Method for extracting lithium through microwave acidification roasting and mechanical force ball milling leaching

Abstract

The invention relates to the technical field of metallurgy, in particular to a method for extracting lithium through microwave acidification roasting and mechanical force ball milling leaching. According to the method for extracting lithium through microwave acidification roasting and mechanical force ball-milling leaching, microwave energy can be used for assisting calcination transformation of spodumene, and microwave energy is used for roasting an acid leaching material, so that the calcination effect is rapidly and efficiently achieved, and the use amount of sulfuric acid and calcination energy consumption are reduced. And a planetary ball mill is used for performing mechanical ball milling and water leaching on the caked roasted material after acid leaching and calcination, so that the water leaching efficiency is improved, and the lithium extraction rate is improved.

Description

Technical Field

[0001] The present invention relates to the field of metallurgy technology, and more specifically, to a method for extracting lithium by leaching using microwave acidification roasting and mechanical ball milling. Background Art

[0002] Lithium is a key element in the batteries used in portable information technology devices, electric vehicles, and energy storage systems. It has high electrochemical activity and low density. Due to its special properties, lithium plays an irreplaceable role in many fields. With the rapid development of lithium-ion energy over the past decade, lithium has become a key element of the modern energy revolution and has a high strategic value. Relevant technology companies have made ensuring the supply of lithium a top priority. China's lithium resources mainly come from salt lake brine and lithium-containing ores. Spodumene is a typical lithium-containing resource. Spodumene has the highest lithium oxide content (up to 3-8%), a stable chemical composition, and fewer impurities. It is the most valuable lithium-containing ore resource for development.

[0003] Spodumene is a single-chain silicate in the pyroxene family, existing in three different structures: α, β, and γ phases. Natural spodumene exists in the α phase, and in ordinary production, it needs to be transformed by high-temperature calcination at 1000-1100°C, from the α phase to the relatively porous, more reactive, and easier to extract β phase. Microwave-assisted calcination uses microwave energy to assist silicon carbide rod heating to achieve the purpose of rapid heating. At room temperature, spodumene hardly absorbs microwave energy, but spodumene in a high-temperature state has a good absorption capacity for microwave energy. The use of microwave-assisted calcination can greatly shorten the calcination time and reduce energy consumption. The traditional sulfuric acid method acidifies the β-phase spodumene with sulfuric acid, then roasts it at high temperature, and then stirs and leaches it in water. This method uses a large amount of sulfuric acid, has high energy consumption, and causes serious pollution. Although the sulfuric acid method has many disadvantages, sulfuric acid roasting is still the mainstream in actual production. However, the increasingly competitive lithium battery market now places higher requirements on upstream lithium extraction processes, so improving the sulfuric acid method is the current top priority. Summary of the invention

[0004] The purpose of the present invention is to provide a method for leaching and extracting lithium by microwave acidification roasting and mechanical ball milling, which can utilize microwave energy to assist calcination and transformation of spodumene and use microwave energy to roast acid leaching materials, thereby achieving a calcination effect quickly and efficiently, reducing the amount of sulfuric acid used and the calcination energy consumption. A planetary ball mill is used to mechanically ball mill and water-immerse the roasted material agglomerated after acid leaching and calcination, thereby improving the water leaching efficiency and thus improving the lithium extraction rate.

[0005] In order to achieve these purposes and other advantages according to the present invention, a method for leaching and extracting lithium by microwave acidification roasting and mechanical ball milling is provided, comprising the following steps:

[0006] S1. calcining α-phase spodumene through microwaves to transform it into β-phase spodumene;

[0007] S2, mixing the β-phase spodumene obtained in S1 with concentrated sulfuric acid, grinding them evenly and then calcining them with microwaves to obtain an acid-leached roasted material;

[0008] S3, placing the acid-leached roasted material obtained in S2 in a planetary ball mill, adding water to perform ball milling and water leaching to obtain a lithium-containing solution;

[0009] S4, filtering the lithium-containing solution obtained in S3, washing it multiple times, and collecting the filtrate to obtain a lithium-containing filtrate.

[0010] Furthermore, in the method of leaching and extracting lithium by microwave acidification roasting and mechanical ball milling, the particle size of the α-phase spodumene in S1 is greater than 200 mesh, the lithium oxide content is 2-6%, and the water content is 2-7%.

[0011] Furthermore, in the method of extracting lithium by microwave acidification roasting and mechanical ball milling, the power of the microwave heating device during microwave calcination in S1 is 0.1-4KW, the microwave calcination time is 1-30min, and the microwave calcination is stopped when the temperature of the α-phase spodumene reaches 1100-1200°C.

[0012] Furthermore, in the method for leaching and extracting lithium using microwave acidification roasting and mechanical ball milling, the mass concentration of concentrated sulfuric acid used in S2 is 80-98%, and the mass ratio of β-phase spodumene to concentrated sulfuric acid is 1:0.1-0.5.

[0013] Furthermore, in the method of extracting lithium by microwave acidification roasting and mechanical ball milling, the power of the microwave heating device during microwave calcination in S2 is 550-1100W, and the microwave calcination time is 10-120s.

