Process for the preparation of battery grade lithium carbonate based on granulation of lithium ore

Abstract

The application discloses a kind of battery-grade lithium carbonate preparation processes based on lithium ore granulation, steps include: lithium ore concentrate, calcination auxiliary reagent is mixed, precision grinding, granulation, obtain lithium ore concentrate particle;Lithium ore concentrate particle is calcined, and calcined clinker is obtained;Calcined clinker is carried out static countercurrent water immersion, and solid-liquid separation obtains leaching stock solution and ore particle;Leaching stock solution is purified by impurity removal, evaporated concentration, resin deep impurity removal, then mixed with refined sodium carbonate solution treated by resin adsorption to carry out lithium precipitation, and slurry washing obtains battery-grade lithium carbonate.The process of the application, once lithium precipitation can obtain required battery-grade lithium carbonate without refining, and lithium comprehensive recovery rate is high, wherein lithium comprehensive recovery rate is as high as 85%~90%, with the advantages of simple overall process, high safety, low energy consumption, low cost, high production efficiency, green environmental protection and the like, which can maximize the economic benefit of lithium ore resources, and is of great significance for enterprises to improve economic benefit.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium carbonate production, and relates to a preparation process of battery-grade lithium carbonate, in particular to a preparation process of battery-grade lithium carbonate based on lithium ore granulation. BACKGROUND

[0002] Metal lithium and its compounds have excellent performance and have been widely used in many industries. Metal lithium and its compounds are mainly extracted from lithium-containing minerals. Spodumene and lepidolite are the most widely distributed lithium-containing minerals. Spodumene is the main source of lithium extraction, and its lithium extraction process is mature, and the lithium grade is high. Compared with spodumene, lepidolite is more difficult to extract lithium. On the one hand, the grade of lepidolite is low, and the amount of slag is large. After magnetic separation or flotation, the Li2O content in the concentrate is only 1.3% to 2%, and it is accompanied by high content of iron and fluorine. When smelting and extracting lithium, there are problems such as low yield and easy environmental pollution. On the other hand, it is difficult to achieve comprehensive utilization of rare and valuable metal resources such as rubidium and cesium contained in lepidolite ore. Therefore, obtaining an economic, efficient and environmentally friendly lithium extraction process is an important direction for the development of lepidolite resources.

[0003] In recent years, the industry has carried out in-depth and extensive research on the production of lithium carbonate from lepidolite. Among them, the sulfate roasting method is the most widely used salt method for lithium extraction. Its principle is that after high-temperature calcination of lepidolite, the structure becomes loose, ion exchange reaction is easy to occur, and then the metal ions in the roasting auxiliary material occupy the original lithium ion structure position, replacing Li + from the original position, so that it changes from insoluble aluminosilicate to soluble sulfate, and then leaching to obtain lithium sulfate solution. After lithium precipitation, the lithium precipitation mother liquor is concentrated by evaporation and frozen to separate sodium, and sodium potassium sulfate mixed salt is obtained, which can be returned to the front end of the batching process as a roasting auxiliary material, effectively reducing the cost of auxiliary materials. In addition, rubidium and cesium in the solution can be directly recovered by solvent extraction to obtain rubidium sulfate and cesium sulfate, effectively improving the comprehensive utilization rate of resources. Compared with acid method, alkali method and chlorinated salt roasting method, the lithium extraction cost of the sulfate roasting method is low, the equipment corrosion is small, the impurities contained in the leaching solution are less, the purification is easy, and the sulfate system is easy to wash and remove, which has little effect on the quality of the lithium carbonate product, so it can guarantee the quality of the ternary material in the back end. Therefore, it has become the main method for extracting lithium and valuable elements from lepidolite and has been widely used in industrial production. However, even if the sulfate roasting method is used, the product obtained from lepidolite is mostly industrial-grade Li2CO3. In production, enterprises often need to continue one or more refining processes to obtain qualified battery-grade lithium carbonate, including hydrogenation pyrolysis, ion exchange or electrolysis, etc. There are still many problems such as multiple processes, complex process, low production efficiency, high production cost, easy to cause loss of lithium source, low lithium extraction rate, etc.

[0004] In view of the problems of existing lithium ore preparation process for battery-grade lithium carbonate, such as multiple processes, complex process, low production efficiency, high production cost, easy to cause lithium source loss, low lithium extraction rate and low yield of lithium carbonate, researchers have proposed a one-time lithium precipitation process for preparing battery-grade lithium carbonate, which includes the steps of crushing lithium mica concentrate powder, mixing and batching, roasting, lithium extraction, impurity removal, and battery-grade lithium carbonate preparation by lithium precipitation. The process does not go through the process of producing industrial-grade lithium carbonate, but directly precipitates battery-grade lithium carbonate products. The above-mentioned one-time lithium precipitation process for preparing battery-grade lithium carbonate can simplify the process steps and improve the production efficiency, but the process still has problems such as low comprehensive lithium recovery rate and difficulty in balancing low cost and environmental protection, because: (1) The powder mixture of lithium concentrate and roasting auxiliary materials is directly roasted in the furnace, which is easy to cause uneven heating and appear underfiring or overfiring. Underfiring will affect the displacement reaction of lithium concentrate and roasting auxiliary materials, and cannot promote lithium ions to fully displace into soluble sulfates, resulting in a large discount in lithium leaching rate and lithium extraction rate. Overfiring will consume unnecessary fuel and increase cost. Direct roasting of powder can produce a large amount of dust, resulting in high dust content in flue gas, high risk of environmental pollution, and high process cost of flue gas treatment; (2) Directly using lithium ore concentrate powder as raw material, the fine particles after roasting are easy to aggregate and settle in the subsequent leaching process, which is not conducive to the leaching of lithium ions. The effect of dynamic leaching is also limited, and the production cost is also increased due to the consumption of electric energy to provide disturbance force. Furthermore, the liquid-solid ratio of dynamic leaching is high, which requires more water leaching solution, and also increases the treatment burden of leaching raw solution. Especially in large-scale industrial production, a large amount of water needs to be evaporated, which requires more MVR equipment, resulting in high process cost. Therefore, it is of great significance to develop a one-time lithium precipitation process for preparing battery-grade lithium carbonate with high lithium recovery rate, economic efficiency and environmental protection. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a battery-grade lithium carbonate preparation process based on lithium ore granulation with low cost, high lithium comprehensive recovery rate and green environmental protection.

[0006] To solve the above technical problems, the following technical solutions are adopted.

