Short-process lithium extraction method for lithium clay ore

Abstract

A short-process lithium extraction method for a lithium clay ore. The method comprises the following steps: calcining the lithium clay ore to obtain a cured material; dissolving the cured material, concentrated sulfuric acid and an alkali metal sulfate in pure water to perform a hydrothermal reaction, and filtering same to obtain a leachate; adsorbing the leachate with a calcium-magnesium-removal resin column for impurity removal, so as to obtain an impurity-removed solution; and adding a saturated sodium carbonate solution to the impurity-removed liquid, and filtering same to obtain lithium carbonate filter residues. By means of a pressure leaching method, the lithium leaching rate is increased, and Al3+ is also precipitated in the form of an alunite, wherein the main component of the formed alunite is XAl3(SO4)2(OH)2 (where X is Na or K). The alunite is insoluble in water and slightly soluble in sulfuric acid, has relatively good crystallinity, less adsorption entrainment of free ions, and almost no lithium entrainment. By using this characteristic of alunite, Al3+ dissolved out from the lithium ore by acid is converted into an alunite precipitate, thereby reducing the Al / Li ratio of the leachate; in addition, a small amount of calcium and magnesium ions are adsorbed by using the calcium-magnesium-removal resin, and finally lithium is collected in the form of lithium carbonate.

Description

A short-process lithium extraction method for lithium clay ore Technical Field

[0001] The present disclosure relates to the field of metallurgy, and in particular to a short-process method for extracting lithium from lithium clay ore. Background Art

[0002] Lithium resources are widely used in lithium-ion batteries and other related fields. With the rapid development of the lithium-ion battery industry, the demand for lithium resources in industrial production is increasing at an increasingly faster rate. In recent years, there has even been a situation where lithium raw materials are in short supply.

[0003] my country's lithium resources are primarily found in two forms: salt lakes and lithium mines. The lithium grades of different lithium mines and sources in different geographical locations vary significantly. Generally speaking, the lithium element in mainstream lithium mines is primarily found in the form of spodumene, lepidolite, and lithium clay.

[0004] Spodumene and lepidolite have slightly higher lithium grades, with flotation concentrates typically reaching around 4% and 2%, respectively. However, lithium clay rarely achieves a lithium grade above 0.5%. Given the limited reserves of high-grade lithium resources, attention should be focused on lower-grade raw materials like lithium clay.

[0005] There are a lot of Al and Si elements in lithium clay. In order to extract lithium from it efficiently, the traditional acid leaching method is usually accompanied by the leaching of a large amount of aluminum, so the Al / Li ratio in the resulting leachate is very high. However, in order to recover the lithium element in the leachate as high-purity lithium salt, the Al must be removed first. The traditional method is to remove the Al impurities by Al(OH)3 precipitation by adjusting the pH value of the solution. Among them, Al(OH)3, as a floc, will carry away a large amount of Li + Adsorption (more than 10%) has a significant impact on the overall lithium recovery rate.

[0006] Therefore, it is necessary to develop a highly selective lithium extraction method for low-grade lithium ore, with a low Al / Li ratio in the resulting leachate, to avoid lithium loss due to impurity removal, thereby improving the overall lithium recovery rate.

[0007] Summary of the Invention

[0008] Based on this, the purpose of the present disclosure is to provide a method for recovering lithium resources from low-lithium-grade lithium clay ores, mainly by achieving selective lithium extraction from lithium clay minerals, thereby reducing the Al / Li ratio of the leachate and improving the comprehensive lithium yield.

[0009] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0010] calcining lithium clay ore to obtain slaking material;

[0011] Dissolving the slaking material, concentrated sulfuric acid and alkali metal sulfate in pure water, performing a hydrothermal reaction, and filtering to obtain a leachate;

[0012] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0013] A saturated sodium carbonate solution is added to the impurity removal liquid, and the mixture is filtered to obtain a lithium carbonate filter residue.