[0014] Furthermore, in the method for extracting lithium by microwave acidification roasting and mechanical ball milling leaching, during ball milling and water leaching in S3, the mass ratio of ball milling medium, acid leaching roasted material and water is 1:1-10:1:5.

[0015] Furthermore, in the method of leaching and extracting lithium by microwave acidification roasting and mechanical ball milling, during the ball milling water immersion in S3, the rotation speed of the planetary ball mill is 100-500r / min, the ball milling time is 15-60min, and the ball milling direction is changed every 5-30min.

[0016] Furthermore, in the method for leaching and extracting lithium using microwave acidification roasting and mechanical ball milling, washing in S4 is performed until the filtrate is neutral.

[0017] The beneficial effects of the present invention are:

[0018] 1. In the method for leaching and extracting lithium of the present invention, microwave-assisted calcination of spodumene transformation and acid leaching calcination and mechanical ball milling leaching are adopted, which provides new ideas and methods for reducing the energy consumption and transformation time of spodumene transformation and reducing the amount of sulfuric acid for lithium extraction by sulfuric acid method, reducing energy consumption, reducing reaction time and improving water leaching efficiency.

[0019] 2. In the method for leaching and extracting lithium of the present invention, β spodumene is mixed with concentrated sulfuric acid, and microwave calcination is performed after grinding evenly. Compared with traditional calcination, heating is started from the outside of the material, and heating is performed by convection, conduction, radiation and other methods. The heat conduction efficiency is low and the heat loss is also large. Microwave calcination is mainly determined by the penetration depth of microwave energy and the absorption degree of microwave energy by the material. As a polar molecule, sulfuric acid molecules will change with the change of the external electric field under the action of the rapidly changing high-frequency electromagnetic field, causing the movement and mutual friction effect of sulfuric acid molecules, generating heat energy in this process, and heating is completed directly inside the spodumene, with fast heating speed, low heat loss and uniform heating. And due to the movement of sulfuric acid molecules, the reaction with spodumene molecules will be more active and the reaction will be more thorough. Microwave calcination can save a lot of energy consumption compared with traditional muffle furnace calcination, and the calcination time is greatly reduced, the process time is reduced, the required concentrated sulfuric acid dosage is also reduced, and the waste residue output is reduced.

[0020] 3. In the method for leaching and extracting lithium of the present invention, spodumene may agglomerate after acid leaching and calcination, and the agglomerated roasted material may not be thoroughly immersed in water when stirred for immersion. The acid leaching roasted material is treated by ball milling for immersion, which can fully immerse the agglomerated roasted material in water and fully release the soluble lithium sulfate, thereby improving the lithium extraction rate.

[0021] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0023] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships as shown, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0024] Example 1

[0025] A method for extracting lithium by microwave acidification roasting and mechanical ball milling leaching comprises the following steps:

[0026] S1. calcining α-phase spodumene through microwaves to transform it into β-phase spodumene;

[0027] The particle size of the α-phase spodumene in S1 is greater than 200 meshes, the lithium oxide content is 3%, and the water content is 2%; the power of the microwave heating device during microwave calcination is 3KW, and the microwave calcination is stopped when the temperature of the α-phase spodumene reaches 1200°C;

[0028] S2, mixing the β-phase spodumene obtained in S1 with concentrated sulfuric acid, grinding them evenly and then calcining them with microwaves to obtain an acid-leached roasted material;

[0029] The mass concentration of concentrated sulfuric acid is 98%, and the mass ratio of β-phase spodumene to concentrated sulfuric acid is 1:0.2; the power of the microwave heating device during microwave calcination is 750W, and the microwave calcination time is 20s;

[0030] S3, placing the acid-leached roasted material obtained in S2 in a planetary ball mill, adding water to perform ball milling and water leaching to obtain a lithium-containing solution;

[0031] When the ball mill is used for water immersion, the mass ratio of the ball milling medium, the acid leaching roasted material and the water is 1:2:1; the rotation speed of the planetary ball mill is 250r / min, the ball milling time is 30min, and the ball milling direction is changed every 10min;

[0032] S4, filtering the lithium-containing solution obtained in S3, and washing it for multiple times until the filtrate is neutral, and collecting the filtrates to obtain a lithium-containing filtrate, and the final lithium yield is 99%.

[0033] Example 2

[0034] A method for extracting lithium by microwave acidification roasting and mechanical ball milling leaching comprises the following steps:

[0035] S1. calcining α-phase spodumene through microwaves to transform it into β-phase spodumene;

[0036] The particle size of the α-phase spodumene in S1 is greater than 200 meshes, the lithium oxide content is 2.5%, and the water content is 5%. The power of the microwave heating device during microwave calcination is 2KW, and the microwave calcination is stopped when the temperature of the α-phase spodumene reaches 1150°C.

