Method and apparatus for extracting lithium

Abstract

The application discloses a lithium extraction method and equipment, and aims at solving the technical problems of long process and serious environmental pollution in the sulfuric acid method. The method comprises the following steps: through mixing a first material with a sulfate ion-based acidifying agent to perform a sulfation reaction, the first material is converted into a second material containing lithium sulfate, the first material contains a lithium-based compound, and the lithium sulfate is obtained from the lithium-based compound through the sulfation reaction; after or at the same time of converting the first material into the second material containing lithium sulfate by mixing the first material with the sulfate ion-based acidifying agent to perform the sulfation reaction, the second material is calcined to fully perform the sulfation reaction and remove the sulfate ion-based acidifying agent which is not completely reacted; the lithium sulfate in the second material is gasified and volatilized from the second solid phase material by heating the second material, and the solid phase material remaining after the lithium sulfate in the second material is gasified and volatilized is a third material.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of lithium metallurgy, in particular to a lithium ore pretreatment device, a lithium extraction method, a lithium extraction equipment and a lithium source preparation method. BACKGROUND

[0002] The most common lithium-containing minerals are lithium ore (spodumene and lepidolite) and brine, and based on these two raw materials, lithium source preparation processes can be divided into lithium ore preparation lithium source method and brine preparation lithium source method.

[0003] "Lithium source" is generally a collective term for lithium carbonate (Li2CO3) and lithium hydroxide (LiOH·H2O), and can be divided into industrial-grade lithium source and battery-grade lithium source according to purity requirements. For example, the mass percentage of lithium carbonate in industrial-grade lithium carbonate is 98%-99%, and the mass percentage of lithium carbonate in battery-grade lithium carbonate is ≥99.5%.

[0004] At present, the lithium ore preparation lithium source method mainly adopts the sulfuric acid method. The sulfuric acid method belongs to hydrometallurgy. In this method, the lithium sulfate solution obtained by wet leaching needs to be subjected to multiple impurity removal processes to obtain refined lithium sulfate solution, so the overall process flow is long and the environmental pollution is large. SUMMARY

[0005] An object of some embodiments of the present application is to provide a lithium extraction method and equipment to solve the technical problems of long process flow and large environmental pollution of the sulfuric acid method.

[0006] An object of some embodiments of the present application is to provide a lithium source preparation method, which can be used as a subsequent step of the above-mentioned lithium extraction method to obtain battery-grade lithium source in a relatively simple manner.

[0007] An object of some embodiments of the present application is to provide a lithium ore pretreatment device and lithium extraction equipment, which can provide a lithium ore pretreatment scheme for the above-mentioned lithium extraction method and equipment, reduce environmental pollution in lithium ore pretreatment, and realize waste heat utilization.

[0008] In a first aspect, a lithium extraction method is provided, comprising: converting a first solid phase material into a second solid phase material containing lithium sulfate by mixing the first solid phase material with a sulfate ion-based acidifying agent to perform a dry sulfuric acidization reaction, the first solid phase material containing a lithium-based compound, and the lithium sulfate being obtained from the lithium-based compound through the dry sulfuric acidization reaction; volatilizing the lithium sulfate in the second solid phase material from the second solid phase material by heating the second solid phase material, the remaining solid phase material after the lithium sulfate in the second solid phase material is volatilized being a third solid phase material; and recovering the gaseous lithium sulfate, the mass percentage of lithium sulfate in the solid lithium sulfate being ≥95% when the gaseous lithium sulfate is cooled into the solid lithium sulfate.

[0009] In the lithium extraction method of the first aspect above, optionally, the first solid phase material, in addition to the lithium-based compound, is mainly composed of at least one of the first type of compound, the second type of compound and the third type of compound; the first type of compound is a metal compound and is converted into a first type of metal sulfate through the dry sulfation reaction, and the first type of metal sulfate is converted into a first type of metal oxide through the heating and decomposes sulfur dioxide gas; the second type of compound is a metal compound and is converted into a second type of metal sulfate through the dry sulfation reaction, and the second type of metal sulfate is not converted by the heating; the third type of compound is a non-metallic compound and is not converted by both the dry sulfation reaction and the heating.

[0010] In the lithium extraction method of the first aspect above, optionally, the first solid phase material comes from lithium ore; if the first solid phase material contains the first type of compound, the first type of compound is mainly composed of at least one metal oxide; if the first solid phase material contains the second type of compound, the second type of compound is mainly composed of at least one metal oxide; if the first solid phase material contains the third type of compound, the third type of compound is mainly composed of at least one non-metal oxide.

[0011] Optionally, in the lithium extraction method of the first aspect, the first compound comprises at least one of aluminum oxide, iron oxide, calcium oxide, magnesium oxide, and manganese oxide; the second compound comprises at least one of sodium oxide, potassium oxide, rubidium oxide, and cesium oxide; and the third compound comprises silicon oxide. Optionally, in the lithium extraction method of the first aspect, the lithium ore is spodumene or lepidolite.

[0012] Optionally, in the lithium extraction method of the first aspect above, the first solid phase is obtained by pretreatment of lithium ore, and the pretreatment includes roasting the lithium ore to loosen the structure of the lithium ore (such as converting the spodumene crystal form from α to β) and defluorinating when the lithium ore contains fluorine, and refining the lithium ore to make the lithium ore into particles.

[0013] Optionally, in the lithium extraction method of the first aspect above, the dry sulfation reaction is to fully mix the first solid phase with the sulfate ion-based acidifier while keeping the entire substance in the first solid phase in a solid state.

[0014] Optionally, in the lithium extraction method of the first aspect above, during the dry sulfation reaction, the first solid phase and the sulfate ion-based acidulant are fully mixed and reacted in a ratio of 1-1.3 in which the molar ratio of sulfate ions in the sulfate ion-based acidulant to the total reactants in the first solid phase is maintained.

[0015] Optionally, in the lithium extraction method of the first aspect, the sulfate ion-based acidifying agent is concentrated sulfuric acid.

