Method for treating clay type lithium ore through multi-composite-field medium-low-temperature roasting and continuous water leaching

Abstract

The invention provides a method for treating clay type lithium ore through multi-composite-field medium-low-temperature roasting and continuous water leaching, and belongs to the technical field of mineral processing. According to the method, multi-field roasting and continuous leaching processes are adopted for treatment, a microwave-suspension composite roasting device is adopted for multi-field roasting, and a plurality of continuous leaching devices are adopted for continuous leaching. The method provided by the invention has the advantages of simple process flow, high roasting efficiency and low energy consumption, and can effectively destroy mineral lattices of the clay type lithium ore; in addition, by means of the continuous leaching technological process, the lithium extraction rate is greatly increased, the lithium leaching rate is increased, the use amount of an acid leaching agent is reduced, sulfuric acid is recycled, the water demand is reduced, the problem of lithium resource shortage is solved, and a theoretical basis is provided for subsequent industrial production.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a method and equipment for low-temperature roasting-continuous water leaching treatment of clay-type lithium ore in a multi-complex field. Background Technology

[0002] The lithium resource industry is booming, and China is the world's largest consumer of lithium resources. To alleviate the long-standing resource shortage faced by my country's lithium industry, the efficient utilization and development of various types of lithium mineral resources is one of the directions for lithium resource development.

[0003] Clay-type lithium deposits, also known as sedimentary lithium deposits, have seen the discovery of numerous large-scale clay-type lithium mines globally in recent years. Due to their low abundance and grade, clay-type lithium deposits were previously considered undevelopable or difficult to exploit. Currently, however, clay-type lithium deposits, as a new type of lithium resource, are widely distributed and have relatively large reserves. Despite their low grade, considerable lithium resources can still be extracted from clay-type lithium deposits through reasonable mining and processing technologies. This provides a diversified option for global lithium resource supply and helps alleviate pressure on mainstream lithium resource supply. However, there are currently no precedents for large-scale industrial utilization of clay-type lithium deposits; therefore, the research and development of lithium separation and extraction technologies for this type of low-lithium ore is particularly urgent and important.

[0004] The efficient and clean utilization of clay-type lithium deposits not only helps expand lithium reserves and enhance my country's competitiveness in the global lithium market, but also meets the growing social demand for lithium resources. This is of great significance for ensuring the sustainable development of the new energy industry.

[0005] Currently, the main utilization method for low-grade clay-type lithium ore is roasting-leaching. Suspension magnetized roasting is one of the most effective methods for processing refractory ores, with advantages such as high mass and heat transfer efficiency, low energy consumption, high efficiency, and good equipment stability. Patent CN117947261B discloses a method for treating laterite nickel ore leaching residue using suspension magnetized roasting. Experiments were conducted using a suspension magnetized roasting system to treat refractory laterite nickel ore leaching residue. Under conditions of roasting temperature 580℃, magnetic separator intensity 1000-2000 Oe, and magnetic separation time 30-120 min, a total iron grade of 61-62% and a concentrate recovery rate >70% can be obtained. However, it is unknown whether this method can be used for lithium ore processing, and the recovery rate obtained is not high.

[0006] Patent CN119040620A discloses a method for synergistically processing red mud and refractory iron ore using a suspension magnetization roasting method; patent CN110530160B discloses a suspension magnetization roasting system for continuous microwave processing of iron ore. However, these methods focus primarily on the magnetization roasting of iron ore, designing three interconnected roasting systems around the "magnetization roasting-reduction reaction." These roasting systems consist of a microwave pretreatment chamber, a gas reduction chamber, and a cooling chamber. The temperature in the microwave pretreatment chamber reaches 800-1100℃, and the subsequent roasting process still requires a reduction roasting process at 450-600℃, making the roasting process complex and energy-intensive.