[0007] A battery-grade lithium carbonate preparation process based on lithium ore granulation, comprising the following steps:

[0008] (1) mixing, fine grinding and granulating lithium ore concentrate and roasting auxiliary reagents to obtain lithium ore concentrate particles;

[0009] (2) roasting the lithium ore concentrate particles to obtain roasted clinker;

[0010] (3) the calcined clinker is subjected to static countercurrent water immersion and solid-liquid separation to obtain a leaching original solution and ore particles;

[0011] (4) the leaching original solution is mixed with lime slurry to adjust pH and remove impurities to obtain a post-impurity-removal solution and impurity-removal residue;

[0012] (5) the post-impurity-removal solution is mixed with sodium carbonate to perform purification to obtain a post-purification solution and purification residue;

[0013] (6) the post-purification solution is subjected to evaporation concentration and solid-liquid separation after cooling to obtain first sodium-potassium mixed salt and a post-salting separation solution;

[0014] (7) calcium and magnesium in the post-salting separation solution are adsorbed by ion exchange resin to obtain a pre-lithium-precipitation solution;

[0015] (8) the pre-lithium-precipitation solution is mixed with refined sodium carbonate solution to perform lithium precipitation to obtain crude lithium carbonate and a lithium-precipitation mother liquor;

[0016] (9) the crude lithium carbonate is subjected to slurry washing and filtration drying to obtain battery-grade lithium carbonate.

[0017] The battery-grade lithium carbonate preparation process is further improved, in step (3), the pH of the water immersion solution used in the static countercurrent water immersion is 8-9, and the solid-liquid mass ratio of the static countercurrent water immersion is 1:0.8-2, more preferably 1:0.8.

[0018] The battery-grade lithium carbonate preparation process is further improved, in step (3), the temperature of the static countercurrent water immersion is 5-95°C, more preferably 25-50°C, the time of the static countercurrent water immersion is 0.1-24h, more preferably 8-12h; the static countercurrent water immersion is multi-stage water immersion, and the number of stages of the static countercurrent water immersion is 3-6, more preferably 4.

[0019] The battery-grade lithium carbonate preparation process is further improved, in step (7), the content of calcium ions in the pre-lithium-precipitation solution is <0.1mg / L; the refined sodium carbonate solution is prepared by adsorbing calcium and magnesium in a sodium carbonate solution by ion exchange resin; and the content of calcium ions in the refined sodium carbonate solution is <0.1mg / L.

[0020] The battery-grade lithium carbonate preparation process is further improved, in step (4), the mass concentration of the lime slurry is 5%-30%; the lime slurry is calculated by taking calcium oxide into account, and the mass of calcium oxide in the lime slurry is 1 / 6 of the theoretical amount of sulfate in the leaching original solution; the temperature of the impurity removal is 20-50°C, and the holding time of the impurity removal is 0.5-1h.

[0021] The battery-grade lithium carbonate preparation process is further improved, in step (5), the purification temperature is 80-95 DEG C, and the purification holding time is 1 h.

[0022] The battery-grade lithium carbonate preparation process is further improved, in step (6), the evaporation concentration multiple of the purified solution is 1.8-2.65 times.

[0023] The battery-grade lithium carbonate preparation process is further improved, in step (7), the mass of Na2CO3 in the refined sodium carbonate solution is 1.2-1.5 times the theoretical mass of lithium ions in the lithium precipitation solution.

[0024] The battery-grade lithium carbonate preparation process is further improved, in step (8), the lithium precipitation temperature is 80-95 DEG C, and the lithium precipitation time is 0.5-2 h, preferably 1 h.

[0025] The battery-grade lithium carbonate preparation process is further improved, in step (9), the liquid-solid ratio of the carbonated lithium crude product slurry washing is 3-5:1; the slurry washing temperature is 80-95 DEG C, the slurry washing time is 10-30 min, and the slurry washing frequency is 1-3 times.

[0026] The battery-grade lithium carbonate preparation process is further improved, in step (3), the ore particles are leached to obtain leaching residues and leaching water; the leaching uses industrial water and / or condensed water obtained by evaporation concentration; the leaching residues are reused as raw materials of cement or cementitious materials; and the leaching water is returned to step (3) for water leaching of the calcined clinker.

[0027] The battery-grade lithium carbonate preparation process is further improved, in step (4), the impurity removal residues are returned to step (1) as calcination auxiliary agents; and in step (5), the purification residues are returned to step (1) as calcination auxiliary agents.

[0028] The battery-grade lithium carbonate preparation process is further improved, in step (6), the first sodium-potassium mixed salt is returned to step (1) as a calcination additive. In the present application, the sodium-potassium mixed salt is used to replace Na2SO4 and K2SO4 in the calcination auxiliary agent.

[0029] The battery-grade lithium carbonate preparation process is further improved, in step (8), the lithium precipitation mother liquor is adjusted with acid to remove carbon, and neutralized with liquid alkali to obtain a carbon removal mother liquor, the carbon removal mother liquor is concentrated by evaporation and then solid-liquid separation is performed to obtain an evaporation crystallization mother liquor and a second sodium-potassium mixed salt, the evaporation crystallization mother liquor is subjected to solid-liquid separation after being cooled by freezing to obtain a post-freezing liquid and a third sodium-potassium mixed salt; the second sodium-potassium mixed salt and the third sodium-potassium mixed salt are returned to step (1) as roasting auxiliary reagents; and the post-freezing liquid is treated by extraction, washing, back extraction and evaporation crystallization to obtain cesium salt, rubidium salt and a raffinate.

[0030] The battery-grade lithium carbonate preparation process is further improved, the fine grinding obtains mixed powder with a particle size of more than 200 meshes, and more preferably mixed powder with a particle size of 300 meshes to 1000 meshes, and the particle size of the lithium ore concentrate particles is 5 mm to 12 mm, and more preferably 8 mm to 10 mm.

[0031] The battery-grade lithium carbonate preparation process is further improved, in step (1), the roasting auxiliary reagents include gypsum and CaCO3, and the mass ratio of the lithium ore concentrate and the roasting auxiliary reagents is 1:0.2-1.6.

[0032] The battery-grade lithium carbonate preparation process is further improved, the roasting auxiliary reagents further include at least one of Na2SO4, K2SO4 and blue coal.

[0033] The battery-grade lithium carbonate preparation process is further improved, the roasting auxiliary reagents further include Na2SO4, K2SO4 and blue coal, the mass ratio of the gypsum, calculated as CaSO4·2H2O, and the lithium ore concentrate is 0.1-0.5:1, and more preferably 0.25-0.45:1, the mass ratio of the CaCO3, calculated as pure CaCO3, and the lithium ore concentrate is 0.1-0.6:1, and more preferably 0.1-0.3:1, the mass ratio of the Na2SO4 and the lithium ore concentrate is 0-0.2:1, and is not 0, and more preferably 0.01-0.15:1, the mass ratio of the K2SO4 and the lithium ore concentrate is 0-0.2:1, and is not 0, and more preferably 0.01-0.15:1, and the mass ratio of the blue coal and the lithium ore concentrate is 0-0.1:1, and is not 0, and more preferably 0.01-0.05:1.

