Resourceful treatment method for lithium-containing material

Abstract

The invention belongs to the technical field of waste residue recycling, and provides a resourceful treatment method of a lithium-containing material. By means of leaching, metal (Al, K, Na, Cs, Rb, Li, Ca, Mg, Fe, Tl and other heavy metal) in the lithium-containing material can be leached out, and harmlessness of the lithium-containing material is achieved; the brine rich in metal salt is oxidized to remove iron and thallium, so that iron, thallium and other heavy metals in the brine can be fixed and removed in a hydroxide form; cooling crystallization is carried out, so that alkali metal ions and aluminum in the brine can be fixed and removed in the form of aluminum sulfate alum salt; the carbonate precipitation can fix and remove metal ions such as aluminum, calcium and magnesium in the brine in the form of carbonate; magnesium and calcium in the brine can be fixed and removed in the form of calcium-magnesium mud through impurity removal; after evaporation and concentration, recovery of lithium carbonate is realized, and recovery of sodium sulfate is realized through evaporation and crystallization. According to the resourceful treatment method, valuable metal in the lithium-containing material is recycled, and harmless treatment is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste residue recycling, and particularly relates to a resource treatment method of lithium-containing material. BACKGROUND

[0002] Currently known lithium-containing ores include lepidolite and spodumene, etc., in order to obtain a high lithium yield, a method of high-temperature roasting by sulfuric acid or sulfate and then leaching is usually adopted. Mineral separation and enrichment, sulfate roasting and then leaching are common lithium extraction processes, and a large amount of lithium-containing tailings is generated in the lithium extraction process, and the lithium-containing tailings generally contain 0.2-0.7wt% of lithium oxide and are rich in valuable elements such as cesium, rubidium, potassium and aluminum.

[0003] The lithium-containing tailings may contain trace amounts of thallium elements, and thallium is usually fixed in the crystal structure of the ore and is not easy to be dissolved from the solid, but through human activities such as mineral separation and roasting, thallium is easy to be dissolved and released into the environment, which poses a great risk to the environment.

[0004] The existing technology generally adopts landfill or building material to treat the lithium-containing tailings, which causes resource waste and poses a safety risk due to the presence of thallium. SUMMARY

[0005] In view of this, the present application aims to provide a resource treatment method of lithium-containing material. The resource treatment method provided by the present application realizes the harmless treatment of lithium-containing material and effectively recovers valuable elements in the lithium-containing material.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] The present application provides a resource treatment method of lithium-containing material, which comprises the following steps:

[0008] The lithium-containing material is slurried, and the obtained slurry is preheated to obtain preheated slurry;

[0009] The preheated slurry is mixed with sulfuric acid, and leaching is performed under the action of water vapor to obtain leaching residue and brine;

[0010] The brine is mixed with hydrogen peroxide, and iron and thallium are removed by oxidation under the conditions of aeration and acidity to obtain impurity-removed residue and thallium-removed brine;

[0011] The thallium-removed brine is cooled and crystallized to obtain aluminum sulfate salt and purified liquid;

[0012] The purified liquid is subjected to carbonated precipitation under the conditions of aeration and alkalinity to obtain purified residue and lithium-rich brine;

[0013] The lithium-rich brine is purified under alkaline conditions, and the purified solution is evaporated and concentrated under neutral conditions to obtain concentrated brine.

[0014] The concentrated brine and sodium carbonate are mixed and filtered at high temperature to obtain crude lithium carbonate and lithium precipitation mother liquor.

[0015] The lithium precipitation mother liquor was evaporated and crystallized to obtain sodium sulfate;

[0016] The lithium-containing materials include lithium-containing tailings and / or lithium-containing raw ore.

[0017] Preferably, the solid content of the slurry is 20-50%, and the preheating temperature is above 60°C.

[0018] Preferably, the sulfuric acid is concentrated sulfuric acid, and the ratio of the concentrated sulfuric acid to the lithium-containing material is 300-700 mL: 1000 g;

[0019] The pressure of the water vapor is 0.4–0.8 MPa.

[0020] Preferably, the leaching temperature is above 120°C and the leaching time is 0.3 to 4 hours.

