Clay lithium ore pretreatment and lithium extraction method

Abstract

The invention provides a clay lithium ore pretreatment method which comprises the steps that clay lithium ore powder is soaked in an acid solution containing a surface active agent, and the surface active agent is at least one of a cationic surface active agent, a non-ionic surface active agent and an ampholytic surface active agent; the acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution and a phosphoric acid solution; the invention further provides a method for extracting lithium from the clay lithium ore. The method comprises the pretreatment method. The acid solution containing the surfactant is used for pretreatment, hydroxyl groups attached to the surface of the clay lithium ore powder can be activated, the bleaching effect is achieved, and subsequent dissolution of non-ferrous metal ions such as Fe is reduced; the surface tension of the clay lithium ore powder can be reduced, the contact area of an acid solution is increased, the clay lithium ore powder is more sufficiently infiltrated and permeated by the acid solution, and the leaching rate of lithium is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium extraction from lithium ore, and in particular to a method for pretreating clay lithium ore and extracting lithium. Background Art

[0002] With the rapid development of the new energy lithium battery industry, the demand for lithium resources has grown rapidly, and the production capacity of existing lithium resource deposits has been difficult to meet. The grade of clay lithium ore is low, and lithium may be present in illite and lithium chlorite in an adsorbed or isomorphic manner. Because of its fine embedded particle size and the isomorphic ore structure with illite, lithium chlorite is difficult to concentrate and concentrate, resulting in huge metallurgical roasting and leaching volumes and high energy consumption. At present, there are few literature reports on the development and utilization of clay lithium extraction, and the corresponding comprehensive utilization technology is also in the exploratory stage. It is urgent to develop a technology for extracting lithium from clay lithium ore to supplement the industrial supply of lithium extraction from brine and pegmatite ores, so as to alleviate the tense situation of rapid growth in demand for lithium resources. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a method for extracting lithium from clay lithium ore, aiming to solve at least one of the above problems to at least a certain extent.

[0004] In one aspect, the present invention provides a method for pretreating clay lithium ore. Specifically, the pretreating method comprises: soaking clay lithium ore powder in an acid solution containing a surfactant, wherein:

[0005] The surfactant is at least one of a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant;

[0006] The acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, and a phosphoric acid solution.

[0007] The applicant has found that pre-treating the lithium clay ore powder with an acid solution containing a surfactant can activate the hydroxyl groups attached to the surface of the lithium clay ore powder and has a bleaching effect, thereby reducing the subsequent dissolution of non-ferrous metal ions such as Fe.

[0008] Secondly, surfactants can reduce the surface tension of clay lithium ore powder, increase the contact area of ​​the acid solution, make the clay lithium ore powder more fully infiltrated and penetrated by the acid solution, effectively reduce the phenomenon of partial agglomeration of clay lithium ore powder, disperse it more evenly, and improve the leaching rate of lithium.

[0009] In the present invention, during the pretreatment, common medium-strong acids can be used, such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid (the concentration of the acid solution is 10wt% to 50wt%), etc.; because medium-strong acids can effectively destroy the structural groups on the surface of clay lithium ore to promote the replacement leaching of lithium, while weak acids (such as oxalic acid) cannot destroy the structural groups on the surface of clay lithium ore, and the replacement leaching effect on lithium is not good, and the cost of organic acid treatment is high, which may cause eutrophication of water bodies (pollution problem).

[0010] According to an embodiment of the present invention, the preprocessing method may further include at least one of the following additional technical features:

[0011] According to an embodiment of the present invention, the concentration of the surfactant in the acid solution is 0.1-0.5 wt %.

[0012] Specifically, the concentration of the surfactant in the acid solution is 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt% or any value within the range of 0.1 to 0.5wt%.

[0013] According to an embodiment of the present invention, the concentration of the acid solution is 10-50 wt %; preferably, the concentration of the acid solution is 10-35 wt %.

[0014] Specifically, the concentration of the acid solution is 10wt%, 12wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 50wt% or any value within the range of 10-50wt%.

[0015] According to an embodiment of the present invention, the soaking temperature is 40-60° C. and the soaking time is 4-6 hours.

[0016] Specifically, the immersion temperature is 40°C, 45°C, 50°C, 55°C, 60°C or any value within the range of 40-60°C; the immersion time is 4h, 4.5h, 5h, 5.5h, 6h or any value within the range of 4-6h.

[0017] According to an embodiment of the present invention, the pretreatment further comprises: separating the soaked clay lithium ore powder into solid and liquid, washing with pure water and drying for standby use.

[0018] According to an embodiment of the present invention, the cationic surfactant is at least one of alkyl succinic acid monoester quaternary ammonium salt, cocamidopropyl-PG-dimethyl ammonium chloride phosphate sodium, and benzalkonium bromide;

[0019] The nonionic surfactant is at least one of a fluorocarbon surfactant, isomeric tridecanol polyoxyethylene (9) ether, and an alkylphenol polyoxyethylene ether;

[0020] The amphoteric surfactant is at least one of a combination of octadecylamidopropyl dimethylamine oxide and sodium lauryl sulfate, dodecyl sulfopropyl betaine, imidazoline sulfate, and coconut oil sodium amphoteric acetate.

[0021] According to an embodiment of the present invention, the fluorocarbon surfactant is at least one of YM-313, YM-3010, YM-305A, and YM-309.

[0022] According to an embodiment of the present invention, when a plurality of surfactants are used in combination, they can be combined in any proportion.

[0023] According to an embodiment of the present invention, when the surfactant is a combination of octadecyl amidopropyl dimethyl amine oxide and sodium lauryl sulfate, the mass ratio of octadecyl amidopropyl dimethyl amine oxide to sodium lauryl sulfate is 1:1 to 10:1.

