Method for preparing lithium salt product from solid-state lithium resource in short process

Abstract

The invention provides a method for preparing a lithium salt product from a solid-state lithium resource in a short process. The method comprises the following steps: crushing and grinding the solid-state lithium resource; then uniformly mixing with alkali and an auxiliary agent; blending the mixed materials into slurry, putting the slurry into a half-type reaction kettle, fully autoclaving and dissolving out, and filtering to obtain a lithium-containing solution; and washing the obtained mixed slurry with water, and filtering to obtain a lithium-containing solution. Carrying out evaporation concentration-freezing crystallization on the obtained lithium-containing solution, or carrying out carbonization lithium precipitation to obtain a crude lithium salt product; and recrystallizing the crude lithium salt product to obtain a refined lithium salt product. The obtained refined lithium salt product is dried, crushed, demagnetized and the like, and a battery-grade lithium salt product is obtained. The auxiliary agent separated out by crystallization and / or the generated alkaline filtrate can be recycled and returned to a dissolution system for dissolution in the next process. According to the method, the crystal structure of the solid-state lithium resource can be directly destroyed at lower alkali consumption and lower temperature, and the problems of high activation roasting energy consumption, long flow and the like in the traditional lithium extraction process are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal extraction, metallurgy and separation, and efficient utilization of ore lithium resources, and in particular to a method for preparing lithium salt products using solid lithium resources in a short process. Background Art

[0002] Lithium (Li) is known as "white oil" due to its excellent physical and chemical properties as an "energy metal". It is in strong demand in the fields of power batteries and energy storage. Lithium usually exists in nature as solid lithium and liquid lithium compounds. Solid lithium resources are still the main source for the preparation of high-end lithium salt products due to their high grade and short production cycle. Common solid lithium resources include spodumene (LiAlSi 2 O 6 ), lithium mica, iron lithium mica, etc. The microstructure is mainly composed of aluminum oxide octahedron [AlO 6 ] and silicon-oxygen tetrahedron [SiO 4 ] are densely arranged, and lithium is bound in a dense lattice.

[0003] The current mainstream extraction process of solid lithium ore is mainly to activate and roast it at high temperature, then mix it with sulfuric acid and acidify and roast it at 250°C to convert the originally insoluble lithium into water-soluble Li 2 SO 4 , and then prepare lithium carbonate by concentration and carbonization of lithium; or prepare lithium hydroxide by freezing and causticizing. This process is a relatively mature process in the preparation of lithium salt products from solid lithium resources due to its high extraction rate and simple operation. However, it still has problems such as high energy consumption of roasting transformation, large consumption of concentrated acid for acidification roasting, and long process that produces a large amount of neutralization waste residue. Therefore, how to achieve a short process for preparing lithium salt products from lithium ore is of great significance to ensuring the sustainable development of the lithium salt industry. Summary of the invention

[0004] In view of this, the present invention provides a method for preparing lithium salt products from solid lithium resources in a short process. The method of the present invention can directly destroy the crystal structure of solid lithium resources at a lower alkali consumption and lower temperature, avoiding the problems of high energy consumption and long process of activation roasting in the traditional lithium extraction process.

[0005] The present invention provides a method for preparing lithium salt products using solid lithium resources in a short process, comprising the following steps:

[0006] Step (1): crushing, grinding and screening the solid lithium resource to obtain solid lithium resource powder;

[0007] Step (2): mixing the solid lithium resource powder with an alkaline substance, an additive and water to obtain a slurry;

[0008] Step (3): performing pressure cooking and dissolution on the slurry to obtain a dissolution solution;

[0009] Step (4): washing the eluate with water, separating the solid from the liquid, and obtaining a lithium-containing solution;

[0010] Step (5): evaporating and concentrating the lithium-containing solution, and separating the solid from the liquid to obtain a lithium-containing concentrated solution;

[0011] Step (6): crystallizing or carbonizing the lithium-containing concentrated solution to obtain a crude lithium salt product;

[0012] Step (7): recrystallizing the crude lithium salt product to obtain a refined lithium salt; and post-treating the refined lithium salt to obtain a battery-grade lithium salt product.

[0013] Preferably, in step (1), the solid lithium resource is at least one of spodumene, lepidolite, and ferrolithium mica.

[0014] Preferably, in step (2), the alkaline substance is at least one of sodium hydroxide, ammonia water, potassium hydroxide and calcium hydroxide;

[0015] The auxiliary agent is at least one of sodium carbonate, sodium sulfate, sodium aluminate, potassium sulfate, ammonium sulfate, calcium sulfate, calcium oxide, and slaked lime.

