Method for pretreating and extracting lithium from a lithium clay ore

Abstract

The present application provides a kind of clay lithium ore pretreatment method, the pretreatment method includes: clay lithium ore powder is soaked in acid solution containing surfactant, wherein the surfactant is at least one of cationic surfactant, nonionic surfactant, amphoteric surfactant;The acid solution is at least one of sulfuric acid solution, hydrochloric acid solution, nitric acid solution, phosphoric acid solution;The present application also provides a kind of clay lithium ore lithium extraction method, including the pretreatment method described above.The present application uses acid solution containing surfactant for pretreatment, can activate the hydroxyl group attached to the surface of clay lithium ore powder, and has bleaching effect, reduces the subsequent Fe etc. Color metal ion dissolution;Can reduce the surface tension of clay lithium ore powder, increase the contact area of acid solution, so that clay lithium ore powder is more fully infiltrated and penetrated by acid solution, improve the leaching rate of lithium.

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, demand for lithium resources is growing rapidly, and the production capacity of existing lithium deposits is already struggling to meet demand. Clay lithium ores are low-grade, and lithium may be present in illite and chlorite in an adsorbed or isomorphic manner. Chlorite, due to its fine-grained distribution and its isomorphic ore structure with illite, is difficult to concentrate and concentrate, resulting in large metallurgical roasting and leaching volumes and high energy consumption. Currently, there are few literature reports on the development and utilization of clay-based lithium extraction, and corresponding comprehensive utilization technologies are still in the exploratory stage. There is an urgent need to develop a technology for extracting lithium from clay lithium ores to supplement the industrial supply of lithium extraction from brine and pegmatite ores, thereby alleviating the tension caused by the rapid growth of lithium resource demand. Summary of the Invention

[0003] In response to 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 pretreatment 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 discovered that pre-treating the clay lithium ore powder with an acid solution containing a surfactant 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.

[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 lithium leaching rate.

[0009] In the present invention, common medium-strong acids can be used during pretreatment, 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 displacement leaching of lithium, while weak acids (such as oxalic acid) cannot destroy the structural groups on the surface of clay lithium ore, and the displacement leaching effect on lithium is poor. In addition, the cost of organic acid treatment is high and 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 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt% or any value within the range of 0.1 to 0.5 wt%.

[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 soaking temperature is 40°C, 45°C, 50°C, 55°C, 60°C or any value within the range of 40-60°C; the soaking 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: performing solid-liquid separation on the soaked clay lithium ore powder, 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 succinate monoester quaternary ammonium salt, cocamidopropyl-PG-dimethylammonium chloride phosphate sodium, and benzalkonium bromide;

[0019] The nonionic surfactant is at least one of a fluorocarbon surfactant, an 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 amphoacetate.

[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 multiple 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 dimethylamine oxide and sodium lauryl sulfate, the mass ratio of octadecyl amidopropyl dimethylamine 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 lauryl sulfate, the mass ratio of octadecyl amidopropyl dimethyl amine oxide to sodium lauryl 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] In another aspect, 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); solid-liquid separation 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 returns 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 steps (2) to (4) is 5 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 the lithium can be completely retained in the next leachate. By directly evaporating the lithium-containing compound, the impurity removal process can be effectively simplified and the lithium concentration in the leachate 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 further 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 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 drop significantly; 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 leachate 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), the washing water is replenished to the amount required for leaching and used in 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 leachate 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 the 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 leachate obtained in step (5) is concentrated to a lithium-containing solution with 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 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 leachate 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 within the range of 8 to 12 g / L.

[0065] In the present invention, a 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 added amount of the precipitant I 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-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 concentrate 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 within the range of 15 to 20 g / L.

[0076] According to an embodiment of the present invention, in step (7), the filtrate obtained in step (6) is concentrated to a lithium-containing concentrated solution having a lithium concentration of 15 to 20 g / L, and then 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 utilizes 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 nonferrous metal ions such as Fe. It can also reduce the surface tension of the clay lithium ore powder, increase the contact area of ​​the acid solution, and allow the clay lithium ore powder to be more fully infiltrated and penetrated by the acid solution, thereby improving the lithium leaching rate. In the method for extracting lithium from clay lithium ore provided by the present invention, the leachate is directly evaporated to dryness to obtain a lithium-containing sulfate, which is then returned to the calcination process. This has the advantages of simplifying the impurity removal process, reducing material costs, and achieving the effect of enriching the 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 one 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 is shown;

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

[0089] The following describes embodiments of the present invention in detail. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs. All patents and publications related to the present invention are incorporated herein by reference in their entirety. The terms "comprising" or "including" are open-ended expressions, i.e., including the contents specified in the present invention, but not excluding 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, which comprises: 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 then drying for standby use.