[0024] Specifically, when the surfactant is a combination of octadecyl amidopropyl dimethyl amine oxide and sodium dodecyl sulfate, the mass ratio of octadecyl amidopropyl dimethyl amine oxide to sodium dodecyl sulfate is 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1 or any value within the range of 1:1 to 10:1.

[0025] On the other hand, the present invention provides a method for extracting lithium from clay lithium ore. Specifically, the method comprises the following steps:

[0026] (1) Pretreatment: pretreatment is performed using the above method;

[0027] (2) mixing: mixing the clay lithium ore powder treated in step (1) with a roasting aid;

[0028] (3) calcining: calcining the mixture obtained in step (2);

[0029] (4) leaching: leaching the roasted sample obtained in step (3); separating the solid and the liquid to obtain a leachate;

[0030] (5) Evaporating the salt and cyclically roasting: the leachate obtained in step (4) is directly evaporated to obtain a lithium-containing compound, and after drying, it is returned to step (2), and the above steps (2) to (4) are circulated to obtain a lithium-containing leachate.

[0031] According to an embodiment of the present invention, the number of cycles of the above steps (2) to (4) is 5 times or more.

[0032] According to an embodiment of the present invention, returning the lithium-containing compound to the roasting stage in step (5) does not cause lithium loss, and can be completely retained in the next leaching solution. By directly evaporating to form a lithium-containing compound, the impurity removal operation process can be effectively simplified and the lithium concentration in the leaching solution can be effectively enriched (the lithium concentration is increased from 0.4 g / L to 2.0 g / L).

[0033] According to an embodiment of the present invention, before performing step (1), a grinding step is also included: screening clay lithium ore with a lithium grade of 0.2% to 0.8% to prepare clay lithium ore powder with a mesh size of 100 to 300 meshes.

[0034] According to an embodiment of the present invention, step (2) may further include at least one of the following additional technical features:

[0035] According to an embodiment of the present invention, in step (2), the roasting aid is a sulfate, and further, the sulfate is one or more of potassium sulfate, sodium sulfate, calcium sulfate, and ammonium sulfate.

[0036] According to an embodiment of the present invention, when a plurality of roasting aids are used in combination, they can be combined in any proportion.

[0037] Preferably, the roasting aid is a combination of potassium sulfate and sodium sulfate.

[0038] According to an embodiment of the present invention, when potassium sulfate and sodium sulfate are used in combination, the mass ratio of potassium sulfate to sodium sulfate is 3 to 7:1.

[0039] Specifically, the mass ratio of potassium sulfate to sodium sulfate is 3:1, 4:1, 5:1, 6:1, 7:1 or any value within the range of 3 to 7:1.

[0040] According to an embodiment of the present invention, in step (2), the mass ratio of the roasting aid to the clay lithium ore powder is 0.5 to 1:1.

[0041] Preferably, in step (2), the mass ratio of the roasting aid to the clay lithium ore powder is 0.8 to 1:1.

[0042] Specifically, the mass ratio of the roasting aid to the clay lithium ore powder is 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1 or any value within the range of 0.5 to 1:1.

[0043] In the present invention, when the mass ratio of the roasting aid to the clay lithium ore powder is lower than 0.5:1, the lithium leaching rate will significantly decrease; when it is higher than 1:1, the lithium leaching rate tends to be stable, which is not economical.

[0044] According to an embodiment of the present invention, step (3) may further include at least one of the following additional technical features:

[0045] According to an embodiment of the present invention, the heating rate of the calcination step is 1-10° C. / min, the calcination temperature is 600-900° C., and the calcination time is 0.5-2 h.

[0046] Specifically, the heating rate of the calcination step is 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min or any value in the range of 1 to 10°C / min; the calcination temperature is 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C or any value in the range of 600 to 900°C; the calcination time is 0.5h, 1h, 1.5h, 2h or any value in the range of 0.5 to 2h.

[0047] According to an embodiment of the present invention, step (4) may further include at least one of the following additional technical features:

[0048] According to an embodiment of the present invention, in step (4), leaching is performed with pure water.

[0049] According to an embodiment of the present invention, in step (4), the leaching solid-liquid ratio is 1:2 to 1:5; the leaching temperature is 30 to 90° C.; and the leaching time is 0.5 to 2 h.

[0050] Specifically, in step (4), the leaching solid-liquid ratio is 2:1, 1:1, 1:2, 1:3, 1:4, 1:5 or any value in the range of 1:2 to 1:5; the leaching temperature is 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or any value in the range of 30 to 90°C; and the leaching time is 0.5h, 1h, 1.5h, 2h or any value in the range of 0.5 to 2h.

[0051] In the present invention, if the amount of pure water used during leaching is too little, a saturated sulfate solution is easily formed, resulting in incomplete lithium leaching; if the amount of pure water used during leaching is too high, the amount of concentrated leaching solution required is too large, resulting in high energy consumption.

[0052] According to an embodiment of the present invention, in step (4), the leached residue obtained after solid-liquid separation is washed with pure water, and the washing solid-liquid ratio is 1:1 to 1:3.

[0053] Specifically, in step (4), the washing solid-liquid ratio is 1:1, 1:2, 1:3 or any value within the range of 1:1 to 1:3.

[0054] According to an embodiment of the present invention, in step (4), washing water is supplemented to the amount required for leaching for the next leaching process until the roasting process cycle is completed.

[0055] According to an embodiment of the present invention, step (5) may further include at least one of the following additional technical features:

[0056] According to an embodiment of the present invention, in step (5), the leaching solution obtained in step (4) is directly evaporated to dryness to obtain a lithium-containing compound, and the process is returned to step (2). Subsequently, a roasting aid is added to a required amount, and the above steps (2) to (4) are repeated.

