A method for extracting lithium by low-temperature transformation roasting of complex lithium ores or lithium-containing waste through pretreatment

Abstract

The present invention discloses a method for extracting lithium by low-temperature transformation roasting in the pretreatment of complex lithium ores or lithium-containing waste materials. The method comprises the following steps: uniformly mixing one or more of petalite concentrate, spodumene concentrate, lithium porcelain stone and lithium-containing glass waste materials with aluminum electrolysis cell overhaul slag, fluoride and concentrated sulfuric acid, and then performing low-temperature calcination pretreatment to obtain a pretreated material; performing transformation roasting on the pretreated material to obtain a transformed material; then, uniformly mixing the transformed material with concentrated sulfuric acid and performing low-temperature acidification roasting to obtain an acidified material; finally, placing the acidified material in water, performing water leaching and separating the solid and liquid to obtain a lithium leaching solution. The technical solution of the present invention can achieve the coordinated consumption of various lithium resources, has a high comprehensive lithium utilization rate, low energy consumption for transformation roasting, simple process and low cost, is suitable for industrial application, and is of great significance for the efficient development and utilization of natural hard rock-type lithium ores and secondary lithium resources, and has extremely broad application and promotion prospects.

Description

Technical Field

[0001] The present invention relates to the field of extracting lithium from natural hard rock-type lithium ores and secondary lithium resources, and particularly relates to a method for extracting lithium by low-temperature transformation roasting of pretreatment of complex lithium ores or lithium-containing waste materials. Background Art

[0002] Lithium is the foundation for the development of China's new energy industry, and the demand for lithium products such as lithium carbonate and lithium hydroxide is also increasing continuously. Petalite is an important hard rock-type lithium ore resource, and its chemical composition is LiAlSi4O 10, with a theoretical Li2O content of approximately 4.91%, is usually associated with minerals such as spodumene and mica; compared with spodumene (LiAlSi2O6), petalite contains more SiO2 components in its crystal structure, and usually requires more dosage when using chemical aids to break its crystal structure. The efficient utilization of petalite is of great significance for ensuring the stable supply of lithium resources in China and supporting the development of emerging industries. Methods for extracting lithium from lithium-containing minerals include the sulfate method, the sulfuric acid method, the high-pressure alkali-boiling method, the chlorination method, etc. For lithium extraction from petalite, Patent CN118360497A reports a method of roasting with sulfate and fluoride, and then leaching lithium with water, but the amount of leaching residue is higher than that of the leached lithium ore, increasing the environmental burden, and the roasting time is too long, resulting in low operation efficiency. Patent CN116121560B reports a process of roasting and transformation with sulfate and sodium aluminosilicate, acidifying with sulfuric acid and then leaching lithium with water, but this method has a high roasting temperature, greater than 1100°C, and a large dosage of transformation aids and high costs. Patent CN118256739A discloses a method for extracting lithium from lithium porcelain stone ore, which can achieve lithium extraction by combining strong acid and weak acid (the weak acid acts as a catalyst) and leaching for 6 - 12 hours at 70 - 90°C, but the acid consumption of this process is 4 - 6 times that of the sulfuric acid method for spodumene, and the excessive acid consumption will inevitably result in a high leaching rate of impurity elements such as aluminum, increasing the purification burden and cost. Patent CN117602652A discloses a method for extracting lithium from lithium-containing glass waste. This process needs to be carried out in a pressure reaction kettle, and the dosages of the leaching agent (sodium hydroxide) and the crystal transformation agent (sodium chloride and potassium chloride) are relatively high, about 20% of the mass of the glass waste, with high reagent costs. The leaching solution needs to be acidified with hydrochloric acid and causticized with sodium hydroxide successively. The whole reaction process goes from alkali to acid and then to alkali, with large reagent consumption. Generally speaking, there is no report on a mature process for lithium extraction from petalite at present. In this invention, the traditional sulfuric acid method is used to treat it, which can achieve efficient lithium extraction, but the roasting temperature needs to be above 1100°C, with high energy consumption; while for lithium extraction from lithium porcelain stone and lithium-containing glass waste, although the high-temperature process can be avoided, the lithium extraction rate is still insufficient. Due to the large amount of acid and alkali used, the leaching amount of impurity ions is high, and the purification process is more complex than that of the sulfuric acid method for spodumene, with a higher lithium loss rate. Therefore, there is an urgent need to develop a lithium extraction technology for composite lithium resources (petalite, spodumene, lithium porcelain stone, and lithium-containing glass waste) that is economically feasible, easy to practice, has a simple leaching solution composition, is easy to purify, and has a high lithium recovery rate. Summary of the Invention

[0003] The object of the present invention is to overcome the disadvantages of the prior art, and provides a method for extracting lithium by low-temperature transformation roasting of complex lithium ore or lithium-containing waste, which method comprises the following steps: uniformly mixing one or more of petalite concentrate, spodumene concentrate, lithium porcelain stone and lithium-containing glass waste with aluminum electrolysis cell overhaul slag, fluoride and concentrated sulfuric acid, and then performing low-temperature calcination pretreatment to obtain a pretreated material; performing transformation roasting on the pretreated material to obtain a transformed material; then, uniformly mixing the transformed material with concentrated sulfuric acid and performing low-temperature acidification calcination to obtain an acidified material; finally, placing the acidified material in water, performing water leaching and separating solid from liquid to obtain a lithium leaching solution; the technical solution of the present invention can realize the coordinated consumption of various lithium resources, has a high comprehensive lithium utilization rate, low energy consumption for transformation roasting, simple process and low cost, is suitable for industrial application, and is of great significance for the efficient development and utilization of natural hard-rock type lithium ore and secondary lithium resources, and has extremely great application and popularization prospects.

