A method for extracting lithium based on granulation of lithium ore

Abstract

This invention discloses a lithium extraction method based on lithium ore granulation. The method includes roasting and leaching lithium ore concentrate particles to extract lithium. The lithium ore concentrate particles are obtained by mixing lithium ore concentrate, roasting additives, and volatile binders, followed by fine grinding, mixing with water, and granulation. The lithium ore concentrate particles used in this invention have advantages such as high pelletizing rate, high particle strength, and a large contact area between the lithium ore and the roasting raw material. When used as a lithium extraction raw material for roasting and water leaching, it not only significantly improves the roasting effect and achieves complete transformation and replacement of lithium ore under lower energy consumption conditions, but also allows the roasted product to be directly leached under normal temperature and pressure conditions. The leaching efficiency is high, the lithium extraction rate is high, and the leaching water can be reused repeatedly without generating secondary pollution such as wastewater. Furthermore, there is no need to crush the roasted product before leaching, and the use of acids and alkalis can be avoided, making it more environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of lithium extraction technology and relates to a lithium extraction method based on lithium ore granulation. Background Technology

[0002] With the rapid development of power batteries and energy storage devices in the new energy field, the demand for lithium carbonate, as an important raw material, is increasing daily. Extracting lithium from lithium ore is a crucial industrial method for obtaining lithium carbonate. The process of lithium extraction from lithium ore involves first roasting the ore to convert lithium into soluble lithium salts. Then, the roasted product is leached, transferring lithium from the ore to the leachate. Finally, the leachate is purified to obtain lithium carbonate. Therefore, improving the roasting and leaching effects is key to obtaining more high-purity lithium carbonate, with improving the roasting effect being crucial for improving the leaching effect.

[0003] In industrial applications, rotary kilns and tunnel kilns are commonly used for roasting lithium ore. Among them, rotary kilns have advantages in terms of process, capacity, investment, land occupation, energy consumption, waste heat utilization, and environmental protection, and therefore have greater application prospects. However, to achieve complete transformation or replacement of lithium ore, very high roasting temperatures are usually required, typically 1100℃~1200℃ in industrial applications. This not only results in high energy consumption and large carbon emissions, but also causes the furnace charge to melt and form rings at high temperatures, which is detrimental to normal production. In particular, when lithium ore is directly fed into the furnace for roasting, the ring formation phenomenon in the rotary kiln becomes more severe, and uneven heating can easily lead to over-burning or under-burning, which is not conducive to improving the lithium extraction rate. Furthermore, it easily consumes large amounts of natural gas, resulting in excessively high costs, and also easily generates a large amount of dust, leading to high dust content in the flue gas and a heavy load on flue gas treatment.To address the aforementioned technical deficiencies, researchers have proposed methods for granulating bulk lithium ore. Specifically, lithium ore is mixed with roasting additives, auxiliaries, and water before roasting, and then granulated using a granulator to obtain lithium ore particles, which serve as the roasting raw material. However, these granulation methods still suffer from the following defects: (1) The lithium ore particle size is too large, making it difficult to fully contact the roasting material, resulting in poor roasting reaction. Furthermore, it is difficult to form and easily breaks. Even if the lithium ore is crushed or dry-ground and screened before mixing to remove large particles, it is still difficult to obtain smaller lithium ore particles. Defects such as insufficient contact with the roasting material and poor forming effect still exist. Moreover, when mixed with other roasting materials… Before mixing, the lithium ore is crushed and dry-ground, which easily forms excessively fine materials. These materials are difficult to utilize effectively and easily lead to the waste of lithium resources. (2) When lithium ore is mixed with roasting additives and water, on the one hand, because lithium ore is easy to separate into layers, it is difficult to form particles or the particle strength is low. In particular, for flaky lepidolite and layered spodumene, it is even more difficult to form particles and the particle strength is even lower, resulting in poor granulation effect and low pelletizing rate. As a result, the particles are very easy to break during roasting, which is not conducive to the effective roasting of lithium ore. Ultimately, the lithium extraction rate is still low. On the other hand, the particles obtained by directly mixing lithium ore with roasting additives make the particles easy to agglomerate during roasting, leading to The particle size becomes larger and denser, resulting in difficulty for the leachate to quickly penetrate the interior of the roasted product in the subsequent leaching steps, which easily leads to defects such as low leaching rate and poor leaching effect. This also results in a low lithium extraction rate. At the same time, in order to overcome the above difficulties, the roasted product usually needs to be crushed before leaching, or an acid solution or alkaline solution is used as the leachate. Obviously, this is not conducive to simplifying the lithium extraction process, and it is easy to increase production costs and cause secondary pollution. (3) In order to overcome the defects of difficult particle forming or low strength, binders are added to the raw materials. However, the addition of these binders will not only increase the density of the roasted product, making the leaching of the roasted product more difficult and the leaching effect worse, but also This will increase the energy consumption of roasting, leading to a sharp increase in production costs. At the same time, the use of these binders will also increase the output of waste residue, leading to a significant increase in the difficulty and cost of waste residue treatment. (4) In order to further improve the transformation and replacement effect, additives are added to the raw materials. However, the addition of these additives will, on the one hand, increase the density of roasted products, making it more difficult to leach roasted products, or require additional crushing treatment, and additional acid and pressure treatment during the leaching process, increasing the production difficulty. On the other hand, it will also increase the energy consumption of roasting, leading to a sharp increase in production costs. Moreover, the use of these additives will also increase the output of wastewater and waste residue, which will significantly increase the difficulty and cost of subsequent treatment and also easily lead to secondary pollution.Therefore, overcoming the technical defects in the above-mentioned lithium ore granulation methods to obtain lithium ore concentrate particles with high pelletizing rate, high particle strength, and large contact area between lithium ore and roasting raw materials is of great significance for improving roasting reaction effect, reducing roasting energy consumption, and improving lithium leaching efficiency and leaching effect. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a lithium extraction method based on lithium ore granulation that has good roasting reaction effect, low roasting energy consumption, high leaching efficiency, high lithium leaching rate, and is green and environmentally friendly.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0006] A lithium extraction method based on lithium ore granulation includes the following steps:

