Method for extracting lithium from a clay-type lithium ore

Abstract

The application provides a method for extracting lithium from clay-type lithium ore, which comprises the following steps: mixing the clay-type lithium ore with an acid liquor to perform a slurry conditioning reaction, performing solid-liquid separation to obtain an iron salt leaching liquor and an iron-removed clay-type lithium residue; mixing the iron-removed clay-type lithium residue with ammonium sulfate to obtain green material; performing curing on the green material to obtain clinker; performing dissolution on the clinker to obtain a lithium-aluminum leaching liquor and a high-silicon residue; adding ammonia gas and / or ammonia water into the lithium-aluminum leaching liquor, and performing solid-liquid separation to obtain lithium-containing aluminum hydroxide and an ammonium sulfate solution; performing desulfurization treatment on the lithium-containing aluminum hydroxide, and then performing roasting and leaching to obtain a lithium-rich liquid and aluminum oxide. The method overcomes the deficiencies in the lithium extraction technology of clay-type lithium ore, has a short process, low energy consumption, and realizes the separation and extraction of lithium, aluminum, iron and silicon in the system.

Description

Technical Field

[0001] This invention belongs to the field of lithium production and relates to a method for extracting lithium from clay-type lithium ore. Background Technology

[0002] Lithium, as an important strategic energy metal, is currently widely used in new energy, nuclear energy, medical, and ceramic fields, and is known as "white oil." Currently, lithium extraction raw materials are divided into three types: hard rock types such as spodumene, lepidolite, and phosphite; brine types such as salt lake brine, mineral springs, and well brine; and clay types. Clay-type lithium deposits, due to their later discovery and complex lithium occurrence states, have not yet been developed and utilized on a large scale. With the continuous increase in demand for lithium resources, the development and utilization of clay-type lithium deposits will inevitably become a key focus in the future to alleviate the lithium resource shortage.

[0003] Currently, lithium extraction methods from clay-type lithium ore researched both domestically and internationally can be broadly categorized into additive roasting, acid roasting, and alkaline roasting. Additive roasting involves roasting a mixture of clay-type lithium ore with sulfates such as calcium sulfate, calcium fluoride, and sodium sulfate. While this method yields impressive lithium leaching results, the introduction of elements like fluorine, calcium, and potassium into the solution increases the cost of subsequent purification. Furthermore, the furnace gas is highly corrosive, placing high demands on equipment. The alkaline roasting method uses lime and sodium hydroxide, resulting in large slag volumes and high equipment maintenance costs. The acid roasting method directly uses sulfuric acid for low-temperature ripening, achieving a leaching rate exceeding 90%. However, it requires a large amount of sulfuric acid, and the roasting process generates significant amounts of sulfur oxides, leading to severe equipment corrosion and high flue gas treatment costs. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention provides a method for lithium extraction from clay-type lithium ore. The method overcomes the shortcomings of the existing technology for lithium extraction from clay-type lithium ore, has a short process, low energy consumption, and achieves the separation and extraction of lithium, aluminum, iron, and silicon in this system.

[0005] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0006] This invention provides a method for extracting lithium from clay-type lithium ore, the method comprising the following steps:

[0007] (1) Mix clay-type lithium ore with acid solution to carry out slurry reaction to obtain iron salt leachate and iron-removed clay-type lithium slag.

[0008] (2) Mix the iron-removing clay-type lithium slag obtained in step (1) with ammonium sulfate to obtain raw material; and cook the raw material to obtain cooked material.

[0009] (3) The clinker described in step (2) is leached to obtain lithium aluminum leachate and high-silicon slag;

[0010] (4) Add ammonia gas and / or ammonia water to the lithium aluminum leaching solution in step (3) and separate the solid and liquid to obtain lithium aluminum hydroxide and ammonium sulfate solution;

[0011] (5) The lithium-containing aluminum hydroxide described in step (4) is subjected to desulfurization treatment, followed by roasting and leaching to obtain lithium-rich liquid and aluminum oxide.