[0091] like Figure 2 As shown, the clay lithium ore powder is pretreated with an acid solution containing 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 in the figure, surfactants can reduce the surface tension of clay lithium ore powder, increase the contact area of ​​acid solution, make the clay lithium ore powder more fully infiltrated and penetrated by 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 clay lithium ore powder treated in step (1) with a roasting aid in proportion; the mass ratio of the roasting aid to the clay lithium ore powder is 0.5 to 1:1; the roasting aid is sulfate;

[0097] (3) Calcination: Calcination of 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: Grind the roasted sample obtained in step (3) into powder and then leach it with pure water; the leaching solid-liquid ratio is 1:2 to 1:5; leach at 30 to 90°C for 0.5 to 2 hours, cool, separate the solid and liquid, and obtain leachate and leach residue; wash the leach residue with pure water, and the washing solid-liquid ratio is 1:1 to 1:3; replenish the washing water to the amount required for leaching for the next leaching process until the roasting process cycle is completed;

[0099] (5) Evaporating the salt and cyclically roasting: directly evaporating the leachate obtained in step (4) to obtain lithium-containing sulfate, returning it 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 with 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 mixture is reacted 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 with 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: add 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), react at 80 to 100° C. for 0.5 to 2 h, and precipitate 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 with reference to the examples, but it will be understood 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 sheets or conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer of the reagents or instruments is not specified, 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 succinate monoester quaternary ammonium salt), stir at 40°C for 4 h, separate the solid and liquid, and wash the acid-treated clay lithium ore powder with pure water and dry it;

[0110] (2) Mixing: Take 90g of potassium sulfate and 30g of sodium sulfate and grind and mix them thoroughly 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: The roasted sample obtained in step (3) was ground into powder and then leached with 960 g of pure water at a constant temperature of 80° C. for 2 h. After cooling, solid-liquid separation was performed to obtain a leachate and a leach residue; the leach residue was washed with 640 g of pure water, and the washing water was replenished to 960 g for the next leaching process until the roasting process cycle was completed;

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

[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), and the mixture is reacted at 80° C. for 1 h and filtered while hot;

[0115] (7) Concentrating the filtrate: The filtrate obtained in step (6) is further concentrated to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled for crystallization, and solid-liquid separation to obtain a concentrated filtrate;

[0116] (8) Lithium precipitation: saturated sodium carbonate solution was added dropwise 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 was 1:2), and the mixture was reacted at 90° C. for 1 h to 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 a 10 wt% sulfuric acid solution (containing 0.1 wt% YM-313), stir at 40° C. for 4 h, separate the solid and liquid, and 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: The clay lithium ore powder was soaked in 100 mL of a 10 wt% sulfuric acid solution (containing a combination of 0.15 wt% octadecylamidopropyl dimethylamine oxide and sodium lauryl sulfate, wherein the mass ratio of octadecylamidopropyl dimethylamine oxide to sodium lauryl sulfate was 5:1), stirred at 40° C. for 4 h, and then solid-liquid separation was performed. The acid-treated clay lithium ore powder was washed with pure water and dried.

[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% of alkyl succinate monoester quaternary ammonium salt) and stir at 40°C for 6 h. Then, separate the solid and liquid. Wash the acid-treated clay lithium ore powder with pure water and dry it.

[0127] (2) Mixing: 130 g of potassium sulfate and 30 g of sodium sulfate were taken and thoroughly ground and mixed with the pretreated clay lithium ore powder;

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

[0129] (4) Leaching: The roasted sample obtained in step (3) was ground into powder and then leached with 1080 g of pure water at a constant temperature of 80° C. for 2 h. After cooling, solid-liquid separation was performed to obtain leachate and leach residue; the leach residue was washed with 720 g of pure water, and the washing water was replenished to 1080 g for the next leaching process until the roasting process cycle was completed;

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

[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), and the mixture is reacted at 80° C. for 1 h and filtered while hot;

[0132] (7) Concentrating the filtrate: The filtrate obtained in step (6) is further concentrated to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled for crystallization, and solid-liquid separation to obtain a concentrated filtrate;

[0133] (8) Lithium precipitation: saturated sodium carbonate solution was added dropwise 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 was 1:2), and the mixture was reacted at 90° C. for 1 h to 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: The clay lithium ore powder was soaked in 100 mL of a 20 wt% sulfuric acid solution (containing a combination of 0.25 wt% octadecylamidopropyl dimethylamine oxide and sodium lauryl sulfate, wherein the mass ratio of octadecylamidopropyl dimethylamine oxide to sodium lauryl sulfate was 7:1), stirred at 40° C. for 6 h, and then solid-liquid separation was performed. The acid-treated clay lithium ore powder was washed with pure water and dried.