[0004] To achieve the above technical effects, the following technical solution is adopted:

[0005] A method for extracting lithium by low-temperature transformation roasting of complex lithium ore or lithium-containing waste, comprising the following steps:

[0006] Step S1: uniformly mixing a lithium-containing composite material with aluminum electrolysis cell overhaul slag, fluoride and concentrated sulfuric acid, and then performing low-temperature calcination pretreatment to obtain a pretreated material; the lithium-containing composite material is one or more of petalite concentrate, spodumene concentrate, lithium porcelain stone and lithium-containing glass waste;

[0007] Step S2: performing transformation roasting on the pretreated material obtained in Step S1 to obtain a transformed material;

[0008] Step S3: uniformly mixing the transformed material obtained in Step S2 with concentrated sulfuric acid and performing low-temperature acidification calcination to obtain an acidified material;

[0009] Step S4: placing the acidified material obtained in Step S3 in water, performing water leaching, and then separating solid from liquid to obtain a lithium leaching solution, so as to achieve efficient lithium extraction.

[0010] Further, the lithium oxide content of the petalite concentrate is 1.0 - 4.5 wt%; the lithium oxide content of the spodumene concentrate is 3.0 - 6.5 wt%; the lithium oxide content of the lithium porcelain stone is 0.5 - 4.0 wt%; the lithium oxide content of the lithium-containing glass waste is 1.0 - 6.0 wt%; the lithium oxide content of the aluminum electrolysis cell overhaul slag is 0.5 - 3.5 wt%.

[0011] Further, the F content of the aluminum electrolysis cell overhaul slag is 3.0 - 15.0 wt%, and the fluoride includes calcium fluoride.

[0012] Further, the mass ratio of the lithium-containing composite material, aluminum electrolysis overhaul slag, and fluoride in step S1 is 5-40:1-2:0.5-1; the molar amount of concentrated sulfuric acid added in step S1 is 1 to 4 times the molar amount of F in the aluminum electrolysis overhaul slag and fluoride.

[0013] If the dosage of aluminum electrolysis overhaul slag is too low, it is not sufficient to continuously support the transformation of composite lithium ore during pretreatment and transformation roasting. If the dosage is too high, the composite lithium ore will be transformed into a dense lithium sodium aluminum silicate solid solution phase during transformation roasting, making it difficult to achieve ion replacement with sulfuric acid and resulting in a low lithium extraction rate.

[0014] Further, the low-temperature calcination pretreatment temperature in step S1 is 200-320 °C; the low-temperature activation calcination time in step S1 is 30-60 min.

[0015] Further, the transformation roasting temperature in step S2 is 800-950 °C; the transformation roasting time in step S2 is 20-100 min.

[0016] Controlling the transformation roasting temperature and time within a reasonable range can ensure a high lithium extraction rate. When the roasting temperature is too low or the time is too short, the synergistic transformation of the lithium-containing composite material, spodumene concentrate, petalite, lithium-containing glass waste, aluminum electrolysis overhaul slag, and fluoride cannot be completed. When the roasting temperature is too high or the time is too long, the roasting energy consumption will increase.

[0017] Further, the dosage of mixed sulfuric acid for the transformed material in step S3 is 1.2-1.4 times the theoretical acid consumption when all the lithium elements in the lithium-containing composite material are converted into lithium sulfate, and the sulfuric acid is concentrated sulfuric acid.

[0018] If the sulfuric acid dosage is too low, the lithium replacement rate is low, and sufficient lithium extraction cannot be achieved by water leaching; if the sulfuric acid dosage is too high, the impurity leaching rate is high, the purification burden is large, the lithium inclusion loss rate is high, the equipment corrosion is aggravated, and the economy is insufficient.

[0019] Further, the low-temperature acidification calcination temperature in step S3 is 150-300 °C; the low-temperature acidification calcination time in step S3 is 10-60 min.

[0020] Controlling the acidification reaction temperature and time within a reasonable range can improve the replacement efficiency of Li + with H + to ensure a high lithium extraction rate. If the acidification reaction temperature is too high or the time is too long, the energy consumption will increase.

[0021] Further, the water leaching reaction conditions in step S4 are: liquid-solid ratio of 1-5 mL:1 g, temperature of 25-90 °C, and time of 5-60 min.

[0022] Too low liquid-solid ratio, leaching temperature, and too short leaching time cannot ensure the full dissolution of lithium sulfate, resulting in insufficient lithium extraction rate; while too high liquid-solid ratio will increase the subsequent evaporation and concentration costs; too high leaching temperature will increase the energy consumption cost; too long leaching time will reduce the production efficiency.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) Coordinated consumption of various lithium resources. Lithium is extracted simultaneously from primary lithium-containing minerals such as petalite, spodumene, and lithium porcelain stone, as well as secondary lithium-containing resources such as lithium-containing glass waste and spent potlining.

[0025] (2) High comprehensive lithium utilization rate and low energy consumption for transformation roasting. The traditional sulfuric acid method for separately treating petalite, spodumene, etc. requires a high-temperature transformation roasting process at 1100 °C, and the energy consumption is more than half of the entire lithium salt production process. The lithium extraction rate of lithium porcelain stone and secondary lithium-containing resources such as lithium-containing glass waste and spent potlining by single sulfuric acid leaching is insufficient. Based on low-temperature activation with sulfuric acid, fluoride activation roasting is used to achieve pre-attack and attachment to the structures of complex minerals and raw materials. During the transformation roasting, the fluoride first quickly removes the surface of the complex ore and difficult-to-attack sites. The activated spent potlining continuously supplies a small amount of fluoride to continuously attack the complex ore and raw materials that have been pre-attacked by the fluoride, disintegrating the structures of the complex ore and raw materials; the lithium-containing composite materials petalite concentrate, spodumene concentrate, lithium porcelain stone, and lithium-containing glass waste, together with spent potlining and fluoride, achieve mineral phase synergistic transformation at 800 - 950 °C. Then, combined with subsequent low-temperature acidification roasting, the replacement of Li + with H + can be fully realized, thereby significantly increasing the lithium extraction rate during the water leaching stage, and the lithium extraction rate is maintained above 96%. The energy consumption of the present invention is better than that of the traditional sulfuric acid method for single treatment of petalite concentrate, spodumene concentrate, and lithium porcelain stone, and the lithium extraction rate is also better than that of the single treatment processes for petalite concentrate, spodumene concentrate, lithium porcelain stone, lithium-containing glass waste, and spent potlining.