[0034] The battery-grade lithium carbonate preparation process is further improved, in step (2), the roasting temperature is 800-950°C, and more preferably 800-850°C, and the holding time of the roasting is 0.5-2.5h, and more preferably 0.5-1h.

[0035] In the present application, the gypsum can be CaSO4.2H2O, anhydrite, mixed gypsum or industrial by-product gypsum; the CaCO3 can be analytical pure or be used for metallurgy; the Na2SO4 and K2SO4 can be analytical pure, industrial by-product mirabilite or mixed salt of sodium and potassium produced in the later stage.

[0036] In the present application, the preparation method of the lithium ore concentrate comprises the following steps:

[0037] The lithium ore crude ore is crushed, and then is subjected to magnetic separation or flotation, and then is dried to obtain the lithium ore concentrate.

[0038] The present application does not have special requirements for the specific implementation process of crushing, magnetic separation or flotation.

[0039] In the present application, the lithium ore concentrate is a lepidolite concentrate, and the mass percentage of Li2O in the lepidolite concentrate is 1% to 3%.

[0040] In the present application, the roasting is carried out in a rotary kiln or a tunnel kiln, and more preferably, the roasting is carried out in a rotary kiln.

[0041] In the present application, the roasting clinker is subjected to static countercurrent water leaching by adding water to obtain a leaching stock solution, and the leaching stock solution is a lithium sulfate solution.

[0042] In the present application, the water used for the static countercurrent water leaching includes washing water returned from the later end process and steam condensate water, the washing water is leaching water for the ore particles, pressure filtration washing water for the impurity removal residue and the purification residue, regenerated liquid after resin acid washing, water washing acid washing water, transformed liquid after resin alkali washing, water washing alkali washing water, but is not limited to this; the steam condensate water is secondary steam condensate water generated by evaporation of the purified liquid and the decarburization mother liquor, but is not limited to this.

[0043] In the present application, by pH adjustment and impurity removal, the lime slurry can react with the fluoride ions and the magnesium ions in the leaching stock solution to remove the fluoride ions and the magnesium ions.

[0044] In the present application, after the ion exchange resin is used for deep removal of calcium and magnesium, a saturated resin after adsorption is obtained; the regeneration treatment of the saturated resin after adsorption comprises the following steps: the saturated resin after adsorption is replaced with pure water to obtain a water washing liquid, and the water washing liquid can be used as a pre-lithium precipitation liquid; the resin after the pure water replacement is desorbed with dilute sulfuric acid to obtain a resin regenerated liquid and a desorbed resin; the desorbed resin is washed with pure water to remove the dilute sulfuric acid to obtain water washing acid washing water and a water washing acid after resin; the water washing acid after resin is washed with a sodium hydroxide solution for transformation to obtain a resin transformed liquid and a transformed resin; and the transformed resin is washed with pure water to remove the sodium hydroxide to obtain water washing alkali washing water and regenerated ion exchange resin. In the present application, preferably, the resin regenerated liquid, the water washing acid washing water, the resin transformed liquid and the water washing alkali washing water are used as countercurrent leaching water leaching liquid.

[0045] The present application has the advantage over the prior art in that:

[0046] (1) In view of the problems of low lithium comprehensive recovery rate, easy environmental pollution, high cost and the like existing in the present one-time lithium precipitation process for preparing battery-grade lithium carbonate, the application creatively proposes a battery-grade lithium carbonate preparation process based on lithium ore granulation, the lithium ore concentrate is first made into particles, which can improve the roasting effect and the leaching effect, specifically, the lithium ore concentrate and roasting auxiliary reagents are mixed and finely ground, which can make the two fully contact and facilitate the subsequent roasting reaction, so that as much lithium, rubidium and cesium as possible in the lithium ore concentrate is replaced, which is beneficial to improve the leaching rate of lithium, rubidium and cesium in the subsequent process, thereby improving the recovery rate, at the same time, the mixed powder after fine grinding is made into lithium ore concentrate particles with high strength and not easy to break, which is beneficial to the subsequent roasting and water leaching, which can not only effectively avoid under-roasting or over-roasting during roasting and produce a large amount of dust, but also adapt to the countercurrent static water leaching process used in the subsequent process, thereby being beneficial to improve the leaching effect of the roasting product. On this basis, the roasting clinker is subjected to leaching treatment by countercurrent static water leaching, which can efficiently leach lithium, rubidium and cesium in the lithium ore concentrate under the conditions of low energy consumption and small amount of leaching liquid, and the leaching rate is all greater than or equal to 90%, especially, in the process of the application, the pH of the water leaching liquid is 8-9, which is weak alkaline, which can ensure that the aluminum, iron and zinc in the lithium ore concentrate are not leached, the impurity content of the leaching liquid is small, and most of the F in the lithium ore concentrate is fixed in the form of CaF2 during roasting, which can also effectively avoid the corrosion of F on the equipment, thereby improving the comprehensive recovery rate of lithium, providing the stability and safety of the production process, and being more beneficial to improve the economic benefit. However, if the dynamic leaching method is used for leaching treatment, not only the same leaching effect cannot be achieved, but also a large amount of energy is consumed to provide disturbance force, and a large amount of leaching liquid is also required, which will increase the subsequent treatment burden and cost, and is not conducive to simplifying the process and reducing the cost; in addition, since the roasting clinker is easy to aggregate and sink to the bottom in the prior art, if the static countercurrent leaching is used, not only the defects of high energy consumption and large amount of leaching liquid still exist, but also the equipment is blocked, which is not conducive to the popularization and use of static countercurrent leaching. Further, since the static countercurrent water leaching process used in the application can improve the concentration of the leaching original liquid and reduce the volume of the leaching original liquid, it is also beneficial to reduce the treatment amount of the subsequent treatment process, thereby improving the production efficiency and reducing the production cost, and finally making the preparation process of the application exhibit lower energy consumption, lower cost and more efficient production efficiency, which has very important significance for enterprises to reduce cost and increase production; especially, the lithium precipitation pre-liquid obtained after the leaching original liquid is subjected to pH adjustment, impurity removal, purification, evaporation concentration and resin adsorption has small volume and high purity, so that the required battery-grade lithium carbonate can be obtained by simple lithium precipitation, without the need for a complex lithium carbonate impurity removal and purification process in the later stage.The present application is based on the lithium ore granulation battery grade lithium carbonate preparation process, the first lithium without refining can obtain the purity of 99.5%~99.87% battery grade lithium carbonate, more importantly, can significantly improve the lithium comprehensive recovery rate, wherein the lithium comprehensive recovery rate is as high as 85%~90%, and compared with the known actual industrial production process, the lithium comprehensive recovery rate that can be obtained is generally about 70%, and it is difficult to exceed 80%, at the same time, the preparation process also has the advantages of simple overall process, high safety, low energy consumption, low cost, high production efficiency, green environmental protection and the like, can maximize the economic benefit of lithium ore resources, and has important significance for enterprises to improve economic benefit.