[0016] The lithium extraction method of the first aspect above may optionally further include, after or simultaneously with the first solid phase being mixed with a sulfate ion-based acidulant to undergo a dry sulfation reaction to convert the first solid phase into a second solid phase containing lithium sulfate, calcining the second solid phase to fully complete the dry sulfation reaction and remove incompletely reacted sulfate ion-based acidulant, and then heating the second solid phase to vaporize the lithium sulfate in the second solid phase and volatilize it from the second solid phase.

[0017] Optionally, in the lithium extraction method of the first aspect, the heating is specifically heating the second solid phase to a maximum of 1350° C. under conditions below one atmosphere.

[0018] Optionally, in the lithium extraction method of the first aspect, the first solid phase and the sulfate ion-based acidifying agent are both prepared in the form of particles and mixed with each other.

[0019] Optionally, in the lithium extraction method of the first aspect above, the recovery of vaporized lithium sulfate includes recovering heat from the vaporized lithium sulfate through flue gas cooling and heat exchange and outputting cooled flue gas containing solid lithium sulfate converted from vaporized lithium sulfate, and performing gas-solid separation on the cooled flue gas through flue gas filtration and discharging a first filtered solid phase and a first filtered gas phase respectively, wherein the first filtered solid phase is mainly solid lithium sulfate, and the mass percentage of lithium sulfate in the first filtered solid phase is ≥95%.

[0020] Optionally, in the lithium extraction method of the first aspect above, the recovery of vaporized lithium sulfate comprises mixing vaporized lithium sulfate with a sodium carbonate solution or a sodium hydroxide solution so that the lithium sulfate reacts with the sodium carbonate or sodium hydroxide to prepare lithium carbonate or lithium hydroxide.

[0021] The lithium extraction method described in the first aspect of the present invention produces high-purity lithium sulfate without requiring complex wet processing steps. This significantly reduces the amount of liquid to be processed after subsequent aqueous dissolution, significantly reducing the scale and process of subsequent impurity removal and purification. The process residue is dry, which facilitates storage, utilization, and environmental protection.

[0022] In a second aspect, a lithium extraction apparatus is provided, which can be used to implement the lithium extraction method of the first aspect. The apparatus comprises: a mixing reactor for mixing a first solid phase with a sulfate ion-based acidifier to undergo a dry sulfation reaction, thereby converting the first solid phase into a second solid phase containing lithium sulfate. The first solid phase contains a lithium-based compound, and the lithium sulfate is obtained from the lithium-based compound through the dry sulfation reaction; a heating gasifier for heating the second solid phase to vaporize the lithium sulfate in the second solid phase and volatilize it from the second solid phase. The solid phase remaining after the lithium sulfate in the second solid phase is vaporized and volatilized is a third solid phase; and a vaporized lithium sulfate recovery device for recovering the vaporized lithium sulfate. When the vaporized lithium sulfate is cooled to solid lithium sulfate, the mass percentage of lithium sulfate in the solid lithium sulfate is ≥95%.

[0023] The lithium extraction equipment of the second aspect mentioned above is optional, and the gasified lithium sulfate recovery device includes: a flue gas cooling heat exchanger for recovering heat from the high-temperature flue gas discharged from the heating gasification furnace and outputting cooled flue gas containing solid lithium sulfate converted from gasified lithium sulfate; a first flue gas filter for performing gas-solid separation on the cooled flue gas and separately discharging a first filtered solid phase and a first filtered gas phase, wherein the first filtered solid phase is mainly solid lithium sulfate.

[0024] The lithium extraction equipment in the second aspect mentioned above may optionally further include: a roasting kiln, which is arranged between the mixing reactor and the heating gasification furnace, and is used for, after or at the same time as mixing the first solid phase with the sulfate ion-based acidulant to carry out a dry sulfation reaction to convert the first solid phase into a second solid phase containing lithium sulfate, roasting the second solid phase to fully complete the dry sulfation reaction and remove the incompletely reacted sulfate ion-based acidulant, and then heating the second solid phase to vaporize the lithium sulfate in the second solid phase and volatilize it from the second solid phase.

[0025] In a third aspect, a lithium extraction method is provided, comprising: converting a first material into a second material containing lithium sulfate by mixing it with a sulfate ion-based acidifier to perform a sulfation reaction, wherein the first material contains a lithium-based compound, and the lithium sulfate is obtained from the lithium-based compound through the sulfation reaction; after or simultaneously with converting the first material into the second material containing lithium sulfate by mixing it with a sulfate ion-based acidifier to perform a sulfation reaction, calcining the second material to fully complete the sulfation reaction and remove incompletely reacted sulfate ion-based acidifier; heating the second material to vaporize the lithium sulfate in the second material and volatilize it from the second solid phase, wherein the solid phase remaining after the lithium sulfate in the second material is vaporized and volatilized is the third material; and recovering the vaporized lithium sulfate.

[0026] In the lithium extraction method of the third aspect above, optionally, the first material is a first solid phase material, and the first solid phase material, in addition to the lithium-based compound, is mainly composed of at least one of the first type of compound, the second type of compound and the third type of compound; the first type of compound is a metal compound and is converted into a first type of metal sulfate through the sulfation reaction, and the first type of metal sulfate is converted into a first type of metal oxide through the heating and decomposes sulfur dioxide gas; the second type of compound is a metal compound and is converted into a second type of metal sulfate through the sulfation reaction, and the second type of metal sulfate is not converted by the heating; the third type of compound is a non-metallic compound and is not converted by both the sulfation reaction and the heating.

[0027] In the lithium extraction method of the third aspect above, optionally, the first solid phase comes from lithium ore; if the first solid phase contains the first type of compound, the first type of compound is mainly composed of at least one metal oxide; if the first solid phase contains the second type of compound, the second type of compound is mainly composed of at least one metal oxide; if the first solid phase contains the third type of compound, the third type of compound is mainly composed of at least one non-metal oxide.

[0028] Optionally, in the lithium extraction method of the third aspect, the first compound comprises at least one of aluminum oxide, iron oxide, calcium oxide, magnesium oxide, and manganese oxide; the first compound comprises at least one of sodium oxide, potassium oxide, rubidium oxide, and cesium oxide; and the third compound comprises silicon oxide. Optionally, in the lithium extraction method of the third aspect, the lithium ore is spodumene or lepidolite.