[0037] S2, mixing the β-phase spodumene obtained in S1 with concentrated sulfuric acid, grinding them evenly and then calcining them with microwaves to obtain an acid-leached roasted material;

[0038] The mass concentration of concentrated sulfuric acid is 95%, and the mass ratio of β-phase spodumene to concentrated sulfuric acid is 1:0.25; the power of the microwave heating device during microwave calcination is 850W, and the microwave calcination time is 30s;

[0039] S3, placing the acid-leached roasted material obtained in S2 in a planetary ball mill, adding water to perform ball milling and water leaching to obtain a lithium-containing solution;

[0040] When the ball mill is used for water immersion, the mass ratio of the ball milling medium, the acid leaching roasted material and the water is 1:3:1; the rotation speed of the planetary ball mill is 350r / min, the ball milling time is 45min, and the ball milling direction is changed every 10min;

[0041] S4, filtering the lithium-containing solution obtained in S3, and washing it for multiple times until the filtrate is neutral, and collecting the filtrates to obtain a lithium-containing filtrate, and the final lithium yield is 95%.

[0042] Example 3

[0043] A method for extracting lithium by microwave acidification roasting and mechanical ball milling leaching comprises the following steps:

[0044] S1. calcining α-phase spodumene through microwaves to transform it into β-phase spodumene;

[0045] The particle size of the α-phase spodumene in S1 is greater than 200 meshes, the lithium oxide content is 4%, and the water content is 7%. The power of the microwave heating device during microwave calcination is 1KW, and the microwave calcination is stopped when the temperature of the α-phase spodumene reaches 1100°C.

[0046] S2, mixing the β-phase spodumene obtained in S1 with concentrated sulfuric acid, grinding them evenly and then calcining them with microwaves to obtain an acid-leached roasted material;

[0047] The mass concentration of concentrated sulfuric acid is 98%, and the mass ratio of β-phase spodumene to concentrated sulfuric acid is 1:0.15; the power of the microwave heating device during microwave calcination is 650W, and the microwave calcination time is 15s;

[0048] S3, placing the acid-leached roasted material obtained in S2 in a planetary ball mill, adding water to perform ball milling and water leaching to obtain a lithium-containing solution;

[0049] When the ball mill is used for water immersion, the mass ratio of the ball milling medium, the acid leaching roasted material and the water is 1:1:1; the rotation speed of the planetary ball mill is 150r / min, the ball milling time is 15min, and the ball milling direction is changed every 5min;

[0050] S4. The lithium-containing solution obtained in S3 is filtered and washed for multiple times until the filtrate is neutral, and the filtrates are collected to obtain a lithium-containing filtrate, and the final lithium yield is 92%.

[0051] Comparative Example 1

[0052] A method for extracting lithium by microwave acidification roasting and mechanical ball milling leaching, wherein the preparation method is the same as that of Example 1, except that the amount of concentrated sulfuric acid in S2 is 10%, and the final lithium yield is 53%.

[0053] Comparative Example 2

[0054] A method for extracting lithium by microwave acidification roasting and mechanical ball milling leaching, wherein the preparation method is the same as that of Example 1, the only difference being that the acid leaching microwave calcination time in S2 is 120s, and the final lithium yield is 72%.

[0055] It can be seen from the above-mentioned comparative examples 1 and 2 that when β-phase spodumene is mixed with concentrated sulfuric acid for microwave calcination, the amount of concentrated sulfuric acid used and the acid leaching microwave calcination time will affect the final lithium yield.

[0056] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the embodiments shown and described herein.

Claims

1. A method for leaching and extracting lithium by microwave acidification roasting and mechanical ball milling, characterized in that: The following steps are involved: S1. calcining α-phase spodumene through microwaves to transform it into β-phase spodumene; S2, mixing the β-phase spodumene obtained in S1 with concentrated sulfuric acid, grinding them evenly and then calcining them with microwaves to obtain an acid-leached roasted material; S3, placing the acid-leached roasted material obtained in S2 in a planetary ball mill, adding water to perform ball milling and water leaching to obtain a lithium-containing solution; S4, filtering the lithium-containing solution obtained in S3, washing it multiple times, and collecting the filtrate to obtain a lithium-containing filtrate.

2. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: The particle size of the α-phase spodumene in S1 is greater than 200 meshes, the lithium oxide content is 2-6%, and the water content is 2-7%.

3. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: During microwave calcination in S1, the power of the microwave heating device is 0.1-4KW, the microwave calcination time is 1-30min, and the microwave calcination is stopped when the temperature of the α-phase spodumene reaches 1100-1200°C.

4. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: The mass concentration of concentrated sulfuric acid used in S2 is 80-98%, and the mass ratio of β-phase spodumene to concentrated sulfuric acid is 1:0.1-0.

5.

5. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: During microwave calcination in S2, the power of the microwave heating device is 550-1100 W, and the microwave calcination time is 10-120 s.

6. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: During the ball milling and water leaching in S3, the mass ratio of the ball milling medium, the acid leaching roasted material and the water is 1:1-10:1:

5.

7. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: When the ball mill in S3 is immersed in water, the rotation speed of the planetary ball mill is 100-500 r / min, the ball milling time is 15-60 min, and the ball milling direction is changed every 5-30 min.

8. The method for extracting lithium by microwave acidification roasting and mechanical ball milling according to claim 1, characterized in that: Wash in S4 until the filtrate is neutral.