[0047] (2) In the process of the present application, by mixing lithium ore concentrate and roasting auxiliary reagent, precision grinding, and controlling the particle size of the powder after precision grinding to be more than 200 mesh, the lithium ore concentrate and the roasting additive can be more fully contacted, so that the displacement reaction in the roasting process is more complete, which can further improve the leaching rate of lithium, rubidium and cesium, and is beneficial to significantly improve their recovery rate. In addition, by optimizing the particle size of the lithium ore concentrate particles to 5mm~12mm, it is more conducive to granulation forming, guarantees the granulation strength, and the particles of appropriate size are also conducive to full roasting and efficient leaching of lithium, rubidium and cesium.

[0048] (3) In the process of the present application, the gypsum, CaCO3, Na2SO4, K2SO4 and semi-coke are compounded as roasting auxiliary reagents, wherein the gypsum and CaCO3 can efficiently displace lithium, rubidium and cesium from the insoluble salt in the lithium ore concentrate particles into the soluble salt, the use of Na2SO4 and K2SO4 can further improve the effect of the displacement reaction, and the semi-coke has a binding effect and is easy to volatilize at high temperature, so it is added as a volatile binder, which can better guarantee the sphericity and particle strength of the mixed powder particles, and is beneficial to prevent the particles from being broken in the roasting process, thereby avoiding the problem of material melting and ring formation in the roasting process; on the other hand, the semi-coke can be gasified in the roasting process due to its easy volatilization, thereby forming porous channels in the roasting product and obtaining porous roasting clinker with a large specific surface area, which is beneficial to adapt to the static countercurrent water leaching process and improve the subsequent leaching rate and leaching effect, and can also reduce the yield of tailings; in addition, the semi-coke has a high heat value and can be used as a heat supplementing agent, so that the lithium ore concentrate particles prepared by adding the semi-coke as a roasting auxiliary reagent are uniformly dispersed in the particles, and the roasting is more uniform and sufficient due to the heat released by the semi-coke when it is self-ignited by heat, thereby ensuring the effective performance of the high-temperature displacement reaction to the greatest extent and effectively avoiding the roasting loss of lithium, and to some extent, the fuel consumption of roasting can also be reduced, saving costs. Therefore, under the combined action of gypsum, CaCO3, Na2SO4, K2SO4 and semi-coke, the prepared lithium ore concentrate particles can not only effectively overcome the problems of under-roasting or over-roasting in the roasting process and make the displacement reaction in the roasting process more sufficient, but also effectively avoid unnecessary fuel waste, and can also overcome the problems of large amount of dust and high dust content in flue gas caused by direct roasting of powder, and more importantly, it is the basis for subsequent static countercurrent water leaching of lithium and one-step lithium precipitation to obtain high-yield and high-purity battery-grade lithium carbonate.

[0049] (4) In the process of the present application, by optimizing the process conditions of static countercurrent water leaching, such as a solid-liquid mass ratio of 1:0.8-2, a temperature of 5-95℃, a time of 0.1-24h and a number of stages of 3-6, the technical effects of "small amount of water leaching liquid, fast leaching and high leaching rate" can be further guaranteed, and the processing volume of subsequent process steps such as evaporation concentration, impurity removal and purification can be minimized, which is beneficial to energy saving and cost reduction.

[0050] (5) In the process of the present application, the comprehensive recovery and utilization of rare and valuable metal resources such as rubidium and cesium can be realized, and the impurity removal residue and purification residue in the process, the sodium-potassium mixed salt, the washing water and steam condensate water in each step, which are process by-products, can be recycled and reused in the process, which has good comprehensive utilization and is beneficial to further reducing costs and being environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0051] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application.

[0052] Figure 1 A flowchart of a process for preparing battery-grade lithium carbonate based on lithium ore granulation in the embodiments of the present application. DETAILED DESCRIPTION

[0053] The present application will be further described below in conjunction with the drawings of the specification and specific preferred embodiments, but the protection scope of the present application is not limited thereby. The materials and instruments used in the following embodiments are commercially available if not specifically stated.

[0054] Embodiment 1

[0055] A process for preparing battery-grade lithium carbonate based on lithium ore granulation, in the embodiments, a lepidolite mine in Hunan is used as raw material; the lepidolite mine is crushed and then floated to obtain lepidolite concentrate; the main components and contents of the lepidolite concentrate are shown in Table 1.

[0056] Table 1 Main components and contents (mass fraction %) of lepidolite concentrate in Embodiment 1

[0057] Component Li2O [Rb2O] Cs2O WO3 SiO2 Al2O3 CaO MgO Content 1.55 0.72 0.048 <0.05 50.58 19.28 0.12 0.073 Component Na2O K2O TiO2 F Cl Sn TFe TS Content 0.15 8.37 0.16 5.52 0.029 0.068 9.77 <0.03

[0058] The specific process flow is shown in Figure 1 and includes the following steps:

[0059] (1) After the lepidolite concentrate is dried, the lepidolite concentrate, gypsum (calculated as CaSO4·2H2O), CaCO3, Na2SO4, K2SO4 and coke are mixed in a mass ratio of 1:0.25:0.1:0.1:0.05:0.02, and the auxiliary roasting reagents are added; each reagent is a new reagent added externally when the system is initially started; after the process is running, Na2SO4 and K2SO4 are mixed salts produced in the system, CaSO4·2H2O and CaCO3 are partly from the impurity removal and purification return material, and partly from the new reagents added, and coke is a new reagent added; after the ore is mixed, the mixture is uniformly ground, i.e. the mixture is mixed and ground by a vertical mill to obtain a mixed powder with a particle size of 300 mesh accounting for 90%.

[0060] (2) The mixed powder obtained in step (1) is pressed by a granulator to obtain lepidolite concentrate particles with a particle size of 8 mm.

[0061] (3) The lithium mica concentrate particles obtained in step (2) are dried by roasting flue gas and then put into a rotary kiln, and roasted at 830℃ for 40min; the roasted clinker obtained from the kiln is cooled and mixed with water leaching solution with pH of 8-9, and then static 4-stage countercurrent tank leaching is carried out, with liquid-solid ratio of 0.8:1, leaching temperature of 25℃, and leaching time of 12h; in the system starting stage, the water leaching solution is water, and after the system is running, the water leaching solution is clouded particle leaching water, pressure filtration washing water of impurity removal residue and purification residue, resin acid washing regenerated solution, water washing acid washing water, resin alkali washing transformed solution, water washing alkali washing water, purified solution and secondary steam condensate water generated by evaporation of decarburization mother liquor; during leaching, lithium, rubidium and cesium displaced during roasting are dissolved in the water leaching solution, and fluorine is fixed in the roasted clinker in the form of CaF2; after leaching, the clouded particles left by the open circuit of the leaching original solution are transported to the clouded particle storage after leaching, and used as raw materials for cement preparation or colloidal materials.