[0007] (1) Roasting lithium ore concentrate particles;

[0008] (2) The product obtained after roasting is placed in water for leaching to complete the extraction of lithium;

[0009] The granulation method for the lithium ore concentrate particles includes the following steps:

[0010] S1. Mix lithium ore concentrate, roasting additives and volatile binders to obtain mixture B;

[0011] S2. Finely grind mixture B until the particle size is above 200 mesh to obtain mixture C;

[0012] S3. Mix mixture C with water to obtain mixture D;

[0013] S4. Granulate the mixture D to obtain lithium ore concentrate particles.

[0014] In a further improvement to the above-mentioned lithium extraction method, step S1 involves the following steps in which the preparation of mixture B includes:

[0015] S1-1. Mix lithium ore concentrate and roasting additives to obtain mixture A;

[0016] S1-2. Mix mixture A with volatile binder to obtain mixture B.

[0017] In a further improvement to the above-mentioned lithium extraction method, in step S1-1, the mass ratio of the lithium ore concentrate to the roasting additive is 1:0.1 to 0.8.

[0018] In a further improvement to the above-described lithium extraction method, in step S1-1, the calcination additive is at least one of calcium sulfate, calcium carbonate, sodium sulfate, and potassium sulfate, or a mixture thereof.

[0019] In a further improvement to the above-mentioned lithium extraction method, in step S1-1, the lithium ore concentrate is at least one of spodumene concentrate, lepidolite concentrate, and lithium clay concentrate; and the lithium mass percentage content in the lithium ore concentrate is ≥1.5%.

[0020] In a further improvement to the above-mentioned lithium extraction method, in step S1-1, the mass ratio of the lithium ore concentrate to the roasting additive is 1:0.3 to 0.7.

[0021] In a further improvement to the above-mentioned lithium extraction method, in steps S1-2, the amount of volatile binder added is 0.1% to 20% of the total mass of the mixture A; the volatile binder is at least one of semi-coke and petroleum coke.

[0022] In a further improvement to the above-mentioned lithium extraction method, in steps S1-2, the amount of volatile binder added is 1% to 10% of the total mass of the mixture A.

[0023] In a further improvement to the above-mentioned lithium extraction method, in step S2, the particle size of the mixture C is above 300 mesh.

[0024] In a further improvement to the lithium extraction method described above, in step S3, the amount of water added is 5% to 20% of the total mass of the mixture C.