[0012] In this invention, using ammonium sulfate as an additive for sulfate roasting has advantages such as low roasting temperature and no introduction of impurity ions during the roasting process, and theoretically, no sulfide gases are produced. Moreover, ammonium sulfate is safer than sulfuric acid; its aqueous solution has a pH of around 5.5, is almost non-corrosive, and has lower equipment requirements than that for sulfuric acid.

[0013] In this invention, the clay-type lithium ore is treated before raw material preparation to remove iron, preventing the formation of ferric hydroxide from iron in subsequent steps. Ferric hydroxide can adsorb lithium, reducing the lithium extraction rate. Desulfurization aims to improve the purity of aluminum hydroxide, as alumina containing sulfur impurities has no economic value.

[0014] As a preferred technical solution of the present invention, the acid solution in step (1) includes sulfuric acid.

[0015] As a preferred technical solution of the present invention, the time for the slurry preparation reaction in step (1) is 1 to 3 hours, such as 1 hour, 1.2 hours, 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 2.8 hours or 3 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, the temperature of the slurry preparation reaction in step (1) is 70 to 100°C, such as 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] As a preferred technical solution of the present invention, the mass ratio of ammonium sulfate to the iron-removing clay-type lithium slag in step (2) is 3 to 7:1, such as 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1 or 7:1, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] As a preferred technical solution of the present invention, the ripening temperature in step (2) is 300 to 600°C, such as 300°C, 350°C, 400°C, 450°C, 500°C, 550°C or 600°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the ripening time in step (2) is 1 to 5 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours or 5 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] As a preferred technical solution of the present invention, the ammonium sulfate solution in step (4) is returned to step (2) for the preparation of raw materials.

[0021] As a preferred technical solution of the present invention, the lithium-containing aluminum hydroxide in step (5) is mixed with alkali for desulfurization treatment.

[0022] Preferably, the alkali includes any one or a combination of at least two of ammonia, sodium hydroxide, and sodium carbonate.

[0023] As a preferred technical solution of the present invention, the roasting temperature in step (5) is 500 to 1100°C, such as 500°C, 600°C, 700°C, 800°C, 900°C, 1000°C or 1100°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] As a preferred technical solution of the present invention, the leaching temperature in step (5) is 70 to 100°C, such as 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, the leaching time in step (5) is 0.5 to 3 hours, such as 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] As a preferred technical solution of the present invention, the method for extracting lithium from clay-type lithium ore includes the following steps:

[0027] (1) Mix clay-type lithium ore with sulfuric acid to carry out a slurry preparation reaction. The temperature of the slurry preparation reaction is 70-100℃ and the time is 1-3h. Solid-liquid separation is performed to obtain iron salt leachate and iron-free clay-type lithium slag.

[0028] (2) The iron-removing clay-type lithium slag obtained in step (1) is mixed with ammonium sulfate at a mass ratio of 1:3 to 7 to obtain raw material; the raw material is cooked to obtain cooked material, the cooking temperature is 300 to 600°C and the time is 1 to 5 hours.

[0029] (3) The clinker described in step (2) is leached to obtain lithium aluminum leachate and high-silicon slag;

[0030] (4) Add ammonia or ammonia water to the lithium aluminum leaching solution in step (3) and separate the solid and liquid to obtain lithium aluminum hydroxide and ammonium sulfate solution;

[0031] (5) The lithium-containing aluminum hydroxide from step (4) is mixed with alkali for desulfurization treatment, then roasted at 500-1100°C, and leached at 70-100°C for 0.5-3 hours to obtain lithium-rich liquid and aluminum oxide.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] (1) This invention does not add any additives that will introduce new impurities. It can effectively extract lithium, aluminum and iron from clay-type lithium ore. The leaching rates of lithium, aluminum and iron are 90%, 70% and 95% or more, respectively. It adopts the process of removing iron first and then aging and leaching. It uses advanced aluminum hydroxide desulfurization technology to ensure that sulfur trioxide is not produced during the aluminum hydroxide roasting process, thereby reducing the difficulty of flue gas treatment and the requirements for roasting furnace materials.