[0007] Patent CN115747488B discloses a method for vanadium extraction using suspension roasting-alkali ripening. This method utilizes a suspension magnetized roasting system to raise the temperature to 850-950℃, but requires additional fluidized bed heating, making the operation complex. Both patents CN110530160B and CN115747488B share the characteristic of using microwave roasting as the main roasting process, with microwave roasting temperatures exceeding 800℃. They also require preheating or post-reduction processes. Both methods have higher energy consumption and more complex processes, but microwave roasting offers better results and higher production efficiency.

[0008] The leaching process of clay-type lithium ore is generally divided into water leaching, acid leaching, combined acid-base leaching, and field-enhanced leaching. Patent CN117682540A discloses an experimental study on the preparation of lithium hydroxide from clay-type lithium ore leachate by electrolysis. First, a lithium sulfate solution is obtained by homogeneous membrane electrodialysis, and then the lithium sulfate solution is electrolyzed in a three-chamber membrane electrolysis chamber to obtain lithium hydroxide. Patent CN118086693A discloses a method for lithium extraction from clay-type lithium ore by roasting and cyclic leaching with simultaneous impurity removal. This invention involves roasting the clay-type lithium ore with a mixture of ammonium bisulfate and sodium bisulfate, followed by a single-pass, multiple-stage leaching impurity removal process, with ≤30 cycles, aiming to obtain a low-impurity lithium-containing leachate. However, trace elements are difficult to completely separate through washing or leaching cycles alone. This process focuses on the simultaneous extraction of lithium and impurity removal, involving the continuous replenishment of the previous filtrate to subsequent washing processes. During this process, clean water is continuously added until each batch of powder contains the same amount of calcined ore, reducing the accumulation rate of impurity ions such as calcium and manganese, lowering solution viscosity, significantly increasing the number of leaching cycles, and improving the lithium leaching rate. However, this patent requires continuous replenishment of leaching solution and clean water, resulting in huge water consumption, a complex process flow, and increased difficulty in subsequent evaporation and concentration.

[0009] Patent CN117684019A discloses a method for extracting lithium from clay-type lithium ore using a mixture of sulfuric acid and ferric chloride. This method involves leaching roasted ore powder with sulfuric acid and ferric chloride, resulting in a lithium leaching rate exceeding 90%. While this invention is simple to operate and has a short process flow, it suffers from excessive subsequent impurities and a complex leaching agent composition, making industrial-scale application difficult.

[0010] Therefore, how to provide a method for lithium extraction from clay-type lithium ore that has a simple process flow, high roasting efficiency, low energy consumption, and can significantly improve the lithium extraction and recovery efficiency has become an urgent technical problem to be solved. Summary of the Invention

[0011] This invention aims to solve the aforementioned technical problems by providing a method for low-temperature roasting and continuous water leaching of clay-type lithium ore in a multi-composite field. The technical objective of this invention is to address the issues of complex processes, high energy consumption, low roasting efficiency, and low lithium recovery rates in existing clay-type lithium ore processing methods, and to provide a lithium ore processing method with a simple process flow, high roasting efficiency, low energy consumption, and the ability to significantly improve lithium extraction and recovery efficiency.

[0012] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0013] This invention provides a method for low-temperature roasting and continuous water leaching of clay-type lithium ore in a multi-field composite process. The method employs multi-field roasting and continuous leaching. The multi-field roasting utilizes a microwave-suspension composite roasting device, comprising a microwave transmitter, a suspension roasting tube, and a quartz air distribution plate. The microwave transmitter is located on both sides of the suspension roasting tube, and the quartz air distribution plate is installed inside the suspension roasting tube. The continuous leaching employs multiple continuous leaching devices, comprising multiple magnetic stirrers and multiple filtrate collection tubes. The magnetic stirrers are used to stir the leaching solution after multi-field roasting, and the filtrate collection tubes are used to collect the filtrate after magnetic stirring.

[0014] The method includes the following steps:

[0015] (1) Crush and grind clay-type lithium ore;

[0016] (2) Add roasting aid to the above clay-type lithium ore, wherein the roasting aid includes any one or a combination of two of calcium carbonate, calcium sulfate, calcium chloride, and calcium oxide; the amount of roasting aid is 5-40% of the total weight of the mineral.