[0057] When the roasting aid is sulfate, the lithium-containing compound is lithium-containing sulfate.

[0058] According to an embodiment of the present invention, the method for extracting lithium from clay lithium ore may further include at least one of the following additional technical features:

[0059] (6) Calcium and magnesium precipitation: the lithium-containing leaching solution obtained in step (5) is concentrated to a lithium-containing solution having a lithium concentration of 8 to 12 g / L, the pH of the solution is adjusted, and a precipitant I is added to carry out a calcium and magnesium precipitation reaction to precipitate a white precipitate, which is filtered while hot;

[0060] (7) Concentrating the filtrate: concentrating the filtrate obtained in step (6) to a lithium-containing concentrated solution with a lithium concentration of 15 to 20 g / L, precipitating crystals, and performing solid-liquid separation to obtain a concentrated filtrate;

[0061] (8) lithium precipitation: adding a precipitant II to the concentrated filtrate obtained in step (7) to carry out lithium precipitation reaction to precipitate a white solid;

[0062] (9) Finished lithium carbonate product: The white solid obtained in step (8) is separated, washed, and dried to obtain a finished lithium carbonate product.

[0063] According to an embodiment of the present invention, step (6) may further include at least one of the following additional technical features:

[0064] Specifically, in step (6), the lithium-containing leaching solution obtained in step (5) is concentrated to a lithium-containing solution having a lithium concentration of 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L or any value in the range of 8 to 12 g / L.

[0065] In the present invention, the lithium concentration of 8 to 12 g / L means that the mass of lithium element in each liter of solution is 8 to 12 g.

[0066] According to an embodiment of the present invention, in step (6), the pH value of the solution is adjusted using solid sodium hydroxide.

[0067] According to an embodiment of the present invention, in step (6), the pH of the solution is adjusted to 10-13.

[0068] Specifically, in step (6), the pH of the solution is adjusted to 10, 11, 12 or 13.

[0069] According to an embodiment of the present invention, in step (6), the precipitant I is a saturated sodium carbonate solution.

[0070] According to an embodiment of the present invention, in step (6), the molar ratio of the amount of the precipitant I added to the calcium element in the lithium-containing solution is 1:1 to 1:1.3.

[0071] Specifically, in step (6), the molar ratio of the amount of the precipitant I added to the calcium element in the lithium-containing solution is 1:1, 1:1.1, 1:1.2, 1:1.3 or any value within the range of 1:1 to 1:1.3.

[0072] According to an embodiment of the present invention, in step (6), the temperature of the calcium and magnesium precipitation reaction is 70-100° C. and the reaction time is 0.5-2 h.

[0073] Specifically, in step (6), the temperature of the calcium-magnesium precipitation reaction is 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C or any value in the range of 70-100°C; the reaction time is 0.5h, 1h, 1.5h, 2h or any value in the range of 0.5-2h.

[0074] According to an embodiment of the present invention, step (7) may further include at least one of the following additional technical features:

[0075] Specifically, in step (7), the filtrate obtained in step (6) is concentrated to a lithium-containing concentrated solution having a lithium concentration of 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L, 20 g / L or any value in the range of 15 to 20 g / L.

[0076] According to an embodiment of the present invention, in step (7), after the filtrate obtained in step (6) is concentrated to a lithium-containing concentrated solution with a lithium concentration of 15 to 20 g / L, crystals are precipitated by freeze crystallization. When the roasting aid used is sulfate, the crystals are sulfate crystals.

[0077] According to an embodiment of the present invention, step (8) may further include at least one of the following additional technical features:

[0078] According to an embodiment of the present invention, in step (8), the precipitant II is a saturated sodium carbonate solution.

[0079] According to an embodiment of the present invention, in step (8), the molar ratio of the amount of the precipitant II added to the lithium element in the concentrated filtrate is 1:1.5 to 1:3.

[0080] Specifically, in step (8), the molar ratio of the amount of the precipitant II added to the lithium element in the concentrated filtrate is 1:1.5, 1:2, 1:2.5, 1:3 or any value within the range of 1:1.5 to 1:3.

[0081] According to an embodiment of the present invention, in step (8), the temperature of the lithium precipitation reaction is 80-100° C., and the reaction time is 0.5-2 h.

[0082] Specifically, in step (8), the temperature of the lithium precipitation reaction is 80°C, 85°C, 90°C, 95°C, 100°C or any value in the range of 80-100°C, and the reaction time is 0.5h, 1h, 1.5h, 2h or any value in the range of 0.5-2h.

[0083] The present invention also provides lithium carbonate prepared by the lithium extraction method of the present invention, wherein the purity of the lithium carbonate is industrial grade.

[0084] Compared with the prior art, the present invention has the following technical effects:

[0085] The present invention uses an acid solution containing a surfactant for pretreatment, which can activate the hydroxyl groups attached to the surface of the clay lithium ore powder, and has a bleaching effect, reducing the subsequent dissolution of non-ferrous metal ions such as Fe; it can reduce the surface tension of the clay lithium ore powder, increase the contact area of ​​the acid solution, and make the clay lithium ore powder more fully infiltrated and penetrated by the acid solution, thereby improving the leaching rate of lithium. In the method for extracting lithium from clay lithium ore provided by the present invention, the leachate is directly evaporated to obtain lithium-containing sulfate, which is subsequently returned for roasting, which has the advantages of simplifying the impurity removal process and reducing material costs, and can achieve the effect of enriching lithium concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Figure 1 A schematic flow chart of a method for extracting lithium from clay lithium ore according to an embodiment of the present invention is shown;

[0087] Figure 2 A schematic diagram showing activation of hydroxyl groups attached to the surface of clay lithium ore according to the pretreatment method of the present invention;

[0088] Figure 3 A schematic diagram showing the reduction of the surface tension of lithium clay ore according to the pretreatment method of the present invention. DETAILED DESCRIPTION

[0089] The embodiments of the present invention are described in detail below. Unless otherwise specified, all scientific and technological terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. All patents and publications to which the present invention relates are incorporated herein by reference in their entirety. The term "comprising" or "including" is an open expression, i.e., including the contents specified in the present invention, but does not exclude the contents of other aspects.