[0034] (2) This invention utilizes the adsorption properties of aluminum hydroxide. A neutralizing agent is used to adjust the pH of the leachate so that the aluminum in it precipitates in the form of aluminum hydroxide. At the same time as precipitation, lithium ions in the solution are adsorbed and precipitated, with an adsorption capacity of 99.5%. Then, the lithium-containing aluminum hydroxide after desulfurization is roasted. The aluminum oxide generated by roasting is then leached in water, which can increase the lithium enrichment rate in the solution by more than 2 times and the deintercalation rate is as high as 95%. Metallurgical grade aluminum oxide that is conducive to resource utilization and lithium-rich solution with impurity ion concentrations of iron, aluminum, manganese, magnesium and calcium below 200 mg / L are obtained. The lithium-rich solution can be purified to prepare lithium carbonate, lithium phosphate, lithium hydroxide and the like. Attached Figure Description

[0035] Figure 1 A schematic flowchart illustrating a method for extracting lithium from clay-type lithium ore, provided for a specific embodiment of the present invention.

[0036] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0037] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0038] This invention provides a method for extracting lithium from clay-type lithium ore, the method comprising the following steps:

[0039] (1) Mix clay-type lithium ore with acid solution to carry out slurry reaction, and separate solid and liquid to obtain iron salt leachate and iron-free clay-type lithium slag.

[0040] (2) Mix the iron-removing clay-type lithium slag obtained in step (1) with ammonium sulfate to obtain raw material; and cook the raw material to obtain cooked material.

[0041] (3) The clinker described in step (2) is leached to obtain lithium aluminum leachate and high-silicon slag;

[0042] (4) Add alkali to the lithium aluminum leaching solution in step (3) and separate the solid and liquid to obtain lithium aluminum hydroxide and ammonium sulfate solution;

[0043] (5) The lithium-containing aluminum hydroxide described in step (4) is subjected to desulfurization treatment, followed by roasting and leaching to obtain lithium-rich liquid and aluminum oxide.

[0044] In one specific embodiment of the present invention, the clay-type lithium ore is subjected to fine grinding before the slurry preparation reaction in step (1), and the fine grinding can be performed by wet grinding or dry grinding.

[0045] In one specific embodiment of the present invention, in the slurry preparation reaction described in step (1), the iron element of the clay-type lithium ore reacts with the acid to generate soluble iron salts (such as ferric sulfate) which enter the liquid phase, thereby separating them from other valuable elements in the clay-type lithium ore.

[0046] In one specific embodiment of the present invention, the amount and concentration of acid in the slurry preparation reaction in step (1) can be specifically selected according to the content of iron and other elements in clay-type lithium ore, and are not specifically limited here.

[0047] In one specific embodiment of the present invention, before the iron-free clay-type lithium slag is prepared in step (2), it is washed, preferably by multi-stage countercurrent washing to remove excess acid and residual soluble iron salts.

[0048] In one specific embodiment of the present invention, a neutralizing agent (such as ammonia) is added to a leaching solution containing soluble iron salts (such as ferric sulfate), and solid-liquid separation is performed to obtain an ammonium sulfate solution and iron-containing slag. The ammonium sulfate solution, after evaporation and crystallization, can be used for the preparation of raw materials in step (2). In another specific embodiment of the present invention, the leaching solution containing soluble iron salts (such as ferric sulfate) is combined with the liquid from a multi-stage countercurrent washing of iron-removed clay-type lithium slag, and then a neutralizing agent (such as ammonia) is added. The conditions for the multi-stage countercurrent washing can be specifically selected according to the pH and iron content of the washing liquid, and are not specifically limited here.

[0049] In one specific embodiment of the present invention, step (2) of mixing iron-free clay-type lithium slag with ammonium sulfate can be done by grinding.

[0050] In one specific embodiment of the present invention, in step (3), the clinker and the leaching solvent (such as water) are leached in a stirred atmospheric pressure reaction tank. Lithium and aluminum enter the solution in the form of sulfates, while silicon remains in the residue to form high-silicon slag. Solid-liquid separation is performed, and the high-silicon slag is subjected to multi-stage countercurrent washing to ensure that lithium and aluminum in the clinker are fully dissolved, resulting in a lithium-containing aluminum sulfate solution and high-silicon slag. The conditions for leaching and multi-stage countercurrent washing can be specifically selected according to the content of lithium and aluminum in the leaching solution and the washing solution, and are not specifically limited here.