[0017] (3) The product obtained in step (2) is subjected to microwave roasting pretreatment. The microwave roasting temperature is controlled at 200-350℃, the roasting time is 5-20min, and the microwave power is 300W to obtain the pretreated product.

[0018] (4) The pretreated product is then added to a microwave-suspension composite roasting device for multi-composite field roasting treatment. The roasting temperature is 600-850℃, the roasting time is 30-60min, the gas flow rate range of multi-composite field roasting is 200mL / min-1000mL / min, the roasting gas is air, and the microwave power is set to 300W-800W.

[0019] (5) Add the lithium ore after multiple roasting in step (4) to the leaching equipment for continuous leaching treatment. The leaching agent is water, and the mass ratio of the leaching agent to the lithium ore is 5:1-5:4. Collect the leaching liquid and leaching residue, and continuously leach the leaching residue until the leaching process is terminated.

[0020] (6) Combine and collect the leachate after multiple consecutive leaching steps, filter the combined leachate to obtain lithium-containing solution and filter residue, and calculate and obtain the optimal leaching rate and average leaching rate.

[0021] This invention addresses the issues of high temperature requirements, high energy consumption, and complex roasting processes associated with conventional microwave roasting. Based on the lithium occurrence state of clay-type lithium ore, it combines microwave preheating with microwave suspension roasting. Utilizing a multi-field roasting process involving both microwave roasting radiation and suspension roasting heat, it achieves the dehydroxylation reaction of clay-type lithium ore and the composite suspension roasting process of roasting aids and clay-type lithium ore. Furthermore, the subsequent leaching of the roasted product employs a continuous water leaching process, significantly improving the lithium leaching rate of different clay-type lithium ores, reducing differences in leaching indicators, achieving clean and efficient leaching, and facilitating industrial application. In summary, this invention proposes a method for multi-field roasting and continuous leaching of clay-type lithium ore.

[0022] Furthermore, the grinding process in step (1) involves controlling the proportion of mineral particles with a particle size of -0.15 mm to be 70-90%.

[0023] Furthermore, the distance between the microwave transmitter and the suspended calcination tube is 3 cm.

[0024] Furthermore, in step (5), the lithium ore after multiple roastings is cooled to 80°C and then subjected to continuous leaching treatment.

[0025] Furthermore, the number of magnetic stirrers in the leaching equipment in step (5) is 3 to 5.

[0026] Furthermore, the leaching time in step (5) is 30 to 240 minutes.

[0027] Furthermore, the temperature of the leachate in step (5) is 80-95℃.

[0028] Furthermore, in step (5), the leaching residue obtained after the first leaching is placed into the second leaching device for further leaching; the leaching residue obtained after leaching in the second leaching device is placed into the third leaching device for further leaching, and so on.

[0029] Furthermore, in step (5), the lithium leaching rate in the first and nth leaching devices is calculated. If the first lithium leaching rate η1 > 80%, the nth lithium leaching rate ηf < 25%, and 10 > η1 / ηf > 3, then the leaching process is terminated.

[0030] The above-described method for calculating the leaching rate of the present invention mainly controls the number of times n is too high. If the value of n is too large, the first lithium leaching rate η1 will increase slowly or reach equilibrium, while the value of ηf in the nth time will be low, resulting in the value of η1 / ηf being significantly greater than 10. At this time, the lithium leaching rate no longer has practical industrial significance.

[0031] Furthermore, the average leaching rate in step (6) should be greater than 50%. The average leaching rate is used to determine the overall leaching status of clay-type lithium ore and serves as one of the bases for leaching termination. In subsequent low-concentration water leaching, the lithium leaching rate can be increased by methods such as merging and evaporation concentration.

[0032] Specifically, the formula for calculating the lithium leaching rate in this invention is as follows:

[0033]

[0034] Where α is the lithium leaching rate, %; m 渣 For leaching residue quality, g; w 渣 The mass fraction of lithium in the leaching residue, %; m 原 The mass of the initial raw material is expressed in g and w. 原 The percentage is the mass fraction of lithium in the raw material.