[0014] The present invention is realized by pressure leaching method, which mainly aims to improve the lithium leaching rate while making Al 3+ The alunite formed by precipitation in the form of alum is mainly composed of XAl3(SO4)2(OH)2, where X is an alkali metal element. The alunite is insoluble in water, slightly soluble in sulfuric acid, and has good crystallinity. The stronger the crystallinity, the more regular the material particles, and the less free ion adsorption and entrainment, so it almost does not entrain lithium. The disclosed technology makes full use of this characteristic of alunite, and the Al dissolved by acid from lithium ore is removed. 3+ It is converted into alunite precipitate. After the reaction, the pH of the solution is above 3, the alunite will not dissolve, and the Al / Li ratio of the leachate is reduced. At the same time, a small amount of calcium and magnesium ions are adsorbed by calcium and magnesium removal resin, and finally lithium is collected in the form of lithium carbonate.

[0015] Preferably, the calcination temperature of the lithium clay ore is 500-1000° C. Calcination at this temperature causes the lithium clay ore to undergo a dehydroxylation phase transition, thereby destroying the complex bonding between other elements in the lithium clay ore and lithium. After heat treatment, lithium exists in the form of Li2O.

[0016] Preferably, the calcination time of the lithium clay ore is 1 to 12 hours. If the calcination time is too short, the lithium clay ore cannot completely undergo dehydroxylation phase transformation. If the calcination time is too long, it has no beneficial effect on the dehydroxylation phase transformation and the cost is higher.

[0017] Preferably, the mass ratio of the slaking material to the concentrated sulfuric acid is 1:0.1-1. If the amount of sulfuric acid is too low, it cannot dissolve the lithium element in the slaking material. If the amount of sulfuric acid is too high, it has no beneficial effect on the lithium dissolution effect and the cost is higher.

[0018] Preferably, the mass ratio of the slaking material to the alkali metal sulfate is 1:0.1-2.5. If the alkali metal sulfate is too little, it cannot provide enough alkali metal ions to form alunite; if the alkali metal sulfate is too much, it has no beneficial effect and the cost is too high. Among them, lithium clay usually contains an indefinite amount of sodium and potassium elements that can be utilized. The amount of alkali metal sulfate used should depend on the sodium and potassium content in the raw materials.

[0019] Preferably, the alkali metal sulfate is at least one of potassium sulfate and sodium sulfate. In the alunite formed by sodium sulfate or potassium sulfate, the Na and K sites are in the interlayer position, which can support the crystal structure of the alunite, and Li + The radius is small, and Na and K sites cannot exist, so there is no lithium alunite phase, which reduces the entrainment of lithium ions and improves the lithium yield.

[0020] Preferably, the mass concentration of the concentrated sulfuric acid is 98%.

[0021] Preferably, the liquid-to-solid ratio of the hydrothermal reaction is 2-6:1 (ml:g), wherein: the liquid is the total volume of the concentrated sulfuric acid and the pure water, and the solid is the total mass of the slaked material and the alkali metal sulfate. If the liquid-to-solid ratio is too low, the acidity of the solution is too high, which places high requirements on the equipment. If the liquid-to-solid ratio is too high, the acidity is too low, which may lead to a decrease in the lithium leaching rate.

[0022] Preferably, the temperature of the hydrothermal reaction is 100-230°C. The hydrothermal reaction is to promote the 3+ The alum-forming reaction will only have a significant promoting effect when the temperature reaches above 100°C. When the temperature is in the range of 100-230°C, the higher the temperature, the faster the reaction rate and the shorter the reaction time. However, when the temperature is higher than 230°C, the improvement in the alum-forming reaction rate is slight. Continuing to increase the temperature will only increase energy consumption and increase costs.

[0023] Preferably, the hydrothermal reaction time is 1 to 12 hours. If the reaction time is less than 1 hour, Al 3+ The conversion rate to alum is low. If the reaction time is too long, it will not be beneficial to improve the conversion rate, but will instead cause an increase in energy consumption costs.

[0024] Preferably, the pressure of the hydrothermal reaction is the saturated vapor pressure of water at the corresponding reaction temperature, that is, 0.1 to 2.8 MPa. Reacting under high pressure can improve the crystallinity of alunite, further reduce the entrainment of lithium ions, and improve the yield of lithium.