[0025] In a further improvement to the above-mentioned lithium extraction method, in step S4, the particle size of the lithium ore concentrate particles is 8mm to 10mm.

[0026] In a further improvement to the above-mentioned lithium extraction method, in step S2, the particle size of the mixture C is 300 mesh to 1000 mesh.

[0027] In a further improvement to the above-mentioned lithium extraction method, in step (1), a rotary kiln is used to roast the lithium ore concentrate particles; the roasting temperature is 850℃~900℃; and the roasting time is 30min~50min.

[0028] In a further improvement to the above lithium extraction method, in step (2), the liquid-to-solid ratio is controlled to be 0.8 to 1:1 during the leaching process; and the leaching time is 3 to 4 days.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] To address the shortcomings of existing lithium ore granulation methods, such as complex processes, high operational difficulty, low pellet formation rate, low particle strength, and small contact area between lithium ore and roasting raw materials, resulting in poor roasting reaction, high roasting energy consumption, low leaching rate, low lithium leaching rate, and secondary pollution, this invention creatively proposes a lithium extraction method based on lithium ore granulation. First, lithium ore concentrate, roasting additives, and volatile binders are mixed to ensure uniform mixing and sufficient contact between the lithium mica concentrate and the roasting additives. This allows the lithium mica concentrate to bond and fix with the volatile binder, thereby improving the efficiency of lithium mica concentrate extraction. The increased contact area with the roasting additives improves subsequent roasting efficiency (i.e., increases leaching rate). Simultaneously, the added volatile binders, with their high calorific value, can act as heat-generating aids, reducing natural gas consumption during roasting. Furthermore, the vaporization of these volatile binders during roasting creates porous channels in the roasted product, further enhancing the leaching rate and efficiency, while also reducing tailings production. Further, the mixture of lithium ore concentrate, roasting additives, and volatile binders undergoes fine grinding. This fine grinding reduces the lithium ore mesh size from approximately 100 mesh to 2 mesh. Grinding the lithium ore concentrate to a finer mesh (00 mesh or finer) gradually transforms its morphology into granules. This not only facilitates subsequent granulation but also increases the contact area between the lithium mica concentrate and the roasting additives, promoting roasting conversion and improving lithium extraction rate. By altering the morphology of the lithium ore concentrate, fine grinding also enhances the adhesion strength of volatile binders to the lithium mica concentrate and roasting additives, resulting in higher-strength granules. This effectively prevents granule breakage during roasting, thus avoiding material melting and ring formation. Finally, the mixture is granulated. This method yields lithium ore concentrate particles with high pelletizing rate, high particle strength, and a large contact area between lithium ore and roasting raw materials. Based on this, the obtained lithium ore concentrate particles are used as lithium extraction raw materials for roasting and water leaching. This not only significantly improves the roasting effect and enables complete transformation and replacement of lithium ore under lower energy consumption conditions, but also allows the roasted product to be directly water-leached under normal temperature and pressure conditions. The water leaching efficiency is high, the lithium leaching rate is high, and the water used for leaching can be reused without generating secondary pollution such as wastewater. At the same time, there is no need to crush the roasted product before water leaching, and the use of acids and alkalis can also be avoided, making it more green and environmentally friendly. Attached Figure Description

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0032] Figure 1 This is a schematic diagram of the lithium extraction process based on lithium ore granulation in an embodiment of the present invention.

[0033] Figure 2 This is a graph showing the lithium leaching effect of the roasted product in the first three cycles of Example 1 of the present invention.

[0034] Figure 3 This is a graph showing the lithium leaching effect of the roasted product in the first three cycles of Example 2 of the present invention.

[0035] Figure 4 This is a graph showing the lithium leaching effect of the roasted product in the first three cycles of Example 3 of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, all materials and instruments used in the following embodiments are commercially available.

[0037] Example 1

[0038] A lithium extraction method based on lithium ore granulation, specifically using lepidolite concentrate granules as raw material for lithium extraction, is illustrated in the following process flow diagram. Figure 1 As shown, it includes the following steps:

[0039] S1. Take 100 kg of lepidolite concentrate (100 mesh, lithium content 2%) and mix it with roasting additives at a mass ratio of 1:0.6. The roasting additives are a mixture of calcium sulfate, calcium carbonate, sodium sulfate, and potassium sulfate, and the mass ratio of lepidolite concentrate to calcium sulfate, calcium carbonate, sodium sulfate, and potassium sulfate is 1:0.3:0.1:0.1:0.1, ensuring that the lepidolite concentrate and roasting additives are mixed evenly and in full contact, resulting in mixture A. In this invention, the type of roasting additive and the proportion of different types of roasting additives can be adjusted according to actual conditions.