[0029] Optionally, in the lithium extraction method of the third aspect, the first solid phase is obtained by pretreatment of lithium ore, and the pretreatment includes roasting the lithium ore to loosen the structure of the lithium ore and defluorinating when the lithium ore contains fluorine, and refining the lithium ore to make the lithium ore into particles.

[0030] Optionally, in the lithium extraction method of the third aspect, the sulfation reaction is to fully mix the first material and the sulfate ion-based acidifier while keeping the entire substance in the first material in a solid or muddy state.

[0031] Optionally, in the lithium extraction method of the third aspect, during the sulfation reaction, the first material and the sulfate ion-based acidulant are fully mixed and reacted in a ratio of 1-1.3 in molar ratio of sulfate ions in the sulfate ion-based acidulant to the total reactants in the first material.

[0032] Optionally, in the lithium extraction method of the third aspect, the sulfate ion-based acidifying agent is specifically concentrated sulfuric acid.

[0033] Optionally, in the lithium extraction method of the third aspect, the heating is to heat the second solid phase to a maximum of 1350° C. at a pressure below 1 atmosphere. Optionally, in the lithium extraction method of the third aspect, the calcination temperature is 180° C.-300° C.

[0034] Optionally, in the lithium extraction method of the third aspect, the first material and the sulfate ion-based acidifying agent are both prepared in the form of particles and mixed with each other.

[0035] Optionally, in the lithium extraction method of the third aspect mentioned above, the recovery of vaporized lithium sulfate includes recovering heat from the vaporized lithium sulfate through flue gas cooling and heat exchange and outputting cooled flue gas containing solid lithium sulfate converted from vaporized lithium sulfate, and performing gas-solid separation on the cooled flue gas through flue gas filtration and discharging a first filtered solid phase and a first filtered gas phase respectively, wherein the first filtered solid phase is mainly solid lithium sulfate, and the mass percentage of lithium sulfate in the first filtered solid phase is ≥95%.

[0036] Optionally, in the lithium extraction method of the third aspect above, the recovery of vaporized lithium sulfate comprises mixing vaporized lithium sulfate with a sodium carbonate solution or a sodium hydroxide solution so that the lithium sulfate reacts with the sodium carbonate or sodium hydroxide to prepare lithium carbonate or lithium hydroxide.

[0037] The lithium extraction method described in the third aspect above can produce high-purity lithium sulfate without the need for complex wet processes. This significantly reduces the amount of liquid to be processed after the subsequent aqueous solution, significantly reducing the scale and process of subsequent impurity removal and purification. The process residue is dry, which facilitates storage, utilization, and environmental protection.

[0038] Compared with the lithium extraction method of the third aspect, the sulfation reaction of the lithium extraction method of the third aspect can fully mix and react the first material with the sulfate ion-based acidifier while keeping the entire substance in the first material in a muddy state.

[0039] In a fourth aspect, a lithium extraction apparatus is provided, which can be used to implement the lithium extraction method of the second aspect. The apparatus comprises: a mixing reactor for mixing a first material with a sulfate ion-based acidifier to undergo a sulfation reaction, thereby converting the first material into a second material containing lithium sulfate, wherein the first material contains a lithium-based compound, and the lithium sulfate is obtained from the lithium-based compound through the sulfation reaction; a roasting kiln for roasting the second material after or simultaneously with the mixing of the first material with the sulfate ion-based acidifier to undergo a sulfation reaction, thereby converting the first material into the second material containing lithium sulfate, to complete the sulfation reaction and remove unreacted sulfate ion-based acidifier; a heating gasification furnace for heating the second material to vaporize the lithium sulfate in the second material and volatilize it from the second material, wherein the solid phase remaining after the vaporization and volatilization of the lithium sulfate in the second material is the third material; and a vaporized lithium sulfate recovery device for recovering the vaporized lithium sulfate.

[0040] The lithium extraction equipment of the fourth aspect mentioned above is optional, and the gasified lithium sulfate recovery device includes: a flue gas cooling heat exchanger for recovering heat from the high-temperature flue gas discharged from the heating gasification furnace and outputting cooled flue gas containing solid lithium sulfate converted from gasified lithium sulfate; a first flue gas filter for performing gas-solid separation on the cooled flue gas and separately discharging a first filtered solid phase and a first filtered gas phase, wherein the first filtered solid phase is mainly solid lithium sulfate.

[0041] Optionally, in the lithium extraction equipment of the fourth aspect above, the roasting kiln is connected to a roasting flue gas treatment system; the roasting flue gas treatment system includes: a second flue gas filter, used to perform gas-solid separation on the roasting flue gas discharged from the roasting kiln and discharge a second filtered solid phase and a second filtered gas phase respectively; a flue gas desulfurization equipment, used to receive the second filtered gas phase and perform desulfurization treatment on the second filtered gas phase and discharge the desulfurized tail gas; a material conveying equipment, used to receive the second filtered solid phase and return the filtered solid phase to the first material or the second material.

[0042] Optionally, in the lithium extraction equipment of the fourth aspect, the flue gas desulfurization equipment outputs the recovered sulfur to the sulfate ion-based acidulant supply system in the form of the sulfate ion-based acidulant or as a raw material for the sulfate ion-based acidulant.

[0043] The lithium extraction equipment of the fourth aspect mentioned above is optional, and the flue gas desulfurization equipment adopts a catalytic flue gas desulfurization device. The catalytic flue gas desulfurization device adsorbs sulfur dioxide, water, and oxygen contained in the filtered gas phase on the catalyst and reacts to generate sulfuric acid under the catalytic action of the active components. When the sulfuric acid attached to the catalyst reaches a certain level, dilute sulfuric acid and / or water are used as regeneration liquid to spray the catalyst to remove the sulfuric acid attached to the catalyst and release the active sites of the catalyst. The regeneration liquid after use is used as sulfuric acid for preparing the sulfate ion-based acidifier.

[0044] Optionally, in the lithium extraction equipment of the fourth aspect, the first filtered gas phase discharged from the first flue gas filter is subjected to desulfurization treatment by the flue gas desulfurization equipment.