[0025] Preferably, the amount of the saturated sodium carbonate solution added is 1 to 3 times that of the impurity removal solution, wherein the impurity removal solution is calculated based on the molar amount of Li and the saturated sodium carbonate solution is calculated based on the molar amount of Na. Increasing the concentration of carbonate ions can precipitate as much lithium as possible, thereby improving the lithium yield.

[0026] Preferably, the impurity removal liquid is heated to 90-100° C., and then the saturated sodium carbonate solution at the same temperature as the impurity removal liquid is added; increasing the temperature can reduce the solubility of lithium carbonate and increase the yield of lithium.

[0027] Preferably, after adding saturated sodium carbonate solution to the impurity removal liquid, the reaction is carried out for 0.1 to 3 hours. If the reaction time is too short, lithium carbonate particles with good crystallinity cannot be obtained. If the reaction time is too long, the beneficial effect is limited, but the energy consumption cost is high.

[0028] Preferably, a saturated sodium carbonate solution is added to the impurity removal liquid, and the liquid is filtered while hot after the reaction. Hot filtering can reduce lithium loss and improve lithium recovery.

[0029] Preferably, the lithium carbonate filter residue is dried.

[0030] Preferably, the drying temperature is 60-120°C, the drying time is 3 to 12 hours, and the lower limit of the drying temperature is 60°C, which can ensure the volatilization of water. Below this temperature, the drying effect cannot be achieved. The upper limit of the drying temperature is 120°C. Above this temperature, it may cause dehydration too quickly, the particle structure is destroyed, and the product performance is not met. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is an XRD diagram of the leaching residue described in Example 1, the leaching residue described in Comparative Example 1, and the lithium clay ore described in Example 1. DETAILED DESCRIPTION

[0032] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0033] calcining the lithium clay ore at 500-1000°C for 1-12 hours to obtain a slaking material;

[0034] The slaked material, concentrated sulfuric acid with a concentration of 98%, and an alkali metal sulfate are dissolved in pure water, and reacted at 100-230° C. for 1-12 hours. The reaction pressure is the saturated vapor pressure of water at that temperature. The reaction liquid-to-solid ratio is 2-6:1 (ml:g), wherein the liquid is the total volume of the concentrated sulfuric acid and the pure water, and the solid is the total mass of the slaked material and the alkali metal sulfate. The mass ratio of the slaked material to the concentrated sulfuric acid is 1:0.1-1, and the mass ratio of the slaked material to the alkali metal sulfate is 1:0.1-2.5. The alkali metal sulfate is at least one of potassium sulfate and sodium sulfate. Filtering while hot obtains a leachate.

[0035] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0036] The impurity removal liquid is heated to 90-100° C., and a saturated sodium carbonate solution at the same temperature as the impurity removal liquid is added, reacting for 0.1-12 hours, filtering while hot to obtain a lithium carbonate residue, and drying the residue at a drying temperature of 60-120° C. for 3-12 hours. The amount of the saturated sodium carbonate solution added is 1-3 times that of the impurity removal liquid, the impurity removal liquid is calculated based on the molar amount of Li, and the saturated sodium carbonate solution is calculated based on the molar amount of Na.

[0037] Example 1

[0038] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0039] 1 kg of lithium clay ore powder was calcined at 500 ° C for 12 h to obtain a slaking material;

[0040] The slaking material, 100 g of 98% concentrated sulfuric acid, and 100 g of sodium sulfate were mixed, and pure water was added to a liquid-solid ratio of 2:1 (ml:g), where the liquid is the total volume of the pure water and the concentrated sulfuric acid, and the solid is the total mass of the slaking material and the sodium sulfate; a hydrothermal reaction was carried out at a temperature of 230° C. and a pressure of 2.8 MPa for 1 hour, and a leachate and a leach residue were obtained after filtration;

[0041] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0042] The impurity removal liquid was heated to 90° C., and an amount of saturated sodium carbonate solution equal to that of the impurity removal liquid was added, wherein the impurity removal liquid was calculated based on the molar amount of Li, and the saturated sodium carbonate solution was calculated based on the molar amount of Na; after reacting for 1 hour, the mixture was filtered while hot to obtain a lithium carbonate filter residue, which was then dried at 120° C. for 3 hours.