[0090] According to the embodiment provided by the present invention, the present invention particularly provides a clay lithium ore pretreatment method, the pretreatment method comprising: soaking the clay lithium ore powder in an acid solution with a concentration of 10 to 50 wt% (containing 0.1 to 0.5 wt% of a surfactant) at 40 to 60°C for 4 to 6 hours; performing solid-liquid separation, washing with pure water and drying for standby use.

[0091] like Figure 2 As shown, the clay lithium ore powder is pretreated with an acid solution added with a surfactant, which can activate the hydroxyl groups attached to the surface of the clay lithium ore powder and has a bleaching effect, thereby reducing the subsequent dissolution of non-ferrous metal ions such as Fe.

[0092] like Figure 3 As shown, surfactants can reduce the surface tension of clay lithium ore powder, increase the contact area of ​​the acid solution, make the clay lithium ore powder more fully infiltrated and penetrated by the acid solution, effectively reduce the phenomenon of partial agglomeration of clay lithium ore powder, disperse more evenly, and improve the leaching rate of lithium.

[0093] The present invention particularly provides a method for extracting lithium from clay lithium ore, the method comprising the following steps:

[0094] (0) Grinding: Screening clay lithium ore with a lithium grade of 0.2% to 0.8%, and grinding it into clay lithium ore powder with a mesh size of 100 to 300 meshes;

[0095] (1) Pretreatment: pretreatment is performed using the above method;

[0096] (2) Mixing: mixing the lithium clay ore powder treated in step (1) with a roasting aid in a certain proportion; the mass ratio of the roasting aid to the lithium clay ore powder is 0.5 to 1:1; the roasting aid is sulfate;

[0097] (3) Calcination: Calcination the mixture obtained in step (2); controlling the heating rate to be 1 to 10°C / min, the calcination temperature to be 600 to 900°C, and the calcination time to be 0.5 to 2h;

[0098] (4) Leaching: grinding the roasted sample obtained in step (3) into powder and then leaching with pure water; the solid-liquid ratio of the leaching is 1:2 to 1:5; leaching at 30 to 90° C. for 0.5 to 2 hours, cooling, and solid-liquid separation to obtain a leachate and a leaching residue; washing the leaching residue with pure water, and the washing solid-liquid ratio is 1:1 to 1:3; the washing water is supplemented to the amount required for leaching for the next leaching process until the roasting process cycle is completed;

[0099] (5) Evaporating the salt and cyclic roasting: directly evaporating the leachate obtained in step (4) to obtain lithium-containing sulfate, returning to step (2) for mixing after drying, and adding potassium sulfate to the required amount of roasting aid, and repeating the above steps (2) to (4) for 5 times to obtain a lithium-containing leachate;

[0100] (6) Calcium and magnesium precipitation: the lithium-containing leachate obtained in step (5) is concentrated to a lithium-containing solution having a lithium concentration of 8 to 12 g / L, the pH of the solution is adjusted to 10 to 13 with solid sodium hydroxide, and then a saturated sodium carbonate solution is added (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1 to 1:1.3), and the reaction is carried out at 70 to 100° C. for 0.5 to 2 h to precipitate a white precipitate, which is filtered while hot;

[0101] (7) Concentrating the filtrate: concentrating the filtrate obtained in step (6) to a lithium-containing concentrated solution having a lithium concentration of 15 to 20 g / L, precipitating sulfate crystals by freeze crystallization, and performing solid-liquid separation to obtain a concentrated filtrate;

[0102] (8) lithium precipitation: adding a saturated sodium carbonate solution to the concentrated filtrate obtained in step (7) (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:1.5 to 1:3), reacting at 80 to 100° C. for 0.5 to 2 h, and precipitating a white solid;

[0103] (9) Finished lithium carbonate product: The white solid obtained in step (8) is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0104] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. In the examples, if no specific conditions are specified, the conditions described in the specification or the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0105] The clay mine used in the experiment is Guizhou clay lithium mine, the main components of which include boehmite, illite, lithium chlorite, sericite, kaolinite, etc.

[0106] Chemical composition <![CDATA[Li2O]]> <![CDATA[Al2O3]]> <![CDATA[SiO2]]> <![CDATA[Fe2O3]]> <![CDATA[K2O]]> <![CDATA[Na2O]]> MgO CaO Wt / % 0.38 48.10 37.08 2.09 4.82 2.32 0.56 0.11

[0107] Example 1

[0108] (0) Grinding: Grind 200 g of clay lithium ore into 200 mesh clay lithium ore powder;

[0109] (1) Pretreatment: Soak the clay lithium ore powder in 100 mL of 10 wt % sulfuric acid solution (containing 0.1 wt % alkyl succinic acid monoester quaternary ammonium salt), stir at 40° C. for 4 h, separate the solid and liquid, wash the acid-treated clay lithium ore powder with pure water, and dry it;

[0110] (2) Mixing: Take 90 g of potassium sulfate and 30 g of sodium sulfate and grind and mix them with the pretreated clay lithium ore powder;

[0111] (3) Calcination: The mixture obtained in step (2) was compacted and calcined at 750° C. for 1 h (the heating rate during the calcination process was controlled at 5° C. / min);

[0112] (4) Leaching: Grind the roasted sample obtained in step (3) into powder and then leach it with 960 g of pure water at a constant temperature of 80° C. for 2 h. After cooling, separate the solid and liquid to obtain a leachate and a leach residue. Wash the leach residue with 640 g of pure water, and add 960 g of washing water to the next leaching process until the roasting process cycle is completed.