[0026] (3) The solution of the present invention is safe and easy to implement, and can be technically innovated based on the traditional sulfuric acid method in industry for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. The drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0028] Figure 1It is a process schematic diagram of a method for pretreating complex lithium ore or lithium-containing waste by low-temperature transformation roasting to extract lithium provided by an embodiment of the present invention. Detailed implementation manners

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0032] Example 1:

[0033] According to Figure 1 as shown, the lithium extraction operation of spodumene concentrate is carried out:

[0034] Take 50 g of spodumene concentrate with a lithium oxide content of 3.45 wt.%, 10 g of spent potlining from aluminum electrolysis with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 5 g of calcium fluoride and 0.331 moles of concentrated sulfuric acid (i.e., 2 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 300 °C and the calcination time is 40 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 900 °C and the roasting time is set at 60 min. After the roasted material is cooled to room temperature, it is ball-milled to less than 200 mesh, and then concentrated sulfuric acid is added according to 1.3 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 200 °C and the calcination time is 20 min to obtain an acidified material. Subsequently, the acidified material is placed in water according to a liquid-solid ratio of 2 mL:1 g for water leaching. The leaching temperature is set at 30 °C and the time is 20 min. After leaching, filter to obtain a lithium leaching solution and leaching lithium tailings.

[0035] Through detection and analysis, the leaching rate of Li in the leaching solution obtained in Example 1 is 97.44%, indicating that the present technical solution can extract lithium from the composite lithium resources of spodumene concentrate and spent potlining from aluminum electrolysis at a lower energy consumption (900 °C).

[0036] Example 2:

[0037] According to Figure 1 shown below, the lithium extraction operation of spodumene concentrate is carried out:

[0038] Take 40 g of spodumene concentrate with a lithium oxide content of 5.00 wt.%, 1 g of aluminum electrolysis overhaul slag with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 0.5 g of calcium fluoride, and 0.0662 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 200 °C, and the calcination time is 60 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 950 °C, and the roasting time is set at 100 min. After the roasted material is cooled to room temperature, it is ball-milled to less than 200 mesh, and then concentrated sulfuric acid is added according to 1.4 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 300 °C, and the calcination time is 40 min to obtain an acidified material. Subsequently, the acidified material is placed in water for water leaching according to a liquid-solid ratio of 2 mL:1 g. The leaching temperature is set at 30 °C, and the time is 20 min. After leaching, filter to obtain a lithium leaching solution and leaching lithium tailings.

[0039] Through detection and analysis, the leaching rate of Li in the leaching solution obtained in Example 1 is 96.99%, indicating that this technical solution can extract lithium from the composite lithium resources of spodumene concentrate and aluminum electrolysis overhaul slag at a relatively low energy consumption (900 °C).

[0040] Example 3:

[0041] According to Figure 1 shown below, the lithium extraction operation of lithium porcelain stone concentrate is carried out:

[0042] Take 40 g of lithium porcelain stone concentrate with a lithium oxide content of 1.00 wt.%, 2 g of aluminum electrolysis overhaul slag with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 1 g of calcium fluoride, and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 300 °C, and the calcination time is 40 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 800 °C, and the roasting time is set at 60 min. After the roasted material is cooled to room temperature, it is ball-milled to less than 200 mesh, and then concentrated sulfuric acid is added according to 1.2 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 200 °C, and the calcination time is 60 min to obtain an acidified material. Subsequently, the acidified material is placed in water for water leaching according to a liquid-solid ratio of 3 mL:1 g. The leaching temperature is set at 40 °C, and the time is 40 min. After leaching, filter to obtain a lithium leaching solution and leaching lithium tailings.

[0043] After detection and analysis, the leaching rate of Li in the leaching solution obtained in Example 1 was 97.49%, indicating that this technical solution can extract lithium from the composite lithium resources of spodumene concentrate and spent potlining of aluminum electrolysis at a relatively low energy consumption (900 °C).

[0044] Example 4:

[0045] According to Figure 1 shown below, perform the lithium extraction operation on the lithium-containing glass waste:

[0046] Take 40 g of lithium-containing glass waste with a lithium oxide content of 1.00 wt.%, 2 g of spent potlining of aluminum electrolysis with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 1 g of calcium fluoride, and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 320 °C, and the calcination time is 30 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 900 °C, and the roasting time is set at 80 min. After the roasted material is cooled to room temperature, it is ball-milled to less than 200 mesh, and then concentrated sulfuric acid is added according to 1.3 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 200 °C, and the calcination time is 20 min to obtain an acidified material. Subsequently, the acidified material is placed in water according to a liquid-solid ratio of 4 mL:1 g for water leaching. The leaching temperature is set at 30 °C, and the time is 30 min. After leaching, filter to obtain a lithium leaching solution and leaching lithium tailings.

[0047] After detection and analysis, the leaching rate of Li in the leaching solution obtained in Example 1 was 98.17%, indicating that this technical solution can extract lithium from the composite lithium resources of lithium-containing glass waste and spent potlining of aluminum electrolysis at a relatively low energy consumption (900 °C).