[0016] Preferably, in step (2), the mass ratio of the solid lithium resource powder, the alkaline substance and the auxiliary agent is 1:(0.01-10):(0.01-10).

[0017] Preferably, in step (2), the amount of water used is such that the solid-liquid ratio reaches 1g:(0.1-10)L.

[0018] Preferably, in step (3), the temperature of the autoclave dissolution is 50 to 300° C. and the pressure is 0.01 to 8.31 MPa.

[0019] Preferably, in step (4), the volume ratio of the dissolution solution to water is 1:(0.5-20).

[0020] Preferably, in step (5), the temperature of the evaporation concentration is 50-120° C.; the degree of the evaporation concentration is such that the lithium concentration is ≥10 g / L.

[0021] Preferably, in step (6), the crystallization comprises: first cooling and crystallizing to precipitate a solid phase, separating the solid from the liquid to obtain a lithium-containing liquid, and then evaporating and crystallizing the obtained lithium-containing liquid to obtain a crude lithium salt product;

[0022] The lithium carbonization precipitation comprises: mixing the lithium-containing concentrated solution with sodium carbonate to carry out lithium carbonization precipitation reaction, and separating the solid from the liquid to obtain a crude lithium salt product.

[0023] Preferably, in step (7), the recrystallization temperature is 50 to 80° C.

[0024] After step (7), the method further includes step (8) of recycling: the solid phase precipitated during the crystallization process of step (6) is re-introduced into the system to participate in the next round of process for recycling; and / or the alkaline filtrate generated during the crystallization process of step (6) is re-introduced into the system to participate in the next round of process for recycling.

[0025] The present invention provides a method for preparing lithium salt products from solid lithium resources in a short process, comprising the following steps: crushing and grinding the solid lithium resources; then mixing them evenly with alkali and auxiliary agents; adjusting the mixed materials into slurry and putting them into a Halogen reactor, fully boiling and dissolving them, filtering them to obtain a lithium-containing solution; washing the obtained mixed slurry with water, and filtering them to obtain a lithium-containing solution. The obtained lithium-containing solution is evaporated and concentrated-freeze crystallized, or carbonized and precipitated with lithium to obtain a crude lithium salt product; the crude lithium salt product is recrystallized to obtain a refined lithium salt product. The obtained refined lithium salt product is dried, crushed, demagnetized, and the like to obtain a battery-grade lithium salt product. The crystallized auxiliary agent can be recycled back to the dissolution system for dissolution in the next process. Compared with the prior art, the advantage of the present invention is that it takes the direct dissolution and lithium extraction of solid lithium resources without high-temperature activation roasting as the starting point, adopts an improved alkaline pressure cooking system to achieve lower alkali consumption and direct destruction of the crystal structure of solid lithium resources at lower temperature, avoids the problems of high energy consumption and long process of activation roasting in the traditional lithium extraction process, and realizes the direct dissolution of solid lithium resources at lower temperature and lower alkali concentration. The dissolution liquid system can prepare lithium carbonate or lithium hydroxide according to market demand, and can avoid the large consumption of alkali in the pH adjustment process, providing a new technical idea for the short-process preparation of lithium salt products from solid lithium resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 A schematic diagram of the process of preparing lithium salt products using a short process using solid lithium resources provided by the present invention. DETAILED DESCRIPTION

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0029] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0030] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0031] Herein, when it comes to numerical ranges, unless otherwise specified, the numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0032] In this article, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 50-300 mesh means that the units of the left endpoint "50" and the right endpoint "300" are both mesh.

[0033] The present invention provides a method for preparing lithium salt products using solid lithium resources in a short process, comprising the following steps:

[0034] Step (1): crushing, grinding and screening the solid lithium resource to obtain solid lithium resource powder;

[0035] Step (2): mixing the solid lithium resource powder with an alkaline substance, an additive and water to obtain a slurry;

[0036] Step (3): performing pressure cooking and dissolution on the slurry to obtain a dissolution solution;

[0037] Step (4): washing the eluate with water, separating the solid from the liquid, and obtaining a lithium-containing solution;

[0038] Step (5): evaporating and concentrating the lithium-containing solution, and separating the solid from the liquid to obtain a lithium-containing concentrated solution;

[0039] Step (6): crystallizing or carbonizing the lithium-containing concentrated solution to obtain a crude lithium salt product;

[0040] Step (7): recrystallizing the crude lithium salt product to obtain a refined lithium salt; and post-treating the refined lithium salt to obtain a battery-grade lithium salt product.

[0041] See also Figure 1 , Figure 1 A schematic diagram of the process of preparing lithium salt products using a short process using solid lithium resources provided by the present invention.