[0021] Preferably, the concentration of the hydrogen peroxide is 20-30%, and the amount of hydrogen peroxide added is 0.1-1% of the volume of the brine;

[0022] During the oxidation process to remove thallium iron, the aeration gas is air, the aeration amount is 2 to 4 times the volume of the brine, the aeration time is more than 4 hours, and the acidic pH value is 2 to 3.5.

[0023] Preferably, the cooling crystallization temperature is 5°C.

[0024] Preferably, during the carbonate precipitation process, the aeration gas is CO2, and the alkaline pH value is 8-11.

[0025] Preferably, during the impurity removal process, the alkaline pH value is 12.

[0026] Preferably, the concentration of lithium ions in the concentrated brine is ≥5 g / L.

[0027] Preferably, the concentrated brine and sodium carbonate are mixed at a temperature of 95°C or higher, and the amount of sodium carbonate added is 5-15% of the mass of the concentrated brine.

[0028] This invention provides a method for the resource-based treatment of lithium-containing materials, comprising the following steps: pulping the lithium-containing materials; preheating the resulting slurry to obtain a preheated slurry; mixing the preheated slurry with sulfuric acid and leaching it under steam to obtain leaching residue and brine; mixing the brine with hydrogen peroxide and oxidizing it under aeration and acidic conditions to remove iron and thallium, obtaining impurity-removed residue and thallium-removed brine; cooling and crystallizing the thallium-removed brine to obtain aluminum sulfate and a purified solution; precipitating carbonate in the purified solution under aeration and alkaline conditions to obtain purified residue and lithium-rich brine; removing impurities from the lithium-rich brine under alkaline conditions, and evaporating and concentrating the resulting impurity-removed solution under neutral conditions to obtain concentrated brine; mixing the concentrated brine with sodium carbonate and filtering it at high temperature to obtain crude lithium carbonate and lithium precipitation mother liquor; evaporating and crystallizing the lithium precipitation mother liquor to obtain sodium sulfate; wherein the lithium-containing materials include lithium-containing tailings and / or lithium-containing ore.

[0029] The leaching process of this invention can leach metals (Al, K, Na, Cs, Rb, Li, Ca, Mg, Fe, Tl, and other heavy metals) from lithium-containing materials, achieving the harmless treatment of lithium-containing materials. Oxidation of brine rich in metal salts removes iron and thallium, fixing and removing iron, thallium, and heavy metals in the brine as hydroxides. Cooling and crystallization fixes and separates alkali metal ions (K, Cs, Rb) and aluminum in the brine as aluminum sulfate alum salts. Carbonate precipitation fixes and removes metal ions (Ca, Mg, Al, etc.) in the brine as carbonates and basic carbonates. Impurity removal further fixes and removes residual magnesium and calcium in the brine as calcium magnesium sludge. After evaporation and concentration, lithium carbonate is recovered, and sodium sulfate is recovered through evaporation and crystallization. The resource-based treatment method provided by this invention achieves the recovery of valuable metals from lithium-containing materials and achieves harmless treatment. Attached Figure Description

[0030] Figure 1 A flowchart illustrating the resource recovery method for lithium-containing materials provided by this invention. Detailed Implementation

[0031] Figure 1 The following is a flowchart of the resource recovery method for lithium-containing materials provided by the present invention, in conjunction with... Figure 1 The resource utilization method for lithium-containing materials provided by the present invention is described in detail.

[0032] This invention provides a method for the resource recovery of lithium-containing materials, comprising the following steps:

[0033] The lithium-containing material is pulped, and the resulting pulp is preheated to obtain a preheated pulp.

[0034] The preheated slurry is mixed with sulfuric acid and leached under the action of steam to obtain leaching residue and brine.

[0035] The brine and hydrogen peroxide are mixed and oxidized under aeration and acidic conditions to remove iron and thallium, resulting in brine with impurities and thallium removed.

[0036] The thallium-removed brine is cooled and crystallized to obtain aluminum sulfate alum salt and purified solution;

[0037] The purified liquid undergoes carbonate precipitation (carbon precipitation) under aeration and alkaline conditions to obtain purified residue and lithium-rich brine.

[0038] The lithium-rich brine is purified under alkaline conditions, and the purified solution is evaporated and concentrated under neutral conditions to obtain concentrated brine.

