Lithium extraction method based on lithium ore granulation

Abstract

The invention discloses a lithium extraction method based on lithium ore granulation, the method comprises the following steps: roasting and leaching lithium ore concentrate particles to complete lithium extraction, and the adopted lithium ore concentrate particles are obtained by mixing lithium ore concentrate, a roasting additive and a volatile binder, finely grinding, mixing with water and granulating. According to the method, the adopted lithium ore concentrate particles have the advantages of high pelletizing rate, high particle strength, large contact area between the lithium ore and the roasting raw material and the like, and when the lithium ore concentrate particles are used as the lithium extraction raw material for roasting and water leaching, the roasting effect can be remarkably improved, and complete transformation and complete replacement of the lithium ore can be realized under the condition of lower energy consumption; and the roasted product can be directly subjected to water leaching under the conditions of normal temperature and normal pressure, the water leaching efficiency is high, the lithium leaching rate is high, water for water leaching can be repeatedly used, secondary pollution such as waste water cannot be generated, meanwhile, the roasted product does not need to be crushed before water leaching, acid and alkali can be avoided, and the method is more environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium extraction and relates to a lithium extraction method based on lithium ore granulation. Background Art

[0002] With the rapid development of power batteries and energy storage devices in the field of new energy, the demand for lithium carbonate as an important raw material is increasing day by day. Among them, extracting lithium from lithium ore is an important way to obtain lithium carbonate in industry. In the process of extracting lithium from lithium ore, the lithium ore is first roasted to transform the lithium in the lithium ore or form a soluble lithium salt, and then the roasted product is leached to transfer lithium from the ore to the leachate. Finally, the leachate is treated to remove impurities to obtain lithium carbonate products. It can be seen that improving the roasting effect and the leaching effect is the key to ensuring that more high-purity lithium carbonate products are obtained, and improving the roasting effect is the key to improving the leaching effect.

[0003] In industrial applications, rotary kilns and tunnel kilns are usually used to roast lithium ore. Among them, rotary kilns have more advantages in terms of process, production capacity, investment, land occupation, energy consumption, waste heat utilization, environmental protection, etc., and therefore have more application prospects. In addition, in order to make the lithium ore completely transformed or replaced, a very high roasting temperature is usually required. Industrial water is generally 1100℃~1200℃, which not only causes high energy consumption and large carbon emissions, but also roasting in rotary kilns at high temperatures will cause the problem of melting and ring formation of furnace materials, which is not conducive to normal production. In particular, when lithium ore bulk materials are directly put into the furnace for roasting, the ring formation phenomenon of the rotary kiln will be more serious, and it is easy to over-burn or under-burn due to uneven heating, which is not conducive to improving the extraction rate of lithium, and it is easy to consume a large amount of natural gas, resulting in excessively high costs. At the same time, it is also easy to generate a large amount of dust, resulting in a high dust content in the flue gas and a large flue gas treatment load.In view of the above technical defects, researchers have proposed a method for granulating lithium ore bulk. Before roasting, the lithium ore is first granulated with roasting additives, auxiliary agents and water. Specifically, the lithium ore is mixed with roasting additives, auxiliary agents and water, and granulated by a granulator to obtain lithium ore particles as roasting raw materials. However, these granulation methods still have the following defects: (1) The particle size of the lithium ore is relatively large, which not only makes it difficult to fully contact with the roasting materials, resulting in poor roasting reaction effect, but also makes it difficult to shape and is easy to break. Even before mixing, the lithium ore is crushed or dry-milled, sieved, and large particles are removed, it is still difficult to obtain lithium ore with smaller particle size. There are still defects such as insufficient contact with the roasting materials and poor molding effect. In addition, when the lithium ore is mixed with other roasting materials, it is difficult to form lithium ore. Before mixing, the lithium ore is crushed and dry-milled, which easily forms over-fine materials. These materials are difficult to be effectively utilized, which easily leads to waste of lithium resources. (2) When the lithium ore is mixed with the roasting additive and water, on the one hand, the lithium ore is easy to delaminate, which makes it difficult to form particles, or the particle strength is low. In particular, for the flaky lithium mica and layered spodumene, it is more difficult to form particles, and the particle strength is lower, resulting in poor granulation effect and low ball formation rate. In addition, the particles are very easy to break during the roasting process, which is not conducive to the effective roasting of the lithium ore, and ultimately leads to a low lithium extraction rate. On the other hand, the particles obtained by directly mixing the lithium ore with the roasting additive make the particles easy to agglomerate during the roasting process, which leads to The particle size becomes larger and denser. As a result, in the subsequent leaching step, it is difficult for the leaching solution to quickly enter the interior of the calcined product, which easily leads to defects such as low leaching rate and poor leaching effect. This also makes the lithium extraction rate low. At the same time, in order to overcome the above difficulties, before leaching the calcined product, it is usually necessary to crush the calcined product, or use an acid solution or an alkaline solution as the leaching solution. 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 molding or low strength of the particles, binders are added to the raw materials. However, the addition of these binders will not only increase the density of the calcined product, making the leaching of the calcined product more difficult and the leaching effect worse, but also The use of these binders will increase the energy consumption of roasting, resulting in a sharp increase in production costs. At the same time, the use of these binders will also increase the output of waste slag, resulting in a significant increase in the difficulty and cost of waste slag treatment; (4) In order to further improve the transformation and replacement effects, additives are added to the raw materials. However, the addition of these additives, on the one hand, will increase the density of the roasting products, making the leaching of the roasting products more difficult, or require additional crushing treatment, and require additional acid and pressure treatment during the leaching process, increasing the difficulty of production. On the other hand, it will also increase the energy consumption of roasting, resulting in a sharp increase in production costs. In addition, the use of these additives will also increase the output of wastewater and waste slag, which will significantly increase the difficulty and cost of subsequent treatment and is also prone to secondary pollution.Therefore, how to overcome the technical defects existing in the above-mentioned lithium ore granulation method to obtain lithium ore concentrate particles with high ball formation 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 deficiencies of the prior art and provide a lithium extraction method based on lithium ore granulation which has good roasting reaction effect, low roasting energy consumption, high leaching efficiency, high lithium leaching rate and is green and environmentally friendly.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A lithium extraction method based on lithium ore pelletizing comprises the following steps:

