Lithium extraction method of clay lithium ore

Abstract

The invention belongs to the field of ore processing, and provides a lithium extraction method of clay lithium ore, which comprises the following steps: mixing the clay lithium ore with an acid solution to obtain an acid mixed material; roasting the acid mixed material to obtain a roasted material; and mixing the roasted material, a leaching agent and a carbonate radical impurity removal agent, and leaching to obtain a lithium-containing leaching solution, leaching residues and carbon dioxide gas. Acid mixing materials are prepared and directly roasted, so that the utilization rate of acid is effectively increased, and acid pollution is reduced; by adding a specific impurity removal agent during leaching, the integration of leaching and impurity removal is realized, the process is simplified, the cost is reduced, and the impurity removal effect is enhanced by the generated carbon dioxide gas.

Description

Technical Field

[0001] The invention belongs to the field of ore processing and relates to a method for extracting lithium from clay lithium ore. Background Art

[0002] With the booming development of emerging industries such as electric vehicles and energy storage systems, the demand for lithium resources is growing, and the mining and extraction technology of lithium resources is also facing unprecedented challenges. Clay-type lithium ore is a new type of lithium mineral resource, but because the lithium grade of clay-type lithium ore is extremely low, compared with traditional high-grade lithium ores such as spodumene and lithium mica, its extraction technology requirements are more stringent, and traditional methods are often difficult to effectively cope with, which has prompted researchers to continuously explore and develop new extraction strategies.

[0003] Regarding the existing processing and recovery process of clay lithium ore, the field has early tried to adopt the strategy of sulfuric acid leaching. Experiments have shown that a lithium ion extraction rate of about 72.34% can be achieved. However, the content of impurity ions (such as aluminum and iron ions) in the leaching solution of this method is high. The presence of these impurities seriously hinders the purity and preparation efficiency of subsequent lithium carbonate, reducing the economy and feasibility of the overall process.

[0004] The iron sulfate leaching method improves the lithium extraction efficiency to some extent, reaching a lithium extraction rate of about 73.6%. However, this method results in a large amount of iron ions in the leachate, which are also difficult to remove, not only affecting the quality of lithium carbonate, but also increasing the complexity and cost of subsequent purification steps.

[0005] In response to the above problems, CN107344725A proposed an innovative sulfuric acid direct leaching method to extract lithium from lithium ore. The process is to mix lithium ore, sulfuric acid and water in a specific proportion, and then introduce sodium fluoride and fluorite concentrate as catalysts to react under specific pressure and temperature conditions. This method aims to improve the extraction efficiency and reaction rate of lithium, but in actual operation, the process has obvious limitations. Due to the introduction of fluoride, the fluorine content in the leaching solution increases significantly, which not only requires a complex fluorine separation system to be equipped later, increasing the complexity and cost of the process flow, but may also cause equipment corrosion problems. Because fluoride is highly corrosive, long-term use is easy to damage production equipment and shorten the service life of the equipment.

[0006] In view of the above challenges, it is particularly important to develop an efficient, environmentally friendly and economical lithium extraction technology for clay-type lithium ore, so that it can effectively reduce the impurity content while ensuring a high lithium extraction rate, simplify the subsequent purification process, and reduce the adverse impact on the environment. Summary of the invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for extracting lithium from clay lithium ore, wherein the method comprises mixing clay lithium ore with an acid solution to obtain an acid-mixed material; roasting the acid-mixed material to obtain a roasted material; mixing the roasted material, a leaching agent and a carbonate impurity remover, and leaching to obtain a lithium-containing leachate, leached slag and carbon dioxide gas. By preparing the acid-mixed material and directly roasting it, the utilization rate of the acid is effectively increased and acid pollution is reduced; by adding a specific impurity remover during leaching, the integration of leaching and impurity removal is achieved, the process is simplified, the cost is reduced, and the generated carbon dioxide gas enhances the impurity removal effect.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a method for extracting lithium from a clay lithium ore, the method comprising:

[0010] The clay lithium ore is mixed with an acid solution to obtain an acid-mixed material; the acid-mixed material is roasted to obtain a roasted material; the roasted material, a leaching agent and a carbonate impurity remover are mixed and leached to obtain a lithium-containing leaching solution, leaching slag and carbon dioxide gas.