[0043] Example 2

[0044] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0045] 1 kg of lithium clay powder was calcined at 600 ° C for 1 h to obtain a slaking material;

[0046] The slaking material, 500 g of 98% concentrated sulfuric acid, and 600 g of potassium sulfate were mixed, and pure water was added to a liquid-solid ratio of 6:1 (ml:g), where the liquid is the total volume of pure water and concentrated sulfuric acid, and the solid is the total mass of the slaking material and potassium sulfate; a hydrothermal reaction was carried out at a temperature of 100° C. and a pressure of 0.1 MPa for 3 h, and a leachate was obtained after filtration;

[0047] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0048] The impurity removal liquid was heated to 100° C., and a saturated sodium carbonate solution was added at a temperature three times that of the impurity removal liquid, wherein the impurity removal liquid was calculated based on the molar amount of Li and the saturated sodium carbonate solution was calculated based on the molar amount of Na. After reacting for 9 hours, the mixture was filtered while hot to obtain a lithium carbonate residue, which was then dried at 60° C. for 12 hours.

[0049] Example 3

[0050] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0051] 1 kg of lithium clay powder was calcined at 1000 ° C for 3 h to obtain a slaking material;

[0052] The slaking material, 300 g of 98% concentrated sulfuric acid, and 300 g of sodium sulfate were mixed, and pure water was added to a liquid-solid ratio of 3:1 (ml:g), where the liquid is the total volume of the pure water and the concentrated sulfuric acid, and the solid is the total mass of the slaking material and the sodium sulfate; a hydrothermal reaction was carried out at a temperature of 140° C. and a pressure of 0.36 MPa for 12 h, and a leachate was obtained after filtration;

[0053] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0054] The impurity removal liquid was heated to 95° C., and a saturated sodium carbonate solution twice as much as the impurity removal liquid was added, wherein the impurity removal liquid was calculated based on the molar amount of Li and the saturated sodium carbonate solution was calculated based on the molar amount of Na; after reacting for 9 hours, the mixture was filtered while hot to obtain a lithium carbonate residue, which was then dried at 80° C. for 9 hours.

[0055] Example 4

[0056] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0057] 1 kg of lithium clay ore powder was calcined at 700 ° C for 6 h to obtain a slaking material;

[0058] The slaking material, 400 g of 98% concentrated sulfuric acid, and 200 g of potassium sulfate were mixed, and pure water was added to a liquid-solid ratio of 4:1 (ml:g), where the liquid is the total volume of pure water and concentrated sulfuric acid, and the solid is the total mass of the slaking material and potassium sulfate; a hydrothermal reaction was carried out at a temperature of 180° C. and a pressure of 1.0 MPa for 2 h, and a leachate was obtained after filtration;

[0059] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0060] The impurity removal liquid was heated to 100° C., and a saturated sodium carbonate solution was added at a concentration of 1.5 times that of the impurity removal liquid, wherein the impurity removal liquid was calculated based on the molar amount of Li and the saturated sodium carbonate solution was calculated based on the molar amount of Na. After reacting for 6 h, the mixture was filtered while hot to obtain a lithium carbonate residue, which was then dried at 90° C. for 6 h.