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

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

[0009] The granulation method of the lithium ore concentrate particles comprises the following steps:

[0010] S1, mixing lithium ore concentrate, roasting additive and volatile binder to obtain mixture B;

[0011] S2, finely grinding the mixture B until the particle size is above 200 meshes to obtain the mixture C;

[0012] S3, mixing mixed material C with water to obtain mixed material D;

[0013] S4, granulating the mixed material D to obtain lithium ore concentrate particles.

[0014] The above lithium extraction method is further improved, in step S1, the preparation method of the mixture B comprises the following steps:

[0015] S1-1, mixing lithium ore concentrate and roasting additives to obtain a mixture A;

[0016] S1-2, mixing mixed material A with a volatile binder to obtain mixed material B.

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

[0018] The above-mentioned lithium extraction method is further improved, in step S1-1, the roasting additive is at least one of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate, or a mixture thereof.

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

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

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

[0022] The above lithium extraction method is further improved, in which in step S1-2, the amount of the volatile binder added is 1% to 10% of the total mass of the mixture A.

[0023] The above lithium extraction method is further improved, in step S2, the particle size of the mixture C is above 300 mesh.

[0024] The above lithium extraction method is further improved, in step S3, the amount of water added is 5% to 20% of the total mass of the mixed material C.

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

[0026] The above lithium extraction method is further improved, in step S2, the particle size of the mixture C is 300 mesh to 1000 mesh.