[0011] The main drawback of the acid direct leaching of clay lithium ore in the prior art is that the content of impurity metal ions such as Al and Fe in the lithium-containing leachate is high, and the existing impurity removal method, by adding calcium hydroxide, calcium oxide, and sodium hydroxide to the obtained lithium-containing leachate, not only has a high cost of impurity removers, but also increases the process steps, and also causes a large number of lithium ions in the lithium-containing leachate to be adsorbed, resulting in lithium loss. In view of this, the present invention optimizes the acid lithium extraction process, uses an acid solution to mix clay lithium ore to obtain an acid mixture, and directly roasts the acid mixture to increase the utilization rate of the acid, and also reduces the pollution of the acid volatilization to the environment; while leaching, by adding a low-cost carbonate impurity remover, such as calcium carbonate, to achieve leaching and impurity removal integration, which not only reduces the process steps, but also can effectively remove almost all Al and Fe ions. During the leaching process, the produced carbon dioxide gas can, on the one hand, precipitate impurities, such as aluminum hydroxide in particle form, further reducing its adsorption to lithium ions, so that the lithium ion leaching rate can reach as high as 95% or more, maximizing resource utilization, and on the other hand, reduce the viscosity of the leached residue, thereby accelerating the solid-liquid separation rate and speeding up the process; the obtained carbon dioxide can also be recycled for subsequent carbonization of lithium precipitation or formation of carbonic acid to assist the leaching process.

[0012] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0013] As a preferred technical solution of the present invention, the mass percentage of lithium oxide in the clay lithium ore is 0.1% to 1%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0014] Preferably, before the clay lithium ore is mixed with the acid solution, it is crushed in advance until the mass of particles with a particle size of 200 mesh accounts for 30% to 80%, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., to obtain a crushed material, which is then mixed with the acid solution.

[0015] Preferably, the lithium extraction method includes mixing clay lithium ore with concentrated acid to obtain a mixture, and then adding water to dilute the mixture until the solid content is 75% to 85%, for example, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85%, etc., preferably 80%, to form a mixture of clay lithium ore and acid solution to obtain the acid-mixed material.

[0016] In the present invention, concentrated acid can be added first and then water is added for dilution, and the concentrated acid and water form an acid solution. If the concentration of the acid component in the acid solution is too high, the lithium ion yield will not be significantly improved, and more impurity metal ions will be dissolved. If the concentration is too low, the slurry will not be viscous, which will affect the subsequent granulation and / or molding effect, and directly affect the lithium ion yield.

[0017] Preferably, the concentrated acid includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

[0018] In the present invention, the mass fraction of concentrated sulfuric acid is preferably 93% or more; the mass fraction of concentrated hydrochloric acid is preferably 36% or more; and the mass fraction of concentrated nitric acid is preferably 68% or more.

[0019] As a preferred technical solution of the present invention, the mass ratio of the clay lithium ore to the concentrated acid is 1:(0.05-2), for example, 1:0.05, 1:0.08, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1 or 1:1.2, etc., preferably 1:(0.05-1), and more preferably 1:(0.08-0.8).

[0020] As a preferred technical solution of the present invention, the acid-mixed material is first granulated and / or formed, and then calcined.

[0021] A feature of the lithium extraction method of the present invention is that the acid-mixed material is directly roasted as a wet material without drying to remove moisture. The acid-mixed material can be granulated and / or pre-formed as needed, such as into a honeycomb or spherical shape, and then directly put into the furnace for roasting. The acid-mixed material is also conducive to granulation and / or molding because it has no dust.

[0022] Preferably, the calcination temperature is 100-300°C, for example 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C or 300°C, and the calcination time is 0.5-3h, for example 0.5h, 0.8h, 1h, 1.3h, 1.5h, 1.8h, 2h, 2.3h, 2.5h, 2.8h or 3h, etc.

[0023] As a preferred technical solution of the present invention, the roasted material is first crushed until the mass of particles with a particle size of 200 mesh accounts for 50% to 80%, for example, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., to obtain clinker, which is then subjected to the leaching.

[0024] As a preferred technical solution of the present invention, the leaching agent includes pure water or an acid solution with a mass fraction of 5% to 50%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc.