[0042] Regarding step (1) grinding:

[0043] The solid lithium resource is crushed, ground and sieved to obtain solid lithium resource powder.

[0044] In the present invention, the solid lithium resource is preferably at least one of spodumene, lepidolite, and ferrolithium mica.

[0045] In the present invention, the crushing and grinding methods are not particularly limited and can be performed according to conventional methods in the art.

[0046] In the present invention, the sieving preferably uses a sieve of 50 to 300 meshes, that is, granular powder with a particle size of 50 to 300 meshes is sieved out, specifically 50 mesh, 100 mesh, 150 mesh, 200 mesh, 250 mesh, and 300 mesh.

[0047] Regarding step (2) mixing:

[0048] The solid lithium resource powder is mixed with an alkaline substance, an auxiliary agent and water to obtain a slurry.

[0049] In the present invention, the alkaline substance is preferably at least one of sodium hydroxide, ammonia water, potassium hydroxide and calcium hydroxide.

[0050] In the present invention, the auxiliary agent is preferably at least one of sodium carbonate, sodium sulfate, sodium aluminate, potassium sulfate, ammonium sulfate, calcium sulfate, calcium oxide, and slaked lime.

[0051] In one embodiment of the present invention, the alkaline substance is sodium hydroxide, and the auxiliary agent is sodium sulfate and calcium oxide. In another embodiment of the present invention, the alkaline substance is sodium hydroxide, and the auxiliary agent is calcium oxide.

[0052] In the present invention, the mass ratio of the solid lithium resource powder, the alkaline substance and the auxiliary agent is preferably 1:(0.01-10):(0.01-10), more preferably 1:(1-5):(0.5-5), further preferably 1:(2-3):(0.5-4), and in some embodiments of the present invention it is 1:3:4, 1:2:0.5, 1:4:1, 1:1:1.

[0053] In the present invention, the dosage relationship of the water and other raw materials is preferably such that the solid-liquid ratio reaches 1g: (0.1-10) mL, more preferably 1g: (5-10) mL, further preferably 1g: (8-10) mL, and in some embodiments of the present invention, it is 1g: 5 mL, 1g: 7 mL, 1g: 8 mL, 1g: 9 mL, 1g: 10 mL, etc.

[0054] In the present invention, there is no special limitation on the mixing method, and the above materials can be mixed and uniformly adjusted into slurry according to the conventional mixing method in the art.

[0055] Regarding step (3) dissolution:

[0056] The slurry is subjected to autoclave dissolution to obtain a dissolution liquid.

[0057] In the present invention, the autoclave dissolution can be carried out in a reactor, specifically in a Hastelloy reactor. Autoclave dissolution refers to dissolving the useful components in the ore in a solution under high temperature and high pressure conditions, while the impurities are precipitated in a solid form; after the autoclave dissolution is completed, the solution and the solid impurities can be separated by solid-liquid separation means.

[0058] In the present invention, the temperature of the autoclave dissolution is preferably 50-300° C., specifically 50° C., 100° C., 150° C., 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 265° C., 270° C., 280° C., 290° C., 300° C. The pressure of the autoclave dissolution is 0.01-8.31 MPa, specifically 0.01 MPa, 0.1 MPa, 0.46 MPa, 1.50 MPa, 1.85 MPa, 2.24 MPa, 2.71 MPa, 3.25 MPa, 3.85 MPa, 4.54 MPa, 4.93 MPa, 5.35 MPa, 6.20 MPa, 7.14 MPa. The pressure cooking dissolution time is preferably 10min to 12h, specifically 10min, 30min, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h. In the present invention, the pressure cooking dissolution process is preferably accompanied by stirring; the stirring rate is preferably 50 to 500r / min, specifically 50r / min, 100r / min, 150r / min, 200r / min, 250r / min, 300r / min, 350r / min, 400r / min, 450r / min, 500r / min. In the present invention, after pressure cooking dissolution, a dissolution liquid is obtained. The dissolution liquid refers to the slurry that has not been subjected to solid-liquid separation after pressure cooking.

[0059] Regarding step (4) separation:

[0060] The eluted solution is washed with water and solid-liquid separation is performed to obtain a lithium-containing solution.

[0061] In the present invention, water is added to the eluate (slurry) obtained in step (3) for washing, wherein the volume ratio of the eluate to water is preferably 1:(0.5-20), more preferably 1:(5-15), specifically 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, and most preferably 1:10.

[0062] In the present invention, the solid-liquid separation method is not particularly limited and can be any conventional method in the art, such as filtration, centrifugal separation, etc., preferably filtration. After solid-liquid separation, a lithium-containing solution is obtained.