[0040] S2. Mixing mixture A with the roasting additive (semi-coke) at a ratio of 3% of the total mass of mixture A, the lithium mica concentrate and roasting additive are bonded together under the action of the semi-coke, resulting in mixture B. In this invention, the lithium ore concentrate and roasting additive are mixed first, and then a volatile binder is added. This not only facilitates the formation of a material with good mixing uniformity but also increases the contact area between the lithium mica concentrate and the roasting additive.

[0041] S3. Add mixture B to the ball mill and grind it until the particle size reaches 300 mesh to obtain mixture C.

[0042] S4. Add water at a rate of 8% of the total mass of mixture C, and mix mixture C with water to obtain mixture D.

[0043] S5. The mixture D is granulated using a disc granulator to obtain lithium mica concentrate particles with a particle size of 10 mm.

[0044] S6. The lithium ore concentrate particles are roasted in a rotary kiln at a temperature of 900℃ for 45 minutes.

[0045] S7. The roasted product is leached in water at a liquid-to-solid ratio of 0.8:1 for 4 days to extract lithium. In this step, the roasted product is not crushed; leaching is performed directly using a countercurrent leaching method. Specifically, the roasted product is sequentially soaked in leachate obtained from different leaching stages, maintaining a liquid-to-solid ratio of 0.8:1 throughout the leaching process. Each leaching session lasts one day, for a total of 4 days of leaching. Finally, the residual lithium content in the leached product is measured. Based on this, combined with the initial lithium content in the lithium ore concentrate, the lithium leaching rate is calculated.

[0046] In step S7, the leachate obtained after leaching also includes the following treatments: filtration, purification, concentration, lithium precipitation, carbonization purification, drying and packaging, to obtain battery-grade lithium carbonate products.

[0047] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lithium mica concentrate particles obtained in Example 1 were tested, and the results are shown in Table 1.

[0048] Example 2

[0049] A lithium extraction method based on lithium ore granulation, specifically using lepidolite concentrate granules as raw material for lithium extraction, is illustrated in the following process flow diagram. Figure 1 As shown, it includes the following steps:

[0050] S1. Take 200 kg of lithium mica concentrate (100 mesh, lithium content 1.8%) and mix it with roasting additives at a mass ratio of 1:0.7. The roasting additives are a mixture of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate. The mass ratio of lithium mica concentrate to calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate is 1:0.3:0.1:0.2:0.1. This ensures that the lithium mica concentrate and roasting additives are mixed evenly and in full contact, resulting in mixture A.

[0051] S2. According to the addition amount of roasting auxiliary material being 4% of the total mass of mixture A, mixture A is mixed with roasting auxiliary material (semi-coke). Under the action of semi-coke, the lithium mica concentrate and roasting additives are bonded together to obtain mixture B. The semi-coke in mixture B is...

[0052] S3. Add mixture B to the ball mill and grind it until the particle size reaches 400 mesh to obtain mixture C.

[0053] S4. Add water at a rate of 10% of the total mass of mixture C, and mix mixture C with water to obtain mixture D.

[0054] S5. The mixture D is granulated using a disc granulator to obtain lithium mica concentrate particles with a particle size of 9 mm.

[0055] S6. The lithium ore concentrate particles are roasted in a rotary kiln at a temperature of 900℃ for 45 minutes.

[0056] S7. The roasted product is leached in water at a liquid-to-solid ratio of 0.8:1 for 4 days to extract lithium. In this step, the roasted product is not crushed; leaching is performed directly using a countercurrent leaching method. Specifically, the roasted product is sequentially soaked in leachate obtained from different leaching stages, maintaining a liquid-to-solid ratio of 0.8:1 throughout the leaching process. Each leaching session lasts one day, for a total of 4 days of leaching. Finally, the residual lithium content in the leached product is measured. Based on this, combined with the initial lithium content in the lithium ore concentrate, the lithium leaching rate is calculated.

[0057] In step S7, the leachate obtained after leaching also includes the following treatments: filtration, purification, concentration, lithium precipitation, carbonization purification, drying and packaging, to obtain battery-grade lithium carbonate products.