[0048] Example 5:

[0049] According to Figure 1 shown below, perform the lithium extraction operation on the petalite concentrate and spodumene concentrate:

[0050] Take 20 g of petalite concentrate with a lithium oxide content of 3.45 wt.%, 20 g of lithium porcelain concentrate with a lithium oxide content of 1.00 wt.%, 2 g of spent potlining from aluminum electrolysis with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 1 g of calcium fluoride, and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 300 °C, and the calcination time is 40 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 900 °C, and the roasting time is set at 60 min. After the roasted material is cooled to room temperature, it is ball-milled to below 200 mesh, and then concentrated sulfuric acid is added according to 1.4 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 150 °C, and the calcination time is 60 min to obtain an acidified material. Subsequently, the acidified material is immersed in water according to a liquid-solid ratio of 5 mL:1 g. The leaching temperature is set at 80 °C, and the time is 40 min. After leaching, filtration is carried out to obtain a lithium leaching solution and leaching lithium tailings.

[0051] Through detection and analysis, the leaching rate of Li in the leaching solution obtained in Example 1 is 96.47%, indicating that this technical solution can extract lithium from composite lithium resources of petalite concentrate, lithium porcelain concentrate, and spent potlining from aluminum electrolysis at a relatively low energy consumption (900 °C).

[0052] Example 6:

[0053] According to Figure 1 as shown, carry out the lithium extraction operation of petalite concentrate and lithium-containing glass waste:

[0054] Take 20 g of petalite concentrate with a lithium oxide content of 3.45 wt.%, 20 g of lithium-containing glass waste with a lithium oxide content of 1.00 wt.%, 2 g of spent potlining from aluminum electrolysis with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 1 g of calcium fluoride, and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 300 °C, and the calcination time is 60 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 900 °C, and the roasting time is set at 80 min. After the roasted material is cooled to room temperature, it is ball-milled to below 200 mesh, and then concentrated sulfuric acid is added according to 1.3 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 200 °C, and the calcination time is 60 min to obtain an acidified material. Subsequently, the acidified material is immersed in water according to a liquid-solid ratio of 1 mL:1 g. The leaching temperature is set at 30 °C, and the time is 60 min. After leaching, filtration is carried out to obtain a lithium leaching solution and leaching lithium tailings.

[0055] After detection and analysis, the leaching rate of Li in the leachate obtained in Example 1 was 98.69%, indicating that the present technical solution can extract lithium from the composite lithium resources of spodumene concentrate, lithium-containing glass waste and spent potlining of aluminum electrolysis at a relatively low energy consumption (900°C).

[0056] Example 7:

[0057] According to Figure 1 shown below, the lithium extraction operation of spodumene concentrate and lithium-containing glass waste was carried out:

[0058] Take 10 g of spodumene concentrate with a lithium oxide content of 5.00 wt.%, 30 g of lithium-containing glass waste with a lithium oxide content of 1.00 wt.%, 2 g of spent potlining of aluminum electrolysis with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 1 g of calcium fluoride and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature was set at 300°C and the calcination time was 40 min. Then continue to heat up for transformation roasting. The roasting temperature was set at 900°C and the roasting time was set at 60 min. After the roasted material was cooled to room temperature, it was ball-milled to less than 200 mesh, and then concentrated sulfuric acid was added according to 1.3 times the theoretical acid consumption and mixed evenly. The mixed acid material was placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature was set at 200°C and the calcination time was 40 min to obtain an acidified material. Subsequently, the acidified material was placed in water according to a liquid-solid ratio of 3 mL:1 g for water leaching. The leaching temperature was set at 90°C and the time was 40 min. After leaching, the lithium leachate and leaching tailings were obtained by filtration.

[0059] After detection and analysis, the leaching rate of Li in the leachate obtained in Example 1 was 98.37%, indicating that the present technical solution can extract lithium from the composite lithium resources of spodumene concentrate, lithium-containing glass waste and spent potlining of aluminum electrolysis at a relatively low energy consumption (900°C).

[0060] Example 8:

[0061] According to Figure 1 shown below, the lithium extraction operation of lithium porcelain stone concentrate and lithium-containing glass waste was carried out:

[0062] Take 10 g of spodumene concentrate with a lithium oxide content of 1.00 wt.%, 30 g of lithium-containing glass waste with a lithium oxide content of 1.00 wt.%, 2 g of aluminum electrolysis cell overhaul slag with a fluorine content of 7.08% (lithium oxide content is 1.5 wt.%), 1 g of calcium fluoride, and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 300 °C, and the calcination time is 40 min. Then continue to raise the temperature for transformation roasting. The roasting temperature is set at 950 °C, and the roasting time is set at 60 min. After the roasted material is cooled to room temperature, it is ball-milled to below 200 mesh, and then concentrated sulfuric acid is added according to 1.3 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 300 °C, and the calcination time is 20 min to obtain an acidified material. Subsequently, the acidified material is placed in water for water leaching according to a liquid-solid ratio of 2 mL:1 g. The leaching temperature is set at 25 °C, and the time is 10 min. After leaching, filter to obtain a lithium leaching solution and lithium leaching tailings.

[0063] Through detection and analysis, the leaching rate of Li in the leaching solution obtained in Example 1 is 96.18%, indicating that this technical solution can extract lithium from composite lithium resources of spodumene concentrate, lithium-containing glass waste, and aluminum electrolysis cell overhaul slag at a relatively low energy consumption (900 °C).

