in energy waste. The temperature range of 95°C to 105°C achieves the optimal balance of energy consumption control while ensuring the sufficiency of the reaction. Effectively removing silicon impurities in the pre-desiliconization stage can avoid the competitive reaction between silicate ions and lithium ions in the subsequent dissolution process, thereby providing lithium chlorite (LiAl4(Si3Al)O 10 The dissolution of (OH)8) provides a more stable alkaline environment. Exemplarily, the temperature of the pre-desiliconization can be 95°C, 97°C, 99°C, 101°C, 103°C, 105°C, etc.

[0051] In some embodiments, the pre-desiliconization time is 4 hours to 8 hours.

[0052] A reaction time of 4 to 8 hours ensures that the kaolinite fully reacts with the strong alkali solution, preventing the formation of scars from unreacted silicon minerals during the subsequent high-temperature dissolution process. Pre-desiliconization times shorter than 4 hours may result in incomplete reaction, affecting the desiliconization effect; pre-desiliconization times longer than 8 hours may increase energy consumption and production costs. Therefore, a pre-desiliconization time of 4 to 8 hours ensures that the silicon minerals fully react and achieves a good desiliconization effect. For example, the pre-desiliconization time can be 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, etc.

[0053] In some embodiments, the dissolution treatment time is not less than 45 minutes.

[0054] During the dissolution process, the aluminum-containing minerals in the bauxite react with alkali to form soluble sodium aluminate. Sufficient dissolution time can ensure that this reaction is fully carried out, thereby increasing the amount of sodium aluminate produced. This not only helps the subsequent extraction of aluminum, but also creates more favorable conditions for the dissolution of lithium. A dissolution treatment time of not less than 45 minutes can ensure that the lithium chlorite has enough time to fully react with the dissolution agent (such as caustic soda), thereby destroying its layered structure, making lithium ions more easily released, and increasing the dissolution rate of lithium. A dissolution time shorter than 45 minutes will cause calcium ions to react with the lithium chlorite (LiAl4(Si3Al)O 10The layered structure of (OH)8) does not react sufficiently, which may lead to incomplete dissolution and affect the extraction efficiency of target elements such as lithium. Therefore, setting the dissolution time to no less than 45 minutes can ensure the dissolution effect. Exemplary dissolution treatment times can be 45 minutes, 47 minutes, 49 minutes, 51 minutes, 53 minutes, 55 minutes, etc.

[0055] In some embodiments, the temperature of the dissolution treatment is not less than 260°C.

[0056] As the main carrier of lithium in bauxite, the dissolution process of lithium chlorite usually requires high energy input. Setting the dissolution temperature to no less than 260°C can significantly accelerate the chemical reaction between lithium chlorite and the dissolution agent (such as caustic soda), destroying its stable layered structure, releasing lithium from the mineral lattice and converting it into soluble Li + In addition, under high temperature conditions of not less than 260°C, the sodium aluminate generated by the reaction of aluminum-containing minerals in bauxite with alkali has a higher solubility. Maintaining the high solubility of sodium aluminate can reduce its residue in the solid phase, thereby improving the extraction efficiency of aluminum and lithium. An environment of not less than 260°C can also significantly inhibit the dissolution of Li in sodium aluminate solution. + With Al(OH) 4- The side reaction of producing lithium aluminate (LiAl2(OH)7·2H2O). 2- ) activity is enhanced at temperatures of not less than 260°C, and lithium ions in the lithium aluminate are replaced by reactions, preventing lithium from being lost to red mud. Exemplary dissolution treatment temperatures may include 260°C, 262°C, 264°C, 266°C, 268°C, 270°C, and the like.

[0057] S5, performing solid-liquid separation on the dissolved slurry to obtain a lithium-containing sodium aluminate solution;

[0058] In the embodiments of the present application, solid-liquid separation refers to a process in which a flocculant is added to the slurry to cause solid particles therein to flocculate and settle. The flocculant can be a polyacrylamide, and solid-liquid separation can be performed using common equipment such as a sedimentation tank, a filter, and a filter press.

[0059] In some embodiments, the mass concentration of suspended matter in the lithium-containing sodium aluminate solution is less than 0.25 g / L.