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

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

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

[0030] Aiming at the shortcomings of the existing lithium ore granulation method, such as complex process, great difficulty in operation, low granulation rate, low granule strength, small contact area between lithium ore and roasting raw materials, and the resulting defects of poor roasting reaction effect, high roasting energy consumption, low leaching rate, low lithium leaching rate, secondary pollution, etc., the present invention creatively proposes a lithium extraction method based on lithium ore granulation, firstly mixing lithium ore concentrate, roasting additive and volatile binder, so that the lithium mica concentrate and the roasting additive are evenly mixed and fully contacted, so that the lithium mica concentrate and the volatile binder are bonded and fixed together, thereby facilitating the improvement of the lithium mica concentrate. The contact area with the roasting additive is beneficial to the subsequent roasting effect (i.e., the improvement of the leaching rate). At the same time, the added volatile binder has a high calorific value and can also be used as a heat supplementary agent, which can not only reduce the natural gas consumption of roasting, but also these volatile binders will be gasified during the roasting process, thereby forming porous channels in the roasting product, which is beneficial to improve the subsequent leaching rate and leaching effect, and at the same time, it can also reduce the output of tailings; further, the mixture of lithium ore concentrate, roasting additives and volatile binder is finely ground. By finely grinding the mixture, the lithium ore can be ground from about 100 mesh to 2 00 mesh or more, so that the lithium ore concentrate becomes finer, and the morphology is gradually transformed into granules, which is not only conducive to the subsequent granulation molding, but also can further increase the contact area between the lithium mica concentrate and the roasting additive, promote the roasting conversion effect, and help to improve the lithium extraction rate by changing the morphology of the lithium ore concentrate. At the same time, fine grinding can also improve the bonding strength of the volatile binder to the lithium mica concentrate and the roasting additive, which is conducive to making higher strength particles, and is conducive to effectively preventing the particles from breaking during the roasting process, thereby effectively avoiding the problem of material melting and ringing during the roasting process. Finally, the mixed material is granulated. Lithium ore concentrate particles with high ball formation rate, high particle strength and large contact area between lithium ore and roasting raw materials are obtained. On this basis, the prepared lithium ore concentrate particles are used as lithium extraction raw materials for roasting and water leaching, which can not only significantly improve the roasting effect, but also achieve complete transformation and complete replacement of lithium ore under conditions of lower energy consumption. Moreover, the roasted products 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 water leaching can be reused without generating secondary pollution such as wastewater. At the same time, there is no need to crush the roasted products before water leaching, and the use of acids and alkalis can be avoided, which is more green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

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

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

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

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

[0036] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available unless otherwise specified.

[0037] Example 1

[0038] A lithium extraction method based on lithium ore granulation, specifically, lithium mica concentrate particles made from lithium mica concentrate as raw material are used for lithium extraction, and the lithium extraction process flow chart is as follows: Figure 1 As shown, the following steps are included:

[0039] S1, take 100 kg of lithium mica concentrate (100 mesh, lithium mass percentage is 2%), according to the mass ratio of lithium ore concentrate to roasting additive is 1:0.6, wherein the roasting additive is a mixture of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate, and the mass ratio of lithium mica concentrate to calcium sulfate, calcium carbonate, sodium sulfate, potassium sulfate is 1:0.3:0.1:0.1:0.1, so that the lithium mica concentrate and the roasting additive are evenly mixed and fully contacted to obtain mixed material A. In the present invention, the type of roasting additive and the dosage ratio of different types of roasting additives are adjusted according to actual conditions.

[0040] S2, according to the addition amount of roasting auxiliary material is 3% of the total mass of mixture A, mixture A is mixed with roasting auxiliary material (blue charcoal), and under the action of blue charcoal, lithium mica concentrate and roasting additive are bonded together to obtain mixture B, and blue charcoal in the mixture B. In the present invention, lithium ore concentrate is first mixed with the roasting additive, and then a volatile binder is added, which is not only more conducive to forming a material with good mixing uniformity, but also conducive to increasing the contact area between the lithium mica concentrate and the roasting additive.

[0041] S3. Add the mixed material B into a ball mill and grind the mixed material B until the particle size reaches 300 meshes to obtain a mixed material C.

[0042] S4. Mix the mixture C with water in an amount of 8% of the total mass of the mixture C to obtain a mixture D.

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

[0044] S6. Roasting the lithium ore concentrate particles in a rotary kiln, wherein the roasting temperature is 900° C. and the time is 45 minutes.