[0064] Example 9:

[0065] According to Figure 1 as shown, carry out the lithium extraction operation on petalite concentrate, spodumene concentrate, and lithium-containing glass waste:

[0066] Take 10 g of petalite concentrate with a lithium oxide content of 3.45 wt.%, 10 g of spodumene concentrate with a lithium oxide content of 1.00 wt.%, 20 g of lithium-containing glass waste with a lithium oxide content of 1.00 wt.%, 2 g of aluminum electrolysis cell overhaul slag with a fluorine content of 7.08% (lithium oxide content is 1.5 wt.%), 1 g of calcium fluoride, and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 320 °C, and the calcination time is 60 min. Then continue to raise the temperature for transformation roasting. The roasting temperature is set at 950 °C, and the roasting time is set at 60 min. After the roasted material is cooled to room temperature, it is ball-milled to below 200 mesh, and then concentrated sulfuric acid is added according to 1.4 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 300 °C, and the calcination time is 20 min to obtain an acidified material. Subsequently, the acidified material is placed in water for water leaching according to a liquid-solid ratio of 3 mL:1 g. The leaching temperature is set at 30 °C, and the time is 20 min. After leaching, filter to obtain a lithium leaching solution and lithium leaching tailings.

[0067] After detection and analysis, the leaching rate of Li in the leachate obtained in Example 1 was 97.88%, indicating that this technical solution can extract lithium from the composite lithium resources of spodumene concentrate, lithium feldspar concentrate, lithium-containing glass waste and spent potlining at a relatively low energy consumption (900°C).

[0068] Example 10:

[0069] According to Figure 1 as shown, the lithium extraction operation of spodumene concentrate, spodumene concentrate, lithium feldspar concentrate and lithium-containing glass waste was carried out:

[0070] Take 10 g of spodumene concentrate with a lithium oxide content of 3.45 wt.%, 10 g of spodumene concentrate with a lithium oxide content of 5.00 wt.%, 10 g of lithium feldspar concentrate with a lithium oxide content of 1.00 wt.%, take 10 g of lithium-containing glass waste with a lithium oxide content of 1.00 wt.%, 2 g of spent potlining with a fluorine content of 7.08% (lithium oxide content of 1.5 wt.%), 1 g of calcium fluoride and 0.132 moles of concentrated sulfuric acid (i.e., 4 times the molar amount of F in the composite raw material), mix them evenly, and then place them in a muffle furnace for low-temperature sulfuric acid activation calcination. The calcination temperature is set at 300°C and the calcination time is 60 min. Then continue to heat up for transformation roasting. The roasting temperature is set at 950°C and the roasting time is set at 100 min. After the roasted material is cooled to room temperature, it is ball-milled to less than 200 mesh, and then concentrated sulfuric acid is added according to 1.3 times the theoretical acid consumption and mixed evenly. The mixed acid material is placed in a muffle furnace for low-temperature acidification calcination. The calcination temperature is set at 300°C and the calcination time is 50 min to obtain an acidified material. Subsequently, the acidified material is placed in water according to a liquid-solid ratio of 4 mL:1 g for water leaching. The leaching temperature is set at 50°C and the time is 50 min. After leaching, filter to obtain a lithium leachate and leaching lithium tailings.

[0071] After detection and analysis, the leaching rate of Li in the leachate obtained in Example 1 was 97.53%, indicating that this technical solution can extract lithium from the composite lithium resources of spodumene concentrate, spodumene concentrate, lithium feldspar concentrate, lithium-containing glass waste and spent potlining at a relatively low energy consumption (900°C).

[0072] Comparative Example 1:

[0073] Based on Example 1, the first step of low-temperature sulfuric acid activation calcination was removed and the others remained unchanged. After detection and analysis, the leaching rate of Li in the leachate obtained in Comparative Example 1 was 62.37%.

[0074] Comparative Example 2:

[0075] Based on Example 1, in the first step of low-temperature sulfuric acid activation calcination, calcium fluoride is not added, and in the second step of transformation roasting, calcium fluoride is added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 2 is 68.46%.

[0076] Comparative Example 3:

[0077] Based on Example 1, in the first step of low-temperature sulfuric acid activation calcination, aluminum electrolysis overhaul slag is not added, and in the second step of transformation roasting, aluminum electrolysis overhaul slag is added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 3 is 69.86%.

[0078] Comparative Example 4:

[0079] Based on Example 1, in the first step of low-temperature sulfuric acid activation calcination, spodumene concentrate is not added, and in the second step of transformation roasting, spodumene concentrate is added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 4 is 64.55%.

[0080] Comparative Example 5:

[0081] Based on Example 1, in the first step of low-temperature sulfuric acid activation calcination, neither aluminum electrolysis overhaul slag nor calcium fluoride is added, and in the second step of transformation roasting, aluminum electrolysis overhaul slag and calcium fluoride are added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 5 is 62.41%.

[0082] Comparative Example 6:

[0083] Based on Example 1, in the first step of low-temperature sulfuric acid activation calcination, neither spodumene concentrate nor calcium fluoride is added, and in the second step of transformation roasting, spodumene concentrate and calcium fluoride are added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 6 is 64.95%.

[0084] Comparative Example 7:

[0085] Based on Example 1, the third step of low-temperature acidification calcination is not carried out, and direct water leaching is performed while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 7 is 52.48%.

[0086] Comparative Example 8:

[0087] Based on Example 1, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to soaking with the same concentrated sulfuric acid without temperature-raising activation calcination while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 8 is 63.89%.

[0088] Comparative Example 9:

[0089] Based on Example 1, instead of performing the first-step low-temperature sulfuric acid activation calcination, the raw materials were pre-ground in a ball mill for 60 min and then subjected to transformation roasting, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 9 was 63.11%.

[0090] Comparative Example 10:

[0091] Based on Example 1, instead of performing the first-step low-temperature sulfuric acid activation calcination, the raw materials were mixed with the same equivalent of sulfuric acid and subjected to ultrasonic treatment for 30 min, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 10 was 64.67%.