[0062] (4) The leaching original solution obtained in step (3) is pumped to the impurity removal section to remove F and Mg, wherein the Li in the leaching original solution is 9.7g / L, the Rb is 1.3g / L, and the Cs is 173mg / L; specifically, the leaching original solution is put into an impurity removal reaction kettle, lime slurry with mass percentage of 20% is added, the mass of calcium oxide in the lime slurry is 1 / 6 of the theoretical amount of sulfate in the leaching original solution, stirring is carried out at 20℃ for 1h, the reacted slurry is subjected to solid-liquid separation by a pressure filter, the impurity removal residue is returned to step (1) after water washing and used as lithium mica roasting auxiliary material, and the washing water is returned to step (3) and used as water leaching solution.

[0063] (5) The impurity removal solution obtained in step (4) is pumped to a purification reaction kettle, and then sodium carbonate is added, the amount of sodium carbonate is 1.5 times of the theoretical amount of calcium ions in the precipitated impurity removal solution, stirring is carried out at 90℃ for 1h, the reacted slurry is subjected to solid-liquid separation by a pressure filter, the purification residue is returned to step (1) after water washing and used as lithium mica roasting auxiliary material, and the washing water is returned to step (3) and used as water leaching solution.

[0064] (6) The purified solution obtained in step (5) is subjected to evaporation concentration, when crystallization occurs, natural cooling is carried out to 50℃, and then centrifugal filtration is carried out to obtain a salt precipitation solution, and the filter residue is a sodium-potassium mixed salt which can be returned to step (1) as part of the roasting auxiliary reagent.

[0065] (7) The salt precipitation solution obtained in step (6) is put into a resin adsorption system, the solution is put into a resin column at a certain flow rate, and the calcium and magnesium ions in the solution are selectively adsorbed by the chelating groups on the resin, and the outlet flow is a lithium precipitation solution with calcium ion content of <0.1mg / L; a sodium carbonate solution is prepared, the sodium carbonate solution is subjected to deep removal of calcium and magnesium impurity ions by ion exchange resin, and a refined sodium carbonate solution with calcium ion content of <0.1mg / L is obtained; wherein the resin is ion exchange resin, and the type is LSC-960 of Lanxiao Technology.

[0066] The ion exchange resin after deep removal of calcium and magnesium becomes saturated resin after adsorption, and the saturated resin after adsorption is subjected to regeneration treatment, including: the saturated resin after adsorption is replaced with pure water to obtain a water washing liquid as a pre-lithium precipitation liquid; the resin after pure water replacement is eluted with dilute sulfuric acid to obtain a resin after regeneration; the resin after elution is washed with pure water to remove dilute sulfuric acid to obtain an acid washing water; the resin after acid washing is washed with a sodium hydroxide solution for transformation to obtain a resin after transformation; and the resin after transformation is washed with pure water to remove sodium hydroxide to obtain an alkali washing water. In this embodiment, the resin after regeneration, the acid washing water, the resin after transformation, and the alkali washing water are used as the countercurrent leaching water in step (3).

[0067] (8) The refined sodium carbonate solution obtained in step (7) is pumped into a lithium precipitation reactor, the stirring motor is turned on, steam is introduced to heat to 80℃, then the pre-lithium precipitation liquid obtained in step (7) is injected, the mass of sodium carbonate in the sodium carbonate solution is 1.2 times the theoretical amount of lithium precipitation required by the pre-lithium precipitation liquid, and after 1h of reaction, centrifugal filtration is performed to obtain lithium carbonate crude and a lithium precipitation mother liquor.

[0068] (9) The lithium carbonate crude obtained in step (8) is introduced into a slurry washing tank, pure water is introduced according to a liquid-solid ratio of 3:1, stirring and washing are performed at 80℃ for 10min, the slurry washing is performed once, and after completion, solid-liquid separation is performed in a centrifuge, and the centrifugal filtrate is sent to step (7) to participate in the preparation of the sodium carbonate solution, and the obtained lithium carbonate after drying is battery-grade lithium carbonate with a purity of 99.68%, and the detailed results are shown in Table 4.

[0069] (10) After the lithium precipitation mother liquor obtained in step (8) is precisely filtered to recover lithium carbonate, sodium-potassium mixed salt is recovered through decarburization and neutralization, evaporation crystallization, and freezing-out of sodium, and returned to the front end for use as a roasting auxiliary reagent, and the recovered sodium-potassium salt liquid is introduced into a rubidium and cesium extraction system to recover rubidium and cesium salts.

[0070] The battery-grade lithium carbonate preparation process based on lithium ore granulation provided in this embodiment can achieve a lithium leaching rate of up to 92%, a lithium comprehensive recovery rate of up to 90%, and a purity of 99.68% of the battery-grade lithium carbonate obtained after one-time lithium precipitation without refinement, meeting the relevant requirements.

[0071] Example 2

[0072] A battery-grade lithium carbonate preparation process based on lithium ore granulation, in which lithium mica ore produced by a lithium mica mine in Jiangxi is used as raw material; the lithium mica ore is crushed and subjected to magnetic separation to obtain lithium mica concentrate; and the main components and contents of the lithium mica concentrate are shown in Table 2.

[0073] Table 2 Main components and contents (mass fraction %) of lithium mica concentrate in Example 2

[0074] Component Li2O [Rb2O] Cs2O WO3 SiO2 Al2O3 CaO MgO Content 1.80 0.68 0.052 <0.05 51.43 18.44 0.15 0.06 Component Na2O K2O TiO2 F Cl Sn TFe TS Content 0.25 7.87 0.21 6.25 0.033 0.054 10.01 <0.03

[0075] The specific process flow is shown in Figure 1 and includes the following steps:

[0076] (1) After the lithium mica concentrate is dried, lithium mica concentrate, gypsum (calculated as CaSO4·2H2O), CaCO3, Na2SO4, K2SO4 and coke are mixed in a mass ratio of 1:0.3:0.2:0.05:0.02:0.01, and roasting auxiliary reagents are added. When the system is started for the first time, each reagent is a new reagent added externally. After the process is running, Na2SO4 and K2SO4 are mixed salts produced in the system, CaSO4·2H2O and CaCO3 are partly from the impurity removal and purification return material, and partly from the new reagent added, and coke is a new reagent added. After the ore is mixed, it is uniformly ground to obtain a mixed powder with a particle size of 500 mesh accounting for 85%.

[0077] (2) The mixed powder obtained in step (1) is pressed into lithium mica concentrate particles with a particle size of 9 mm by a granulator.