[0025] Preferably, the acid component in the acid solution includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

[0026] As a preferred technical solution of the present invention, the carbonate impurity remover includes at least one of calcium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

[0027] Preferably, the carbonate remover comprises calcium carbonate.

[0028] The present invention preferably uses calcium carbonate as the carbonate impurity remover. Calcium carbonate can promote the hydrolysis of metallic iron and aluminum ions and reduce the formation of flocculents to adsorb lithium ions. Calcium carbonate has low use cost, does not introduce new impurities of sodium or potassium, and does not increase the saturated calcium ion concentration in the solution, which is beneficial to improving the purity of lithium-containing leaching solution and lithium precipitation mother solution.

[0029] Preferably, the mass of the carbonate remover accounts for 0.05% to 0.8% of the mass of the roasting material, for example, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75 or 0.8%, etc.

[0030] In the present invention, the carbonate impurity remover is used as an auxiliary material. Excessive use will result in more tailings and more lithium ions will be adsorbed.

[0031] Preferably, the carbon dioxide gas is used in a lithium carbonization precipitation process.

[0032] As a preferred technical solution of the present invention, the leaching is carried out under normal pressure.

[0033] Preferably, the leaching temperature is 20-90°C, for example, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C, etc.; the leaching time is 5-60min, for example, 5min, 10min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min or 60min, etc.

[0034] As a preferred technical solution of the present invention, the leached residue is washed once and twice in sequence to obtain primary wash water and secondary wash water respectively, the primary wash water is reused for the leaching, and the secondary wash water is reused for the primary washing.

[0035] Due to space limitations and to avoid redundancy, the present invention does not list all point values ​​within the above numerical range one by one, but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0036] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0037] The invention optimizes the acid lithium extraction process, uses acid solution to mix clay lithium ore to obtain acid mixed material, and directly roasts the acid mixed material to increase the utilization rate of the acid, and also reduces the environmental pollution caused by acid volatilization; by adding low-cost carbonate impurity removers, such as calcium carbonate, during leaching, the leaching and impurity removal are integrated, which not only reduces the process steps, but also effectively removes almost all Al and Fe ions. During the leaching process, the produced carbon dioxide gas can precipitate impurities, such as aluminum hydroxide in the form of particles, further reducing its adsorption to lithium ions, so that the lithium ion leaching rate can reach more than 95%, maximizing resource utilization, and reducing the viscosity of the leached residue, thereby accelerating the solid-liquid separation rate and the process; the obtained carbon dioxide can also be recycled for subsequent carbonization and precipitation of lithium or reused to participate in the leaching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the process of extracting lithium from clay lithium ore in Example 1. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0040] It should be clear to those skilled in the art that the embodiments are only intended to help understand the present invention and should not be considered as specific limitations of the present invention.

[0041] The main component contents of the clay lithium ore used in the following examples and comparative examples are shown in Table 1.

[0042] Table 1

[0043] Mass percentage (wt%) Li Na K Ca Mg Fe Al Si Clay lithium ore A (low grade) 0.25 0.67 0.43 1.11 0.16 1.37 15.52 13.67 Clay lithium ore B (very low grade) 0.12 0.41 0.80 1.21 0.23 1.12 12.94 8.95 Clay lithium ore C (normal grade) 0.49 0.57 0.65 0.87 0.11 1.01 20.99 10.98

[0044] Example 1

[0045] This embodiment provides a method for extracting lithium from clay lithium ore, the method comprising:

[0046] (1) crushing the clay lithium ore A with a crusher until the mass of particles with a particle size of 200 mesh accounts for 65%, thereby obtaining a crushed material;

[0047] (2) mixing the crushed material with 98% concentrated sulfuric acid solution at a mass ratio of 1:0.8, stirring evenly, and then diluting with water to a solid content of 80%, and granulating;

[0048] (3) directly placing the granulated acid-mixed material into a high-temperature furnace for calcination, controlling the calcination temperature to 200° C. and the calcination time to 1.8 h to obtain a calcined material;

[0049] (4) crushing the roasted material with a crusher until the mass of particles with a particle size of 200 mesh accounts for 65%, thereby obtaining clinker;

