A method for enhancing the lithium leaching rate of a lithium ore of the clay type

Abstract

The application discloses a method for strengthening lithium leaching rate of clay type lithium ore, and belongs to the technical field of low-grade clay type lithium ore extraction methods. The method uses concentrated sulfuric acid as a roasting aid, and can dissociate lithium-containing minerals through low-temperature roasting under a low reagent dosage. Since gangue minerals can wrap lithium during the sulfuric acid roasting process, the wrapped lithium can be secondarily dissociated by adding a sulfate solution during leaching, so that the purpose of high-efficiency lithium leaching under low temperature and low reagent dosage is achieved. While ensuring high lithium leaching rate and low impurity element leaching rate, the chemical reagent dosage, especially the sulfuric acid dosage, in the roasting and leaching processes is effectively reduced, and the method has the characteristics of small corrosion and safety.

Description

Technical Field

[0001] This invention belongs to the technical field of extraction methods for low-grade clay-type lithium ore, and particularly relates to a method for enhancing the lithium leaching rate of clay-type lithium ore. Background Technology

[0002] Lithium's unique advantages in the new energy field have led to explosive growth in its application scale. Major economies worldwide have listed lithium resources as key minerals, highlighting its strategic significance in global development. Lithium resources can generally be classified into three main categories: brine-type, hard-rock-type, and clay-type. Currently, research on the development and utilization of clay-type lithium resources is limited. However, with the discovery of abundant clay-type lithium resources and the increasing demand for lithium, clay-type lithium deposits may become an important direction for my country's future lithium resource development and utilization. Therefore, developing efficient extraction methods for clay-type lithium ore is of great importance.

[0003] Currently, there is no mature process for developing clay-type lithium ore in China. Lithium extraction from clay-type lithium ore suffers from problems such as high energy consumption during roasting, high reagent consumption, and numerous impurities. For example, patent CN117684019A proposes roasting clay-type lithium ore and then leaching the ore powder with a mixture of sulfuric acid and ferric chloride. This method can effectively extract lithium from clay-type lithium ore, but the sulfuric acid concentration used is 1–6 mol / L, the ferric chloride concentration is 1–30 wt%, and the ore powder and leaching agent are mixed at a solid-liquid ratio of 5 mg / L, resulting in large reagent consumption and high costs. Patent CN115786732A relates to a method for extracting lithium from clay-type lithium ore, proposing a method of mixing and ripening clay-type lithium ore with concentrated sulfuric acid, followed by water leaching. This method can effectively extract lithium, but the mass ratio of ore powder to concentrated sulfuric acid is 1:0.25–1:0.35, and the amount of sulfuric acid used is still relatively large.

[0004] Therefore, in view of the above situation, a method to reduce the dosage of reagents and enhance the lithium leaching rate of clay lithium ore is provided, which is of great significance for the efficient utilization of clay lithium ore. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for enhancing the lithium leaching rate of clay-type lithium ore.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for enhancing the lithium leaching rate of clay-type lithium ore. Concentrated sulfuric acid is used as a roasting aid and sulfate solution is used as a leaching agent to roast and leach the clay-type lithium ore to obtain a lithium leachate.

[0008] Preferably, the mass ratio of the clay-type lithium ore to concentrated sulfuric acid is 1:(0.03-0.1).

[0009] Preferably, the concentrated sulfuric acid has a mass concentration of 90-98%.

[0010] Preferably, the roasting temperature is 400-500℃ and the time is 1-2 hours.

[0011] Preferably, the mass concentration of the sulfate solution is 2-5%.

[0012] Preferably, the liquid-to-solid ratio is controlled to be (3-5):1 during the leaching process.

[0013] Preferably, the temperature is controlled at 45-90°C and the leaching time is 1-2 hours during the leaching process.

[0014] Preferably, the sulfate in the sulfate solution includes one or more of ferric sulfate, sodium sulfate, and potassium sulfate.