[0045] S7, according to the liquid-solid ratio of 0.8: 1, the product obtained after roasting is placed in water for leaching for 4 days to complete the extraction of lithium. In this step, there is no need to crush the roasted product, and the leaching is carried out directly. The roasted product is leached by countercurrent leaching, specifically, the roasted product is soaked in the leachate obtained in different leaching stages in turn, and the leaching is completed under the condition of keeping the liquid-solid ratio at 0.8: 1, wherein the single leaching time is one day, and the total water immersion is 4 days. Finally, the residual content of lithium in the roasted product after leaching treatment is determined, and the lithium leaching rate of water leaching is calculated by combining the initial content of lithium in the lithium ore concentrate.

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

[0047] The ball formation rate, particle strength, and subsequent roasting effect and leaching effect of the lithium mica concentrate particles prepared 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, lithium mica concentrate particles made from lithium mica concentrate as raw material are used for lithium extraction, and the lithium extraction process flow chart is as follows: Figure 1 As shown, the following steps are included:

[0050] S1, take 200 kg of lithium mica concentrate (100 mesh, lithium mass percentage is 1.8%), according to the mass ratio of lithium ore concentrate to roasting additive is 1:0.7, wherein the roasting additive is a mixture of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate, and 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, so that the lithium mica concentrate and the roasting additive are evenly mixed and fully contacted to obtain mixed material 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 (blue charcoal), and under the action of blue charcoal, the lithium mica concentrate and the roasting additive are bonded together to obtain mixture B, wherein the blue charcoal in the mixture B is.

[0052] S3. Add the mixed material B into a ball mill and grind the mixed material B until the particle size reaches 400 meshes to obtain a mixed material C.

[0053] S4. Mix the mixture C with water so that the amount of water added is 10% of the total mass of the mixture C to obtain a mixture D.

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

[0055] S6. Roasting the lithium ore concentrate particles in a rotary kiln, wherein the roasting temperature is 900° C. and the time is 45 minutes.

[0056] S7, according to the liquid-solid ratio of 0.8: 1, the product obtained after roasting is placed in water for leaching for 4 days to complete the extraction of lithium. In this step, there is no need to crush the roasted product, and the leaching is carried out directly. The roasted product is leached by countercurrent leaching, specifically, the roasted product is soaked in the leachate obtained in different leaching stages in turn, and the leaching is completed under the condition of keeping the liquid-solid ratio at 0.8: 1, wherein the single leaching time is one day, and the total water immersion is 4 days. Finally, the residual content of lithium in the roasted product after leaching treatment is determined, and the lithium leaching rate of water leaching is calculated by combining the initial content of lithium in the lithium ore concentrate.

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

[0058] The ball formation rate, particle strength, and subsequent roasting and leaching effects of the lithium mica concentrate particles prepared 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, lithium mica concentrate particles made from lithium mica concentrate as raw material are used for lithium extraction, and the lithium extraction process flow chart is as follows: Figure 1 As shown, the following steps are included:

[0061] S1, take 200 kg of lithium mica concentrate (100 mesh, lithium mass percentage is 2.5%), according to the mass ratio of lithium ore concentrate to roasting additive is 1:0.5, wherein the roasting additive is a mixture of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate, and 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, so that the lithium mica concentrate and the roasting additive are evenly mixed and fully contacted to obtain mixed material A.

[0062] S2. According to the addition amount of roasting auxiliary materials being 5% of the total mass of mixed material A, mixed material A is mixed with roasting auxiliary materials (blue charcoal), and under the action of blue charcoal, the lithium mica concentrate and the roasting additives are bonded together to obtain mixed material B, wherein the blue charcoal in the mixed material B is.

[0063] S3. Add the mixed material B into a ball mill and grind the mixed material B until the particle size reaches 500 meshes to obtain a mixed material C.

[0064] S4. Mix the mixture C with water in an amount of 13% of the total mass of the mixture C to obtain a mixture D.

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

[0066] S6. Roasting the lithium ore concentrate particles in a rotary kiln, wherein the roasting temperature is 900° C. and the time is 45 minutes.