[0063] Regarding step (5) concentration:

[0064] The lithium-containing solution is evaporated and concentrated, and the solid and liquid are separated to obtain a lithium-containing concentrated solution.

[0065] In the present invention, the temperature of the evaporation concentration is preferably 50-120° C., specifically 50° C., 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., 120° C. In the present invention, the degree of evaporation concentration is preferably such that the lithium concentration is ≥10 g / L, preferably 10-20 g / L, and in some embodiments of the present invention is 10 g / L, 12 g / L, 13 g / L, 14 g / L.

[0066] Regarding step (6) of preparing crude salt:

[0067] The lithium-containing concentrated solution is crystallized or carbonized to precipitate lithium to obtain a crude lithium salt product.

[0068] In the present invention, the crystallization preferably includes: first cooling and crystallizing to precipitate the solid phase, separating the lithium-containing liquid from the solid and liquid, and then evaporating and crystallizing the obtained lithium-containing liquid to obtain a crude lithium salt product. Wherein, the temperature of the cooling crystallization is preferably -15 to 0°C, specifically -15°C, -10°C, -5°C, and 0°C. The temperature of the evaporation crystallization is preferably 50 to 100°C, specifically 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C. In one embodiment of the present invention, the solid lithium resource used is spodumene, the alkaline substance used is sodium hydroxide, and the auxiliary agents are sodium sulfate and calcium oxide; the lithium-containing concentrated solution is crystallized, and the crystallization includes: first cooling and crystallizing to precipitate sodium sulfate, separating the lithium-containing liquid from the solid and liquid, and then evaporating and crystallizing the obtained lithium-containing liquid to obtain crude lithium hydroxide.

[0069] In the present invention, the solid phase precipitated during the above crystallization process (mainly the auxiliary agent mentioned above) is re-introduced into the system to participate in the next round of process (ie, recycled as an auxiliary agent).

[0070] In the present invention, the carbonization and precipitation of lithium preferably includes: mixing the lithium-containing concentrated solution with sodium carbonate to perform carbonization and precipitation of lithium, and separating the solid and liquid to obtain a crude lithium salt product. In one embodiment of the present invention, the solid lithium resource used is lepidolite, the alkaline substance used is sodium hydroxide, and the auxiliary agent is calcium oxide; the lithium-containing concentrated solution is carbonized and precipitated with lithium, and the carbonization and precipitation of lithium includes: mixing the lithium-containing concentrated solution with sodium carbonate to perform carbonization and precipitation of lithium, and separating the solid and liquid to obtain crude lithium carbonate.

[0071] Regarding step (7) purification:

[0072] The crude lithium salt product is recrystallized to obtain a refined lithium salt; and the refined lithium salt is post-processed to obtain a battery-grade lithium salt product.

[0073] In the present invention, the recrystallization preferably includes: redissolution, re-evaporation and concentration, cooling and crystallization. Among them, the solvent for recrystallization (i.e. the solvent used for redissolution) is preferably at least one of ultrapure water, sodium hydroxide solution, and lithium hydroxide solution. The temperature of the recrystallization (i.e. the temperature of re-evaporation and concentration) is preferably 50-80°C, specifically 50°C, 60°C, 70°C, and 80°C. After redissolution and re-evaporation and concentration, cooling and crystallization are performed to obtain refined lithium salt.

[0074] In the present invention, after obtaining the refined lithium salt, post-treatment is performed. The post-treatment preferably includes: drying, crushing and demagnetization. There are no special restrictions on the above operations, and they can be performed in a conventional manner in the art. After the above post-treatment, a high-purity battery-grade lithium salt product is obtained.

[0075] The lithium salt product obtained by the present invention is lithium hydroxide or lithium carbonate.

[0076] In the present invention, after step (7), it is preferred to further include step (8) of recycling: the solid phase precipitated in the crystallization process of step (6) is re-introduced into the system to participate in the next round of process for recycling (i.e., the precipitated auxiliary agent is re-introduced into the system for recycling); and / or, the alkaline filtrate generated in the crystallization process of step (6) is re-introduced into the system to participate in the next round of process for recycling (i.e., the filtered filtrate is re-introduced into the system as a circulating feed liquid for recycling). The volume ratio of the circulating feed liquid to the fresh feed liquid in the circulation process is preferably (0.1-10):1.

[0077] In some embodiments of the present invention, a method for preparing a lithium salt product using a short process using solid-state lithium resources comprises:

[0078] Step (1) grinding: crushing, grinding and screening the spodumene concentrate to obtain spodumene powder.