[0035] The beneficial effects of the present invention are as follows:

[0036] The method provided by this invention has the advantages of simple process flow, high roasting efficiency, low energy consumption, and can effectively destroy the mineral lattice of clay-type lithium ore. In addition, by using a continuous leaching process, the lithium extraction rate is greatly improved, the lithium leaching rate is increased, the amount of acid leaching agent is reduced, sulfuric acid is recycled, the water demand is reduced, the lithium resource shortage problem is alleviated, and a theoretical basis is provided for subsequent industrial production. Attached Figure Description

[0037] Figure 1 Flowchart of equipment for multi-field roasting-continuous leaching treatment of clay-type lithium ore;

[0038] Figure 2 This is a process flow diagram for multi-field roasting-continuous water leaching treatment of clay-type lithium ore; wherein, 1, microwave transmitter; 2, suspension roasting tube; 3, quartz air distribution plate; 4, magnetic stirrer; 5, filtrate collection tube. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described in detail below with reference to embodiments. It should be noted that the following embodiments are for explanation and illustration only and are not intended to limit the invention. Non-essential improvements and adjustments made by those skilled in the art based on the above description are still within the scope of protection of this invention.

[0040] Example 1

[0041] The flowchart of a multi-field roasting-continuous leaching process for clay-type lithium ore provided by this invention is as follows: Figure 1 As shown, this diagram mainly illustrates the important equipment and processes used in the entire schematic process. It includes the following main equipment:

[0042] 1. Microwave transmitter; 2. Suspension roasting tube; 3. Quartz cloth air plate; 4. Magnetic stirrer; 5. Filtrate collection tube.

[0043] The present invention provides a process flow for multi-field roasting-continuous leaching treatment of clay-type lithium ore as follows: Figure 2 As shown.

[0044] Example 1

[0045] A clay-type lithium deposit in southwestern Sichuan Province has the following main chemical components: Li₂O 0.14%, SiO₂ 37.68%, Al₂O₃ 40.53%, Fe₂O₃ 5.12%, CaO 0.56%, MgO 0.41%, and K₂O 0.33%.

[0046] This embodiment provides a method for multi-field roasting-continuous leaching of clay-type lithium ore, including the following steps:

[0047] (1) Clay-type lithium ore is crushed and ground to -0.15mm, accounting for 85wt%;

[0048] (2) Add calcium sulfate as a roasting aid, the amount of which accounts for 20 wt% of the total mineral content;

[0049] (3) The lithium ore powder mixed with roasting aids was pre-roasted using a microwave device. The pre-roasting temperature was controlled at 300℃, the pre-roasting time was 15min, and the microwave power was 300W. The pre-treated product was obtained after microwave pre-roasting.

[0050] (4) Turn on the heater of the suspension roasting device, set the roasting temperature in the microwave-suspension roasting composite roasting field to 600℃, the roasting time to 30min, the gas flow rate to 600mL / min, and the air atmosphere.

[0051] (5) Roasted lithium ore is placed in a leaching device, the leaching agent is water, the mass ratio of leaching agent to lithium ore is 5:2, the leaching time is 60 min, and the slurry concentration is 25%.

[0052] (6) The leaching equipment was set up with 3 samples, each ore sample was 20g, and 3 batches of samples were leached continuously. After leaching and filtration, the calculated η1 = 88.2%, η2 = 60.8%, and ηf = 24.3, that is, the leaching rate ratio η1 / ηf = 3.63, which meets the standard for terminating the leaching rate.

[0053] (7) After the final merging, evaporation and volume adjustment process, the optimal η1 lithium leaching rate (i.e. the first leaching rate) was 88.2%, and the average leaching rate (the average value of the subsequent overall leaching) was calculated to be 57.76%.

[0054] Example 2

[0055] The main chemical components of a clay-type lithium deposit in western Sichuan Province are: Li₂O 0.35%, SiO₂ 42.61%, Fe₂O₃ 3.12%, CaO 0.44%, MgO 0.29%, and K₂O 0.20%.