[0039] The concentrated brine and sodium carbonate are mixed and filtered at high temperature to obtain crude lithium carbonate and lithium precipitation mother liquor.

[0040] The lithium precipitation mother liquor was evaporated and crystallized to obtain sodium sulfate;

[0041] The lithium-containing materials include lithium-containing tailings and / or lithium-containing raw ore.

[0042] Unless otherwise specified, all raw materials used in this invention are preferably commercially available products.

[0043] The present invention involves preparing a slurry from lithium-containing materials, preheating the resulting slurry, and obtaining a preheated slurry.

[0044] In this invention, the lithium-containing material includes lithium-containing tailings and / or lithium-containing ore; the lithium-containing ore is preferably powder obtained from lepidolite ore after crushing, grinding, and beneficiation; the lithium-containing tailings are preferably tailings obtained from lithium concentrate powder thermal extraction + leaching or tailings obtained from lepidolite beneficiation. In this invention, the solid content of the slurry is preferably 20-50%, more preferably 20-35%. In this invention, the preheating temperature is preferably above 60°C, more preferably 60-100°C, and more preferably 80-90°C. In this invention, the preheating is preferably carried out in a stirring tank, and the stirring tank is preferably equipped with a heating coil.

[0045] After obtaining the preheated slurry, the preheated slurry of the present invention is mixed with sulfuric acid and leached under the action of steam to obtain leaching residue and brine.

[0046] In this invention, the sulfuric acid is preferably concentrated sulfuric acid, and the ratio of concentrated sulfuric acid to lithium-containing material is preferably 300-700 mL: 1000 g, more preferably 400-500 mL: 1000 g. In this invention, the pressure of the water vapor is preferably 0.4-0.8 MPa, specifically preferably 0.8 MPa.

[0047] In this invention, the leaching temperature is preferably above 120°C, more preferably 120-150°C; the leaching time is preferably 0.3-4 hours, more preferably 1 hour.

[0048] In this invention, the leaching is preferably carried out in a pipe mixer.

[0049] In this invention, the leaching of the preheated slurry and sulfuric acid under the action of steam preferably includes: pumping the preheated slurry and steam into a first pipeline mixer to obtain a first mixture; and pumping the first mixture and sulfuric acid into a second pipeline mixer for leaching.

[0050] Following the leaching process, the present invention preferably further includes: sequentially stirring and separating the obtained leaching system into solid and liquid phases. In this invention, the stirring is preferably performed in a stirred tank. In this invention, the solid-liquid separation is preferably performed by pressure filtration.

[0051] In this invention, the lithium oxide content in the leaching residue is preferably ≤0.09% by mass. In this invention, the leaching residue is preferably subjected to post-treatment, which preferably includes sequential countercurrent rinsing, filtration, and drying to obtain feldspar powder, which is preferably sold; the rinsing water obtained from the countercurrent rinsing is preferably reused.

[0052] After obtaining the brine, the brine described in this invention is mixed with hydrogen peroxide and oxidized to remove iron and thallium under aeration and acidic conditions to obtain brine with impurities and thallium removed.

[0053] In this invention, the concentration of hydrogen peroxide is preferably 20-30%, and the amount of hydrogen peroxide added is preferably 0.1-1% of the volume of the brine.

[0054] In this invention, during the oxidation process to remove thallium iron, the aeration gas is preferably air, the aeration amount is preferably 2 to 4 times the volume of the brine, more preferably 2 times, the aeration time is preferably more than 4 hours, and more preferably 4 to 6 hours; the acidic pH value is preferably 2 to 3.5.

[0055] After the iron-thallium is removed by oxidation, the present invention preferably further includes: solid-liquid separation of the iron-thallium removal system, wherein the solid-liquid separation method is preferably filtration.

[0056] In this invention, the impurity-removing slag is a hydroxide precipitate of iron, thallium, and heavy metals (copper, nickel, etc.), which is collected and stored separately and disposed of by a qualified unit.

[0057] After obtaining the thallium-removed brine, the thallium-removed brine of the present invention is cooled and crystallized to obtain aluminum sulfate alum salt and purification solution.