[0060] Suspended matter is residual solid particles that have not been fully separated from the dissolved ore slurry. If the concentration exceeds 0.25 g / L, it will interfere with the subsequent separation, enrichment, and concentration of lithium ions. For example, suspended particles may clog adsorption or ion exchange equipment or compete with lithium ions for reaction sites, reducing separation efficiency. By controlling the mass concentration of suspended matter to less than 0.25 g / L, efficient lithium ion extraction can be ensured. For example, the mass concentration of suspended matter in a lithium-containing sodium aluminate solution can be 0.05 g / L, 0.1 g / L, 0.15 g / L, 0.2 g / L, 0.24 g / L, etc.

[0061] S6. Sequentially enriching and precipitating the lithium ions in the lithium-containing sodium aluminate solution to separate the lithium ions in the lithium-containing sodium aluminate solution.

[0062] Sequentially enriching and precipitating the lithium ions in the lithium-containing sodium aluminate solution may include separating, desorbing, and concentrating the lithium ions in the lithium-containing sodium aluminate solution, and adding sodium phosphate to prepare lithium phosphate.

[0063] Lithium ions in lithium-containing sodium aluminate solutions need to be extracted using some kind of separation technology. This usually involves using the differences in physical or chemical properties of lithium ions from other ions, such as solubility, ionic radius, charge, etc. to separate lithium ions. Separation methods may include:

[0064] Extraction: Using a specific extractant that has a high selectivity for lithium ions and can extract them from the sodium aluminate solution.

[0065] Adsorption: Utilize the adsorption effect of adsorption materials (such as specific resins or activated carbon) on lithium ions to adsorb lithium ions from the solution to the surface of the adsorbent.

[0066] The desorption process is to release lithium ions that have been adsorbed or fixed on a certain carrier for subsequent concentration and treatment. The desorption method is usually matched with the adsorption or extraction method.

[0067] The concentration process is to concentrate the solution containing lithium ions to increase the concentration of lithium ions. The concentration method may include:

[0068] Evaporation concentration: The water in the solution is evaporated by heating, thereby increasing the concentration of lithium ions.

[0069] Membrane concentration: Use membrane technology (such as reverse osmosis, electrodialysis, etc.) to concentrate the solution.

[0070] Finally, the concentrated lithium-containing solution can be reacted with sodium phosphate to prepare lithium phosphate.

[0071] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0072] Example 1

[0073] This embodiment includes the following steps:

[0074] 1. Providing lithium-containing bauxite, wherein the lithium in the lithium-containing bauxite exists in the form of lithium chlorite;

[0075] 2. The bauxite is coarsely crushed and mixed with calcium ferrite and circulating mother liquor to obtain a raw ore slurry, wherein the amount of calcium ferrite added is 8% by weight of the bauxite, and the mass percentage of mineral particles with a particle size of less than 65 μm in the raw ore slurry is 75%;

[0076] 3. The raw ore pulp is subjected to pre-desiliconization and dissolution treatment to obtain a dissolution slurry, wherein the pre-desiliconization temperature is 105° C., the pre-desiliconization time is 8 hours, the dissolution temperature is 280° C., and the dissolution time is 45 minutes;

[0077] 4. The dissolved slurry is fed into a sedimentation tank for solid-liquid separation to obtain a lithium-containing sodium aluminate solution;

[0078] 5. Separate and enrich, desorb, and concentrate the lithium ions in the lithium-containing sodium aluminate solution, and add sodium phosphate to prepare lithium phosphate. The lithium dissolution rate in this embodiment is 99%.