[0092] Comparative Example 11:

[0093] Based on Example 1, the spodumene concentrate in the raw materials was removed, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 11 was 72.53%. When treating aluminum electrolysis cell overhaul slag alone, the lithium extraction rate is lower than that when treating composite lithium resources. This is mainly because during the transformation roasting of single aluminum electrolysis cell overhaul slag, it is easier to melt and form a dense-phase glass body; while during the co-treatment of composite lithium resources, the addition amount of aluminum electrolysis cell overhaul slag is relatively low (mainly acting as a fluorine source), and it can be loaded on the surface of spodumene and petalite to prevent the formation of an amorphous dense phase.

[0094] Comparative Example 12:

[0095] Based on Example 3, the first-step low-temperature sulfuric acid activation calcination was removed, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 12 was 64.97%.

[0096] Comparative Example 13:

[0097] Based on Example 3, in the first-step low-temperature sulfuric acid activation calcination, calcium fluoride was not added, and calcium fluoride was added in the second-step transformation roasting, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 13 was 69.33%.

[0098] Comparative Example 14:

[0099] Based on Example 3, in the first-step low-temperature sulfuric acid activation calcination, aluminum electrolysis cell overhaul slag was not added, and aluminum electrolysis cell overhaul slag was added in the second-step transformation roasting, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 14 was 69.24%.

[0100] Comparative Example 15:

[0101] Based on Example 3, in the first step of low-temperature sulfuric acid activation calcination, spodumene concentrate is not added. In the second step of transformation roasting, spodumene concentrate is added, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 15 is 65.39%.

[0102] Comparative Example 16:

[0103] Based on Example 3, in the first step of low-temperature sulfuric acid activation calcination, neither aluminum electrolysis overhaul slag nor calcium fluoride is added. In the second step of transformation roasting, aluminum electrolysis overhaul slag and calcium fluoride are added, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 16 is 65.47%.

[0104] Comparative Example 17:

[0105] Based on Example 3, in the first step of low-temperature sulfuric acid activation calcination, neither spodumene concentrate nor calcium fluoride is added. In the second step of transformation roasting, spodumene and calcium fluoride are added, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 17 is 66.39%.

[0106] Comparative Example 18:

[0107] Based on Example 3, the third step of low-temperature acidification calcination is not carried out, and water leaching is directly carried out, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 18 is 54.89%.

[0108] Comparative Example 19:

[0109] Based on Example 3, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to soaking with the same concentrated sulfuric acid without temperature rise for activation calcination, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 19 is 65.32%.

[0110] Comparative Example 20:

[0111] Based on Example 3, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to pre-grinding the raw materials in a ball mill for 60 min and then carrying out transformation roasting, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 20 is 65.22%.

[0112] Comparative Example 21:

[0113] Based on Example 3, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to mixing the raw materials with the same equivalent of sulfuric acid and carrying out ultrasonic treatment for 30 min, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 21 is 66.18%.

[0114] Comparative Example 22:

[0115] Based on Example 4, the first-step low-temperature sulfuric acid activation calcination was removed, and the others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 22 was 60.36%.

[0116] Comparative Example 23:

[0117] Based on Example 4, in the first-step low-temperature sulfuric acid activation calcination, calcium fluoride was not added, and calcium fluoride was added in the second-step transformation roasting. The others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 23 was 64.67%.

[0118] Comparative Example 24:

[0119] Based on Example 4, in the first-step low-temperature sulfuric acid activation calcination, aluminum electrolysis overhaul slag was not added, and aluminum electrolysis overhaul slag was added in the second-step transformation roasting. The others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 24 was 66.74%.

[0120] Comparative Example 25:

[0121] Based on Example 4, in the first-step low-temperature sulfuric acid activation calcination, lithium-containing glass waste was not added, and lithium-containing glass waste was added in the second-step transformation roasting. The others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 25 was 62.59%.

[0122] Comparative Example 26:

[0123] Based on Example 4, in the first-step low-temperature sulfuric acid activation calcination, neither aluminum electrolysis overhaul slag nor calcium fluoride was added, and aluminum electrolysis overhaul slag and calcium fluoride were added in the second-step transformation roasting. The others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 26 was 60.68%.

[0124] Comparative Example 27:

[0125] Based on Example 4, in the first-step low-temperature sulfuric acid activation calcination, neither lithium-containing glass waste nor calcium fluoride was added, and lithium-containing glass waste and calcium fluoride were added in the second-step transformation roasting. The others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 27 was 62.39%.

[0126] Comparative Example 28:

[0127] Based on Example 4, the third-step low-temperature acidification calcination was not carried out, and water leaching was directly carried out. The others remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 28 was 48.67%.

[0128] Comparative Example 29:

[0129] Based on Example 4, instead of performing the first-step low-temperature sulfuric acid activation calcination, it was changed to soaking in the same concentrated sulfuric acid without heating for activation calcination, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 29 was 61.29%.

[0130] Comparative Example 30:

[0131] Based on Example 4, instead of performing the first-step low-temperature sulfuric acid activation calcination, the raw materials were pre-ground in a ball mill for 60 min and then subjected to transformation roasting, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 30 was 62.37%.

[0132] Comparative Example 31:

[0133] Based on Example 4, instead of performing the first-step low-temperature sulfuric acid activation calcination, the raw materials were mixed with the same equivalent of sulfuric acid and subjected to ultrasonic treatment for 30 min, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 31 was 62.83%.

[0134] Comparative Example 32:

[0135] Based on Example 9, the first-step low-temperature sulfuric acid activation calcination was removed, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 32 was 58.64%.

[0136] Comparative Example 33:

[0137] Based on Example 9, in the first-step low-temperature sulfuric acid activation calcination, calcium fluoride was not added, and calcium fluoride was added in the second-step transformation roasting, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 33 was 62.33%.