[0067] S7, according to the liquid-solid ratio of 0.8: 1, the product obtained after roasting is placed in water for leaching for 4 days to complete the extraction of lithium. In this step, there is no need to crush the roasted product, and the leaching is carried out directly. The roasted product is leached by countercurrent leaching, specifically, the roasted product is soaked in the leachate obtained in different leaching stages in turn, and the leaching is completed under the condition of keeping the liquid-solid ratio at 0.8: 1, wherein the single leaching time is one day, and the total water immersion is 4 days. Finally, the residual content of lithium in the roasted product after leaching treatment is determined, and the lithium leaching rate of water leaching is calculated by combining the initial content of lithium in the lithium ore concentrate.

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

[0069] The ball formation rate, particle strength, and subsequent roasting effect and leaching effect of the lithium mica concentrate particles prepared 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 Example 3, except that the roasting auxiliary material used in step S2 is petroleum coke.

[0072] The ball formation rate, particle strength, and subsequent roasting and leaching effects of the lithium mica concentrate particles prepared 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 a raw material to prepare spodumene concentrate particles, comprising the following steps:

[0075] S1. Take 200 kg of spodumene concentrate (100 mesh, lithium content of 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 the roasting additive mixed evenly and fully contact to obtain mixed material A.

[0076] S2. Mixture A is mixed with a volatile binder (lignite) according to the amount of volatile binder added being 4% of the total mass of mixture A. Under the action of lignite, the spodumene concentrate and the roasting additive are bonded together to obtain mixture B, wherein the lignite in mixture B is.

[0077] S3. Add the mixed material B into a ball mill and grind the mixed material B until the particle size reaches 400 meshes to obtain a mixed material C.

[0078] S4. Mix the mixture C with water in an amount of 10% of the total mass of the mixture C to obtain a mixture D.

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

[0080] S6. Roasting the lithium ore concentrate particles in a rotary kiln, wherein the roasting temperature is 900° C. and the time is 45 minutes.

[0081] S7, according to the liquid-solid ratio of 0.8: 1, the product obtained after roasting is placed in water for leaching for 4 days to complete the extraction of lithium. In this step, there is no need to crush the roasted product, and the leaching is carried out directly. The roasted product is leached by countercurrent leaching, specifically, the roasted product is soaked in the leachate obtained in different leaching stages in turn, and the leaching is completed under the condition of keeping the liquid-solid ratio at 0.8: 1, wherein the single leaching time is one day, and the total water immersion is 4 days. Finally, the residual content of lithium in the roasted product after leaching treatment is determined, and the lithium leaching rate of water leaching is calculated by combining the initial content of lithium in the lithium ore concentrate.

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

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

[0084] Comparative Example 1

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

[0086] The ball formation rate, particle strength, and subsequent roasting effect and leaching effect of the lithium mica concentrate particles prepared 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 Example 3, except that in step S2, the binder used is clay, which does not have a high calorific value function, and no fine grinding is performed in step S3.

[0089] The ball formation rate, particle strength, and subsequent roasting effect and leaching effect of the lithium mica concentrate particles prepared 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 of Example 3, except that in step S2, barium sulfate (roasting aid) is used instead of volatile binder, and fine grinding is not performed in step S3.

[0092] The ball formation rate, particle strength, and subsequent roasting effect and leaching effect of the lithium mica concentrate particles prepared in Comparative Example 3 were tested, and the results are shown in Table 1.

[0093] Table 1 Comparison of properties of particles prepared in Examples 1-5 and Comparative Examples 1-3

[0094]

[0095]

[0096] It can be seen from Table 1 that, compared with the conventional granulation method, the lithium ore concentrate particles prepared by the granulation method of the present invention have a higher ball formation rate, higher particle strength, and a larger contact area between the lithium ore and the roasting raw material. When it is roasted as a lithium extraction raw material, 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 at normal temperature and pressure, with higher water leaching efficiency and higher lithium leaching rate.