[0079] Example 2

[0080] This embodiment includes the following steps:

[0081] 1. Providing lithium-containing bauxite, wherein the lithium in the lithium-containing bauxite exists in the form of lithium chlorite;

[0082] 2. The bauxite is coarsely crushed and mixed with calcium ferrite and circulating mother liquor to obtain a raw ore slurry, wherein the amount of calcium ferrite added is 1% by weight of the bauxite, and the mass percentage of mineral particles with a particle size of less than 65 μm in the raw ore slurry is 72%;

[0083] 3. The raw ore pulp is subjected to pre-desiliconization and dissolution treatment to obtain a dissolution slurry, wherein the pre-desiliconization temperature is 95° C., the pre-desiliconization time is 4 hours, the dissolution temperature is 260° C., and the dissolution time is 60 minutes;

[0084] 4. The dissolved slurry is fed into a sedimentation tank for solid-liquid separation to obtain a lithium-containing sodium aluminate solution;

[0085] 5. Separate and enrich, desorb, and concentrate the lithium ions in the lithium-containing sodium aluminate solution, and add sodium phosphate to prepare lithium phosphate. The lithium dissolution rate in this embodiment is 95%.

[0086] Example 3

[0087] This embodiment includes the following steps:

[0088] 1. Providing lithium-containing bauxite, wherein the lithium in the lithium-containing bauxite exists in the form of lithium chlorite;

[0089] 2. The bauxite is coarsely crushed and mixed with calcium ferrite and circulating mother liquor to obtain a raw ore slurry, wherein the amount of calcium ferrite added is 4% of the mass of the bauxite, and the mass percentage of mineral particles with a particle size of less than 65 μm in the raw ore slurry is 74%;

[0090] 3. The raw ore pulp is subjected to pre-desiliconization and dissolution treatment to obtain a dissolution slurry, wherein the pre-desiliconization temperature is 100° C., the pre-desiliconization time is 6 hours, the dissolution temperature is 270° C., and the dissolution time is 60 minutes;

[0091] 4. The dissolved slurry is fed into a filter press for solid-liquid separation to obtain a lithium-containing sodium aluminate solution;

[0092] 5. Separate and enrich, desorb, and concentrate the lithium ions in the lithium-containing sodium aluminate solution, and add sodium phosphate to prepare lithium phosphate. The lithium dissolution rate in this embodiment is 96%.

[0093] Example 4

[0094] This embodiment includes the following steps:

[0095] 1. Providing lithium-containing bauxite, wherein the lithium in the lithium-containing bauxite exists in the form of lithium chlorite;

[0096] 2. The bauxite is coarsely crushed and mixed with calcium ferrite and circulating mother liquor to obtain a raw ore slurry, wherein the amount of calcium ferrite added is 6% of the mass of the bauxite, and the mass percentage of mineral particles with a particle size of less than 65 μm in the raw ore slurry is 73%;

[0097] 3. The raw ore pulp is subjected to pre-desiliconization and dissolution treatment to obtain a dissolution slurry, wherein the pre-desiliconization temperature is 100° C., the pre-desiliconization time is 5 hours, the dissolution temperature is 265° C., and the dissolution time is 50 minutes;

[0098] 4. The dissolved slurry is fed into a filter press for solid-liquid separation to obtain a lithium-containing sodium aluminate solution;

[0099] 5. Separate and enrich, desorb, and concentrate the lithium ions in the lithium-containing sodium aluminate solution, and add sodium phosphate to prepare lithium phosphate. The lithium dissolution rate in this embodiment is 97%.

[0100] Example 5

[0101] This embodiment includes the following steps:

[0102] 1. Providing lithium-containing bauxite, wherein the lithium in the lithium-containing bauxite exists in the form of lithium chlorite;

[0103] 2. The bauxite is coarsely crushed and mixed with calcium ferrite and circulating mother liquor to obtain a raw ore slurry, wherein the amount of calcium ferrite added is 7% of the mass of the bauxite, and the mass percentage of the ore particles with a particle size of less than 65 μm in the raw ore slurry is 75%;

[0104] 3. The raw ore pulp is subjected to pre-desiliconization and dissolution treatment to obtain a dissolution slurry, wherein the pre-desiliconization temperature is 100° C., the pre-desiliconization time is 7 hours, the dissolution temperature is 275° C., and the dissolution time is 70 minutes;

[0105] 4. The dissolved slurry is fed into a filter press for solid-liquid separation to obtain a lithium-containing sodium aluminate solution;

[0106] 5. Separate and enrich, desorb, and concentrate the lithium ions in the lithium-containing sodium aluminate solution, and add sodium phosphate to prepare lithium phosphate. The lithium dissolution rate in this embodiment is 98%.