[0058] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lithium mica concentrate particles obtained in Example 2 were tested, and the results are shown in Table 1.

[0059] Example 3

[0060] A lithium extraction method based on lithium ore granulation, specifically using lepidolite concentrate granules as raw material for lithium extraction, is illustrated in the following process flow diagram. Figure 1 As shown, it includes the following steps:

[0061] S1. Take 200 kg of lithium mica concentrate (100 mesh, lithium content 2.5%) and mix it with roasting additives at a mass ratio of 1:0.5. The roasting additives are a mixture of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate. The mass ratio of lithium mica concentrate to calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate is 1:0.2:0.1:0.1:0.1. This ensures that the lithium mica concentrate and roasting additives are mixed evenly and in full contact, resulting in mixture A.

[0062] S2. Mix the roasting auxiliary material (semi-coke) with the roasting auxiliary material (semi-coke) according to the addition amount of roasting auxiliary material being 5% of the total mass of mixture A. Under the action of semi-coke, the lithium mica concentrate and roasting additives are bonded together to obtain mixture B. The semi-coke in mixture B is...

[0063] S3. Add mixture B into a ball mill and grind it until the particle size reaches 500 mesh to obtain mixture C.

[0064] S4. Add water at a rate of 13% of the total mass of mixture C, and mix mixture C with water to obtain mixture D.

[0065] S5. The mixture D is granulated using a disc granulator to obtain lithium mica concentrate particles with a particle size of 8 mm.

[0066] S6. The lithium ore concentrate particles are roasted in a rotary kiln at a temperature of 900℃ for 45 minutes.

[0067] S7. The roasted product is leached in water at a liquid-to-solid ratio of 0.8:1 for 4 days to extract lithium. In this step, the roasted product is not crushed; leaching is performed directly using a countercurrent leaching method. Specifically, the roasted product is sequentially soaked in leachate obtained from different leaching stages, maintaining a liquid-to-solid ratio of 0.8:1 throughout the leaching process. Each leaching session lasts one day, for a total of 4 days of leaching. Finally, the residual lithium content in the leached product is measured. Based on this, combined with the initial lithium content in the lithium ore concentrate, the lithium leaching rate is calculated.

[0068] In step S7, the leachate obtained after leaching also includes the following treatments: filtration, purification, concentration, lithium precipitation, carbonization purification, drying and packaging, to obtain battery-grade lithium carbonate products.

[0069] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lithium mica concentrate particles obtained in Example 3 were tested, and the results are shown in Table 1.

[0070] Example 4

[0071] A lithium extraction method based on lithium ore granulation is basically the same as that in Example 3, except that the roasting auxiliary material used in step S2 is petroleum coke.

[0072] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lithium mica concentrate particles obtained in Example 4 were tested, and the results are shown in Table 1.

[0073] Example 5

[0074] A method for granulating lithium ore concentrate, specifically using spodumene concentrate as raw material to prepare spodumene concentrate particles, includes the following steps:

[0075] S1. Take 200 kg of spodumene concentrate (100 mesh, lithium content 6%), add the roasting additive according to the mass ratio of lithium ore concentrate to roasting additive of 1:0.5, wherein the roasting additive is a mixture of calcium carbonate, sodium sulfate and potassium sulfate, and the mass ratio of spodumene concentrate to calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate is 1:0.2:0.1:0.1:0.1, stir to make the spodumene concentrate and roasting additive evenly mixed and fully contacted, to mix material A.

[0076] S2. The amount of volatile binder added is 4% of the total mass of mixture A. Mix mixture A with volatile binder (semi-coke). Under the action of semi-coke, the spodumene concentrate and roasting additives are bonded together to obtain mixture B. The semi-coke in mixture B is...

[0077] S3. Add mixture B to the ball mill and grind it until the particle size reaches 400 mesh to obtain mixture C.

[0078] S4. Add water at a rate of 10% of the total mass of mixture C, and mix mixture C with water to obtain mixture D.

[0079] S5. The mixture D is granulated using a disc granulator to obtain spodumene concentrate particles with a particle size of 8 mm.

[0080] S6. The lithium ore concentrate particles are roasted in a rotary kiln at a temperature of 900℃ for 45 minutes.