[0045] In a fifth aspect, a method for preparing a lithium source is provided, wherein the lithium source is lithium carbonate or lithium hydroxide. Specifically, the method uses solid lithium sulfate (which can be obtained by the lithium extraction method of the first aspect or the lithium extraction method of the third aspect) with a lithium sulfate mass percentage of ≥95% formed by cooling gasified lithium sulfate as a raw material, dissolving the raw material in water, and then mixing and reacting with sodium carbonate or sodium hydroxide after removing impurities, thereby preparing battery-grade lithium carbonate or lithium hydroxide.

[0046] Optionally, in the lithium source preparation method of the fifth aspect, if battery-grade lithium carbonate is to be prepared, the raw materials can be dissolved in water and then alkalized and impurity removed to obtain a refined lithium sulfate solution, which is then mixed with sodium carbonate to react to obtain battery-grade lithium carbonate.

[0047] Since high-purity lithium sulfate is used as raw material, the amount of liquid to be processed after water dissolution is greatly reduced, which can greatly reduce the scale of subsequent impurity removal and purification production and shorten the process.

[0048] The sixth aspect provides a lithium ore pretreatment device that can provide a lithium ore pretreatment solution for the lithium extraction methods and equipment described above. The device comprises: a pretreatment roasting kiln for roasting lithium ore to loosen the lithium ore structure and defluorinate the lithium ore when it contains fluorine; a roasting flue gas purification system for purifying the flue gas emitted by the pretreatment roasting kiln and recovering dust from the flue gas; a roasting material waste heat utilization system for cooling and utilizing waste heat from the roasted material discharged from the pretreatment roasting kiln; and a crushing device for refining the waste heat-utilized material discharged from the roasting material waste heat utilization system to convert the lithium ore into granular matter.

[0049] In the lithium ore pretreatment device of the sixth aspect above, optionally, the pretreatment roasting kiln adopts a rotary kiln, the input end of the roasting flue gas purification system is connected to the kiln tail of the rotary kiln, and the input end of the roasting material waste heat utilization system is connected to the kiln head of the rotary kiln.

[0050] Optionally, in the lithium ore pretreatment device of the sixth aspect, the roasting flue gas purification system includes a first flue gas dust collector, which physically intercepts dust in the flue gas emitted by the pretreatment roasting kiln through a filter element.

[0051] In the lithium ore pretreatment device of the sixth aspect above, the roasting material waste heat utilization system includes a grate cooler and a second flue gas dust collector connected to the exhaust end of the grate cooler, and the second flue gas dust collector includes a filter element for physically intercepting dust in the flue gas discharged from the grate cooler.

[0052] In a seventh aspect, a lithium extraction device is provided, comprising: a lithium ore pretreatment device, wherein the lithium ore pretreatment device is the lithium ore pretreatment device of the sixth aspect; a mixing reactor for mixing a first solid phase material using the particulate matter with a sulfate ion-based acidifier to perform a dry sulfation reaction to convert the first solid phase material into a second solid phase material containing lithium sulfate; a heating gasifier for heating the second solid phase material so that the lithium sulfate in the second solid phase material is vaporized and volatilized from the second solid phase material, and the solid phase material remaining after the lithium sulfate in the second solid phase material is vaporized and volatilized is a third solid phase material; and a vaporized lithium sulfate recovery device for recovering vaporized lithium sulfate.

[0053] In an eighth aspect, a lithium extraction device is provided, comprising: a lithium ore pretreatment device, wherein the lithium ore pretreatment device is the lithium ore pretreatment device of the sixth aspect; a mixing reactor for mixing a first material using the particulate matter with a sulfate ion-based acidifier for a sulfation reaction to convert the first material into a second material containing lithium sulfate; a roasting kiln for roasting the second material after or at the same time as mixing the first material with the sulfate ion-based acidifier for a sulfation reaction to convert the first material into the second material containing lithium sulfate, so as to fully complete the sulfation reaction and remove incompletely reacted sulfate ion-based acidifier; a heating gasifier for heating the second material so that the lithium sulfate in the second material is vaporized and volatilized from the second material, and the solid phase remaining after the lithium sulfate in the second solid phase is vaporized and volatilized is the third material; and a vaporized lithium sulfate recovery device for recovering vaporized lithium sulfate.

[0054] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages provided by the present application will be partially given in the following description, partially become apparent from the following description, or be learned through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings that constitute part of this specification are used to assist in understanding this application. The contents provided in the drawings and the related descriptions in this specification may be used to explain this application, but shall not constitute an improper limitation on this application. In the drawings:

[0056] Figure 1 This is a schematic diagram of the overall process of producing lithium carbonate from lepidolite according to Example 1 of the present application.

[0057] Figure 2 for Figure 1 Specific process flow chart of the lithium ore pretreatment process.

[0058] Figure 3 for Figure 1 Specific process flow chart of the intermediate acidification and gasification process.

[0059] Figure 4 for Figure 1 Specific process flow chart of Zhongliyuan’s production process.

[0060] Figure 5 for Figure 1 Schematic diagram of material transformation in the process of producing lithium carbonate from lepidolite. DETAILED DESCRIPTION

[0061] The following is a clear and complete description of the embodiments of the present application in conjunction with the accompanying drawings. A person of ordinary skill in the art will be able to implement the embodiments of the present application based on these descriptions. Before describing the embodiments of the present application in conjunction with the accompanying drawings, it should be noted that:

[0062] The technical solutions and technical features provided in each section, including the following description, may be combined with each other unless they conflict. In addition, where possible, these technical solutions, technical features, and related combinations may be assigned specific technical themes and protected by relevant patents.

[0063] The embodiments of the present application involved in the following description are generally only a part of the embodiments rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of patent protection.

[0064] The terms "include," "comprising," "having," and any variations thereof in this specification, the corresponding claims, and related parts are intended to cover non-exclusive inclusions. Other related terms and units are to be reasonably interpreted based on the relevant content provided in this specification.

[0065] Figure 1 This is a schematic diagram of the overall process of producing lithium carbonate from lepidolite according to Example 1 of the present application. The composition of the lepidolite is specifically shown in Table 1.