[0078] (3) The lithium mica concentrate particles obtained in step (2) are dried by roasting flue gas and then introduced into a rotary kiln at 800℃ for roasting for 1h. The roasted clinker obtained from the kiln is cooled and mixed with water immersion liquid with a pH of 8-9 to perform static 4-stage countercurrent tank leaching, with a liquid-solid ratio of 0.8:1, a leaching temperature of 35℃, and a single-stage leaching time of 10h. During the system startup stage, the water immersion liquid is water, and after the system is running, the water immersion liquid is the leachate of mica particles, the washing water of pressure filtration of impurity removal residue and purification residue, the regenerated liquid after resin acid washing, the water washing acid washing water, the liquid after resin alkali washing transformation, the water washing alkali washing water, the purified liquid, and the secondary steam condensate water generated by evaporation of decarburization mother liquor. During leaching, lithium, rubidium and cesium displaced during roasting are dissolved in the water immersion liquid, and fluorine is fixed in the roasted clinker in the form of CaF2. After leaching, the mica particles left in the open circuit of the leaching original liquid are transported to the mica particle storage for temporary storage after leaching, and are sold as raw materials for the preparation of cementitious materials or cement.

[0079] (4) The leaching original liquid obtained in step (3) is pumped to the impurity removal section for F and Mg removal, wherein the Li in the leaching original liquid is 10.95g / L, the Rb is 1.26g / L, and the Cs is 58.14mg / L. Specifically, the leaching original liquid enters the impurity removal reaction kettle, 20% lime slurry is added, the mass of calcium oxide in the lime slurry is 1 / 6 of the theoretical amount of sulfate in the leaching original liquid, stirring is performed at 25℃ for 0.5h, and the slurry after reaction is subjected to solid-liquid separation by a pressure filter. The impurity removal residue is returned to step (1) after water washing for use as a lithium mica roasting auxiliary material, and the washing water is returned to step (3) for use as water immersion liquid.

[0080] (5) Pump the impurity-removed solution obtained in step (4) into a purification reactor, then add sodium carbonate, the amount of sodium carbonate being 1.5 times the theoretical amount of calcium ions in the impurity-removed solution, and stir at 85°C for 1 h. The slurry after the reaction is subjected to solid-liquid separation by a filter press, the purification residue is washed with water and then returned to step (1) as a lithium mica roasting auxiliary material, and the washing water is returned to step (3) as the water leaching solution.

[0081] (6) Evaporate and concentrate the purified solution obtained in step (5), and when crystals are precipitated, naturally cool to 50°C, and then centrifugal filtration is performed to obtain a salt-precipitated solution, and the filter residue is a sodium-potassium mixed salt, which can be returned to step (1) as part of the roasting auxiliary agent.

[0082] (7) The salt-precipitated solution obtained in step (6) is introduced into a resin adsorption system, the solution is introduced into the resin column at a certain flow rate, and the calcium and magnesium ions in the solution are selectively adsorbed by the chelating groups on the resin. The outlet flow is a lithium precipitation solution with a calcium ion content of <0.1 mg / L. A sodium carbonate solution is prepared, and the sodium carbonate solution is subjected to deep removal of calcium and magnesium impurity ions by ion exchange resin to obtain a refined sodium carbonate solution with a calcium ion content of <0.1 mg / L. The resin is an ion exchange resin with a model number of LSC-960 from Lanxiao Technology.

[0083] After deep removal of calcium and magnesium by ion exchange resin, the saturated resin after adsorption is subjected to regeneration treatment, including: displacing the saturated resin after adsorption with pure water to obtain a water washing solution as a lithium precipitation solution; after displacement with pure water, the resin is eluted with dilute sulfuric acid to obtain a resin regeneration solution; the eluted resin is washed with pure water to remove dilute sulfuric acid to obtain an acid washing water; the resin after acid washing is washed with a sodium hydroxide solution for transformation to obtain a resin post-transformation solution; and the transformed resin is washed with pure water to remove sodium hydroxide to obtain an alkali washing water. In this embodiment, the resin regeneration solution, the acid washing water, the resin post-transformation solution, and the alkali washing water are used as the countercurrent leaching water leaching solution in step (3).

[0084] (8) Pump the refined sodium carbonate solution obtained in step (7) into a lithium precipitation reactor, start the stirring motor and introduce steam to heat to 90°C, then inject the lithium precipitation solution obtained in step (7), and the mass of sodium carbonate in the sodium carbonate solution is 1.4 times the theoretical amount of lithium precipitation required by the lithium precipitation solution. After 0.5 h of reaction, centrifugal filtration is performed to obtain lithium carbonate crude and a lithium precipitation mother liquor.

[0085] (9) The lithium carbonate crude obtained in step (8) is put into a slurry washing tank, and pure water is introduced according to a liquid-solid ratio of 4:1, and stirring and washing are carried out at 90°C for 10 min, and the slurry washing is carried out twice, and then the slurry is sent to a centrifuge for solid-liquid separation, and the centrifugal filtrate is sent to step (7) to participate in the preparation of the sodium carbonate solution, and the obtained lithium carbonate is dried to obtain battery-grade lithium carbonate with a purity of 99.74%, and the detailed results are shown in Table 4.

[0086] (10) After the lithium precipitation mother liquor obtained in step (8) is recovered by precision filtration, the lithium carbonate is recovered by decarbonization and neutralization, evaporation crystallization, and sodium precipitation, and the recovered sodium-potassium salt is returned to the front end for use as a roasting auxiliary reagent, and the recovered sodium-potassium salt is sent to a rubidium and cesium extraction system for recovery of rubidium and cesium salt.

[0087] The battery-grade lithium carbonate preparation process based on lithium ore granulation provided in the embodiment can obtain a lithium leaching rate of up to 92%, a lithium comprehensive recovery rate of up to 87%, and battery-grade lithium carbonate with a purity of 99.74% without refining after one-time lithium precipitation, which meets the relevant requirements.

[0088] Example 3

[0089] A battery-grade lithium carbonate preparation process based on lithium ore granulation, the embodiment uses lithium mica ore produced by a certain lithium mica mine in Sichuan as raw material; the lithium mica ore is crushed and then floated to obtain lithium mica concentrate; the main components and contents of the lithium mica concentrate in Example 3 are shown in Table 3.

[0090] Table 3 Main components and contents (mass fraction %) of lithium mica concentrate in Example 3

[0091] Component Li2O [Rb2O] Cs2O WO3 SiO2 Al2O3 CaO MgO Content 1.89 1.02 0.06 <0.05 58.8 16.3 0.22 0.089 Component Na2O K2O TiO2 F Cl Sn TFe TS Content 0.23 3.22 0.06 3.21 0.034 0.032 1.77 <0.05

[0092] The specific process flow is shown in Figure 1 , which includes the following steps:

[0093] (1) After the lithium mica concentrate is dried, the lithium mica concentrate, CaSO4·2H2O, CaCO3, Na2SO4, K2SO4, and the lanthanum carbon are mixed according to a mass ratio of 1:0.45:0.3:0.01:0.01:0.01, and the roasting auxiliary reagents are added, and each reagent is a new reagent added externally when the system is initially started; after the process is running, the Na2SO4 and K2SO4 are mixed salts produced in the system, the CaSO4·2H2O and CaCO3 are partially returned from the impurity removal and purification, and partially are new reagents added, and the lanthanum carbon is a new reagent added; after the ore is mixed, the mixture is uniformly ground to obtain a mixed powder with a particle size of 1000 mesh accounting for 80%.