[0056] A method for multi-field roasting-continuous leaching of clay-type lithium ore includes the following steps:

[0057] (1) The clay-type lithium ore was crushed and ground, and the fineness of the ore sample after grinding was -0.15 mm, accounting for 90%.

[0058] (2) Add calcination aids calcium sulfate, calcium oxide and calcium hydroxide, with a reducing agent ratio of 1:1:1 and a reducing agent content of 30%;

[0059] (3) The mineral powder after mixing with the roasting aid is fed into the composite roasting device from bottom to top; the microwave roasting device is turned on, the microwave roasting temperature is set to 350℃, the roasting time is 20min, and the microwave power is set to 500W. The pretreated product is obtained after microwave roasting.

[0060] (4) Turn on the heater of the suspension roasting device, set the roasting temperature in the microwave-suspension roasting composite roasting field to 800℃, the roasting time to 30min, the gas flow rate to 600mL / min, and the air atmosphere.

[0061] (5) The roasted ore is placed in the leaching equipment, the leaching agent is water, the ratio of leaching agent to ore is 5:1, the leaching time is 90 min, the leaching temperature is 95℃, and the slurry concentration is 20%.

[0062] (6) The number of leaching equipment is set at 3, the mineral sample is 20g each, and leaching is carried out in 3 batches. After leaching and filtration, η1=91.5%, η2=62.8%, ηf=20.3%, that is, the leaching rate ratio η1 / ηf=4.51, which meets the standard for terminating the leaching rate.

[0063] (7) After the final merging, evaporation and volume adjustment process, the final optimal lithium leaching rate was 91.5%, and the average leaching rate was 58.2%.

[0064] Example 3

[0065] The main chemical components of a clay-type lithium deposit in southern Guizhou Province are: Li₂O 0.20%, SiO₂ 42.33%, Al₂O₃ 41.19%, Fe₂O₃ 5.12%, CaO 0.56%, MgO 0.41%, and K₂O 0.33%.

[0066] A method for multi-field roasting-continuous leaching of clay-type lithium ore includes the following steps:

[0067] (1) The above clay-type lithium ore was subjected to crushing and grinding process, and the fineness of the ore sample after grinding was -0.15mm, accounting for 80%;

[0068] (2) Add calcination aids calcium sulfate and calcium oxide, with a reducing agent ratio of 1:1 and a reducing agent content of 25%;

[0069] (3) The mineral powder after mixing the roasting aid is fed into the composite roasting device from bottom to top; the microwave roasting device is turned on, the microwave roasting temperature is set to 200℃, the roasting time is 40min, and the microwave power is set to 200W. After microwave roasting, the pretreated product is obtained.

[0070] (4) Turn on the heater of the suspension roasting device, set the roasting temperature in the microwave-suspension roasting composite roasting field to 650℃, the roasting time to 60min, the gas flow rate to 600mL / min, and the air atmosphere.

[0071] (5) The roasted ore is placed in the leaching equipment, the leaching agent is water, the ratio of leaching agent to ore is 5:1, the leaching time is 90 min, the leaching temperature is 95℃, and the slurry concentration is 20%.

[0072] (6) The leaching equipment was set up with 4 units, each mineral sample was 20g, and leaching was carried out in 3 batches. After leaching and filtration, η1 = 88.1%, η2 = 60.4%, and η3 = 20.8%. (7) After the final merging, evaporation, and volume adjustment process, the final optimal lithium leaching rate was 88.1%, and the average leaching rate was 56.43%.

[0073] Example 4

[0074] A clay-type lithium deposit in Yunnan Province has the following main chemical components: Li₂O 0.12%, SiO₂ 25.45%, Al₂O₃ 58.51%, Fe₂O₃ 3.08%, CaO 0.41%, MgO 0.29%, and K₂O 0.50%.