[0015] Preferably, the lithium leaching rate in the lithium leaching solution is 75-95%.

[0016] Preferably, it includes the following steps:

[0017] (1) Crush and grind clay-type lithium ore to obtain grinding products;

[0018] (2) The grinding product obtained in step (1) is mixed evenly with concentrated sulfuric acid and then roasted to obtain roasted clay-type lithium ore.

[0019] (3) Leach the roasted clay-type lithium ore obtained in step (2) with a sulfate solution to obtain a lithium leachate.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] This invention uses concentrated sulfuric acid as a roasting aid, enabling the dissociation of lithium-containing minerals through low-temperature roasting at low dosages. Because gangue minerals encapsulate lithium during sulfuric acid roasting, a secondary dissociation of the encapsulated lithium is achieved during leaching by adding a sulfate solution. This results in highly efficient lithium leaching at low temperatures and low dosages. While ensuring a high lithium leaching rate and a low impurity element leaching rate, it effectively reduces the amount of chemical reagents used in the roasting and leaching processes, especially sulfuric acid, exhibiting low corrosivity and safety.

[0022] The calcination temperature of this invention is 400-500℃, and the leaching temperature is 45-90℃, which has the advantage of excellent low-temperature performance and can effectively reduce energy consumption.

[0023] The process of this invention is simple, with low energy consumption and cost per unit of processing volume, small acid consumption, and the leaching residue is ordinary solid waste. The product properties are easy to control, and the equipment can be scaled up easily. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0025] Figure 1 This is a process flow diagram of the method for enhancing the lithium leaching rate of clay-type lithium ore in Examples 1-2. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] This invention provides a method for enhancing the lithium leaching rate of clay-type lithium ore. Concentrated sulfuric acid is used as a roasting aid, and sulfate solution is used as a leaching agent to roast and leach the clay-type lithium ore to obtain a lithium leachate.

[0029] This invention uses concentrated sulfuric acid as a roasting aid, enabling the dissociation of lithium-containing minerals through low-temperature roasting at low dosages. Since the gangue minerals encapsulate lithium during sulfuric acid roasting, the encapsulated lithium is further dissociated during leaching by adding a sulfate solution. This achieves efficient lithium leaching at low temperature and low dosage, ensuring a high lithium leaching rate and a low impurity element leaching rate while effectively reducing the amount of chemical reagents used in the roasting and leaching process, especially sulfuric acid. It is characterized by low corrosivity and safety.

[0030] In a preferred embodiment, the mass ratio of the clay-type lithium ore to concentrated sulfuric acid is 1:(0.03-0.1), and in a more preferred embodiment, it is 1:(0.03-0.09). This invention controls the amount of concentrated sulfuric acid within the above range to ensure sufficient dissociation of the lithium-containing minerals during roasting. Insufficient concentrated sulfuric acid will not guarantee the dissociation effect, thus affecting the subsequent leaching effect; excessive concentrated sulfuric acid will increase costs, increase the content of impurities in the leachate, and worsen the secondary encapsulation of lithium by the gangue.

[0031] In a preferred embodiment, the concentrated sulfuric acid has a mass concentration of 90-98%. This invention uses concentrated sulfuric acid within the above-mentioned range. If the concentration of concentrated sulfuric acid is too low, the reaction efficiency will decrease, and excessive moisture will lead to energy loss during roasting. The highest concentration of industrial concentrated sulfuric acid is 98%, therefore, the upper limit for the concentration of concentrated sulfuric acid is 98%.

[0032] In a preferred embodiment, the calcination temperature is 400–500°C, and the time is 1–2 hours. This invention reduces the calcination temperature, offering excellent low-temperature performance and effectively reducing energy consumption.

[0033] In a preferred embodiment, the mass concentration of the sulfate solution is 2-5%. This invention uses a sulfate solution with a mass concentration within the above range to ensure sufficient dissociation of the encapsulated lithium, which is beneficial for improving the lithium leaching rate. Too low a concentration of sulfate solution will lead to reduced reactivity and ineffective dissociation of the encapsulated lithium, while too high a concentration will result in increased impurities, unnecessary reagent waste, and increased costs.