[0051] In one specific embodiment of the present invention, the specific amount of ammonia gas or ammonia water used in step (4) can be selected according to the content of lithium and aluminum elements in the lithium-aluminum leaching solution, and is not specifically limited here.

[0052] In one specific embodiment of the present invention, the amount of alkali used for desulfurization of lithium-containing aluminum hydroxide in step (5) can be specifically selected according to the sulfur content in the lithium-containing aluminum hydroxide, and is not specifically limited here. The conditions for desulfurization treatment of lithium-containing aluminum hydroxide can be as follows: dissolve the lithium-containing aluminum hydroxide in liquid alkali, add sodium hydroxide solution at 70°C until the pH is greater than 12 to obtain a relatively pure sodium aluminate solution, add Al(OH)3 seed crystals to this solution, and prepare sulfur-free lithium-containing aluminum hydroxide precipitate using a seed decomposition method.

[0053] In one specific embodiment of the present invention, the main component of the high-silicon slag is silicon dioxide, which is used to prepare high-silicon filler; the main component of the iron hydroxide slag is iron hydroxide, which is used to prepare polyferric sulfate; and the lithium-rich solution can be purified to prepare lithium carbonate, lithium phosphate, lithium hydroxide, etc.

[0054] Example 1

[0055] This embodiment provides a method for extracting lithium from clay-type lithium ore, the process of which is as follows: Figure 1 As shown, the method includes the following steps:

[0056] (1) 1000g of clay-type lithium ore (mechanically activated and crushed, the main element content (dry basis): alumina 61.09%, lithium oxide 0.38%, silicon dioxide 18.53%, iron oxide 1.87%) was mixed with 15wt% sulfuric acid at a solid-liquid ratio of 5:1 for slurry preparation reaction. The temperature of the slurry preparation reaction was 70℃ and the time was 3h. The leaching was carried out in a two-stage countercurrent manner, and the solid and liquid were separated to obtain ferric sulfate leachate and iron-removed clay-type lithium slag.

[0057] Ammonia water (from the aging treatment in step (2)) is added to the ferric sulfate leachate to precipitate the iron element in the form of ferric hydroxide. After pressurized solid-liquid separation and washing, ferric hydroxide slag and ammonium sulfate solution are obtained. The ammonium sulfate solution is evaporated by falling film and then separated by pressurized separation to return ammonium sulfate to step (2) for raw material preparation and recycling.

[0058] (2) The iron-removing clay-type lithium slag described in step (1) is mixed with ammonium sulfate at a mass ratio of 1:3 to obtain raw material; the raw material is matured to obtain mature material and ammonia gas (the ammonia gas is used to prepare ammonia water), the maturity temperature is 400℃ and the time is 2h;

[0059] (3) The clinker described in step (2) was leached in hot water in a normal pressure reaction tank with stirring for 2 hours, and then separated by three-stage countercurrent under pressure to obtain lithium aluminum leaching solution and high silicon slag; the main components of the high silicon slag are: Al2O3: 23.89%, Li2O: 0.07%, SiO2: 53.61%, Fe2O3: 0.04%;

[0060] (4) Add ammonia water (from the aging treatment in step (2)) to the lithium aluminum leaching solution in step (3), and perform vacuum solid-liquid separation to obtain lithium-containing aluminum hydroxide and ammonium sulfate solution;

[0061] The ammonium sulfate is obtained by falling film evaporation and pressure separation, and then returned to step (2) for raw material preparation and recycling.

[0062] (5) The lithium-containing aluminum hydroxide obtained in step (4) is dissolved in liquid alkali, and sodium hydroxide solution is added at 70°C until the pH is greater than 12 to obtain a relatively pure sodium aluminate solution. Al(OH)3 seed crystals are added to this solution, and sulfur-free lithium-containing aluminum hydroxide precipitate is prepared by seed decomposition method. Then, the sulfur-free lithium-containing aluminum hydroxide is calcined in a rotary kiln at 500°C to obtain lithium-containing aluminum oxide. The lithium-containing aluminum oxide is leached in hot water at 90°C in a stirring atmospheric pressure reaction tank for 2 hours to obtain lithium-rich liquid and aluminum oxide. The main components of the lithium-rich liquid are Li: 1267ppm, Al: 28ppm, Fe: 20ppm, Mn: 9ppm, Ca: 11ppm, Mg: 12ppm, K: 14ppm, Na: 2157ppm, S: 5ppm, and the aluminum oxide components are Al2O3: 98.5%, Fe2O3: 0.01%, Na2O: 0.63%, SiO2: 0.0%, SO3: 0.02%.