[0075] A method for multi-compound roasting-continuous leaching of clay-type lithium ore includes the following steps:

[0076] (1) The above-mentioned clay-type lithium ore is crushed and ground to 90% of the sample size being -0.15mm;

[0077] (2) Add sodium carbonate as a calcination aid, with an amount of 30%;

[0078] (3) The mineral powder after mixing with the roasting aid is fed into the composite roasting device from bottom to top; the microwave roasting device is turned on, the microwave roasting temperature is set to 350℃, the roasting time is 5min, and the microwave power is set to 600W. The pretreated product is obtained after microwave roasting.

[0079] (4) Turn on the heater of the suspension roasting device, set the roasting temperature in the microwave-suspension roasting composite roasting field to 800℃, the roasting time to 30min, the gas flow rate to 400mL / min, and the air atmosphere.

[0080] (5) The roasted ore is placed in the leaching equipment, the leaching agent is water, the ratio of leaching agent to ore is 5:4, the leaching time is 60 min, and the slurry concentration is 25%.

[0081] (6) The number of leaching equipment is set at 3, the mineral sample is 20g each, and leaching is carried out in 3 batches. After leaching and filtration, η1=91.2%, η2=59.9%, ηf=18.1%, that is, the leaching rate ratio η1 / ηf=5.04, which meets the standard for terminating the leaching rate.

[0082] (7) After the final merging, evaporation and volume adjustment process, the final optimal η1 lithium leaching rate was 91.2%, and the average leaching rate was 56.4%.

[0083] Comparative Example 1

[0084] Unlike Example 1, this clay-type lithium ore, after crushing and grinding, had 80% of its particles having a particle size of -0.15 mm. Following the method of Example 1, it underwent low-temperature roasting-continuous water leaching treatment, and the final optimal lithium leaching rate was 84.4%.

[0085] Comparative Example 2

[0086] Unlike Example 1, the microwave roasting pretreatment temperature was set to 200°C, and the combined roasting field temperature of microwave-suspension roasting was set to 500°C. The final optimal lithium leaching rate was 82.8%. The results of Comparative Example 2 indicate that the multi-composite field roasting efficiency of microwave-suspension roasting at lower temperatures is lower, and the reaction between clay-type lithium ore and roasting aids is insufficient.

[0087] Comparative Example 3

[0088] Unlike Example 3, Comparative Example 3 used three leaching devices, with each mineral sample weighing 20g, and leached three batches consecutively. After leaching and filtration, η1 = 80.5%, η2 = 55.2%, and ηf = 16.2%, meaning the leaching rate ratio η1 / ηf = 4.97, meeting the leaching termination standard. However, the average lithium leaching rate in this comparative example was only 38.5%. Therefore, within a reasonable range of leaching cycles, the lithium leaching rate is affected by the number of leaching cycles, and reducing the number of leaching cycles decreases the lithium leaching rate.

[0089] Comparative Example 4

[0090] Compared with Example 3, the detailed steps in Comparative Example 4 are as follows:

[0091] (1) The above clay-type lithium ore was subjected to crushing and grinding process, and the fineness of the ore sample after grinding was -0.15mm, accounting for 80%;

[0092] (2) Add calcination aids calcium sulfate and calcium oxide, with a reducing agent ratio of 1:1 and a reducing agent content of 25%;

[0093] (3) The mineral powder after mixing the roasting aid is fed into the composite roasting device from bottom to top; the microwave roasting device is turned on, the microwave roasting temperature is set to 200℃, the roasting time is 40min, and the microwave power is set to 200W. After microwave roasting, the pretreated product is obtained.

[0094] (4) Turn on the heater of the suspension roasting device, set the roasting temperature in the microwave-suspension roasting composite roasting field to 650℃, the roasting time to 60min, the gas flow rate to 600mL / min, and the air atmosphere.

[0095] (5) The roasted ore is placed in the leaching equipment, the leaching agent is water, the ratio of leaching agent to ore is 5:1, the leaching time is 90 min, the leaching temperature is 95℃, and the slurry concentration is 20%.