[0061] Example 5

[0062] The present invention discloses a short-process method for extracting lithium from lithium clay ore, comprising the following steps:

[0063] 1 kg of lithium clay ore powder was calcined at 800 ° C for 9 h to obtain a slaking material;

[0064] The slaking material, 200 g of 98% concentrated sulfuric acid, and 400 g of potassium sulfate were mixed, and pure water was added to a liquid-solid ratio of 5:1 (ml:g), where the liquid is the total volume of pure water and concentrated sulfuric acid, and the solid is the total mass of the slaking material and potassium sulfate; a hydrothermal reaction was carried out at a temperature of 200° C. and a pressure of 1.55 MPa for 9 hours, and a leachate was obtained after filtration;

[0065] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0066] The impurity removal liquid was heated to 97° C., and a saturated sodium carbonate solution was added in an amount 1.2 times that of the impurity removal liquid, wherein the impurity removal liquid was calculated based on the molar amount of Li and the saturated sodium carbonate solution was calculated based on the molar amount of Na. After reacting for 2 h, the mixture was filtered while hot to obtain a lithium carbonate residue, which was then dried at 100° C. for 1 h.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that sodium sulfate is not added, and the other steps are the same.

[0069] Comparative Example 2

[0070] 1 kg of lithium clay ore powder was calcined at 500 ° C for 12 h to obtain a slaking material;

[0071] The slaked material, 100 g of 98% concentrated sulfuric acid and 100 g of sodium sulfate were mixed, and pure water was added to a liquid-solid ratio of 2:1 (ml:g), where the liquid was the total volume of pure water and concentrated sulfuric acid, and the solid was the total mass of the slaked material and sodium sulfate. After filtering, a leachate and a leach residue were obtained;

[0072] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0073] The impurity removal liquid was heated to 90° C., and an amount of saturated sodium carbonate solution equal to that of the impurity removal liquid was added, wherein the impurity removal liquid was calculated based on the molar amount of Li, and the saturated sodium carbonate solution was calculated based on the molar amount of Na; after reacting for 1 hour, the mixture was filtered while hot to obtain a lithium carbonate filter residue, which was then dried at 120° C. for 3 hours.

[0074] Comparative Example 3

[0075] 1 kg of lithium clay ore powder, 100 g of 98% concentrated sulfuric acid, and 100 g of sodium sulfate were mixed, and pure water was added to a liquid-solid ratio of 2:1 (ml:g), where the liquid was the total volume of pure water and concentrated sulfuric acid, and the solid was the total mass of the lithium clay ore powder and sodium sulfate. A hydrothermal reaction was performed at a temperature of 230 ° C and a pressure of 2.8 MPa for 1 hour, and a leachate and a leach residue were obtained after filtration;

[0076] The leachate is adsorbed and impurity-removed using a calcium and magnesium removal resin column to obtain an impurity-removed liquid;

[0077] The impurity removal liquid was heated to 90° C., and an amount of saturated sodium carbonate solution equal to that of the impurity removal liquid was added, wherein the impurity removal liquid was calculated based on the molar amount of Li, and the saturated sodium carbonate solution was calculated based on the molar amount of Na; after reacting for 1 hour, the mixture was filtered while hot to obtain a lithium carbonate filter residue, which was then dried at 120° C. for 3 hours.

[0078] Table 1 Main element contents of lithium clay ore described in Example 1

[0079] Table 2 Comparison of leachates of Examples and Comparative Examples

[0080] Comparison of experimental process parameters

[0081] Table 1 shows the main element contents of the lithium clay ore described in Example 1, wherein the Li content is only 0.29 wt.%, which is a low-grade lithium ore, and the aluminum content is relatively high.

[0082] Table 2 compares the leachates of the embodiments and the comparative examples. It can be seen that in the leachates of the embodiments, the lithium leaching rates are all greater than 94%. The low Al / Li ratio indicates that the aluminum content is low, corresponding to the low aluminum concentration. In addition, the lithium recovery rates in the embodiments are much higher than those in the comparative examples.

[0083] Table 2 is combined with Figure 1. Compared with Example 1 and Comparative Example 1, Example 1 adds alkali metal sulfate to generate alunite, which causes a large amount of aluminum precipitation, manifested as an extremely low Al / Li ratio in the leachate; in the XRD diagram, it can be seen that the leaching residue of Example 1 contains alunite, while the leaching residue of Comparative Example 1 does not contain alunite.

[0084] Compared with Comparative Example 2, Example 1 undergoes a hydrothermal reaction under high pressure to form alunite, which causes a large amount of aluminum to precipitate, resulting in an extremely low Al / Li ratio in the leachate.