[0066] Table 1

[0067]

[0068] Note: The water content of the ore sample is 9.63 wt%. After being dried at 270°C to constant weight, the physical properties of the various oxides shown in Table 1 are shown in Table 2.

[0069] Table 2

[0070]

[0071] Table 3 shows the physical properties of the sulfates of the various metal elements shown in Table 1.

[0072] Table 3

[0073]

[0074] Therefore, based on the contents shown in Table 1, Table 2 and Table 3, Figure 1As shown, the lithium carbonate production process of lithium mica in Example 1 will adopt such a technical idea, namely: first enter the lithium ore pretreatment process S1, and pretreat the lithium mica. The pretreatment includes loosening the lithium mica structure and defluorinating the lithium mica by roasting the lithium mica, and making the lithium mica into particles (first material) by refining the lithium mica. Wherein, the lithium mica structure is loosened by roasting the lithium mica, usually accompanied by the transformation of the lithium mica ore crystal form, such as the lithium oxide crystal form is transformed from α to β type, so that the structure of the lithium mica ore will become loose from dense, and fluorine and other organic matter will also be removed from the ore during this process. Then enter the acidification and gasification process S2. In the acidification and gasification process S2, the first material is first mixed with a sulfate ion-based acidifier to carry out a sulfation reaction (abbreviated as acidification), so that various oxides (except silicon dioxide) in the first material are converted into sulfate to form a second material, wherein lithium oxide will also be converted into lithium sulfate. Thereafter, the second material is heated to vaporize the lithium sulfate in the second material and volatilize it from the second material (referred to as gasification). Other oxides in the second material are either converted into metal oxides by the heating and decomposed into sulfur dioxide gas, or remain unchanged. Therefore, the gas produced by the gasification is essentially composed of vaporized lithium sulfate and sulfur dioxide, and the solid phase remaining after the lithium sulfate in the second material is vaporized and volatilized is the third material (dry material). Then, the vaporized lithium sulfate is recovered by recovering the heat of the vaporized lithium sulfate through flue gas cooling and heat exchange, and a cooled flue gas containing solid lithium sulfate converted from the vaporized lithium sulfate is output. The cooled flue gas is subjected to gas-solid separation by flue gas filtration, and a first filtered solid phase and a first filtered gas phase are discharged separately. The first filtered solid phase is mainly solid lithium sulfate, and the mass percentage of lithium sulfate in the first filtered solid phase is ≥95% (usually ≥97%), i.e., high-purity lithium sulfate. Finally, the lithium source production step S3 is entered, in which the first filtered solid phase is used as a raw material, the raw material is dissolved in water, and then mixed with sodium carbonate or sodium hydroxide after impurities are removed to react, thereby preparing battery-grade lithium carbonate or lithium hydroxide.

[0075] Figure 5 for Figure 1 The schematic diagram of material transformation in the process of producing lithium carbonate from lepidolite is shown in FIG. Figure 5As shown, after acidification, all oxides in the first material (except silicon dioxide) are converted into sulfates. At this point, the first material is essentially composed of lithium sulfate, aluminum sulfate, iron sulfate, calcium sulfate, magnesium sulfate, manganese sulfate, sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate, and silicon oxide. During vaporization, aluminum sulfate, iron sulfate, calcium sulfate, magnesium sulfate, and manganese sulfate, because their decomposition temperatures are much lower than lithium sulfate, are converted into aluminum oxide, iron oxide, calcium oxide, magnesium oxide, and manganese oxide, respectively, and release sulfur dioxide gas. Sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate, and silicon oxide, because their boiling points are much higher than lithium sulfate, neither vaporize nor decompose. Therefore, the gas produced by controllable vaporization is essentially composed of vaporized lithium sulfate and sulfur dioxide. Incidentally, the vaporized lithium sulfate and sulfur dioxide can be separated by cooling the vaporized lithium sulfate to convert it into solid lithium sulfate.

[0076] The lithium carbonate production process from lepidolite in Example 1 can produce high-purity lithium sulfate without complex and tedious wet processes, significantly reducing the amount of liquid to be processed after subsequent aqueous dissolution, significantly reducing the scale of subsequent impurity removal and purification, and significantly shortening the process. The process residue is dry, which is convenient for storage, utilization, and environmental protection.

[0077] Figure 2 for Figure 1 Specific process flow chart of the lithium ore pretreatment process. Figure 3 for Figure 1 Specific process flow chart of the intermediate acidification and gasification process. Figure 4 for Figure 1 The specific process flow chart of the lithium source production process. Figure 2-Figure 4 As shown, the process for producing lithium carbonate from lepidolite is further explained.

[0078] like Figure 2 As shown, a lithium ore pretreatment device includes: a pretreatment roasting kiln 11, a roasting flue gas purification system 12, a roasting material waste heat utilization system 13, and a crushing and processing device 14. The pretreatment roasting kiln 11 is used to roast lithium ore to loosen its structure and defluorinate if the lithium ore contains fluorine; the roasting flue gas purification system 12 is used to purify the flue gas emitted by the pretreatment roasting kiln 11 and recover dust from the flue gas; the roasting material waste heat utilization system 13 is used to cool the roasted material discharged from the pretreatment roasting kiln 11 and utilize the waste heat; and the crushing and processing device 14 is used to refine the waste heat utilized material discharged from the roasting material waste heat utilization system to reduce the lithium ore into particulate matter. The use of the roasting flue gas purification system 12 and the roasting material waste heat utilization system 13 can reduce environmental pollution from lithium ore pretreatment and achieve waste heat utilization.

[0079] In one specific embodiment, the pretreatment roasting kiln 11 can be a rotary kiln, the input end of the roasting flue gas purification system 12 is connected to the kiln tail of the rotary kiln, and the input end of the roasting material waste heat utilization system 13 is connected to the kiln head of the rotary kiln. During operation, the flue gas discharged from the kiln tail of the rotary kiln enters the roasting flue gas purification system 12, which purifies the flue gas discharged from the pretreatment roasting kiln 11 and recovers the dust in the flue gas; the roasted material discharged from the kiln head of the rotary kiln enters the roasting material waste heat utilization system 13, which cools the roasted material discharged from the pretreatment roasting kiln 11 and utilizes the waste heat.