[0081] S7. The roasted product is leached in water at a liquid-to-solid ratio of 0.8:1 for 4 days to extract lithium. In this step, the roasted product is not crushed; leaching is performed directly using a countercurrent leaching method. Specifically, the roasted product is sequentially soaked in leachate obtained from different leaching stages, maintaining a liquid-to-solid ratio of 0.8:1 throughout the leaching process. Each leaching session lasts one day, for a total of 4 days of leaching. Finally, the residual lithium content in the leached product is measured. Based on this, combined with the initial lithium content in the lithium ore concentrate, the lithium leaching rate is calculated.

[0082] In step S7, the leachate obtained after leaching also includes the following treatments: filtration, purification, concentration, lithium precipitation, carbonization purification, drying and packaging, to obtain battery-grade lithium carbonate products.

[0083] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the spodumene concentrate particles obtained in Example 5 were tested, and the results are shown in Table 1.

[0084] Comparative Example 1

[0085] A method for granulating lithium ore concentrate is basically the same as that in Example 3, except that: no volatile binder is added in step S2, and no fine grinding is performed in step S3.

[0086] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lepidolite concentrate particles obtained in Comparative Example 1 were tested, and the results are shown in Table 1.

[0087] Comparative Example 2

[0088] A method for granulating lithium ore concentrate is basically the same as that in Example 3, except that: in step S2, the binder used is clay, which does not have a high calorific value function, and fine grinding is not performed in step S3.

[0089] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lepidolite concentrate particles obtained in Comparative Example 2 were tested, and the results are shown in Table 1.

[0090] Comparative Example 3

[0091] A method for granulating lithium ore concentrate is basically the same as that in Example 3, except that: in step S2, barium sulfate (calcination aid) is used instead of volatile binder, and fine grinding is not performed in step S3.

[0092] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lepidolite concentrate particles obtained in Comparative Example 3 were tested, and the results are shown in Table 1.

[0093] Table 1. Performance comparison of particles prepared in Examples 1-5 and Comparative Examples 1-3

[0094]

[0095]

[0096] As shown in Table 1, compared with conventional granulation methods, the lithium ore concentrate particles obtained by the granulation method of the present invention have a higher pelletizing rate, higher particle strength, and a larger contact area between lithium ore and roasting raw materials. When used as a lithium extraction raw material for roasting, it can not only significantly improve the roasting effect, but also achieve complete transformation and complete replacement of lithium ore under lower energy consumption conditions. Moreover, the roasted product can be directly water-leached under normal temperature and pressure conditions, with higher water leaching efficiency and higher lithium leaching rate.

[0097] In addition, in Examples 1-3, the leaching concentration of lithium during the first three cycles of the leaching process was also investigated. Figure 2-4 As shown. By Figure 2-4 It is known that in the first cycle, a high-lithium-concentration leachate C was used to leach the roasted product. The results showed that after soaking in water for 1 hour, the lithium leaching rate was only about 50%. Even after soaking for 8 hours, the concentration in the leachate reached equilibrium, but the lithium leaching rate was still below 75%. In the second cycle, a leachate B with a lower lithium concentration than leachate C was used to continue leaching the roasted product. The results showed that the lithium leaching rate further increased, reaching 88%. In the third cycle, a leachate A with a lower lithium concentration than leachate B was used to continue leaching the roasted product. The results showed that the lithium leaching rate further increased, reaching 91%. Furthermore, in the fourth cycle, room-temperature water was used to leach the roasted product, and the results showed that the lithium leaching rate further increased, reaching 95%.

[0098] Example 6

[0099] The effect of different amounts of volatile binder on the granulation effect was investigated. The granulation method was basically the same as that in Example 3, except that the amount of volatile binder added was different, as shown in Table 2.

[0100] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lithium mica concentrate particles obtained in Example 6 were tested, and the results are shown in Table 2.

[0101] Table 2. Performance comparison of particles prepared under different volatile binder addition amounts in Example 6.

[0102]

[0103]

[0104] As shown in Table 2, the granulation method of this invention, by optimizing the addition amount of volatile binder to 1%–20% of the total mass of mixture A, brings the following benefits: 1. Significantly improves the cohesiveness of the lithium ore mixture, achieving a 100% pelletizing rate and increasing particle strength (30 drops from a height of 2 meters without breaking); 2. The volatile binder has a high calorific value, increasing the system's heat source, and the high heat utilization rate during the roasting of the binder and mixture reduces natural gas consumption and costs; 3. After the volatile binder decomposes and volatilizes upon heating, it forms capillary pores inside the particles, facilitating direct water immersion of the subsequently roasted particles. Furthermore, to avoid overburning, the addition amount of volatile binder can be further preferably 1%–10% of the total mass of mixture A.