[0107] Comparative Example 1

[0108] This example includes the following steps:

[0109] 1. Providing lithium-containing bauxite, wherein the lithium in the lithium-containing bauxite exists in the form of lithium chlorite;

[0110] 2. The bauxite is coarsely crushed and mixed with calcium ferrite and circulating mother liquor to obtain a raw ore slurry, wherein the amount of calcium ferrite added is 0% by weight of the bauxite, and the mass percentage of mineral particles with a particle size of less than 65 μm in the raw ore slurry is 75%;

[0111] 3. The raw ore pulp is subjected to pre-desiliconization and dissolution treatment to obtain a dissolution slurry, wherein the pre-desiliconization temperature is 100° C., the pre-desiliconization time is 7 hours, the dissolution temperature is 275° C., and the dissolution time is 70 minutes;

[0112] 4. The dissolved slurry is fed into a filter press for solid-liquid separation to obtain a lithium-containing sodium aluminate solution;

[0113] 5. Separate and enrich, desorb, and concentrate the lithium ions in the lithium-containing sodium aluminate solution, and add sodium phosphate to prepare lithium phosphate. In this example, the lithium dissolution rate is 20%.

[0114] It can be seen from the examples and comparative examples that the lithium dissolution rate can reach 95% to 99% by adding calcium ferrite as a catalyst in the examples, while the dissolution rate of the comparative example without adding calcium ferrite is only 20%.

[0115] In addition, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0116] Significantly improves lithium dissolution rate: By adding calcium ferrite during the ball milling process, the leaching reaction of lithium chlorite is effectively promoted and the reaction between lithium ions and aluminate ions in the sodium aluminate solution is inhibited, thereby significantly increasing the lithium dissolution rate. This not only helps improve the quality of alumina products, but also achieves efficient utilization of lithium resources.

[0117] Optimizing the alumina production process: This method improves on the existing alumina production process without introducing additional complex equipment or process steps, which reduces production costs and improves production efficiency.

[0118] Improve the recovery rate of alumina: Calcium ferrite can also form iron hydrate garnet and enter the red mud. This process helps to improve the recovery rate of alumina and reduce alkali consumption, further improving the economic benefits of production.

[0119] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for increasing the lithium dissolution rate in bauxite, the method comprising: Obtaining lithium-containing bauxite; The lithium-containing bauxite, calcium ferrite and circulating mother liquor are mixed to obtain a mixture; wherein the mass of the calcium ferrite is 1% to 8% of the mass of the lithium-containing bauxite; ball milling the mixture to obtain raw ore slurry; The raw ore pulp is subjected to pre-desiliconization and dissolution treatment in sequence to obtain dissolution ore pulp; performing solid-liquid separation on the dissolved slurry to obtain a lithium-containing sodium aluminate solution; The lithium ions in the lithium-containing sodium aluminate solution are sequentially enriched and precipitated to separate the lithium ions in the lithium-containing sodium aluminate solution.

2. The method according to claim 1, characterized in that The lithium-containing bauxite is a diaspore-type bauxite, and the lithium in the lithium-containing bauxite exists in the form of lithium chlorite.

3. The method according to claim 1, characterized in that The solid content of the raw ore slurry is 300g / L to 350g / L.

4. The method according to claim 1, wherein The mass concentration of caustic soda in the circulating mother liquor is not less than 230 g / L.

5. The method according to claim 1, wherein The mass of the raw ore pulp with a particle size of less than 65 μm accounts for 72% to 75% of the total mass of the raw ore pulp.

6. The method according to claim 1, characterized in that The temperature of the pre-desiliconization is 95°C to 105°C.

7. The method according to claim 1, characterized in that The time of the pre-desiliconization is 4 hours to 8 hours.

8. The method according to claim 1, characterized in that The dissolution treatment time is not less than 45 minutes.

9. The method according to claim 1, characterized in that The temperature of the dissolution treatment is not lower than 260°C.

10. The method according to claim 1, characterized in that In the lithium-containing sodium aluminate solution, the mass concentration of suspended matter is less than 0.25 g / L.

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