[0080] In a specific embodiment, the roasting flue gas purification system 12 includes a first flue gas dust collector 121, which physically intercepts the dust in the flue gas emitted by the pretreatment roasting kiln 11 through a filter element. The filter element in the first flue gas dust collector 121 can be a metal filter element or a ceramic filter element so as to achieve filtration at a higher temperature. In addition, the roasting flue gas purification system 12 may also include a waste heat recovery device 122 and an exhaust gas purification device 123. The waste heat recovery device 122 can use a waste heat boiler to recover the waste heat of the dust-removed flue gas output by the first flue gas dust collector 121. The exhaust gas purification device 123 is used to further purify the flue gas output by the waste heat recovery device 122, such as denitrification, defluorination, etc., and corresponding purification measures are set according to the pollutant composition and content of the flue gas output by the waste heat recovery device 122.

[0081] In a specific embodiment, the roasting material waste heat utilization system 13 includes a grate cooler 131 and a second flue gas dust collector 132 connected to the exhaust end of the grate cooler 131. The second flue gas dust collector 132 includes a filter element to physically intercept dust in the flue gas discharged from the grate cooler 131. Similarly, the filter element in the second flue gas dust collector 132 can be a metal filter element or a ceramic filter element. The grate cooler 131 is an existing cooling device that uses air to cool high-temperature solid materials. Here, the high-temperature airflow generated by the cooling of the grate cooler 131 is filtered and dusted by the second flue gas dust collector 132.

[0082] The crushing and processing device 14 can adopt various existing equipment or a combination of equipment to obtain particles of corresponding particle size. In a specific embodiment, the crushing and processing device 14 mainly consists of a coarse crusher, a fine crusher and a particle classification system arranged in sequence.

[0083] In the lithium carbonate production process of lithium mica in Example 1, the lithium mica is sent to a pretreatment roasting kiln 11 for roasting to loosen the lithium mica structure and defluorinate. The specific roasting conditions can refer to the existing sulfuric acid method. The roasted lithium mica is sent to the roasting material waste heat utilization system 13 and then cooled, and then sent to the crushing processing device 14 for refinement processing to make the lithium mica into particles (first material).

[0084] like Figure 3 As shown, a lithium extraction device includes: a mixing reactor 21, a roasting kiln 22, a heating gasifier 23, and a gasified lithium sulfate recovery device 24. The mixing reactor 21 is used to mix a first material with a sulfate ion-based acidifier to undergo a sulfation reaction, thereby converting the first material into a second material containing lithium sulfate. The roasting kiln 22 is used to roast the second material after or simultaneously with the mixing of the first material with the sulfate ion-based acidifier to undergo a sulfation reaction, thereby converting the first material into the second material containing lithium sulfate, to fully complete the sulfation reaction and remove unreacted sulfate ion-based acidifier. The heating gasifier 23 is used to heat the second material so that the lithium sulfate in the second material is vaporized and volatilized from the second material. The solid phase remaining after the lithium sulfate in the second solid phase is vaporized and volatilized is the third material. The gasified lithium sulfate recovery device 24 is used to recover the vaporized lithium sulfate.

[0085] The mixing reactor 21 can achieve mixing in a variety of ways. Here, a sulfate ion-based acidifier (in the case of concentrated sulfuric acid) is sprayed onto the first material through an atomizing nozzle while stirring the first material (e.g., using blades or fluidized bed stirring). The roasting kiln 22 can be a rotary kiln or a tunnel kiln. The heating gasifier 23 can be a rotary kiln or a tunnel kiln.

[0086] In one embodiment, the vaporized lithium sulfate recovery device 24 includes a flue gas cooling heat exchanger 241 for recovering heat from the high-temperature flue gas exhausted by the heating gasifier 23 and outputting cooled flue gas containing solid lithium sulfate converted from the vaporized lithium sulfate; and a first flue gas filter 242 for performing gas-solid separation on the cooled flue gas and separately discharging a first filtered solid phase and a first filtered gas phase, the first filtered solid phase primarily being solid lithium sulfate. The filter element in the first flue gas filter 242 can be a metal filter element or a ceramic filter element.

[0087] In one embodiment, the roasting kiln 22 is connected to a roasting flue gas treatment system 25; the roasting flue gas treatment system 25 includes: a second flue gas filter 251 for performing gas-solid separation on the roasting flue gas emitted by the roasting kiln 22 and discharging a second filtered solid phase and a second filtered gas phase, respectively; a flue gas desulfurization device 252 for receiving the second filtered gas phase, performing desulfurization treatment on the second filtered gas phase, and discharging the desulfurized tail gas; and a material conveying device for receiving the second filtered solid phase and returning the filtered solid phase to the first material or the second material. The filter element in the second flue gas filter 251 can be a metal filter element or a ceramic filter element.

[0088] In one specific embodiment, the flue gas desulfurization equipment 252 outputs the recovered sulfur to the sulfate ion-based acidulant supply system in the form of the sulfate ion-based acidulant or the raw material of the sulfate ion-based acidulant. For example, the flue gas desulfurization equipment 252 can adopt a catalytic flue gas desulfurization device, in which the sulfur dioxide, water, and oxygen contained in the filtered gas phase are adsorbed on the catalyst and reacted under the catalytic action of the active components to produce sulfuric acid. When the sulfuric acid attached to the catalyst reaches a certain level, dilute sulfuric acid and / or water are used as a regeneration liquid to spray the catalyst to remove the sulfuric acid attached to the catalyst and release the catalyst active sites. The regeneration liquid after use is used as sulfuric acid to prepare the sulfate ion-based acidulant. Catalytic flue gas desulfurization devices are existing technology and will not be described in detail here.

[0089] In a specific embodiment, the first filtered gas phase discharged from the first flue gas filter 242 is desulfurized by the flue gas desulfurization equipment 252 .