[0058] In this invention, the preferred temperature for cooling crystallization is 5°C; the cooling crystallization is preferably carried out under stirring conditions. In this invention, the cooling crystallization is preferably carried out in a stirred crystallization tank.

[0059] In this invention, the concentration of lithium ions in the purification solution is preferably ≥5g / L.

[0060] In this invention, when the concentration of lithium ions in the purified liquid is <5g / L, the purified liquid is preferably reused in the pulping section; when the concentration of lithium ions in the purified liquid is ≥5g / L, subsequent processing is performed.

[0061] After cooling and crystallization, the present invention preferably further includes: performing solid-liquid separation on the cooling and crystallization system, wherein the solid-liquid separation method is preferably filtration.

[0062] In this invention, the aluminum sulfate alum salt preferably includes potassium aluminum sulfate, cesium aluminum sulfate, and rubidium aluminum sulfate.

[0063] After obtaining the purified liquid, the purified liquid of the present invention is subjected to carbonate precipitation under aeration and alkaline conditions to obtain purified residue and lithium-rich brine.

[0064] In this invention, during the carbonate precipitation process, the alkaline pH value is preferably 8 to 11, more preferably 9 to 10; the alkaline pH value is preferably maintained by aeration of gas and liquid alkali.

[0065] After the carbonate precipitate is obtained, the present invention preferably further includes: performing solid-liquid separation on the obtained carbonate precipitate system.

[0066] In this invention, the purified residue is preferably subjected to post-treatment, which preferably includes: rinsing and drying the purified residue to obtain a carbon-fixing material rich in carbonate ions.

[0067] After obtaining lithium-rich brine, the lithium-rich brine of the present invention is purified under alkaline conditions, and the purified solution is evaporated and concentrated under neutral conditions to obtain concentrated brine.

[0068] In this invention, during the impurity removal process, the pH value of the alkaline solution is preferably 12; the alkaline adjusting agent is preferably liquid alkali.

[0069] After the impurity removal process, the present invention preferably further includes: separating the impurity removal system to obtain impurity-removed residue. In the present invention, the impurity-removed residue is preferably calcium-magnesium mud.

[0070] In this invention, the neutral adjusting agent is preferably sulfuric acid.

[0071] In this invention, the concentration of lithium ions in the concentrated brine is preferably ≥5 g / L.

[0072] The present invention does not specify the parameters for evaporation and concentration, as long as the concentration of lithium ions in the concentrated brine is ≥5g / L.

[0073] After obtaining concentrated brine, the concentrated brine of the present invention is mixed with sodium carbonate and filtered at high temperature to obtain crude lithium carbonate and lithium precipitation mother liquor.

[0074] In this invention, the temperature at which the concentrated brine and sodium carbonate are mixed is preferably above 95°C, and the amount of sodium carbonate added is preferably 5-15% of the mass of the concentrated brine, specifically preferably 15%.

[0075] In this invention, the crude lithium carbonate is preferably subjected to post-processing to obtain refined lithium carbonate; the post-processing operation is not specifically limited in this invention, and any operation well known to those skilled in the art can be used.

[0076] After obtaining the lithium precipitation mother liquor, the present invention evaporates and crystallizes the lithium precipitation mother liquor to obtain sodium sulfate.

[0077] The present invention does not specifically limit the operation and parameters of the evaporation and crystallization, and any operation known to those skilled in the art can be used.

[0078] In this invention, the evaporation crystallization preferably also yields evaporation condensate and evaporation mother liquor; the evaporation mother liquor is returned to the front section and mixed with recycled water for use.

[0079] In this invention, for ease of explanation, the following reactions are illustrated. The reactants are not all metal oxides, but may be more complex rock structures. The description of metal oxides is for the convenience of explaining the reaction products.