[0113] (5) Evaporating and calcining the salt: directly evaporating the leaching solution obtained in step (4) to obtain lithium-containing sulfate, returning to the mixing step, adding potassium sulfate to 120 g sulfate, and repeating the above steps (2) to (4) for 5 times to obtain a lithium-containing leaching solution;

[0114] (6) Calcium and magnesium precipitation: the lithium-containing leachate obtained in step (5) is concentrated to a lithium-containing solution with a lithium concentration of 10 g / L, the pH of the system is adjusted to 12 with solid sodium hydroxide, and a saturated sodium carbonate solution is added dropwise (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1.2), reacted at 80° C. for 1 h, and filtered while hot;

[0115] (7) Concentrating the filtrate: concentrating the filtrate obtained in step (6) again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooling and crystallizing, and performing solid-liquid separation to obtain a concentrated filtrate;

[0116] (8) Lithium precipitation: add saturated sodium carbonate solution (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:2) to the concentrated filtrate obtained in step (7), react at 90° C. for 1 h, and precipitate a white solid;

[0117] (9) Finished lithium carbonate product: The white solid obtained in step (8) is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0118] Example 2

[0119] The difference from Example 1 is:

[0120] Step (1) Pretreatment: Soak the clay lithium ore powder in 100 mL of 10 wt% sulfuric acid solution (containing 0.1 wt% YM-313), stir at 40°C for 4 h, separate the solid and liquid, wash the acid-treated clay lithium ore powder with pure water, and dry it.

[0121] Example 3

[0122] The difference from Example 1 is:

[0123] Step (1) pretreatment: soak the clay lithium ore powder in 100 mL of a 10 wt% sulfuric acid solution (containing a combination of 0.15 wt% octadecyl amidopropyl dimethylamine oxide and sodium dodecyl sulfate, wherein the mass ratio of octadecyl amidopropyl dimethylamine oxide to sodium dodecyl sulfate is 5:1), stir at 40° C. for 4 h, separate the solid from the liquid, and wash the acid-treated clay lithium ore powder with pure water and dry it.

[0124] Example 4

[0125] (0) Grinding: Grind 200 g of clay lithium ore into 200 mesh clay lithium ore powder;

[0126] (1) Pretreatment: Soak the clay lithium ore powder in 100 mL of a 20 wt % sulfuric acid solution (containing 0.2 wt % alkyl succinic acid monoester quaternary ammonium salt), stir at 40° C. for 6 h, separate the solid from the liquid, and wash the acid-treated clay lithium ore powder with pure water and dry it;

[0127] (2) Mixing: Take 130 g of potassium sulfate and 30 g of sodium sulfate and grind and mix them with the pretreated clay lithium ore powder;

[0128] (3) Calcination: The mixed material obtained in step (2) is compacted and calcined at 800° C. for 1 h (the heating rate during the calcination process is controlled at 5° C. / min);

[0129] (4) Leaching: Grind the roasted sample obtained in step (3) into powder and then leach it with 1080 g of pure water at a constant temperature of 80° C. for 2 h. After cooling, separate the solid and liquid to obtain a leachate and a leach residue. Wash the leach residue with 720 g of pure water, and add 1080 g of washing water to the next leaching process until the roasting process cycle is completed.

[0130] (5) Evaporating and calcining the salt: directly evaporating the leaching solution obtained in step (4) to obtain lithium-containing sulfate, returning to the mixing step, adding potassium sulfate to 160 g sulfate, and repeating the above steps (2) to (4) for 5 times to obtain a lithium-containing leaching solution;

[0131] (6) Calcium and magnesium precipitation: the lithium-containing leachate obtained in step (5) is concentrated to a lithium-containing solution with a lithium concentration of 10 g / L, the pH of the system is adjusted to 12 with solid sodium hydroxide, and a saturated sodium carbonate solution is added dropwise (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1.2), reacted at 80° C. for 1 h, and filtered while hot;

[0132] (7) Concentrating the filtrate: concentrating the filtrate obtained in step (6) again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooling and crystallizing, and performing solid-liquid separation to obtain a concentrated filtrate;

[0133] (8) Lithium precipitation: add saturated sodium carbonate solution (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:2) to the concentrated filtrate obtained in step (7), react at 90° C. for 1 h, and precipitate a white solid;

[0134] (9) Finished lithium carbonate product: The white solid obtained in step (8) is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0135] Example 5

[0136] The difference from Example 4 is:

[0137] Step (1) Pretreatment: Soak the clay lithium ore powder in 100 mL of 20 wt% sulfuric acid solution (containing 0.2 wt% YM-313), stir at 40°C for 5 h, separate the solid and liquid, wash the acid-treated clay lithium ore powder with pure water, and dry it.

[0138] Example 6

[0139] The difference from Example 4 is:

[0140] Step (1) pretreatment: soak the clay lithium ore powder in 100 mL of 20 wt% sulfuric acid solution (containing a combination of 0.25 wt% octadecyl amidopropyl dimethylamine oxide and sodium dodecyl sulfate, wherein the mass ratio of octadecyl amidopropyl dimethylamine oxide to sodium dodecyl sulfate is 7:1), stir at 40° C. for 6 h, separate the solid and liquid, wash the acid-treated clay lithium ore powder with pure water, and dry it.