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

[0098] Example 6

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

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

[0101] Table 2 Comparison of properties of particles prepared under different volatile binder addition conditions in Example 6

[0102]

[0103]

[0104] As shown in Table 2, in the granulation method of the present invention, by optimizing the amount of volatile binder added to 1% to 20% of the total mass of the mixture A, the benefits are: 1. The bonding property of the lithium ore mixture is greatly improved, the ball formation rate is 100%, and the particle strength is increased (the number of times it falls from 2 meters above the ground without breaking is 30 times); 2. The volatile binder has a high calorific value, which increases the heat source of the system, and the binder and the mixture are roasted, with high thermal utilization, reducing natural gas consumption and reducing costs; 3. After the volatile binder is thermally decomposed and volatilized, capillaries are formed inside the particles, which is conducive to the direct water immersion of the subsequent roasted particles. In addition, in order to avoid overburning, the amount of volatile binder added can be further preferably 1% to 10% of the total mass of the mixture A.

[0105] Example 7

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

[0107] The ball formation rate, particle strength, and subsequent roasting and leaching effects of the lithium mica concentrate particles prepared 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 can be seen from 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, the flaky and layered structure of the lithium ore can be changed, and the adhesion of the lithium ore can be significantly increased; at the same time, it is also beneficial to reduce the roasting energy consumption and improve the lithium leaching rate.

[0112] It can be seen from the above results that in the lithium extraction method of the present invention, by first mixing the lithium ore concentrate, the roasting additive and the volatile binder, the lithium ore concentrate can be prepared into lithium ore concentrate particles with high balling rate, high particle strength and large contact area between the lithium ore and the roasting raw material. Then, when the lithium ore concentrate particles are used as lithium extraction raw materials for lithium extraction, not only can the roasting effect be significantly improved, but also the complete transformation and complete replacement of the lithium ore can be achieved under lower energy consumption conditions. Moreover, the roasted product can be directly water-leached at normal temperature and pressure, with high water leaching efficiency and high lithium leaching rate. The water used for water 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 acid and alkali can be avoided, which is more green and environmentally friendly.

[0113] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A lithium extraction method based on lithium ore granulation, characterized in that: The following steps are involved: (1) roasting lithium ore concentrate particles; (2) placing the product obtained after roasting in water for leaching to complete the extraction of lithium; The granulation method of the lithium ore concentrate particles comprises the following steps: S1, mixing lithium ore concentrate, roasting additive and volatile binder to obtain mixture B; S2, finely grinding the mixture B until the particle size is above 200 meshes to obtain the mixture C; S3, mixing mixed material C with water to obtain mixed material D; S4, granulating the mixed material D to obtain lithium ore concentrate particles.

2. The lithium extraction method according to claim 1, characterized in that: In step S1, the method for preparing the mixture B comprises the following steps: S1-1, mixing lithium ore concentrate and roasting additives to obtain a mixture A; S1-2, mixing mixed material A with a volatile binder to obtain mixed material B.

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 1:0.1-0.8; the roasting additive is at least one of calcium sulfate, calcium carbonate, sodium sulfate and potassium sulfate or a mixture thereof; the lithium ore concentrate is at least one of spodumene concentrate, lepidolite concentrate and lithium clay concentrate; the mass percentage of lithium in the lithium ore concentrate is ≥1.5%.

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

7.

5. The lithium extraction method according to claim 2, characterized in that: In step S1-2, the amount of the volatile binder added is 0.1% to 20% of the total mass of the mixture A; the volatile binder is at least one of lignite and petroleum coke.

6. The lithium extraction method according to claim 5, characterized in that: In step S1-2, the amount of the volatile binder added is 1% to 10% of the total mass of the mixture A.

7. The lithium extraction method according to claim 1, characterized in that: In step S2, the particle size of the mixture C is above 300 mesh; In step S3, the amount of water added is 5% to 20% of the total mass of the mixture C; In step S4, the particle size of the lithium ore concentrate particles is 8 mm to 10 mm.

8. The lithium extraction method according to claim 7, characterized in that: In step S2, the particle size of the mixture C is 300 mesh to 1000 mesh.

9. The lithium extraction method according to any one of claims 1 to 8, characterized in that: In step (1), a rotary kiln is used to roast the lithium ore concentrate particles; the roasting temperature is 850° C. to 900° C.; and the roasting time is 30 min to 50 min.

10. The lithium extraction method according to any one of claims 1 to 8, characterized in that: 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.

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