[0080] Leaching process:

[0081] Al₂O₃ + H₂SO₄ = Al₂(SO₄)₃ + H₂O

[0082] K₂O + H₂SO₄ = K₂SO₄ + H₂O

[0083] Na₂O + H₂SO₄ = Na₂SO₄ + H₂O

[0084] Cs₂O + H₂SO₄ = Cs₂SO₄ + H₂O

[0085] Rb₂O + H₂SO₄ = Rb₂SO₄ + H₂O

[0086] Li₂O + H₂SO₄ = Li₂SO₄ + H₂O

[0087] CaO + H₂SO₄ = CaSO₄ + H₂O

[0088] MgO + H₂SO₄ = MgSO₄ + H₂O

[0089] FeO + H₂SO₄ = FeSO₄ + H₂O

[0090] Tl₂O + H₂SO₄ = Tl₂SO₄ + H₂O

[0091] Oxidation to remove thallium iron:

[0092] Tl + -2e=Tl 3+

[0093] Tl 3+ +3H₂O=Tl(OH)₃↓+3H +

[0094] Fe 2+ -e=Fe 3+

[0095] Fe 3+ +3OH — =Fe(OH)3↓

[0096] The precipitate obtained from the above reaction has a very high stability constant, and the solubility coefficient K of Tl(OH)3 is very high. sp Only 10 -45.2 After separation, the potential pollution hazard of thallium will be eliminated.

[0097] After removing thallium and iron from the brine, freezing and crystallization resulted in a large amount of precipitate.

[0098] Al2(SO4)3+24H2O+K2SO4=K2Al2(SO4)4·24H2O↓

[0099] Al2(SO4)3+24H2O+Cs2SO4=Cs2Al2(SO4)4·24H2O↓

[0100] Al2(SO4)3+24H2O+Rb2SO4=Rb2Al2(SO4)4·24H2O↓

[0101] After separating the above mixed precipitate, repeated redissolution and recooling crystallization processes can yield potassium alum—K2Al2(SO4). 4· 24H2O, Cesium alum—Cs2Al2(SO4)4·24H2O, Rubidium alum—Rb2Al2(SO4)4·24H2O.

[0102] The following detailed description of the resource utilization method for lithium-containing materials provided by the present invention, in conjunction with embodiments, should not be construed as limiting the scope of protection of the present invention.

[0103] Example 1

[0104] The powdered lepidolite, after crushing, grinding, and beneficiation, is mixed with water to form a slurry. Reclaimed water from the later stages is used, with a liquid-to-solid ratio of 3:1. The main valuable elements in this lepidolite are: potassium 5.54%, aluminum 12.92%, lithium oxide 1.394%, rubidium oxide 0.528%, cesium oxide 0.124%, iron 1.535%, as well as calcium, magnesium, thallium, and other heavy metals.

[0105] The slurry was continuously poured into a 75m... 3 The mixture is continuously stirred in a pool equipped with a steam heating coil to maintain the slurry temperature above 60℃, with an optimal temperature of 90℃. A pump delivers the preheated slurry to the first pipe mixer, simultaneously introducing steam (0.8 MPa) to raise the material temperature above 100℃. The heated material then enters the second pipe mixer, where a pump delivers 98% sulfuric acid (the ratio of sulfuric acid to powdered lepidolite after crushing, grinding, and beneficiation is 500 mL: 1000 g) to cause a vigorous reaction between the material and the sulfuric acid. The second pipe mixer is connected to an insulated pipe, the diameter and length of which are matched to the material flow rate to ensure the material remains inside the pipe for at least one hour. After continuous reaction in the pipe, the material enters a 75m... 3 In the mixing tank, maintain 75m 3 While maintaining the appropriate liquid level, the mixture in the mixing tank is separated by pressure filtration, and the filtrate enters the next process; the lithium oxide content in the filter residue is 0.09%, and after multiple countercurrent rinsing, filtration, and drying, it is sold as feldspar powder, and the rinsing water is reused.

[0106] The filtrate is collected in an aeration tank, hydrogen peroxide (20% by mass, 1% of the filtrate volume) is added, and air is continuously aerated (aeration rate twice the filtrate volume) for more than 4 hours. Liquid alkali is added to adjust the pH to 2-3.5. A small amount of precipitate appears in the solution. The solution is filtered, and the filter mud is a hydroxide precipitate containing iron and heavy metals (including thallium). It is collected and stored separately and handed over to a qualified unit for disposal.

[0107] The filtrate was pumped into a stirred crystallizing tank and stirred continuously. Cold water was introduced for heat exchange and cooling until the filtrate was cooled to 5°C. A large number of white crystalline salt particles appeared. The filtrate was filtered to obtain a composite alum salt containing potassium aluminum sulfate, cesium aluminum sulfate, and rubidium aluminum sulfate, which was then processed separately.