[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% of alkyl succinate monoester quaternary ammonium salt) and stir at 40°C for 6 h. Then, separate the solid and liquid. Wash the acid-treated clay lithium ore powder with pure water and dry it.

[0144] (2) Mixing: 170 g of potassium sulfate and 30 g of sodium sulfate were taken and thoroughly ground and mixed 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: The roasted sample obtained in step (3) was ground into powder and then leached with 1200 g of pure water at a constant temperature of 80° C. for 2 h. After cooling, solid-liquid separation was performed to obtain leachate and leach residue; the leach residue was washed with 800 g of pure water, and the washing water was replenished to 1200 g for the next leaching process until the roasting process cycle was completed;

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

[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), and the mixture is reacted at 80° C. for 1 h and filtered while hot;

[0149] (7) Concentrating the filtrate: The filtrate obtained in step (6) is further concentrated to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled for crystallization, and solid-liquid separation to obtain a concentrated filtrate;

[0150] (8) Lithium precipitation: saturated sodium carbonate solution was added dropwise 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 was 1:2), and the mixture was reacted at 90° C. for 1 h to 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: The clay lithium ore powder was soaked in 100 mL of a 30 wt% sulfuric acid solution (containing a combination of 0.3 wt% octadecylamidopropyl dimethylamine oxide and sodium lauryl sulfate, wherein the mass ratio of octadecylamidopropyl dimethylamine oxide to sodium lauryl sulfate was 10:1), stirred at 40° C. for 6 h, and then solid-liquid separation was performed. The acid-treated clay lithium ore powder was washed with pure water and dried.

[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 calcined at 750° C. for 1 h (the heating rate during the calcination process was controlled at 5° C. / min).

[0160] The calcined sample was ground into powder, and then leached at 80°C for 2 h in 960 g of pure water. After cooling, solid-liquid separation was performed to obtain a leachate and a leaching residue. The leaching residue was washed with 640 g of pure water, and the washing water was replenished 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), 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 for crystallization, 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, and a white solid is precipitated. The white solid 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 used to extract lithium using the membrane-adsorption method.

[0163] Comparative Example 2

[0164] 200g of lithium clay ore powder (200 mesh) was immersed in 100mL of 10wt% sulfuric acid solution and stirred at 40°C for 4h. After solid-liquid separation, the acid-treated lithium clay ore powder was washed with pure water and dried. 90g of potassium sulfate and 30g of sodium sulfate were respectively ground and mixed with the acid-treated lithium clay ore powder. After compaction, the mixture was calcined at 750°C for 1h (the heating rate during the calcination process was controlled at 5°C / 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 a leach residue. The leach residue is washed with 640g of pure water, and the washing water is replenished to 960g for the next leaching process until the calcination process cycle is completed. The leachate is directly evaporated to dryness to obtain lithium-containing sulfate. Potassium sulfate is subsequently added to 120g of 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 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 for crystallization, 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 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 succinate 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 then 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 succinate monoester quaternary ammonium salt) 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 a leach residue. The leach residue is washed with 640g of pure water, and the washing water is replenished to 960g for the next leaching process. The leachate is directly evaporated to dryness to obtain lithium-containing sulfate. Return to the mixing step and add potassium sulfate to 120g of 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. After heating to 80°C, 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). After reacting at 80°C for 1 hour, the mixture is filtered while hot. The filtrate is concentrated again to a lithium-containing concentrated solution with a lithium concentration of 20 g / L, cooled for crystallization, 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). The mixture is reacted at 90°C for 1 hour to precipitate a white solid. The white solid is separated, washed with hot water, and dried to obtain a finished lithium carbonate product.

[0174] Performance testing:

[0175] Testing Standards: The leachates obtained after each leaching in Examples 1-9 and Comparative Examples 1-4 were tested using inductively coupled plasma optical emission spectrometry (ICP-OES spectrometry) to determine the elemental content of the lithium-containing ore according to national standards such as GB / T 30836-2014 and GB / T 24533-2009. The lithium leaching rate = 1 - (mass of lithium-containing leaching residue × percentage of lithium in the leaching residue) / (mass of clay lithium ore × percentage of lithium in the clay lithium ore) × 100%, and the lithium content of the clay lithium ore was 0.178%.