[0138] Comparative Example 34:

[0139] Based on Example 9, in the first-step low-temperature sulfuric acid activation calcination, aluminum electrolysis cell overhaul slag was not added, and aluminum electrolysis cell overhaul slag was added in the second-step transformation roasting, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 34 was 61.59%.

[0140] Comparative Example 35:

[0141] Based on Example 9, in the first-step low-temperature sulfuric acid activation calcination, spodumene concentrate was not added, and spodumene concentrate was added in the second-step transformation roasting, and the rest remained unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 35 was 59.66%.

[0142] Comparative Example 36:

[0143] Based on Example 9, in the first step of low-temperature sulfuric acid activation calcination, neither aluminum electrolysis overhaul slag nor calcium fluoride is added. In the second step of transformation roasting, aluminum electrolysis overhaul slag and calcium fluoride are added, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 36 is 58.61%.

[0144] Comparative Example 37:

[0145] Based on Example 9, in the first step of low-temperature sulfuric acid activation calcination, neither spodumene concentrate nor calcium fluoride is added. In the second step of transformation roasting, spodumene concentrate and calcium fluoride are added, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 37 is 60.27%.

[0146] Comparative Example 38:

[0147] Based on Example 9, the third step of low-temperature acidification calcination is not carried out, and water leaching is directly carried out, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 38 is 44.36%.

[0148] Comparative Example 39:

[0149] Based on Example 9, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to soaking with the same concentrated sulfuric acid without temperature-raising activation calcination, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 39 is 58.93%.

[0150] Comparative Example 40:

[0151] Based on Example 9, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to pre-grinding the raw materials in a ball mill for 60 min and then carrying out transformation roasting, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 40 is 59.66%.

[0152] Comparative Example 41:

[0153] Based on Example 9, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to mixing the raw materials with the same equivalent sulfuric acid and carrying out ultrasonic treatment for 30 min, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 41 is 60.18%.

[0154] Comparative Example 42:

[0155] Based on Example 10, the first step of low-temperature sulfuric acid activation calcination is removed, and other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 42 is 52.34%.

[0156] Comparative Example 43:

[0157] Based on Example 10, in the first step of low-temperature sulfuric acid activation calcination, calcium fluoride is not added, and in the second step of transformation roasting, calcium fluoride is added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 43 is 59.64%.

[0158] Comparative Example 44:

[0159] Based on Example 10, in the first step of low-temperature sulfuric acid activation calcination, aluminum electrolysis overhaul slag is not added, and in the second step of transformation roasting, aluminum electrolysis overhaul slag is added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 44 is 57.46%.

[0160] Comparative Example 45:

[0161] Based on Example 10, in the first step of low-temperature sulfuric acid activation calcination, spodumene concentrate is not added, and in the second step of transformation roasting, spodumene concentrate is added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 45 is 55.65%.

[0162] Comparative Example 46:

[0163] Based on Example 10, in the first step of low-temperature sulfuric acid activation calcination, neither aluminum electrolysis overhaul slag nor calcium fluoride is added, and in the second step of transformation roasting, aluminum electrolysis overhaul slag and calcium fluoride are added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 46 is 52.91%.

[0164] Comparative Example 47:

[0165] Based on Example 10, in the first step of low-temperature sulfuric acid activation calcination, neither spodumene concentrate nor calcium fluoride is added, and in the second step of transformation roasting, spodumene concentrate and calcium fluoride are added while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 47 is 55.33%.

[0166] Comparative Example 48:

[0167] Based on Example 10, the third step of low-temperature acidification calcination is not carried out, and water leaching is directly carried out while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 48 is 40.31%.

[0168] Comparative Example 49:

[0169] Based on Example 10, the first step of low-temperature sulfuric acid activation calcination is not carried out, and it is changed to soaking with the same concentrated sulfuric acid without temperature-raising activation calcination while other conditions remain unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained in Comparative Example 49 is 53.17%.

[0170] Comparative Example 50:

[0171] Based on Example 10, instead of performing the first-step low-temperature sulfuric acid activation calcination, the raw materials are pre-ground in a ball mill for 60 min and then subjected to transformation roasting, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 50 is 53.38%.

[0172] Comparative Example 51:

[0173] Based on Example 10, instead of performing the first-step low-temperature sulfuric acid activation calcination, the raw materials are mixed with the same equivalent of sulfuric acid and subjected to ultrasonic treatment for 30 min, with other conditions remaining unchanged. After detection and analysis, the leaching rate of Li in the leaching solution obtained from Comparative Example 51 is 54.19%.

[0174] It can be seen from the above data that in order to process one or more lithium-containing raw materials such as spodumene concentrate, spodumene concentrate, lithium porcelain stone, and lithium-containing glass waste, it is necessary to first perform low-temperature sulfuric acid activation calcination, then perform transformation roasting, and finally perform low-temperature acidification calcination to significantly improve the lithium extraction effect of refractory lithium minerals and lithium-containing raw materials. The principle may be:

[0175] Excessive introduction of other impurity ions by too much aluminum electrolysis cell overhaul slag will cause the ore and lithium-containing raw materials to transform into an amorphous dense phase, resulting in a decrease in lithium extraction rate. Therefore, it is impossible to improve the attack effect by simply increasing the amount of electrolysis cell overhaul slag.