[0079] Step (2) mixing: mixing the spodumene powder obtained in step (1), sodium hydroxide, sodium sulfate, calcium oxide and water to obtain a slurry.

[0080] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor for pressure cooking to obtain a dissolution liquid.

[0081] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution.

[0082] Step (5) concentration: The lithium-containing solution obtained in step (4) is evaporated and concentrated to obtain a lithium-containing concentrated solution.

[0083] Step (6) crystallization: cooling the lithium-containing concentrated solution obtained in step (5) to crystallize sodium sulfate, and after solid-liquid separation, evaporating and crystallizing the obtained lithium-containing solution to obtain crude lithium hydroxide.

[0084] Step (7) purification: The crude lithium hydroxide is redissolved, evaporated and concentrated, cooled and crystallized to obtain fine lithium hydroxide. The obtained fine lithium hydroxide is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium hydroxide monohydrate product.

[0085] Step (8) circulation: the solid phase precipitated in step (6) and the alkaline filtrate produced are returned to the dissolution system for use in the next round of process flow.

[0086] In other embodiments of the present invention, a method for preparing a lithium salt product using a short process using solid-state lithium resources includes:

[0087] Step (1) grinding: crushing, grinding and screening the lepidolite concentrate to obtain lepidolite powder.

[0088] Step (2) mixing: mixing the lepidolite powder obtained in step (1), sodium hydroxide, calcium oxide and water to obtain a slurry.

[0089] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor for pressure cooking to obtain a dissolution liquid.

[0090] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution.

[0091] Step (5) concentration: evaporating and concentrating the lithium-containing solution obtained in step (4) to obtain a lithium-containing concentrated solution.

[0092] Step (6) Carbonization of lithium: adding sodium carbonate to the lithium-containing solution obtained in step (5) to carbonize and precipitate lithium, and filtering to obtain crude lithium carbonate.

[0093] Step (7) purification: The crude lithium carbonate is redissolved, evaporated and concentrated, cooled and crystallized to obtain fine lithium carbonate. The obtained fine lithium carbonate is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium carbonate product.

[0094] In other embodiments of the present invention, a method for preparing a lithium salt product using a short process using solid-state lithium resources includes:

[0095] Step (1) grinding: crushing, grinding and screening the spodumene concentrate to obtain spodumene powder.

[0096] Step (2) mixing: mixing the spodumene powder obtained in step (1), sodium hydroxide, calcium oxide and water to obtain a slurry.

[0097] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor for pressure cooking to obtain a dissolution liquid.

[0098] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution.

[0099] Step (5) concentration: evaporating and concentrating the lithium-containing solution obtained in step (4) to obtain a lithium-containing concentrated solution.

[0100] Step (6) Carbonization of lithium: adding sodium carbonate to the lithium-containing solution obtained in step (5) to carbonize and precipitate lithium, and filtering to obtain crude lithium carbonate.

[0101] Step (7) purification: The crude lithium carbonate is redissolved, evaporated and concentrated, cooled and crystallized to obtain fine lithium carbonate. The obtained fine lithium carbonate is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium carbonate product.

[0102] In other embodiments of the present invention, a method for preparing a lithium salt product using a short process using solid-state lithium resources includes:

[0103] Step (1) grinding: crushing, grinding and screening the lepidolite concentrate to obtain lepidolite powder.

[0104] Step (2) mixing: mixing the lepidolite powder obtained in step (1), sodium hydroxide, sodium sulfate and water to obtain a slurry.

[0105] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor for pressure cooking to obtain a dissolution liquid.

[0106] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution.

[0107] Step (5) concentration: The lithium-containing solution obtained in step (4) is evaporated and concentrated to obtain a lithium-containing concentrated solution.

[0108] Step (6) crystallization: cooling the lithium-containing concentrated solution obtained in step (5) to crystallize sodium sulfate, and after solid-liquid separation, evaporating and crystallizing the obtained lithium-containing solution to obtain crude lithium hydroxide.

[0109] Step (7) purification: The crude lithium hydroxide is redissolved, evaporated and concentrated, cooled and crystallized to obtain fine lithium hydroxide. The obtained fine lithium hydroxide is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium hydroxide monohydrate product.

[0110] Step (8) circulation: the solid phase precipitated in step (6) and the alkaline filtrate produced are returned to the dissolution system for use in the next round of process flow.

[0111] In other embodiments of the present invention, a method for preparing a lithium salt product using a short process using solid-state lithium resources includes:

[0112] Step (1) grinding: crushing, grinding and screening the iron lithium mica concentrate to obtain iron lithium mica powder.