[0034] In a preferred embodiment, the sulfate in the sulfate solution includes one or more of ferric sulfate, sodium sulfate, and potassium sulfate, more preferably ferric sulfate.

[0035] In a preferred embodiment, the solvent for the sulfate solution is water.

[0036] In a preferred embodiment, the liquid-to-solid ratio is controlled at (3-5):1 during the leaching process. By controlling the liquid-to-solid ratio within the above range during the leaching process, this invention achieves efficient leaching of lithium from clay-type lithium ores. Insufficient leaching agent will weaken the dissociation and migration of lithium elements, which is not conducive to the equilibrium shifting in the leaching direction. Excessive leaching agent will increase the amount of reagent used and the processing volume and difficulty of subsequent solid-liquid separation.

[0037] In a preferred embodiment, the leaching process is controlled at a temperature of 45–90°C, and the leaching time is 1–2 hours. This invention reduces the leaching temperature, offering excellent low-temperature performance and effectively reducing energy consumption.

[0038] In a preferred embodiment, the lithium grade of the clay-type lithium ore is 0.1% to 1%.

[0039] In a preferred embodiment, the lithium leaching rate in the lithium leachate is 75-95%.

[0040] In a preferred embodiment, the following steps are included:

[0041] (1) Crush and grind clay-type lithium ore to obtain grinding products;

[0042] (2) The grinding product obtained in step (1) is mixed evenly with concentrated sulfuric acid and then roasted to obtain roasted clay-type lithium ore.

[0043] (3) Leach the roasted clay-type lithium ore obtained in step (2) with a sulfate solution to obtain a lithium leachate.

[0044] In a preferred embodiment, in step (1), the crushing equipment used for crushing includes a jaw crusher; the particle size of the crushed clay-type lithium ore is -5mm.

[0045] In a preferred embodiment, in step (1), the grinding method is dry grinding, and the equipment is a ball mill; the particles of -0.074mm account for 70-80% of the grinding product.

[0046] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0047] Example 1

[0048] A clay-type lithium ore in Yunnan Province has the following main chemical composition (by mass percentage): Li 0.15%, SiO2 24.50%, Al2O3 57.23%, Fe 3.77%, CaO 0.17%, TiO2 2.21%, MgO 0.25%, and K2O 0.13%. The method for enhancing the lithium leaching rate of the clay-type lithium ore is carried out according to the following steps, and the process flow is shown below. Figure 1 :

[0049] (1) Clay-type lithium ore is crushed to -5mm using a jaw crusher, and then dry-grinded using a ball mill to grind the mineral to 75% of the particles to -0.074mm, thus obtaining the grinding product.

[0050] (2) The grinding product obtained in step (1) is mixed with concentrated sulfuric acid with a mass concentration of 98% at a mass ratio of 1:0.03, and then roasted in a roasting furnace at 500°C for 2 hours to obtain roasted clay-type lithium ore.

[0051] (3) The roasted clay-type lithium ore obtained in step (2) was leached with a 5% ferric sulfate solution at a leaching temperature of 90°C, a leaching time of 2 hours, and a liquid-solid ratio of 5:1 to obtain a lithium leaching solution with a lithium leaching rate of 85%, and aluminum and silicon leaching rates of 1% and 2.9%, respectively.

[0052] Example 2

[0053] A clay-type lithium ore in Guizhou Province has the following main chemical composition (by mass percentage): Li 0.12%, SiO2 20.45%, Al2O3 54.11%, Fe 3.57%, CaO 0.14%, TiO2 3.20%, MgO 0.41%, and K2O 0.21%. The method for enhancing the lithium leaching rate of the clay-type lithium ore is carried out according to the following steps, and the process flow is shown below. Figure 1 :

[0054] (1) Clay-type lithium ore is crushed to -5mm using a jaw crusher, and then dry-grinded using a ball mill to grind the mineral to 80% of the particles to -0.074mm, thus obtaining the grinding product.