[0105] Example 7

[0106] The effect of different particle sizes of the mixture on the granulation effect was investigated. The granulation method was basically the same as that in Example 3, except that the particle size of the mixture C was different, as shown in Table 3.

[0107] The pelletizing rate, particle strength, subsequent roasting effect, and leaching effect of the lepidolite concentrate particles obtained in Example 7 were tested, and the results are shown in Table 3.

[0108] Table 3 Comparison of the performance of particles prepared from mixtures of different particle sizes in Example 7

[0109]

[0110]

[0111] As shown in Table 3, in the granulation method of the present invention, by optimizing the particle size of the mixture C to be above 200 mesh, especially the particle size of 300 mesh to 1000 mesh, the mixture can be ground finely, changing the flaky and layered structure of lithium ore, and significantly increasing the adhesion of lithium ore; at the same time, it is also beneficial to reduce roasting energy consumption and improve lithium leaching rate.

[0112] As can be seen from the above results, in the lithium extraction method of the present invention, by first mixing lithium ore concentrate, roasting additives and volatile binders, lithium ore concentrate particles with high pelletizing rate, high particle strength and large contact area between lithium ore and roasting raw materials can be obtained. When lithium ore concentrate particles are used as lithium extraction raw materials, not only can the roasting effect be significantly improved, but the complete transformation and replacement of lithium ore can be achieved under lower energy consumption conditions. Moreover, the product after roasting can be directly water-leached under normal temperature and pressure conditions, with high water leaching efficiency and high lithium leaching rate. The water used for leaching can be reused repeatedly without generating secondary pollution such as wastewater. At the same time, there is no need to crush the roasted product before water leaching, and the use of acids and alkalis can also be avoided, making it more green and environmentally friendly.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A lithium extraction method based on lithium ore granulation, characterized in that, Includes the following steps: (1) The lithium ore concentrate particles are roasted in a rotary kiln; the roasting temperature is 850℃~900℃; the roasting time is 30min~50min. (2) The product obtained after roasting is placed in water for leaching to complete the extraction of lithium; The granulation method for the lithium ore concentrate particles includes the following steps: S1. Lithium ore concentrate, roasting additives, and volatile binders are mixed to obtain mixture B; the preparation method of mixture B includes the following steps: S1-1. Lithium ore concentrate and roasting additive are mixed to obtain mixture A; the mass ratio of lithium ore concentrate to roasting additive is 1:0.1 to 0.8; the roasting additive is at least one of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate or a mixture thereof; S1-2. Mix mixture A with a volatile binder to obtain mixture B; the amount of the volatile binder added is 3% to 20% of the total mass of mixture A; the volatile binder is at least one of semi-coke and petroleum coke. S2. Grind mixture B into fine powder until the particle size is 300-1000 mesh to obtain mixture C. S3. Mix mixture C with water to obtain mixture D; S4. Granulate the mixture D to obtain lithium ore concentrate particles; the particle size of the lithium ore concentrate particles is 8mm to 10mm.

2. The lithium extraction method according to claim 1, characterized in that, In step S1-1, the lithium ore concentrate is at least one of spodumene concentrate, lepidolite concentrate, and lithium clay concentrate; the lithium ore concentrate contains ≥1.5% lithium by mass.

3. The lithium extraction method according to claim 2, characterized in that, In step S1-1, the mass ratio of the lithium ore concentrate to the roasting additive is 1:0.3 to 0.

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4. The lithium extraction method according to claim 1, characterized in that, In steps S1-2, the amount of volatile binder added is 1% to 10% of the total mass of the mixture A.

5. The lithium extraction method according to claim 1, characterized in that, In step S3, the amount of water added is 5% to 20% of the total mass of the mixture C.

6. The lithium extraction method according to any one of claims 1 to 5, characterized in that, In step (2), the liquid-to-solid ratio is controlled to be 0.8 to 1:1 during the leaching process; the leaching time is 3 to 4 days.

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