[0094] (2) The mixed powder obtained in step (1) is pressed into lithium mica particles with a particle size of 10 mm by a granulator.

[0095] (3) The lithium mica concentrate particles obtained in step (2) are dried by roasting flue gas and then put into a rotary kiln at 850°C for 30 minutes. The roasted clinker obtained from the kiln is cooled and mixed with water at pH 8-9, and then static 4-stage countercurrent tank leaching is carried out, with a liquid-solid ratio of 0.8:1, a leaching temperature of 50°C, and a single-stage leaching time of 8 hours. During the system startup stage, the water leaching solution is water; after the system is running, the water leaching solution is the leachate of mica particles, the washing water of the pressure filtration of impurity removal residue and purification residue, the regenerated solution after resin acid washing, the water washing solution after acid washing, the solution after resin alkali washing and transformation, the water washing solution after alkali washing, the purified solution, and the condensed water of secondary steam generated by evaporation of decarburization mother liquor. During leaching, lithium, rubidium, and cesium displaced during the roasting process dissolve in the water leaching solution, and fluorine is fixed in the roasted clinker in the form of CaF2. After leaching, the mica particles left in the leaching original solution are sent to the mica particle warehouse for temporary storage after leaching, and are sold as raw materials for cement preparation or cement preparation.

[0096] (4) The leaching original solution obtained in step (3) is pumped to the impurity removal section for F and Mg removal. The Li in the leaching original solution is 7.66 g / L, the Rb is 2 g / L, and the Cs is 216 mg / L. Specifically, the leaching original solution is put into an impurity removal reaction kettle, 20% lime slurry is added, the mass of calcium oxide in the lime slurry is 1 / 6 of the theoretical amount of sulfate in the leaching original solution, stirring is carried out at 50°C for 0.5 hours, the slurry after reaction is subjected to solid-liquid separation by a pressure filter, the impurity removal residue is washed with water and returned to step (1) as a lithium mica roasting auxiliary material, and the washing water is returned to step (3) as a water leaching solution.

[0097] (5) The impurity-removed solution obtained in step (4) is pumped to a purification reaction kettle, then sodium carbonate is added, the amount of sodium carbonate is 1.2 times the theoretical amount of calcium ions in the precipitated impurity-removed solution, stirring is carried out at 95°C for 1 hour, the slurry after reaction is subjected to solid-liquid separation by a pressure filter, the purification residue is washed with water and returned to step (1) as a lithium mica roasting auxiliary material, and the washing water is returned to step (3) as a water leaching solution.

[0098] (6) The purified solution obtained in step (5) is evaporated and concentrated, when crystallization occurs, it is naturally cooled to 50°C, then centrifugal filtration is carried out to obtain a salt precipitation solution, and the filter residue is a sodium-potassium mixed salt which can be returned to step (1) as part of the roasting auxiliary reagent.

[0099] (7) The salt precipitation solution obtained in step (6) is put into a resin adsorption system, the solution is put into a resin column at a certain flow rate, and the calcium and magnesium ions in the solution are selectively adsorbed by the chelating groups on the resin. The outlet flow is a lithium precipitation solution with a calcium ion content of <0.1 mg / L. A sodium carbonate solution is prepared, and the sodium carbonate solution is subjected to deep removal of calcium and magnesium impurity ions by ion exchange resin to obtain a refined sodium carbonate solution with a calcium ion content of <0.1 mg / L. The resin is an ion exchange resin with a model number of LSC-960 from Lanxiao Technology.

[0100] The ion exchange resin after deep removal of calcium and magnesium becomes saturated resin after adsorption, and the saturated resin after adsorption is subjected to regeneration treatment, including: the saturated resin after adsorption is replaced with pure water to obtain a water washing liquid as a pre-lithium precipitation liquid; the resin after pure water replacement is subjected to desorption with dilute sulfuric acid to obtain a resin after regeneration; the resin after desorption is washed with pure water to remove the dilute sulfuric acid to obtain an acid washing water; the resin after acid washing is subjected to transformation with a sodium hydroxide solution to obtain a resin after transformation; and the resin after transformation is washed with pure water to remove the sodium hydroxide to obtain an alkali washing water. In this embodiment, the resin after regeneration, the acid washing water, the resin after transformation, and the alkali washing water are used as the countercurrent leaching water in step (3).

[0101] (8) The refined sodium carbonate solution obtained in step (7) is pumped into a lithium precipitation reactor, the stirring motor is turned on, steam is introduced to heat to 95°C, then the pre-lithium precipitation liquid obtained in step (7) is injected, the mass of sodium carbonate in the sodium carbonate solution is 1.5 times the theoretical amount of lithium precipitation required by the pre-lithium precipitation liquid, and after 0.5 h of reaction, centrifugal filtration is performed to obtain lithium carbonate crude and a lithium precipitation mother liquor.

[0102] (9) The lithium carbonate crude obtained in step (8) is introduced into a slurry washing tank, pure water is introduced according to a liquid-solid ratio of 5:1, stirring and washing are performed at 95°C for 10 min, the slurry washing is performed 3 times, then the slurry is sent to a centrifuge for solid-liquid separation, and the centrifugal filtrate is sent to step (7) to participate in the preparation of the sodium carbonate solution, and the obtained lithium carbonate after drying is battery-grade lithium carbonate with a purity of 99.87%, and the detailed results are shown in Table 4.

[0103] (10) After the lithium precipitation mother liquor obtained in step (8) is subjected to precise filtration to recover lithium carbonate, sodium-potassium mixed salt is recovered through decarburization and neutralization, evaporation crystallization, and freezing sodium precipitation, and is returned to the front end to be used as a roasting auxiliary reagent, and the sodium-potassium salt after recovery is introduced into a rubidium and cesium extraction system to recover rubidium and cesium salts.

[0104] The battery-grade lithium carbonate preparation process based on lithium ore granulation provided in this embodiment can obtain a lithium leaching rate of up to 90%, a lithium comprehensive recovery rate of up to 88%, and battery-grade lithium carbonate with a purity of 99.87% after one-time lithium precipitation without refinement, which meets the relevant requirements.