[0096] (6) The leaching equipment was set to 4, with each mineral sample weighing 20g, and leaching was carried out in 4 batches. After leaching and filtration, η1 = 88.1%, η2 = 60.4%, η3 = 20.8%, and η4 = 5.6%. The leaching rate of the roasted clay-type lithium ore was only 5.6%, indicating that the lithium element in the clay-type lithium ore had been basically extracted after three leaching processes. However, at this time, η1 / ηf = 15.73, which is greater than 10, indicating that the lithium leaching rate in the last extraction process of the clay-type lithium ore was too low and did not meet the actual industrial significance. (7) After the final merging, evaporation, and volume adjustment process, the final optimal lithium leaching rate was 87.5%, and the average leaching rate was 44.6%, which did not meet the requirements of the average leaching rate, indicating poor continuous water leaching effect.

Claims

1. A method for low-temperature roasting-continuous water leaching treatment of clay-type lithium ore in a multi-complex field, characterized in that, The process employs a multi-stage roasting and continuous leaching process. The multi-stage roasting uses a microwave-suspension composite roasting device, which includes a microwave transmitter (1), a suspension roasting tube (2), and a quartz cloth air plate (3). The microwave transmitter (1) is located on both sides of the suspension roasting tube (2), and the quartz cloth air plate (3) is installed inside the suspension roasting tube (2). The continuous leaching uses multiple continuous leaching devices, which consist of multiple magnetic stirrers (4) and multiple filtrate collection tubes (5). The magnetic stirrers (4) are used to stir the leaching liquid after multi-stage roasting, and the filtrate collection tubes (5) are used to collect the filtrate after magnetic stirring. The method includes the following steps: (1) Crush and grind clay-type lithium ore; (2) Add roasting aid to the above clay-type lithium ore, wherein the roasting aid includes any one or a combination of two of calcium carbonate, calcium sulfate, calcium chloride, and calcium oxide; the amount of roasting aid is 5-40% of the total weight of the mineral. (3) The product obtained in step (2) is subjected to microwave roasting pretreatment. The microwave roasting temperature is controlled at 200-350℃, the roasting time is 5-20min, and the microwave power is 300W to obtain the pretreated product. (4) The pretreated product is added to a microwave-suspension composite roasting device for multi-composite field roasting treatment. The roasting temperature is 600-850℃, the roasting time is 30-60min, the gas flow rate range of multi-composite field roasting is 200mL / min-1000mL / min, the roasting gas is air, and the microwave power is set to 300W-800W. (5) Add the lithium ore roasted in step (4) to the leaching equipment for continuous leaching treatment. The leaching agent is water, and the mass ratio of the leaching agent to the lithium ore is 5:1-5:

4. Collect the leaching liquid and leaching residue, and continuously leach the leaching residue until the leaching process is terminated. (6) Combine and collect the leachate after multiple consecutive leaching steps, filter the combined leachate to obtain lithium-containing solution and filter residue, and calculate and obtain the optimal leaching rate and average leaching rate.

2. The method according to claim 1, characterized in that, The grinding process in step (1) involves controlling the proportion of mineral particles with a particle size of -0.15 mm to be 70-90%.

3. The method according to claim 1, characterized in that, In step (5), the lithium ore after multi-composite field roasting is cooled to 80°C and then subjected to continuous leaching treatment.

4. The method according to claim 1, characterized in that, The number of magnetic stirrers in the leaching equipment in step (5) is 3 to 5.

5. The method according to claim 1, characterized in that, The leaching time in step (5) is 30 to 240 minutes.

6. The method according to claim 1, characterized in that, The temperature of the leachate in step (5) is 80-95℃.

7. The method according to claim 1, characterized in that, In step (5), the leaching residue obtained after the first leaching is put into the second leaching device for further leaching; the leaching residue obtained after leaching in the second leaching device is put into the third leaching device for further leaching, and so on.

8. The method according to claim 1, characterized in that, In step (5), the lithium leaching rate in the first and nth leaching devices is calculated. If the first lithium leaching rate η1 > 80%, the nth lithium leaching rate ηf < 25%, and 10 > η1 / ηf > 3, then the leaching process is terminated.

9. The method according to claim 1, characterized in that, The average leaching rate in step (6) is greater than 50%.

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