[0113] Step (2) mixing: mixing the lepidolite powder obtained in step (1), sodium hydroxide, sodium sulfate and water to obtain a slurry.

[0114] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor for pressure cooking to obtain a dissolution liquid.

[0115] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution.

[0116] Step (5) concentration: The lithium-containing solution obtained in step (4) is evaporated and concentrated to obtain a lithium-containing concentrated solution.

[0117] Step (6) crystallization: cooling the lithium-containing concentrated solution obtained in step (5) to crystallize sodium sulfate, and after solid-liquid separation, evaporating and crystallizing the obtained lithium-containing solution to obtain crude lithium hydroxide.

[0118] Step (7) purification: The crude lithium hydroxide is redissolved, evaporated and concentrated, cooled and crystallized to obtain fine lithium hydroxide. The obtained fine lithium hydroxide is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium hydroxide monohydrate product.

[0119] Step (8) circulation: the solid phase precipitated in step (6) and the alkaline filtrate produced are returned to the dissolution system for use in the next round of process flow.

[0120] The present invention provides a method for preparing lithium salt products from solid lithium resources in a short process. The method takes direct dissolution and extraction of lithium from solid lithium resources without high-temperature activation roasting as a starting point, adopts an improved alkaline pressure cooking system to achieve low alkali consumption and direct destruction of the crystal structure of solid lithium resources at a low temperature, and avoids the problems of high energy consumption and long process of activation roasting in the traditional lithium extraction process, aiming at preparing lithium salt products from solid lithium resources in a short process without roasting. The advantages of the present invention mainly lie in avoiding high-temperature activation roasting, realizing direct dissolution of solid lithium resources at a lower temperature and lower alkali concentration, the dissolution liquid system can prepare lithium carbonate or lithium hydroxide according to market demand, and can avoid the large consumption of alkali in the pH adjustment process, providing a new technical idea for preparing lithium salt products from solid lithium resources in a short process.

[0121] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0122] Example 1

[0123] Taking spodumene as an example, a method for preparing lithium hydroxide from solid lithium resources in a short process includes the following steps:

[0124] Step (1) grinding: crushing and grinding the spodumene concentrate to a particle size of 200 mesh to obtain spodumene powder.

[0125] Step (2) mixing: the spodumene powder obtained in step (1), sodium hydroxide, sodium sulfate and calcium oxide are mixed in a mass ratio of 1:3:3:1, and mixed with water in a liquid-to-solid ratio of 1 g:10 mL to form a slurry.

[0126] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor, and an autoclave reaction is carried out at 265° C. and 4.93 MPa with a stirring rate of 300 r / min to obtain a dissolution solution.

[0127] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution, wherein the volume ratio of slurry (i.e., eluate): water is 1:10.

[0128] Step (5) concentration: The lithium-containing solution obtained in step (4) is concentrated by evaporation at 80° C. to a lithium concentration of 14 g / L to obtain a lithium-containing concentrated solution.

[0129] Step (6) Crystallization: The lithium-containing concentrated solution obtained in step (5) is cooled at -10°C to crystallize sodium sulfate. After solid-liquid separation, the obtained lithium-containing solution is evaporated and crystallized at 50°C to obtain crude lithium hydroxide.

[0130] Step (7) purification: The crude lithium hydroxide is redissolved and then evaporated and concentrated (the redissolution solvent is ultrapure water, and the re-evaporation and concentration temperature is 60° C.), cooled and crystallized to obtain lithium hydroxide fine product. The obtained lithium hydroxide fine product is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium hydroxide monohydrate product (yield is 41%).

[0131] Step (8) circulation: the solid phase precipitated in step (6) and the alkaline filtrate produced are returned to the dissolution system for use in the next round of process flow.

[0132] Example 2

[0133] Taking lepidolite as an example, a method for preparing lithium carbonate from solid lithium resources in a short process includes the following steps:

[0134] Step (1) grinding: crushing and grinding the lepidolite concentrate to a particle size of 300 meshes to obtain lepidolite powder.

[0135] Step (2) mixing: the lepidolite powder obtained in step (1), sodium hydroxide and calcium oxide are mixed in a mass ratio of 1:2:0.5, and mixed with water in a liquid-to-solid ratio of 1 g:8 mL to form a slurry;

[0136] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor, and an autoclave reaction is carried out at 210° C. and 1.85 MPa with a stirring rate of 250 r / min to obtain a dissolution solution.

[0137] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution, wherein the volume ratio of slurry (i.e., eluate): water is 1:10.