[0050] (5) mixing clinker, carbonate impurity remover calcium carbonate and leaching agent pure water, controlling the solid-liquid ratio of clinker to the leaching agent to be 1 g:2.2 mL, controlling the mass of the carbonate impurity remover to account for 0.4% of the mass of the clinker, performing leaching at normal pressure, controlling the leaching temperature to be 45° C., and the leaching time to be 30 min, to obtain a lithium-containing leaching solution, leaching residue and carbon dioxide gas; the lithium-containing leaching solution can be used for a subsequent lithium precipitation process; the leaching residue is sequentially washed once and twice to obtain a primary wash water and a secondary wash water, respectively, the primary wash water is reused for the leaching, and the secondary wash water is reused for the primary wash; the carbon dioxide gas is collected and then carbonized to precipitate lithium.

[0051] Example 2

[0052] This embodiment provides a method for extracting lithium from clay lithium ore. In the method for extracting lithium, clay lithium ore B is used instead of clay lithium ore A in step (1). Except for the above, other conditions are the same as those in Example 1.

[0053] Example 3

[0054] This embodiment provides a method for extracting lithium from clay lithium ore. In the lithium extraction method, clay lithium ore C is used instead of clay lithium ore A in step (1). Except for the above, other conditions are the same as those in Example 1.

[0055] Example 4

[0056] This embodiment provides a method for extracting lithium from clay lithium ore. In the lithium extraction method, in step (2), the mass ratio of the crushed material to the 98% concentrated sulfuric acid solution is adjusted from 1:0.8 to 1:0.05. Except for the above, other conditions are the same as those in Example 1.

[0057] Example 5

[0058] This embodiment provides a method for extracting lithium from clay lithium ore. In the lithium extraction method, in step (2), the mass ratio of the crushed material to the 98% concentrated sulfuric acid solution is adjusted from 1:0.8 to 1:0.5. Except for the above, other conditions are the same as those in Example 1.

[0059] Example 6

[0060] This embodiment provides a method for extracting lithium from clay lithium ore. In the lithium extraction method, in step (2), the mass ratio of the crushed material to the 98% concentrated sulfuric acid solution is adjusted from 1:0.8 to 1:1.0. Except for the above, other conditions are the same as those in Example 1.

[0061] Example 7

[0062] This embodiment provides a method for extracting lithium from clay lithium ore. In the lithium extraction method, in step (5), the mass of the carbonate impurity remover is adjusted from 0.4% to 0.05% of the mass of the clinker. Except for the above, other conditions are the same as those in Example 1.

[0063] Example 8

[0064] This embodiment provides a method for extracting lithium from clay lithium ore. In the lithium extraction method, in step (5), the mass of the carbonate impurity remover is adjusted from 0.4% to 0.8% of the mass of the clinker. Except for the above, other conditions are the same as those in Example 1.

[0065] Comparative Example 1

[0066] This comparative example provides a method for extracting lithium from clay lithium ore. In the method for extracting lithium, in step (5), the carbonate impurity remover is replaced with sodium hydroxide. Except for the above, other conditions are the same as those in Example 1.

[0067] Comparative Example 2

[0068] This comparative example provides a method for extracting lithium from clay lithium ore, using sulfuric acid direct acid leaching in the prior art. The lithium extraction method includes:

[0069] S1. The clay lithium ore A is crushed by a crusher until the mass of particles with a particle size of 200 mesh accounts for 65% to obtain a crushed material;

[0070] S2. Mix the crushed material with 50% dilute sulfuric acid solution at a solid-liquid ratio of 1g:1.6ml, stir and react for 1.8h at room temperature and pressure, and then filter to obtain lithium-containing leaching solution and leaching residue. The leaching residue is washed once and twice in sequence to obtain primary washing water and secondary washing water, respectively. The primary washing water is reused for the leaching, and the secondary washing water is reused for the primary washing.

[0071] The lithium extraction process of the embodiment and the comparative example was monitored, and the lithium recovery rate, etc. were calculated based on the obtained products. The obtained results are recorded in Table 2.