[0141] Example 7

[0142] (0) Grinding: Grind 200 g of clay lithium ore into 200 mesh clay lithium ore powder;

[0143] (1) Pretreatment: Soak the clay lithium ore powder in 100 mL of a 30 wt % sulfuric acid solution (containing 0.3 wt % alkyl succinic acid monoester quaternary ammonium salt), stir at 40° C. for 6 h, separate the solid from the liquid, and wash the acid-treated clay lithium ore powder with pure water and dry it;

[0144] (2) Mixing: Take 170 g of potassium sulfate and 30 g of sodium sulfate and grind and mix them with the pretreated clay lithium ore powder;

[0145] (3) Calcination: The mixture obtained in step (2) was compacted and calcined at 850° C. for 1 h (the heating rate during the calcination process was controlled at 5° C. / min);

[0146] (4) Leaching: Grind the roasted sample obtained in step (3) into powder and then leach it with 1200 g of pure water at a constant temperature of 80° C. for 2 h. After cooling, separate the solid and liquid to obtain a leachate and a leach residue. Wash the leach residue with 800 g of pure water, and add 1200 g of washing water to the next leaching process until the roasting process cycle is completed.

[0147] (5) Evaporating and calcining the salt: directly evaporating the leaching solution obtained in step (4) to obtain lithium-containing sulfate, returning to the mixing step, adding potassium sulfate to 200 g sulfate, and repeating the above steps (2) to (4) for 5 times to obtain a lithium-containing leaching solution;

[0148] (6) Calcium and magnesium precipitation: the lithium-containing leachate obtained in step (5) is concentrated to a lithium-containing solution with a lithium concentration of 10 g / L, the pH of the system is adjusted to 12 with solid sodium hydroxide, and a saturated sodium carbonate solution is added dropwise (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1.2), reacted at 80° C. for 1 h, and filtered while hot;

[0149] (7) Concentrating the filtrate: concentrating the filtrate obtained in step (6) again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooling and crystallizing, and performing solid-liquid separation to obtain a concentrated filtrate;

[0150] (8) Lithium precipitation: add saturated sodium carbonate solution (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:2) to the concentrated filtrate obtained in step (7), react at 90° C. for 1 h, and precipitate a white solid;

[0151] (9) Finished lithium carbonate product: The white solid obtained in step (8) is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0152] Example 8

[0153] The difference from Example 7 is:

[0154] Step (1) Pretreatment: Soak the clay lithium ore powder in 100 mL of 30 wt% sulfuric acid solution (containing 0.3 wt% YM-313), stir at 40°C for 5 h, separate the solid and liquid, wash the acid-treated clay lithium ore powder with pure water, and dry it.

[0155] Example 9

[0156] The difference from Example 7 is:

[0157] Step (1) pretreatment: soak the clay lithium ore powder in 100 mL of a 30 wt % sulfuric acid solution (containing a combination of 0.3 wt % octadecyl amidopropyl dimethylamine oxide and sodium dodecyl sulfate, wherein the mass ratio of octadecyl amidopropyl dimethylamine oxide to sodium dodecyl sulfate is 10:1), stir at 40° C. for 6 h, separate the solid from the liquid, and wash the acid-treated clay lithium ore powder with pure water and dry it.

[0158] Comparative Example 1

[0159] 200 g of clay lithium ore powder (200 mesh), 90 g of potassium sulfate and 30 g of sodium sulfate were fully ground and mixed, compacted and then roasted at 750° C. for 1 h (the heating rate during the roasting process was controlled at 5° C. / min).

[0160] After the calcined sample was ground into powder, 960 g of pure water was added and leached at 80 °C for 2 h. After cooling, solid-liquid separation was performed to obtain leaching liquid and leaching residue. The leaching residue was washed with 640 g of pure water, and the washing water was supplemented to 960 g for the next leaching process.

[0161] The leachate is concentrated to a lithium-containing solution with a lithium concentration of 10 g / L, the pH of the system is adjusted to 12 with solid sodium hydroxide, and a saturated sodium carbonate solution is added dropwise (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1.2), and the mixture is reacted at 80°C for 1 hour, and then filtered while hot. The filtrate is concentrated again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled and crystallized, and solid-liquid separation is performed to obtain a concentrated filtrate; a saturated sodium carbonate solution is added dropwise to the concentrated filtrate (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:2), and the mixture is reacted at 90°C for 1 hour to precipitate a white solid, which is separated, washed with hot water, and dried to obtain lithium carbonate powder.

[0162] Each set of experiments was repeated 5 times, and finally the solutions were combined and concentrated to increase the lithium concentration in the solution, and the mother liquor was extracted for lithium using the membrane-adsorption method.

[0163] Comparative Example 2

[0164] Soak 200g of lithium clay ore powder (200 mesh) in 100mL of 10wt% sulfuric acid solution and stir at 40℃ for 4h. After solid-liquid separation, wash the acid-treated lithium clay ore powder with pure water and dry it. Take 90g of potassium sulfate and 30g of sodium sulfate and grind and mix them with the acid-treated lithium clay ore powder, compact them and roast them at 750℃ for 1h (the heating rate of the roasting process is controlled to be 5℃ / min).

[0165] After the calcined sample is ground into powder, 960g of pure water is added and leached at a constant temperature of 80°C for 2h. After cooling, solid-liquid separation is performed to obtain a leachate and leached residue. The leached residue is washed with 640g of pure water, and the washing water is added to 960g for the next leaching process until the calcination process cycle is completed. The leachate is directly evaporated to obtain lithium-containing sulfate, and potassium sulfate is subsequently added to 120g sulfate and returned to the mixing step. The above steps are repeated 5 times to obtain a lithium-containing leachate.