[0085] Compared with Example 1 and Comparative Example 3, the comprehensive recovery rate of lithium is higher. This is because the lithium clay ore is calcined at high temperature, and a dehydroxylation phase change occurs, thereby destroying the complex bonding between the lithium and the lithium in the lithium clay ore. After heat treatment, the lithium exists in the form of Li2O, which is conducive to subsequent leaching recovery.

Claims

1. A short-process lithium extraction method for lithium clay ore, comprising the following steps: Calcining lithium clay ore to obtain a slaked material; Dissolving the slaked material, concentrated sulfuric acid and alkali metal sulfate in pure water, performing a hydrothermal reaction, and obtaining a leachate after filtering; Using a calcium and magnesium removal resin column to adsorb and remove impurities from the leachate to obtain an impurity-removing liquid; A saturated sodium carbonate solution is added to the impurity removal liquid, and the mixture is filtered to obtain a lithium carbonate filter residue.

2. A short-process lithium extraction method for lithium clay ore according to claim 1, characterized in that: The calcination temperature of the lithium clay ore is 500-1000°C.

3. A short-process lithium extraction method for lithium clay ore according to claim 2, characterized in that: The calcination time of the lithium clay ore is 1 to 12 hours.

4. A short-process lithium extraction method for lithium clay ore according to claim 1, characterized in that: The mass ratio of the slaking material to the concentrated sulfuric acid is 1:0.1-1.

5. A short-process lithium extraction method for lithium clay ore according to claim 1, characterized in that: The mass ratio of the slaking material to the alkali metal sulfate is 1:0.1-2.

5.

6. A short-process lithium extraction method for lithium clay ore according to claim 5, characterized in that: The alkali metal sulfate is at least one of potassium sulfate and sodium sulfate.

7. A short-process lithium extraction method for lithium clay ore according to claim 1, characterized in that: The mass concentration of the concentrated sulfuric acid is 98%.

8. A short-process lithium extraction method for lithium clay ore according to claim 7, characterized in that: The liquid-solid ratio of the hydrothermal reaction is 2-6:1 (ml:g), wherein the liquid is the total volume of the concentrated sulfuric acid and the pure water, and the solid is the total mass of the slaked material and the alkali metal sulfate.

9. A short-process lithium extraction method for lithium clay ore according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 100-230°C.

10. A short-process lithium extraction method for lithium clay ore according to claim 9, characterized in that: The hydrothermal reaction time is 1 to 12 hours.

11. A short-process lithium extraction method for lithium clay ore according to claim 9, characterized in that: The pressure of the hydrothermal reaction is the saturated vapor pressure of water at the corresponding reaction temperature, that is, 0.1 to 2.8 MPa.

12. A short-process lithium extraction method for lithium clay ore according to claim 1, characterized in that: The added amount of the saturated sodium carbonate solution is 1 to 3 times that of the impurity removal liquid, wherein: the impurity removal liquid is calculated based on the molar amount of Li, and the saturated sodium carbonate solution is calculated based on the molar amount of Na.

13. The short-process lithium extraction method of lithium clay ore according to claim 1 further comprises the following steps: The impurity removal liquid is heated to 90-100° C., and then the saturated sodium carbonate solution having the same temperature as the impurity removal liquid is added.

14. The short-process lithium extraction method of lithium clay ore according to claim 13 further comprises the following steps: After adding the saturated sodium carbonate solution into the impurity removal liquid, the reaction is carried out for 0.1-3h.

15. A short-process lithium extraction method for lithium clay ore according to claim 14, characterized in that: The saturated sodium carbonate solution is added to the impurity removal liquid, and filtered while hot after the reaction.

16. The short-process lithium extraction method of lithium clay ore according to claim 1 further comprises the following steps: The lithium carbonate filter residue is dried.

17. A short-process lithium extraction method for lithium clay ore according to claim 16, characterized in that: The drying temperature is 60-120° C., and the drying time is 3-12 hours.

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