[0176] Table 1:

[0177]

[0178]

[0179] As shown in Table 1, Examples 1-9, which pre-treat the clay lithium ore powder with an acid solution containing a surfactant, significantly improve the lithium leaching rate compared to the leaching rate results of Comparative Examples 1-4 under the same calcination conditions. Because surfactants solubilize and reduce the surface tension of the solution, they enable strong acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid to more fully contact the clay lithium ore powder, activating the hydroxyl groups on the clay lithium ore powder's surface and promoting the subsequent replacement of lithium with potassium and sodium salts during the calcination step. The lithium leaching rates of Examples 1-9 ranged from 86.09% to 93.70%, while those of Comparative Examples 1-3 ranged from 71.90% to 73.21%.

[0180] In Comparative Example 1, the clay lithium ore powder was not pretreated with acid. The raw ore was directly mixed with a roasting aid and roasted. The lithium leaching rate was 72.46%, which was significantly lower than the lithium leaching rate of the embodiment. In Comparative Example 2, the clay lithium ore powder was pretreated with sulfuric acid only, without adding a surfactant to assist in soaking. The lithium leaching rate was not significantly improved (73.21%), indicating that the pretreatment of the clay lithium ore powder with sulfuric acid alone had a poor wetting effect and could not effectively replace the structural lithium. In Comparative Example 3, the raw ore was pretreated with oxalic acid (weak acid) added with 0.1wt% alkyl succinate monoester quaternary ammonium salt. The lithium leaching rate was 71.90%, indicating that the weak acid had no effect on the raw ore soaking and could not effectively destroy the structural lithium to promote lithium replacement leaching.

[0181] Comparative Example 4 used a 10wt% sulfuric acid solution containing a surfactant to leach the calcined clay lithium ore sample. Compared with Comparative Example 1, the lithium leaching rate was significantly improved (82.75% / 72.46%). Considering environmental factors, 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 the cost of lithium carbonate extraction. After the first calcination of Example 1 and Comparative Examples 3-4, the Al, Fe, Ca, and Mg contents in the leachate obtained were analyzed by ICP-OES. 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 and roasted, 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; while the lithium leaching rate is improved to a certain extent by leaching with an acid solution containing a surfactant, 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 reference terms "some embodiments", "other embodiments", "embodiments", "examples", etc. mean 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 can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0186] Although the embodiments and examples of the present invention have been shown and described above, it will be understood that the above embodiments and examples are illustrative and are not to be construed as limitations on 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 clay lithium ore pretreatment method, characterized in that: The pretreatment method comprises: soaking 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; 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 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 amphoacetate.

2. The clay lithium ore pretreatment method according to claim 1, wherein The concentration of the surfactant in the acid solution is 0.1-0.5 wt%; The concentration of the acid solution is 10-50 wt%; The soaking temperature is 40-60°C; the soaking time is 4-6 hours; The pretreatment further comprises: performing solid-liquid separation on the soaked clay lithium ore powder, washing with pure water and drying for later use.

3. The clay lithium ore pretreatment method according to claim 2, wherein: The concentration of the acid solution is 10-35 wt%.

4. A method for extracting lithium from clay lithium ore, characterized in that: The method comprises the following steps: (1) Pretreatment: pretreatment is performed using the method described in 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); solid-liquid separation to obtain a leachate; (5) Evaporating the salt and cyclic roasting: the leachate obtained in step (4) is directly evaporated to obtain a lithium-containing compound, and after drying, it returns 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 performing the step (1), the method further includes 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 sulfate; The mass ratio of the roasting aid to the clay lithium ore powder is 0.5~1:

1.

7. The method for extracting lithium from clay lithium ore according to claim 6, characterized in that: The sulfate is one or more of potassium sulfate, sodium sulfate, calcium sulfate and ammonium sulfate.

8. 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 1-10°C / min, the calcination temperature is 600-900°C, and the calcination time is 0.5-2 h.

9. The method for extracting lithium from clay lithium ore according to claim 4, wherein: In step (4), pure water is used for leaching, and the leaching solid-liquid ratio is 1:2~1:5; the leaching temperature is 30~90℃; and the leaching time is 0.5~2 h.

10. The method for extracting lithium from clay lithium ore according to claim 4, characterized in that: In step (5), the number of cycles of steps (2) to (4) is 5 or more.

11. 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 leachate obtained in step (5) is concentrated to a lithium-containing solution with a lithium concentration of 8 to 12 g / L. After adjusting the pH of the solution, 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 with 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 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 the finished lithium carbonate product.

12. The method for extracting lithium from clay lithium ore according to claim 11, wherein: 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 precipitant II added to the lithium element in the concentrated filtrate is 1:1.5~1:3, the temperature of the lithium precipitation reaction is 80~100°C, and the reaction time is 0.5~2 h.

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