[0166] The lithium-containing leachate is concentrated to a lithium-containing filtrate with a lithium concentration of 10 g / L, the pH of the system is adjusted to 12 with solid sodium hydroxide, and a saturated sodium carbonate solution is added dropwise (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1.2), and the reaction is carried out at 80°C for 1 hour, and then filtered while hot. The filtrate is concentrated again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled and crystallized, and the solid-liquid separation is performed to obtain a concentrated filtrate; a saturated sodium carbonate solution is added dropwise to the concentrated filtrate (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:2), and the reaction is carried out at 90°C for 1 hour to precipitate a white solid, which is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0167] Comparative Example 3

[0168] The difference from Example 1 is:

[0169] Step (1) pretreatment: soak the clay lithium ore powder in 200 mL of 45 wt% oxalic acid solution (containing 0.1 wt% alkyl succinic acid monoester quaternary ammonium salt), stir at 40° C. for 4 h, separate the solid and liquid, wash the acid-treated clay lithium ore powder with pure water, and dry it.

[0170] Comparative Example 4

[0171] 200 g of clay lithium ore powder (200 mesh), 90 g of potassium sulfate and 30 g of sodium sulfate were fully ground and mixed, compacted and calcined at 750° C. for 1 h (the heating rate during the calcination process was controlled at 5° C. / min).

[0172] After the calcined sample is ground into powder, 960g of 10wt% sulfuric acid solution (added with 0.1wt% alkyl succinic acid monoester quaternary ammonium salt) is added and leached at 80°C for 2h. After cooling, solid-liquid separation is performed to obtain a leachate and a leach residue. The leach residue is washed with 640g of pure water, and the washing water is supplemented to 960g for the next leaching process. The leachate is directly evaporated to obtain lithium-containing sulfate, and the mixing step is returned to supplement potassium sulfate to 120g sulfate. The above steps are repeated 5 times to obtain a lithium-containing leachate.

[0173] The lithium-containing leachate is concentrated to a lithium-containing filtrate with a lithium concentration of 10 g / L, heated to 80°C, and the pH of the system is adjusted to 12 with solid sodium hydroxide, and a saturated sodium carbonate solution is added dropwise (the molar ratio of the amount of sodium carbonate added to the calcium element in the lithium-containing solution is 1:1.2), reacted at 80°C for 1 hour, and filtered while hot. The filtrate is concentrated again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled and crystallized, and solid-liquid separation is performed to obtain a concentrated filtrate; a saturated sodium carbonate solution is added dropwise to the concentrated filtrate (the molar ratio of the amount of sodium carbonate added to the lithium element in the concentrated filtrate is 1:2), reacted at 90°C for 1 hour, a white solid is precipitated, the white solid is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0174] Performance Test:

[0175] Test standard: The leachate obtained after each leaching of Examples 1-9 and Comparative Examples 1-4 was tested by inductively coupled plasma optical emission spectrometry (ICP-OES spectrometer), and the element content of lithium-containing ore was determined according to national standards such as GB / T 30836-2014 and GB / T 24533-2009. Wherein, lithium leaching rate = 1-(mass of lithium-containing leaching slag × percentage of lithium in leaching slag) / (mass of clay lithium ore × percentage of lithium in clay lithium ore) × 100%, and the lithium content in clay lithium ore was 0.178%.

[0176] Table 1:

[0177]

[0178]

[0179] From the data results in Table 1, it can be seen that Example 1-9 pre-treats the clay lithium ore powder with an acid solution containing a surfactant, and compared with the leaching rate results of Comparative Example 1-4 under the same roasting conditions, the lithium leaching rate is significantly improved. Because the surfactant has the effect of solubilizing and reducing the surface tension of the solution, it can make strong acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid contact with the clay lithium ore powder more fully, play a role in activating the surface hydroxyl groups of the clay lithium ore powder, and promote the subsequent potassium salt and sodium salt lithium replacement in the roasting step. The lithium leaching rate of Example 1-9 is 86.09% to 93.70%, and the lithium leaching rate of Comparative Example 1-3 is 71.90% to 73.21%.

[0180] Comparative Example 1 did not use acid to pretreat the clay lithium ore powder, and directly mixed the raw ore with the roasting aid and roasted it. The lithium leaching rate was 72.46%, which was significantly lower than the lithium leaching rate of the embodiment. Comparative Example 2 only used sulfuric acid to pretreat the clay lithium ore powder, and no surfactant was added to assist in soaking. The lithium leaching rate was not greatly improved (73.21%), indicating that the wetting effect of pretreating the clay lithium ore powder with sulfuric acid alone was poor, and the structural lithium could not be effectively replaced. Comparative Example 3 used oxalic acid (weak acid) added with 0.1wt% alkyl succinic acid monoester quaternary ammonium salt to soak the raw ore for pretreatment, and the lithium leaching rate was 71.90%, indicating that the weak acid had no effect on the soaking of the raw ore, and the weak acid could not effectively destroy the structural lithium to promote the replacement leaching of lithium.

[0181] Comparative Example 4 uses a 10wt% sulfuric acid solution containing a surfactant to leach the sample of the clay lithium ore after roasting. Compared with Comparative Example 1, the lithium leaching rate is significantly improved (82.75% / 72.46%). Considering factors such as environmental protection, acid leaching may cause aluminum and iron ions in the clay lithium ore to leach into the lithium-containing leachate, which will increase the subsequent impurity removal process and increase the cost of extracting lithium carbonate. After the first roasting of Example 1 and Comparative Examples 3-4, the contents of Al, Fe, Ca, and Mg in the leaching solution obtained by leaching were subjected to ICP-OES element testing, and the results are shown in Table 2.