[0072] Table 2

[0073]

[0074] It can be seen from Table 2 that:

[0075] Comparative Examples 1, 2, and 3 show that the process is widely applicable to clay lithium ores of different grades, and the lithium recovery rate and pre-impurity removal effect meet the requirements;

[0076] Comparison of Examples 1, 4, 5, and 6 shows that the lithium recovery rate is greatly affected by the acid dosage. In the early stage, there is a linear relationship. After the mineral acid ratio reaches 1:0.8, further increasing the acid dosage does not significantly improve the lithium recovery rate. Instead, more impurity metal ions are dissolved, increasing the cost of impurity removal in the later stage.

[0077] By comparing Examples 1, 7, and 8, it is found that the dosage of carbonate impurity remover should be moderate. Too little impurity removal is incomplete, and too much tailings will increase the residual lithium ions, which is not conducive to later washing.

[0078] By comparing Example 1 with Comparative Example 1, it is found that the use of strong alkaline impurity removers such as sodium hydroxide will produce a large amount of flocculent precipitates with strong adsorption to adsorb lithium ions, while the use of carbonate impurity removers to promote the hydrolysis of impurity metal ions will change the state of the precipitate and thus reduce the adsorption of the precipitate;

[0079] By comparing Example 1 with Comparative Example 2, it is found that the high temperature of roasting the acid-mixed material in the present invention can promote the effect of the acid on the ore and better destroy the internal structure of the ore, especially the ore such as clay containing complex lithium crystals.

[0080] The present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0081] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0082] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0083] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for extracting lithium from clay lithium ore, characterized in that: The lithium extraction method comprises: The clay lithium ore is mixed with an acid solution to obtain an acid-mixed material; the acid-mixed material is roasted to obtain a roasted material; the roasted material, a leaching agent and a carbonate impurity remover are mixed and leached to obtain a lithium-containing leaching solution, leaching slag and carbon dioxide gas.

2. The lithium extraction method according to claim 1, characterized in that: The mass percentage of lithium oxide in the clay lithium ore is 0.1% to 1%; Preferably, before the clay lithium ore is mixed with the acid solution, it is pre-crushed until the mass of particles with a particle size of 200 mesh accounts for 30% to 80%, thereby obtaining crushed material, which is then mixed with the acid solution.

3. The lithium extraction method according to claim 1 or 2, characterized in that: The lithium extraction method comprises mixing clay lithium ore with concentrated acid to obtain a mixture, and then adding water to dilute the mixture until the solid content is 75% to 85%, thereby forming a mixture of clay lithium ore and acid solution to obtain the acid-mixed material; Preferably, the concentrated acid includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

4. The lithium extraction method according to any one of claim 3, characterized in that: The mass ratio of the clay lithium ore to the concentrated acid is 1:(0.05-2).

5. The lithium extraction method according to any one of claims 1 to 4, characterized in that: The acid-mixed material is first granulated and / or formed, and then roasted; Preferably, the calcination temperature is 100-300° C. and the calcination time is 0.5-3 h.

6. The lithium extraction method according to any one of claims 1 to 5, characterized in that: The roasted material is first crushed until the mass of particles with a particle size of 200 mesh accounts for 50% to 80%, thereby obtaining clinker, which is then subjected to the leaching.

7. The lithium extraction method according to any one of claims 1 to 6, characterized in that: The leaching agent includes pure water or an acid solution with a mass fraction of 5% to 50%; Preferably, the acid component in the acid solution includes at least one of sulfuric acid, hydrochloric acid or nitric acid.

8. The lithium extraction method according to any one of claims 1 to 7, characterized in that: The carbonate impurity remover includes at least one of calcium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate; Preferably, the carbonate impurity remover comprises calcium carbonate; Preferably, the mass of the carbonate impurity remover accounts for 0.05% to 0.8% of the mass of the roasting material; Preferably, the carbon dioxide gas is used in a lithium carbonization precipitation process.

9. The lithium extraction method according to any one of claims 1 to 8, characterized in that: The leaching is carried out under normal pressure; Preferably, the leaching temperature is 20-90° C. and the leaching time is 5-60 min.

10. The lithium extraction method according to any one of claims 1 to 9, characterized in that: The leached residue is washed once and twice in sequence to obtain primary washing water and secondary washing water respectively. The primary washing water is reused for the leaching, and the secondary washing water is reused for the primary washing.

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