[0108] For the filtrate from which a large amount of complex alum salts have been separated, the lithium sulfate concentration is not high, and the cost of direct evaporation and concentration to extract lithium is high. In the early stage of production, this part of the filtrate is recycled for pulping. After the lithium ion concentration in the filtrate reaches more than 5g / L, the filtrate is purified.

[0109] Lithium-rich brine was introduced into an aeration tank, and CO2 was continuously bubbled into the bottom aeration disc and liquid alkali was pumped in to maintain the pH of the system between 8 and 11. A large amount of precipitate appeared. The precipitate was separated, rinsed and dried to obtain carbon fixation material rich in carbonate ions.

[0110] The pH of the filtrate is adjusted to 12 with liquid alkali to precipitate and separate residual calcium, magnesium and other impurities in the solution. After filtration and separation, the pH is adjusted to neutral with sulfuric acid. The purified solution is evaporated and concentrated to make the lithium ion concentration in the brine reach more than 10 g / L. Sodium carbonate (15% of the mass of the concentrated brine) is added to the concentrated brine at a temperature above 95°C. The high-temperature brine is centrifuged to obtain crude lithium carbonate and lithium precipitation mother liquor. The crude lithium carbonate and lithium precipitation mother liquor are further processed according to a known process to obtain refined lithium carbonate, sodium sulfate, evaporation condensate and evaporation mother liquor. The evaporation mother liquor is returned to the front section and mixed with recycled water for reuse.

[0111] Example 2

[0112] The lithium slag from the thermal leaching and lithium extraction process of lithium concentrate powder is mixed with water to form a slurry with a liquid-to-solid ratio of 2:1, ensuring the slurry is fluid and transportable. The lithium slag contains: 0.32% lithium oxide, 4.85% potassium, 8.59% aluminum, 0.49% rubidium oxide, 0.10% cesium oxide, 8.53% sodium, 1.27% iron, 4.57% calcium, 0.11% magnesium, 27.65% silicon, 2.83% sulfur, thallium, and other heavy metals.

[0113] The slurry was continuously poured into a 100m³ 3 The mixture is continuously stirred in a tank equipped with a steam heating coil to maintain the slurry temperature above 60℃, with an optimal temperature of 90℃. A pump delivers the preheated slurry to the first pipe mixer, simultaneously introducing steam (0.8 MPa pressure) to maintain the material temperature above 100℃. The heated material then enters the second pipe mixer, where a pump delivers 98% sulfuric acid (450 mL: 1000 g ratio of sulfuric acid to lithium concentrate powder thermal + leaching lithium residue) to the second pipe mixer, causing a vigorous reaction between the material and the sulfuric acid. The second pipe mixer is connected to an insulated pipe, the diameter and length of which are matched to the material flow rate to ensure the material remains inside the pipe for at least one hour. After continuous reaction in the pipe, the material enters a 50m... 3 In the mixing tank, maintain 50m 3 While maintaining the appropriate liquid level, the mixture in the mixing tank is separated by pressure filtration, and the filtrate enters the next process; the lithium oxide content in the filter residue is 0.07%, and after multiple countercurrent rinsing, filtration, and drying, it is sold as feldspar powder, and the rinsing water is reused.

[0114] The filtrate is collected in an aeration tank, hydrogen peroxide (20% by mass, 0.5% of the filtrate volume) is added, and air is continuously aerated (aeration rate twice the filtrate volume) for more than 4 hours. Liquid alkali is added to adjust the pH to 2-3.5. A small amount of precipitate appears in the solution. The solution is filtered, and the filter mud is a hydroxide precipitate containing iron and heavy metals (including thallium). It is collected and stored separately and handed over to a qualified unit for disposal.

[0115] The filtrate was pumped into a stirring tank and stirred continuously. Cold water was introduced for heat exchange and cooling until the filtrate was cooled to 5°C. A large number of white crystalline salt particles appeared. The filtrate was filtered to obtain a composite alum salt containing potassium aluminum sulfate, cesium aluminum sulfate, and rubidium aluminum sulfate, which was then processed separately.