[0176] The low-temperature sulfuric acid activation calcination of the composite raw material of the present invention is to activate the activity of F in the aluminum electrolysis cell overhaul slag, provide an adequate F source for promoting the crystal structure transformation of complex ores and lithium-containing raw materials during the transformation roasting process, so that a small amount of fluorine can be continuously supplied during the transformation roasting process to continuously attack the complex ores and raw materials, and at the same time, fluoride activation calcination realizes the pre-attack and attachment of the structure of complex minerals and raw materials. During the transformation roasting, the fluoride first quickly removes the surface and difficult-to-attack sites of the complex ore, and the activated aluminum electrolysis cell overhaul slag continuously supplies a small amount of fluorine to continuously attack the complex ores and raw materials that have been pre-attacked by the fluoride, disintegrating the structure of the complex ores and raw materials. This effect can utilize the synergistic effect of the pretreatment activation calcination and the transformation roasting process to disintegrate the structure of the complex ores and raw materials to a state that can be processed by subsequent acidification calcination; the final transformation material low-temperature acidification calcination is to further loosen the complex ores and raw materials that have been processed and disintegrated, and fully displace Li from the loose crystal structure of the complex ores and raw materials + ; and process it to a state where it can be directly water-leached to achieve a significant improvement in the lithium extraction effect. Finally, it can complete the efficient development and utilization of complex natural hard-rock type lithium ores and secondary lithium resources at about 900 °C, reducing the temperature by 200 °C compared with the traditional sulfuric acid method under the condition of 1100 °C, and significantly saving energy consumption.

[0177] Overall, the technical solution of the present invention ensures a continuous and sufficient fluorine source with a low amount of spent potlining from aluminum electrolysis through low-temperature activation calcination with sulfuric acid. At the same time, by utilizing the dual synergistic effects of low-temperature activation of fluorides, after the low-temperature activation pretreatment of fluorides, spent potlining, ore and lithium-containing raw materials, the pre-attack and cleaning of fluorides are combined with the slow release of spent potlining to continuously provide a small amount of fluorine attack. With an extremely small amount of fluorine, the ore and lithium-containing raw materials are forced to undergo polymorphic transformation at a lower temperature during the transformation stage, and the transformation efficiency is extremely high. Combined with subsequent low-temperature acidification calcination, high-efficiency extraction of lithium is achieved. Compared with the traditional high-temperature transformation sulfuric acid method, this solution has the advantages of lower energy consumption and a wider range of lithium resources that can be consumed. The entire process solution has a low cost, is suitable for industrial application, plays an extremely important role in the efficient development and utilization of lithium resources, and has excellent application and promotion prospects.

[0178] At this point, those skilled in the art will recognize that although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and determined to cover all these other variations or modifications.

Claims

1. A method for extracting lithium by low-temperature transformation roasting in the pretreatment of complex lithium ores or lithium-containing waste materials, characterized in that, The lithium extraction method includes the following steps: Step S1: Uniformly mix the lithium-containing composite material with aluminum electrolysis overhaul slag, fluoride, and concentrated sulfuric acid, and then perform low-temperature calcination pretreatment to obtain a pretreated material; The lithium-containing composite material is one or more of petalite concentrate, spodumene concentrate, lithium porcelain stone, and lithium-containing glass waste; Step S2: Perform transformation roasting on the pretreated material in Step S1 to obtain a transformed material; Step S3: Uniformly mix the transformed material in Step S2 with concentrated sulfuric acid, and perform low-temperature acidification calcination to obtain an acidified material; Step S4: Place the acidified material in Step S3 in water for water leaching, and then perform solid-liquid separation to obtain a lithium leaching solution, realizing efficient lithium extraction; The low-temperature calcination pretreatment temperature in Step S1 is 200~320°C; the low-temperature calcination pretreatment time in Step S1 is 30~60 min; The transformation roasting temperature in Step S2 is 800~950°C; the transformation roasting time in Step S2 is 20~100 min; The temperature of the low-temperature acidification calcination in Step S3 is 150~300°C; the low-temperature acidification calcination time in Step S3 is 10~60 min.

2. A method for extracting lithium by low-temperature transformation roasting of pretreatment of complex lithium ore or lithium-containing waste as described in claim 1, characterized in that The lithium oxide content of the petalite concentrate is 1.0~4.5 wt%; the lithium oxide content of the spodumene concentrate is 3.0~6.5 wt%; the lithium oxide content of the lithium porcelain stone is 0.5~4.0 wt%; the lithium oxide content of the lithium-containing glass waste is 1.0~6.0 wt%; the lithium oxide content of the aluminum electrolysis overhaul slag is 0.5~3.5 wt%.

3. A method for extracting lithium by low-temperature transformation roasting of pretreatment of complex lithium ore or lithium-containing waste as described in claim 1, characterized in that, The F content of the aluminum electrolysis overhaul slag is 3.0~15.0 wt%, and the fluoride includes calcium fluoride.

4. A method for extracting lithium by low-temperature transformation roasting of pretreatment of complex lithium ore or lithium-containing waste as described in claim 1, characterized in that, In Step S1, the mass ratio of the lithium-containing composite material, aluminum electrolysis overhaul slag, and fluoride is 5-40:1-2:0.5-1; the molar amount of concentrated sulfuric acid added in Step S1 is 1~4 times the molar amount of F in the aluminum electrolysis overhaul slag and fluoride.

5. A method for extracting lithium by low-temperature transformation roasting of pretreatment of complex lithium ore or lithium-containing waste as described in claim 1, characterized in that, In Step S3, the dosage of sulfuric acid for mixing with the transformed material is 1.2~1.4 times the theoretical acid consumption when all the lithium elements in the lithium-containing composite material are converted into lithium sulfate, and the sulfuric acid is concentrated sulfuric acid.

6. A method for extracting lithium by low-temperature transformation roasting of pretreatment of complex lithium ore or lithium-containing waste as described in claim 1, wherein, The water leaching reaction conditions in Step S4 are: the liquid-solid ratio is 1~5 mL:1 g, the temperature is 25~90°C, and the time is 5~60 min.

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