[0063] Example 2

[0064] This embodiment provides a method for extracting lithium from clay-type lithium ore, the process of which is as follows: Figure 1 As shown, the method includes the following steps:

[0065] (1) 1000g of clay-type lithium ore (mechanically activated and crushed, the main element content (dry basis): 68.39% alumina, 0.53% lithium oxide, 16.53% silicon dioxide, 7.89% iron oxide) was mixed with 10wt% sulfuric acid at a solid-liquid ratio of 4:1 for slurry preparation reaction. The slurry preparation reaction was carried out at a temperature of 100℃ for 1h. Single-stage countercurrent leaching was performed, followed by pressurized solid-liquid separation and washing to obtain ferric sulfate leachate and iron-removed clay-type lithium slag.

[0066] Ammonia water (from the aging treatment in step (2)) is added to the ferric sulfate leachate to precipitate the iron element in the form of ferric hydroxide. After pressure solid-liquid separation and washing, ferric hydroxide slag and ammonium sulfate solution are obtained. The ammonium sulfate solution is subjected to forced circulation evaporation and then centrifuged to obtain ammonium sulfate, which is returned to step (2) for raw material preparation and recycled.

[0067] (2) The iron-removing clay-type lithium slag described in step (1) is mixed with ammonium sulfate at a mass ratio of 1:4 to obtain raw material; the raw material is matured to obtain mature material and ammonia gas (the ammonia gas is used to prepare ammonia water), the maturity temperature is 600℃ and the time is 1h;

[0068] (3) The clinker described in step (2) was leached in hot water using a single-stage mill for 1 hour, and then separated by four-stage countercurrent under pressure to obtain lithium aluminum leaching solution and high-silicon slag; the main components of the high-silicon slag were: Al2O3: 26.17%, Li2O: 0.06%, SiO2: 48.9%, Fe2O3: 0.01%;

[0069] (4) Add ammonia water (from the aging treatment in step (2)) to the lithium aluminum leaching solution in step (3), and perform vacuum solid-liquid separation to obtain lithium-containing aluminum hydroxide and ammonium sulfate solution;

[0070] The ammonium sulfate is obtained by forced circulation evaporation and centrifugation, and then returned to step (2) for raw material preparation and reuse.

[0071] (5) The lithium-containing aluminum hydroxide in step (4) is dissolved in liquid alkali, and sodium hydroxide solution is added at 70°C until the pH is greater than 12 to obtain a relatively pure sodium aluminate solution. Al(OH)3 seed crystals are added to this solution, and sulfur-free lithium-containing aluminum hydroxide precipitate is prepared by seed decomposition method. Then, the sulfur-free lithium-containing aluminum hydroxide is calcined in a rotary kiln at 1200°C to obtain lithium-containing aluminum oxide. The lithium-containing aluminum oxide is leached in hot water at 70°C in a stirring atmospheric pressure reaction tank for 1 hour to obtain lithium-rich liquid and aluminum oxide. The main components of the lithium-rich liquid are Li: 1538ppm, Al: 13ppm, Fe: 0ppm, Mn: 5ppm, Ca: 24ppm, Mg: 12ppm, K: 36ppm, Na: 4117ppm, S: 23ppm, and the aluminum oxide components are Al2O3: 98.6%, Fe2O3: 0.00%, Na2O: 0.65%, SiO2: 0.0%, SO3: 0.02%.