[0138] Step (5) concentration: The lithium-containing solution obtained in step (4) is concentrated by evaporation at 50° C. to a lithium concentration of 10 g / L to obtain a lithium-containing concentrated solution.

[0139] Step (6) Carbonization of lithium: adding sodium carbonate to the lithium-containing solution obtained in step (5) to carbonize and precipitate lithium, and filtering to obtain crude lithium carbonate.

[0140] Step (7) purification: The crude lithium carbonate is redissolved and then evaporated and concentrated (the redissolution solvent is lithium hydroxide solution, and the re-evaporation and concentration temperature is 70° C.), cooled and crystallized to obtain a fine lithium carbonate product. The obtained fine lithium carbonate product is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium carbonate product (yield is 87%).

[0141] Example 3

[0142] Taking spodumene as an example, a method for preparing lithium carbonate from solid lithium resources in a short process includes the following steps:

[0143] Step (1) grinding: crushing and grinding the spodumene concentrate to a particle size of 200 mesh to obtain spodumene concentrate powder.

[0144] Step (2) mixing: the spodumene concentrate powder obtained in step (1), sodium hydroxide and calcium oxide are mixed in a mass ratio of 1:4:1, and mixed with water in a liquid-to-solid ratio of 1 g:7 mL to form a slurry;

[0145] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor, and an autoclave reaction is carried out at 300° C. and 8.31 MPa with a stirring rate of 300 r / min to obtain a dissolution solution.

[0146] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution, wherein the volume ratio of slurry (i.e., eluate): water is 1:10.

[0147] Step (5) concentration: The lithium-containing solution obtained in step (4) is concentrated by evaporation at 120° C. to a lithium concentration of 12 g / L to obtain a lithium-containing concentrated solution.

[0148] Step (6) Carbonization of lithium: adding sodium carbonate to the lithium-containing solution obtained in step (5) to carbonize and precipitate lithium to obtain crude lithium carbonate.

[0149] Step (7) purification: The crude lithium carbonate is redissolved and then evaporated and concentrated (the redissolution solvent is lithium hydroxide solution, and the re-evaporation and concentration temperature is 80° C.), cooled and crystallized to obtain fine lithium carbonate. The obtained fine lithium carbonate is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium carbonate product (yield is 84%).

[0150] Example 4

[0151] Taking lepidolite as an example, a method for preparing lithium carbonate from solid lithium resources in a short process includes the following steps:

[0152] Step (1) grinding: crushing and grinding the lepidolite concentrate to a particle size of 200 meshes to obtain lepidolite powder.

[0153] Step (2) mixing: the lepidolite powder obtained in step (1), sodium hydroxide and sodium sulfate are mixed in a mass ratio of 1:2:0.5, and mixed with water in a liquid-to-solid ratio of 1 g:9 mL to form a slurry;

[0154] Step (3) dissolution: the slurry obtained in step (2) was put into a Hastelloy reactor, and an autoclave reaction was carried out at 210° C. and 1.85 MPa with a stirring rate of 500 r / min to obtain a dissolution solution.

[0155] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution, wherein the volume ratio of slurry (i.e., eluate): water is 1:10.

[0156] Step (5) concentration: The lithium-containing solution obtained in step (4) is concentrated by evaporation at 90° C. to a lithium concentration of 13 g / L to obtain a lithium-containing concentrated solution.

[0157] Step (6) Crystallization: The lithium-containing concentrated solution obtained in step (5) is cooled at -15°C to crystallize sodium sulfate. After solid-liquid separation, the obtained lithium-containing solution is evaporated and crystallized at 60°C to obtain crude lithium hydroxide.

[0158] Step (7) Purification: The crude lithium hydroxide is redissolved and then evaporated and concentrated (the redissolution solvent is ultrapure water, and the re-evaporation and concentration temperature is 70° C.), cooled and crystallized to obtain lithium hydroxide fine product. The obtained lithium hydroxide fine product is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium hydroxide monohydrate product (yield is 43%).

[0159] Step (8) circulation: the solid phase precipitated in step (6) and the alkaline filtrate produced are returned to the dissolution system for use in the next round of process flow.

[0160] Example 5

[0161] Taking iron lithium mica as an example, a method for preparing lithium carbonate from solid lithium resources in a short process includes the following steps:

[0162] Step (1) grinding: crushing and grinding the iron lithium mica concentrate to a particle size of 100 mesh to obtain iron lithium mica powder.

[0163] Step (2) mixing: the iron lithium mica powder obtained in step (1), sodium hydroxide and sodium sulfate are mixed in a mass ratio of 1:1:1, and mixed with water in a liquid-to-solid ratio of 1g:5mL to form a slurry;

[0164] Step (3) dissolution: the slurry obtained in step (2) is put into a Hastelloy reactor, and an autoclave reaction is carried out at 250° C. and 3.25 MPa with a stirring rate of 300 r / min to obtain a dissolution solution.