[0090] In the lithium carbonate production process of lepidolite in Example 1, during the sulfation reaction, the first material and concentrated sulfuric acid are thoroughly mixed and reacted while maintaining the entire substance in the first material in a solid state. The sulfate ion-based acidifier is specifically concentrated sulfuric acid (specifically, a sulfuric acid solution having a mass fraction of 98%). The first material and the concentrated sulfuric acid are thoroughly mixed and reacted in a ratio of 1.1 molar ratio of sulfate ions in the sulfate ion-based acidifier to the total reactants in the first material, so that various oxides (except silicon dioxide) in the first material are converted into sulfates to form a second material. After the first material and the sulfate ion-based acidifier are mixed and subjected to a sulfation reaction to convert the first material into a second material containing lithium sulfate, the second material is roasted in a roasting kiln 22 to fully complete the sulfation reaction and remove unreacted sulfate ion-based acidifier. The roasting temperature is 180° C. to 300° C. Thereafter, the second material is heated by the gasification furnace 23. Specifically, the heating is to heat the second solid phase to 1350° C. under conditions below one atmosphere. At this time, the lithium sulfate in the second material is vaporized and volatilized from the second material (referred to as gasification), and the aluminum sulfate, iron sulfate, calcium sulfate, magnesium sulfate, and manganese sulfate in the second material are converted into metal oxides by the heating and decompose into sulfur dioxide gas. The remaining oxides in the second material are not converted. Therefore, the gas generated by gasification is basically composed of vaporized lithium sulfate and sulfur dioxide, and the solid phase remaining after the lithium sulfate in the second material is vaporized and volatilized is the third material (dry material). Then, the vaporized lithium sulfate is recovered, that is, the heat of the vaporized lithium sulfate is recovered through the flue gas cooling heat exchanger 241 and the cooled flue gas containing solid lithium sulfate converted from the vaporized lithium sulfate is output, and then the cooled flue gas is subjected to gas-solid separation through the first flue gas filter 242 and the first filtered solid phase and the first filtered gas phase are discharged respectively. The first filtered solid phase is mainly solid lithium sulfate, and the mass percentage of lithium sulfate in the first filtered solid phase is ≥95% (usually ≥97%).

[0091] like Figure 4 As shown, the first filtered solid phase is mixed with water by a mixer 31, thereby dissolving the first filtered solid phase with water. The lithium sulfate solution is then alkalized and impurities removed by an impurity removal device 32 to obtain a refined lithium sulfate solution. Sodium carbonate is then added to the refined lithium sulfate solution by a lithium precipitation device 33 to react and produce lithium carbonate. The lithium carbonate is then dried by a drying device 44 to obtain battery-grade lithium carbonate. The alkalization and impurity removal, lithium precipitation, and drying processes are all conventional techniques.

[0092] The lithium mica production lithium carbonate process of the embodiment 2 of the present application is improved on the basis of the lithium mica production lithium carbonate process of the embodiment 1, the mixing reactor 21 and the calcination kiln 22 in the lithium extraction equipment are combined into one, i.e. a rotary kiln is directly used. Meanwhile, the first material and the concentrated sulfuric acid are fully mixed and reacted in the state that the whole of the substances in the first material are in a mud state during the sulfuric acidification reaction, wherein the sulfuric acid radical ion-based acidifying agent specifically uses concentrated sulfuric acid (specifically a 70% mass fraction sulfuric acid solution), and the first material and the concentrated sulfuric acid are fully mixed and reacted according to the molar ratio of the sulfuric acid radical ions in the sulfuric acid radical ion-based acidifying agent to the total reactants in the first material is 1.3, so that the various oxides (except silicon dioxide) in the first material are converted into sulfates to form the second material.

[0093] The lithium mica production lithium carbonate process of the embodiment 3 of the present application is improved on the basis of the lithium mica production lithium carbonate process of the embodiment 1, the calcination kiln 22 is cancelled, and acidification is directly realized through the mixing reactor 21. In the mixing reactor 21, the first material is sprayed in the form of particulate matter, and the concentrated sulfuric acid as the sulfuric acid radical ion-based acidifying agent is also in the form of particulate matter, so that the first material and the sulfuric acid radical ion-based acidifying agent are both prepared in the form of particulate matter and mixed with each other.

[0094] The lithium mica production lithium carbonate process of the embodiment 4 of the present application is improved on the basis of the lithium mica production lithium carbonate process of the embodiment 1, and the gaseous lithium sulfate is directly mixed with a sodium carbonate solution or a sodium hydroxide solution to prepare lithium carbonate or lithium hydroxide by the reaction of lithium sulfate with sodium carbonate or sodium hydroxide when the gaseous lithium sulfate is recovered.

[0095] The above describes the relevant content of the present application. The person skilled in the art can implement the present application based on the above description. Based on the above description of the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of the present application.

Claims

1. A lithium extraction method, characterized in that: include: The first material is mixed with a sulfate ion-based acidifying agent to undergo a sulfation reaction, thereby converting the first material into a second material containing lithium sulfate, wherein the first material contains a lithium-based compound, and the lithium sulfate is obtained from the lithium-based compound through the sulfation reaction; After or simultaneously with the first material being converted into a second material containing lithium sulfate by mixing the first material with a sulfate ion-based acidulant for a sulfation reaction, the second material is calcined to fully complete the sulfation reaction and remove unreacted sulfate ion-based acidulant; heating the second material so that lithium sulfate in the second material is vaporized and volatilized from the second material, wherein the solid phase remaining after the lithium sulfate in the second material is vaporized and volatilized is the third material; and The vaporized lithium sulfate is recovered, and when the vaporized lithium sulfate is cooled to form solid lithium sulfate, the mass percentage of lithium sulfate in the solid lithium sulfate is ≥95%.

2. The lithium extraction method according to claim 1, wherein: The first material is a first solid phase material, and the first solid phase material, in addition to the lithium-based compound, is mainly composed of at least one of the first type of compound, the second type of compound, and the third type of compound; The first type of compound is a metal compound and is converted into a first type of metal sulfate through the sulfation reaction, and the first type of metal sulfate is converted into a first type of metal oxide through the heating and decomposes into sulfur dioxide gas; The second type of compound is a metal compound and is converted into a second type of metal sulfate through the sulfation reaction, and the second type of metal sulfate is not converted by the heating; The third type of compound is a non-metallic compound and is not converted by the sulfation reaction or the heating.