[0072] Example 3

[0073] This embodiment provides a method for extracting lithium from clay-type lithium ore, the process of which is as follows: Figure 1 As shown, the method includes the following steps:

[0074] (1) 1000g of clay-type lithium ore (mechanically activated and crushed, the main element content (dry basis): alumina 58.73%, lithium oxide 0.63%, silicon dioxide 21.78%, iron oxide 6.24%) was mixed with 15wt% sulfuric acid at a solid-liquid ratio of 4:1 for slurry preparation reaction. The slurry preparation reaction was carried out at a temperature of 80℃ for 2h. Three-stage countercurrent leaching, pressurized solid-liquid separation and washing were performed to obtain ferric sulfate leachate and iron-removed clay-type lithium slag.

[0075] Ammonia water (from the aging treatment in step (2)) is added to the ferric sulfate leachate to precipitate the iron element in the form of ferric hydroxide. After pressurized solid-liquid separation and washing, ferric hydroxide slag and ammonium sulfate solution are obtained. The ammonium sulfate solution is evaporated by falling film evaporation and then separated by pressurization to obtain ammonium sulfate, which is returned to step (2) for raw material preparation and recycled.

[0076] (2) The iron-removing clay-type lithium slag described in step (1) is mixed with ammonium sulfate at a mass ratio of 1:6 to obtain raw material; the raw material is matured to obtain mature material and ammonia gas (the ammonia gas is used to prepare ammonia water), the maturity temperature is 400℃ and the time is 5h;

[0077] (3) The clinker described in step (2) was leached in hot water using a two-stage mill for 1 hour, and then separated by four-stage countercurrent under pressure to obtain lithium aluminum leaching solution and high-silicon slag; the main components of the high-silicon slag were: Al2O3: 21.15%, Li2O: 0.08%, SiO2: 58.61%, Fe2O3: 0.02%;

[0078] (4) Add ammonia water (from the aging treatment in step (2)) to the lithium aluminum leaching solution in step (3), and perform vacuum solid-liquid separation to obtain lithium-containing aluminum hydroxide and ammonium sulfate solution;

[0079] The ammonium sulfate is obtained by forced circulation evaporation and centrifugation, and then returned to step (2) for raw material preparation and reuse.

[0080] (5) The lithium-containing aluminum hydroxide in step (4) is dissolved in liquid alkali, and sodium hydroxide solution is added at 70°C until the pH is greater than 12 to obtain a relatively pure sodium aluminate solution. Al(OH)3 seed crystals are added to this solution, and sulfur-free lithium-containing aluminum hydroxide precipitate is prepared by seed decomposition method. Then, the sulfur-free lithium-containing aluminum hydroxide is calcined in a rotary kiln at 1100°C to obtain lithium-containing aluminum oxide. The lithium-containing aluminum oxide is leached in hot water at 90°C in a stirring atmospheric pressure reaction tank for 1 hour to obtain lithium-rich liquid and aluminum oxide. The main components of the lithium-rich liquid are Li: 1836ppm, Al: 33ppm, Fe: 3ppm, Mn: 21ppm, Ca: 9ppm, Mg: 16ppm, K: 25ppm, Na: 4536ppm, S: 5ppm, and the aluminum oxide components are Al2O3: 98.8%, Fe2O3: 0.00%, Na2O: 0.60%, SiO2: 0.0%, SO3: 0.01%.

[0081] Example 4

[0082] Except for step (2), in which the iron clay-type lithium slag and ammonium sulfate are in a mass ratio of 1:7, all other conditions in this embodiment are the same as in Example 1.

[0083] Comparative Example 1

[0084] Except for step (1), which did not involve pre-removal of iron, the conditions in this comparative example were the same as those in Example 1.

[0085] Comparative Example 2

[0086] Except for step (5), where the lithium-containing aluminum hydroxide was not desulfurized and was directly calcined, the conditions in this comparative example were the same as in Example 1. The resulting lithium-rich liquid had the following composition: Li: 1412 ppm, Al: 853 ppm, Fe: 35 ppm, Mn: 12 ppm, Ca: 21 ppm, Mg: 7 ppm, K: 10 ppm, Na: 5 ppm, S: 7580 ppm. The alumina composition was: Al2O3: 89.2%, Fe2O3: 0.13%, Na2O: 0.01%, SiO2: 0.0%, SO3: 9.8%.

[0087] Comparative Example 3

[0088] Except for the temperature of the slurry preparation reaction in step (1) being 20°C, the conditions in this comparative example are the same as those in Example 1.