[0182] Table 2:

[0183]

[0184] It can be seen from Table 2 that: combined with the lithium leaching rate results of Example 1 and Comparative Examples 3-4, after the clay lithium ore is pretreated with an acid solution containing a surfactant and then mixed with a roasting aid for roasting, the lithium leaching rate is relatively high, and the content of impurity elements such as Al, Fe, Ca, and Mg in the leachate is low; and in the method of leaching with an acid solution containing a surfactant, although the lithium leaching rate is improved to a certain extent, the content of impurities such as Al, Fe, Ca, and Mg in the leachate is also high, and the acidic solution is easy to pollute the environment.

[0185] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0186] Although the embodiments and examples of the present invention have been shown and described above, it is to be understood that the above embodiments and examples are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments and examples within the scope of the present invention.

Claims

1. A method for pretreating clay lithium ore, characterized in that: The pretreatment method comprises: soaking the clay lithium ore powder in an acid solution containing a surfactant, wherein: The surfactant is at least one of a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant; The acid solution is at least one of a sulfuric acid solution, a hydrochloric acid solution, a nitric acid solution, and a phosphoric acid solution.

2. The method for pretreating clay lithium ore according to claim 1, characterized in that: The concentration of the surfactant in the acid solution is 0.1 to 0.5 wt %; The concentration of the acid solution is 10 to 50 wt %; preferably, the concentration of the acid solution is 10 to 35 wt %; The soaking temperature is 40 to 60° C. and the soaking time is 4 to 6 hours. The pretreatment further comprises: separating the soaked clay lithium ore powder into solid and liquid, washing with pure water and drying for standby use.

3. The clay lithium ore pretreatment method according to any one of claims 1 or 2, characterized in that: The cationic surfactant is at least one of alkyl succinate monoester quaternary ammonium salt, cocamidopropyl-PG-dimethyl ammonium chloride phosphate sodium, and benzalkonium bromide; The nonionic surfactant is at least one of YM-313, isomeric tridecanol polyoxyethylene (9) ether, and alkylphenol polyoxyethylene ether; The amphoteric surfactant is at least one of a combination of octadecylamidopropyl dimethylamine oxide and sodium lauryl sulfate, dodecyl sulfopropyl betaine, imidazoline sulfate, and coconut oil sodium amphoteric acetate.

4. A method for extracting lithium from clay lithium ore, characterized in that: The method comprises the following steps: (1) Pretreatment: pretreatment is performed by the method according to any one of claims 1 to 3; (2) mixing: mixing the clay lithium ore powder treated in step (1) with a roasting aid; (3) calcining: calcining the mixture obtained in step (2); (4) leaching: leaching the roasted sample obtained in step (3); separating the solid and the liquid to obtain a leachate; (5) Evaporating the salt and cyclically roasting: the leachate obtained in step (4) is directly evaporated to obtain a lithium-containing compound, and after drying, it is returned to step (2), and the above steps (2) to (4) are circulated to obtain a lithium-containing leachate.

5. The method for extracting lithium from clay lithium ore according to claim 4, characterized in that: Before carrying out the step (1), the method further comprises a grinding step: screening clay lithium ore with a lithium grade of 0.2% to 0.8% to prepare clay lithium ore powder with a mesh size of 100 to 300 meshes.

6. The method for extracting lithium from clay lithium ore according to claim 4, characterized in that: In step (2), the roasting aid is a sulfate; preferably, the sulfate is one or more of potassium sulfate, sodium sulfate, calcium sulfate, and ammonium sulfate. The mass ratio of the roasting aid to the clay lithium ore powder is 0.5 to 1:

1.

7. The method for extracting lithium from clay lithium ore according to claim 4, characterized in that: In step (3), the heating rate of the calcination step is 1 to 10°C / min, the calcination temperature is 600 to 900°C, and the calcination time is 0.5 to 2h.

8. The method for extracting lithium from clay lithium ore according to claim 4, characterized in that: In step (4), pure water is used for leaching, and the leaching solid-liquid ratio is 1:2 to 1:5; the leaching temperature is 30 to 90° C.; and the leaching time is 0.5 to 2 hours; Preferably, the number of cycles of steps (2) to (4) is 5 or more.

9. The method for extracting lithium from clay lithium ore according to claim 4, characterized in that: The following post-processing steps are also included: (6) Calcium and magnesium precipitation: the lithium-containing leaching solution obtained in step (5) is concentrated to a lithium-containing solution having a lithium concentration of 8 to 12 g / L, the pH of the solution is adjusted, and a precipitant I is added to carry out a calcium and magnesium precipitation reaction to precipitate a white precipitate, which is filtered while hot; (7) Concentrating the filtrate: concentrating the filtrate obtained in step (6) to a lithium-containing concentrated solution having a lithium concentration of 15 to 20 g / L, precipitating crystals, and performing solid-liquid separation to obtain a concentrated filtrate; (8) lithium precipitation: adding a precipitant II to the concentrated filtrate obtained in step (7) to carry out lithium precipitation reaction to precipitate a white solid; (9) Finished lithium carbonate product: The white solid obtained in step (8) is separated, washed, and dried to obtain a finished lithium carbonate product.

10. The method for extracting lithium from clay lithium ore according to claim 9, characterized in that: In step (6), the pH of the solution is adjusted to 10-13; the precipitant I is a saturated sodium carbonate solution, and the molar ratio of the amount of the precipitant I added to the calcium element in the lithium-containing solution is 1:1-1:1.3; the temperature of the calcium-magnesium precipitation reaction is 70-100° C.; and the reaction time is 0.5-2 h; In step (8), the precipitant II is a saturated sodium carbonate solution, the molar ratio of the amount of the precipitant II added to the lithium element in the concentrated filtrate is 1:1.5 to 1:3, the temperature of the lithium precipitation reaction is 80 to 100°C, and the reaction time is 0.5 to 2h.

Images