[0105] Table 4 Purity and main impurity content of lithium carbonate prepared in Examples 1-3

[0106] Li2CO3 purity (%) K(％) Na (%) Ca (%) Mg (%) Electrode carbon standard ≥99.50 ≤0.001 ≤0.025 ≤0.005 ≤0.008 Example 1 99.68 0.0008 0.0104 0.0032 0.0002 Example 2 99.74 0.0006 0.0092 0.0026 0.0001 Example 3 99.87 0.0005 0.0075 0.0021 0.0001

[0107] Compared with the conventional one-time lithium precipitation process for preparing battery-grade lithium carbonate, the battery-grade lithium carbonate preparation process based on lithium ore granulation can obtain battery-grade lithium carbonate with a purity of 99.5% to 99.87% without refining, and more importantly, can significantly improve the lithium comprehensive recovery rate, wherein the lithium comprehensive recovery rate is as high as 85% to 90%, while the known actual industrial production process can only obtain a lithium comprehensive recovery rate of about 70%, and it is difficult to exceed 80%, and the preparation process has the advantages of simple overall process, high safety, low energy consumption, low cost, high production efficiency, green environmental protection and the like, can maximize the economic benefits of lithium ore resources, and has important significance for enterprises to improve economic benefits.

[0108] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make many possible changes and modifications to the technical solutions of the present application, or modify equivalent embodiments with equivalent changes, without departing from the spirit and technical solutions of the present application. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, still falls within the scope of protection of the technical solutions of the present application.

Claims

1. A process for preparing battery-grade lithium carbonate based on lithium ore granulation, characterized in that, Includes the following steps: (1) Lithium ore concentrate is mixed with roasting aid, finely ground and granulated to obtain lithium ore concentrate particles; (2) The lithium ore concentrate particles are roasted to obtain roasted clinker; (3) The roasted clinker is subjected to static countercurrent water leaching and solid-liquid separation to obtain leachate and ore particles; (4) Mix the leaching solution and lime slurry, adjust the pH and remove impurities to obtain the purified solution and the purified residue; (5) The purified liquid and sodium carbonate are mixed for purification to obtain purified liquid and purified residue; (6) The purified liquid is evaporated and concentrated, and then cooled to separate the solid and liquid to obtain the first sodium-potassium mixed salt and the salt precipitate liquid; (7) Use ion exchange resin to adsorb calcium and magnesium in the salt precipitation solution to obtain lithium precipitation solution; (8) The lithium precipitation pre-lime solution and the refined sodium carbonate solution are mixed for lithium precipitation to obtain crude lithium carbonate and lithium precipitation mother liquor. (9) The crude lithium carbonate is subjected to pulping, washing, filtration and drying to obtain battery-grade lithium carbonate; In step (1), the fine grinding yields a mixed powder with a particle size of 200 mesh or more, and the lithium ore concentrate particles have a particle size of 5 mm to 12 mm. In step (3), the pH of the water immersion solution used in the static countercurrent water immersion is 8 to 9, and the solid-liquid mass ratio of the static countercurrent water immersion is 1:0.8 to 2. In step (7), the calcium ion content in the lithium precipitation solution is <0.1 mg / L; the refined sodium carbonate solution is prepared by adsorbing calcium and magnesium from sodium carbonate solution through an ion exchange resin; the calcium ion content in the refined sodium carbonate solution is <0.1 mg / L. In step (3), the ore particles are leached to obtain leaching residue and leaching water; the leaching uses industrial water and / or condensate obtained by evaporation and concentration; the leaching residue is reused as a raw material for cement or cementitious materials; the leaching water obtained from the leaching is returned to step (3) for water leaching of the roasted clinker. In step (4), the impurity-removed residue is returned to step (1) as a roasting auxiliary agent; in step (5), the purified residue is returned to step (1) as a roasting auxiliary agent. In step (6), the first sodium-potassium mixed salt is returned to step (1) as a roasting additive; In step (8), the lithium precipitation mother liquor is acidified and decarbonized, and neutralized with liquid alkali to obtain a decarbonized mother liquor. The decarbonized mother liquor is evaporated and concentrated, and then solid-liquid separation is performed to obtain an evaporated crystallization mother liquor and a second sodium-potassium mixed salt. The evaporated crystallization mother liquor is then frozen and cooled, and then solid-liquid separation is performed to obtain a frozen liquid and a third sodium-potassium mixed salt. The second sodium-potassium mixed salt and the third sodium-potassium mixed salt are returned to step (1) as calcination auxiliary agents. The frozen liquid is subjected to extraction, washing, back-extraction, and evaporation crystallization to obtain cesium salt, rubidium salt, and raffinate. In step (1), the roasting aid includes gypsum and CaCO3, and the mass ratio of lithium ore concentrate to roasting aid is 1:0.2 to 1.6; The calcination aids also include Na2SO4, K2SO4, and semi-coke; The mass ratio of gypsum (calculated as CaSO4·2H2O) to lithium ore concentrate is 0.1–0.5:1; the mass ratio of CaCO3 (calculated as pure CaCO3) to lithium ore concentrate is 0.1–0.6:1; the mass ratio of Na2SO4 to lithium ore concentrate is 0–0.2:1, and not 0; the mass ratio of K2SO4 to lithium ore concentrate is 0–0.2:1, and not 0; the mass ratio of semi-coke to lithium ore concentrate is 0–0.1:1, and not 0. In step (2), the roasting temperature is 800℃~950℃, and the roasting holding time is 0.5h~2.5h.

2. The battery-grade lithium carbonate preparation process based on lithium ore granulation according to claim 1, characterized in that, In step (3), the temperature of the static countercurrent water immersion is 5℃~95℃, and the time of the static countercurrent water immersion is 0.1h~24h; the static countercurrent water immersion is a multi-stage water immersion, and the number of stages of the static countercurrent water immersion is 3~6 stages.

3. The battery-grade lithium carbonate preparation process based on lithium ore granulation according to claim 1, characterized in that, In step (4), the mass concentration of the lime slurry is 5% to 30%; the lime slurry is calculated as calcium oxide, and the mass of calcium oxide in the lime slurry is 1 / 6 of the theoretical amount of sulfate in the leaching solution; the temperature for removing impurities is 20℃ to 50℃, and the heat preservation time for removing impurities is 0.5h to 1h. In step (5), the purification temperature is 80℃~95℃, and the purification holding time is 1h; In step (6), the evaporation and concentration of the purified liquid is 1.8 to 2.65 times. In step (7), the mass of Na2CO3 in the refined sodium carbonate solution is 1.2 to 1.5 times the theoretical mass of lithium ions in the pre-precipitation solution; In step (8), the temperature for lithium deposition is 80℃~95℃, and the deposition time is 0.5h~2h; In step (9), the liquid-to-solid ratio of the crude lithium carbonate slurry washing is 3 to 5:1; the temperature of the slurry washing is 80°C to 95°C; the time of the slurry washing is 10 min to 30 min; and the number of slurry washings is 1 to 3 times.

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