[0089] Comparative Example 4

[0090] Except for step (2), in which the iron clay-type lithium slag and ammonium sulfate are in a mass ratio of 1:1, all other conditions in this comparative example are the same as in Example 1.

[0091] The extraction rates of lithium, aluminum and iron in Examples 1-4 and Comparative Example 1 were calculated, and the results are shown in Table 1.

[0092] The extraction rates of aluminum and iron are calculated by converting the element content of clay-type lithium ore with the element content of by-products, while the extraction rate of lithium is calculated by converting the element content of clay-type lithium ore with the element content of lithium-rich liquid.

[0093] Table 1

[0094] Example 1 90.2 68.7 97.8 Example 2 92.2 67.3 98.8 Example 3 93.8 65.0 99.8 Example 4 93.6 72.3 98.3 Comparative Example 1 46.5 63.2 99.5 Comparative Example 2 88.5 66.4 98.1 Comparative Example 3 61.9 63.7 30.4 Comparative Example 4 61.4 47.2 98.9

[0095] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0096] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0097] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0098] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for lithium extraction from a clay-type lithium ore, characterized in that, The method includes the following steps: (1) Mix clay-type lithium ore with acid solution to carry out slurry reaction to obtain iron salt leachate and iron-removed clay-type lithium slag; (2) Mix the iron-removing clay-type lithium slag from step (1) with ammonium sulfate to obtain raw material; and cook the raw material to obtain cooked material. (3) The clinker described in step (2) is leached to obtain lithium aluminum leaching solution and high-silicon slag; (4) Add ammonia gas and / or ammonia water to the lithium aluminum leaching solution in step (3) and separate the solid and liquid to obtain lithium aluminum hydroxide and ammonium sulfate solution; (5) The lithium-containing aluminum hydroxide from step (4) is mixed with an alkali for desulfurization treatment, followed by roasting and leaching to obtain lithium-rich liquid and aluminum oxide.

2. The method of claim 1, wherein, The acid solution in step (1) includes sulfuric acid.

3. The method of claim 1, wherein, The time for the slurry preparation reaction in step (1) is 1~3 h, and the temperature for the slurry preparation reaction in step (1) is 70~100℃.

4. The method of claim 1, wherein, In step (2), the mass ratio of ammonium sulfate to the iron-removing clay-type lithium slag is 3~7:

1.

5. The method of claim 1, wherein, The ripening temperature in step (2) is 300~600℃.

6. The method of claim 1, wherein, The ripening time in step (2) is 1 to 5 hours.

7. The method of claim 1, wherein, The ammonium sulfate solution in step (4) is returned to step (2) for raw material preparation.

8. The method of claim 1, wherein, The alkali includes any one or a combination of at least two of ammonia and sodium hydroxide.

9. The method of claim 1, wherein, The roasting temperature in step (5) is 500~1100℃.

10. The method of claim 1, wherein, The leaching temperature in step (5) is 70~100℃.

11. The method of claim 1, wherein, The leaching time in step (5) is 0.5 to 3 hours.

12. The method according to any one of claims 1 to 11, characterized in that, The method includes the following steps: (1) Mix clay-type lithium ore with sulfuric acid to carry out a slurry preparation reaction. The temperature of the slurry preparation reaction is 70~100℃ and the time is 1~3 h. Solid-liquid separation is carried out to obtain iron salt leachate and iron-free clay-type lithium slag. (2) Mix the iron-removing clay-type lithium slag from step (1) with ammonium sulfate at a mass ratio of 1:3~7 to obtain raw material; gluten the raw material to obtain clinker, wherein the gluten temperature is 300~600℃ and the time is 1~5 h; (3) The clinker described in step (2) is leached to obtain lithium aluminum leaching solution and high-silicon slag; (4) Add ammonia or ammonia water to the lithium aluminum leaching solution in step (3) and separate the solid and liquid to obtain lithium aluminum hydroxide and ammonium sulfate solution; (5) The lithium-containing aluminum hydroxide from step (4) is mixed with alkali for desulfurization treatment, then roasted at 500~1100℃, and leached at 70~100℃ for 0.5~3 h to obtain lithium-rich liquid and aluminum oxide.

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