3. The lithium extraction method according to claim 2, wherein: The first solid phase material comes from lithium ore; if the first solid phase material contains the first type of compound, the first type of compound is mainly composed of at least one metal oxide; if the first solid phase material contains the second type of compound, the second type of compound is mainly composed of at least one metal oxide; if the first solid phase material contains the third type of compound, the third type of compound is mainly composed of at least one non-metal oxide.

4. The lithium extraction method according to claim 3, wherein: The first type of compound contains at least one of aluminum oxide, iron oxide, calcium oxide, magnesium oxide, and manganese oxide; the second type of compound contains at least one of sodium oxide, potassium oxide, rubidium oxide, and cesium oxide; and the third type of compound contains silicon oxide.

5. The lithium extraction method according to claim 3, wherein: The lithium ore is spodumene or lepidolite.

6. The lithium extraction method according to claim 3, wherein: The first solid phase is obtained by pre-processing lithium ore, wherein the pre-processing comprises roasting the lithium ore to loosen the structure of the lithium ore and defluorinating the lithium ore when the lithium ore contains fluorine, and refining the lithium ore to make the lithium ore into particles.

7. The lithium extraction method according to claim 1, wherein: The sulfation reaction is to fully mix the first material and the sulfate ion-based acidifier while keeping the first material in a solid or muddy state.

8. The lithium extraction method according to claim 7, wherein: During the sulfation reaction, the first material and the sulfate ion-based acidulant are fully mixed and reacted in a molar ratio of sulfate ions in the sulfate ion-based acidulant to the total reactants in the first material of 1-1.

3.

9. The lithium extraction method according to claim 7, wherein: The sulfate ion-based acidifier is specifically concentrated sulfuric acid.

10. The lithium extraction method according to claim 1, wherein: The heating is specifically heating the second material to a maximum temperature of 1350° C. under a condition of less than one atmosphere; and / or, the calcination temperature is 180° C.-300° C.

11. The lithium extraction method according to claim 10, wherein: The first material and the sulfate ion-based acidifier are both prepared in the form of granules and mixed with each other.

12. The lithium extraction method according to claim 1, wherein: The recovering of vaporized lithium sulfate comprises recovering heat from the vaporized lithium sulfate by flue gas cooling and heat exchange and outputting cooled flue gas containing solid lithium sulfate converted from the vaporized lithium sulfate, performing gas-solid separation on the cooled flue gas by flue gas filtration and respectively discharging a first filtered solid phase and a first filtered gas phase, wherein the first filtered solid phase is mainly solid lithium sulfate, and the mass percentage of lithium sulfate in the first filtered solid phase is ≥95%; Alternatively, the recovery of vaporized lithium sulfate comprises mixing vaporized lithium sulfate with a sodium carbonate solution or a sodium hydroxide solution so that the lithium sulfate reacts with the sodium carbonate or sodium hydroxide to produce lithium carbonate or lithium hydroxide.

13. A lithium extraction device, characterized in that: include: a mixing reactor for mixing a first material with a sulfate ion-based acidifying agent to perform a sulfation reaction to convert the first material into a second material containing lithium sulfate, wherein the first material contains a lithium-based compound, and the lithium sulfate is obtained from the lithium-based compound through the sulfation reaction; a roasting kiln for roasting the second material to fully complete the sulfation reaction and remove incompletely reacted sulfate ion-based acidifying agent after or simultaneously with mixing the first material with the sulfate ion-based acidifying agent to carry out a sulfation reaction to convert the first material into a second material containing lithium sulfate; a heating gasifier, used to heat the second material so that lithium sulfate in the second material is vaporized and volatilized from the second material, wherein the solid phase remaining after the lithium sulfate in the second material is vaporized and volatilized is the third material; and Gasified lithium sulfate recovery device is used to recover gasified lithium sulfate.

14. The lithium extraction equipment according to claim 13, characterized in that: The gasified lithium sulfate recovery device comprises: a flue gas cooling heat exchanger for recovering heat from the high-temperature flue gas discharged from the heating gasifier and outputting cooled flue gas containing solid lithium sulfate converted from gasified lithium sulfate; The first flue gas filter is used to perform gas-solid separation on the cooled flue gas and discharge a first filtered solid phase and a first filtered gas phase respectively, wherein the first filtered solid phase is mainly solid lithium sulfate.

15. The lithium extraction equipment according to claim 13 or 14, characterized in that: The roasting kiln is connected to a roasting fume treatment system; the roasting fume treatment system comprises: a second flue gas filter for performing gas-solid separation on the roasting flue gas emitted by the roasting kiln and discharging a second filtered solid phase and a second filtered gas phase respectively; a flue gas desulfurization device, configured to receive the second filtered gaseous phase, perform desulfurization on the second filtered gaseous phase, and discharge the desulfurized tail gas; The material conveying equipment is used to receive the second filtered solid phase and return the filtered solid phase to the first material or the second material.

16. The lithium extraction device according to claim 15, characterized in that: The flue gas desulfurization equipment outputs the recovered sulfur to the sulfate ion-based acidulant supply system in the form of the sulfate ion-based acidulant or the raw material of the sulfate ion-based acidulant; And / or, the flue gas desulfurization equipment adopts a catalytic flue gas desulfurization device, in which sulfur dioxide, water, and oxygen contained in the filtered gas phase are adsorbed on the catalyst and reacted under the catalytic action of active components to produce sulfuric acid. When the sulfuric acid attached to the catalyst reaches a certain level, dilute sulfuric acid and / or water are used as a regeneration liquid to spray the catalyst to remove the sulfuric acid attached to the catalyst and release the catalyst active sites. The regeneration liquid after use is used as sulfuric acid to prepare the sulfate ion-based acidifying agent; And / or, when the gasified lithium sulfate recovery device includes the flue gas cooling heat exchanger and the first flue gas filter, the first filtered gas phase discharged from the first flue gas filter is desulfurized by the flue gas desulfurization equipment.

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