[0055] (2) The grinding product obtained in step (1) is mixed with concentrated sulfuric acid with a mass concentration of 98% at a mass ratio of 1:0.09, and then roasted in a roasting furnace at 500°C for 1 hour to obtain roasted clay-type lithium ore.

[0056] (3) The roasted clay-type lithium ore obtained in step (2) was leached with a 4% ferric sulfate solution at a leaching temperature of 80°C, a leaching time of 2 hours, and a liquid-solid ratio of 4:1 to obtain a lithium leaching solution with a lithium leaching rate of 90%, and aluminum and silicon leaching rates of 2% and 4%, respectively.

[0057] Comparative Example 1

[0058] The difference from Example 2 is that in step (2), ferric sulfate is used as a calcination aid, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 49% is obtained, and the leaching rates of aluminum and silicon are 3.2% and 1.7%, respectively.

[0059] Comparative Example 2

[0060] The difference from Example 2 is that in step (3), water is used as the leaching agent, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 42% is obtained, and the leaching rates of aluminum and silicon are 1.2% and 0.65%, respectively.

[0061] Comparative Example 3

[0062] The difference from Example 2 is that in step (2), the grinding product obtained in step (1) is mixed with concentrated sulfuric acid at a mass ratio of 1:0.2, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 65% is obtained, and the leaching rates of aluminum and silicon are 9% and 4%, respectively.

[0063] Comparative Example 4

[0064] The difference from Example 2 is that in step (2), the grinding product obtained in step (1) is mixed with concentrated sulfuric acid at a mass ratio of 1:0.01, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 70% is obtained, and the leaching rates of aluminum and silicon are 2.3% and 1.32%, respectively.

[0065] Comparative Example 5

[0066] The difference from Example 2 is that in step (2), concentrated sulfuric acid with a mass concentration of 85% is used, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 81% is obtained, and the leaching rates of aluminum and silicon are 1.7% and 3.1%, respectively.

[0067] Comparative Example 6

[0068] The difference from Example 2 is that in step (3), the liquid-to-solid ratio is 2:1, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 70% is obtained, and the leaching rates of aluminum and silicon are 1.7% and 3.5%, respectively.

[0069] Comparative Example 7

[0070] The difference from Example 2 is that in step (3), an 8% ferric sulfate solution is used, and the rest is the same as in Example 2; a lithium leaching solution with a lithium leaching rate of 88% is obtained, and the leaching rates of aluminum and silicon are 3.4% and 4.2%, respectively.

[0071] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for enhancing the lithium leaching rate of clay-type lithium ore and obtaining a lower impurity element leaching rate, characterized in that, Clay-type lithium ore was roasted and leached using concentrated sulfuric acid as a roasting aid and ferric sulfate solution as a leaching agent to obtain lithium leachate. The specific steps are as follows: (1) Crush and grind clay-type lithium ore to obtain grinding products; (2) The grinding product obtained in step (1) is mixed evenly with concentrated sulfuric acid and then roasted to obtain roasted clay-type lithium ore. (3) Leach the roasted clay-type lithium ore obtained in step (2) with ferric sulfate solution to obtain lithium leachate; The mass ratio of the clay-type lithium ore to concentrated sulfuric acid is 1:0.09; the mass concentration of the ferric sulfate solution is 4%. The roasting temperature is 500℃ and the time is 1 hour; The concentrated sulfuric acid has a mass concentration of 98%. During the leaching process, the liquid-to-solid ratio is controlled at 4:1; The leaching process is controlled at 80℃ for 2 hours; The lithium leaching solution has a lithium leaching rate of 90%. The leaching rates of aluminum and silicon in the lithium leaching solution are 2% and 4%, respectively.

Images