[0165] Step (4) separation: the eluate obtained in step (3) is washed with water and filtered to obtain a lithium-containing solution, wherein the volume ratio of slurry (i.e., eluate): water is 1:5.

[0166] Step (5) concentration: The lithium-containing solution obtained in step (4) is concentrated by evaporation at 50° C. to a lithium concentration of 10 g / L to obtain a lithium-containing concentrated solution.

[0167] Step (6) Crystallization: The lithium-containing concentrated solution obtained in step (5) is cooled at -10°C to crystallize sodium sulfate. After solid-liquid separation, the obtained lithium-containing solution is evaporated and crystallized at 50°C to obtain crude lithium hydroxide.

[0168] Step (7) Purification: The crude lithium hydroxide is redissolved and then evaporated and concentrated (the redissolution solvent is ultrapure water, and the re-evaporation and concentration temperature is 70° C.), cooled and crystallized to obtain lithium hydroxide fine product. The obtained lithium hydroxide fine product is dried, crushed, demagnetized, etc. to obtain a high-purity battery-grade lithium hydroxide monohydrate product (yield is 37%).

[0169] Step (8) circulation: the solid phase precipitated in step (6) and the alkaline filtrate produced are returned to the dissolution system for use in the next round of process flow.

[0170] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing lithium salt products using solid lithium resources in a short process, characterized in that: The following steps are involved: Step (1): crushing, grinding and screening the solid lithium resource to obtain solid lithium resource powder; Step (2): mixing the solid lithium resource powder with an alkaline substance, an additive and water to obtain a slurry; Step (3): performing pressure cooking and dissolution on the slurry to obtain a dissolution solution; Step (4): washing the eluate with water, separating the solid from the liquid, and obtaining a lithium-containing solution; Step (5): evaporating and concentrating the lithium-containing solution, and separating the solid from the liquid to obtain a lithium-containing concentrated solution; Step (6): crystallizing or carbonizing the lithium-containing concentrated solution to obtain a crude lithium salt product; Step (7): recrystallizing the crude lithium salt product to obtain a refined lithium salt; and post-treating the refined lithium salt to obtain a battery-grade lithium salt product.

2. The method according to claim 1, characterized in that In step (1), the solid lithium resource is at least one of spodumene, lepidolite, and ferrolithium mica.

3. The method according to claim 1, characterized in that In step (2), the alkaline substance is at least one of sodium hydroxide, ammonia water, potassium hydroxide, and calcium hydroxide; The auxiliary agent is at least one of sodium carbonate, sodium sulfate, sodium aluminate, potassium sulfate, ammonium sulfate, calcium sulfate, calcium oxide, and slaked lime.

4. The method according to claim 1, characterized in that: In step (2), the mass ratio of the solid lithium resource powder, the alkaline substance and the auxiliary agent is 1:(0.01-10):(0.01-10).

5. The method according to claim 1, characterized in that In step (2), the amount of water used is such that the solid-liquid ratio reaches 1g:(0.1-10)L.

6. The method according to claim 1, characterized in that In step (3), the temperature of the autoclave dissolution is 50-300° C. and the pressure is 0.01-8.31 MPa.

7. The method according to claim 1, characterized in that In step (4), the volume ratio of the dissolution solution to water is 1:(0.5-20).

8. The method according to claim 1, characterized in that In step (5), the temperature of the evaporation and concentration is 50-120° C.; the degree of the evaporation and concentration is such that the lithium concentration is ≥10 g / L.

9. The method according to claim 1, characterized in that: In step (6), the crystallization comprises: first cooling and crystallizing to precipitate a solid phase, separating the solid from the liquid to obtain a lithium-containing liquid, and then evaporating and crystallizing the obtained lithium-containing liquid to obtain a crude lithium salt product; The lithium carbonization precipitation comprises: mixing the lithium-containing concentrated solution with sodium carbonate to carry out lithium carbonization precipitation reaction, and separating the solid from the liquid to obtain a crude lithium salt product.

10. The method according to claim 1, characterized in that In step (7), the recrystallization temperature is 50 to 80° C.; After step (7), the method further includes step (8) of recycling: the solid phase precipitated during the crystallization process of step (6) is re-introduced into the system to participate in the next round of process for recycling; and / or the alkaline filtrate generated during the crystallization process of step (6) is re-introduced into the system to participate in the next round of process for recycling.

Images