[0116] For filtrate from which a large amount of complex alum salts have been separated, if the lithium sulfate concentration is not high, the cost of direct evaporation and concentration to extract lithium is high. In the early stage of production, this part of the filtrate is recycled for pulping. Once the lithium ion concentration in the filtrate reaches more than 5 g / L, the filtrate is purified.

[0117] Lithium-rich brine was introduced into an aeration tank, and CO2 was continuously bubbled into the bottom aeration disc and liquid alkali was pumped in to maintain the pH of the system between 8 and 11. A large amount of precipitate appeared. The precipitate was separated, rinsed and dried to obtain carbon fixation material rich in carbonate ions.

[0118] The pH of the filtrate is adjusted to 12 with liquid alkali to precipitate and separate residual calcium, magnesium and other impurities in the solution. After filtration and separation, the pH is adjusted to neutral with sulfuric acid. The purified solution is evaporated and concentrated to make the lithium ion concentration in the brine reach more than 10 g / L. Sodium carbonate (15% of the mass of the concentrated brine) is added to the concentrated brine at a temperature above 95°C. The high-temperature brine is centrifuged to obtain crude lithium carbonate and lithium precipitation mother liquor. The crude lithium carbonate and lithium precipitation mother liquor are further processed according to a known process to obtain refined lithium carbonate, sodium sulfate, evaporation condensate and evaporation mother liquor. The evaporation mother liquor is returned to the front section and mixed with recycled water for reuse.

[0119] Example 3

[0120] The pressed mud from lepidolite beneficiation is mixed with water to form a slurry with a liquid-to-solid ratio of 2:1, ensuring the slurry is flowable and transportable. This pressed mud is actually low-grade lepidolite powder, containing: Li₂O 0.36%, Rb₂O 0.13%, Cs₂O 0.024%, Fe 0.33%, aluminum 9.46%, K 2.01%, SiO₂ 65.73%, Mg 0.07%, Na 2.13%, CaO 0.52%, H₂O 19.4%, and heavy metals such as thallium.

[0121] The slurry was continuously poured into a 200m³. 3The mixture is continuously stirred in a pool equipped with a steam heating coil to maintain the slurry temperature above 60℃, with an optimal temperature of 90℃. A pump delivers the preheated slurry to the first pipe mixer, simultaneously introducing steam (0.8 MPa pressure) to raise the material temperature above 100℃. The heated material then enters the second pipe mixer, where a pump delivers 98% sulfuric acid (sulfuric acid and lithium mica beneficiation pressing mud in a ratio of 480 mL: 1000 g) to cause a vigorous reaction between the material and the sulfuric acid. The second pipe mixer is connected to an insulated pipe, the diameter and length of which are matched to the material flow rate to ensure the material remains inside the pipe for at least one hour. After continuous reaction in the pipe, the material enters a 75m... 3 In the mixing tank, while maintaining a suitable liquid level, the mixture in the mixing tank is separated by pressure filtration, and the filtrate enters the next process; the lithium oxide content in the filter residue is 0.06%, and after multiple countercurrent rinsing, filtration and drying, it is sold as feldspar powder, and the rinsing water is reused.

[0122] The filtrate is collected in an aeration tank, hydrogen peroxide (20% by mass, 1% of the filtrate volume) is added, and air is continuously aerated (aeration rate twice the filtrate volume) for more than 4 hours. Liquid alkali is added to adjust the pH to 2-3.5. A small amount of precipitate appears in the solution. The solution is filtered, and the filter mud is a hydroxide precipitate containing iron and heavy metals (including thallium). It is collected and stored separately and handed over to a qualified unit for disposal.

[0123] The filtrate was pumped into a stirring tank and stirred continuously. Cold water was introduced for heat exchange and cooling until the filtrate was cooled to 5°C, at which point white crystalline salt particles appeared. The filtrate was then filtered to obtain a composite alum salt containing potassium aluminum sulfate, cesium aluminum sulfate, and rubidium aluminum sulfate, which was then further processed.

[0124] For the filtrate from which the complex alum salts have been separated, the lithium sulfate concentration is not high, and the cost of direct evaporation and concentration to extract lithium is high. In the early stage of production, this part of the filtrate is recycled for pulping. Once the lithium ion concentration in the filtrate reaches more than 5 g / L, the filtrate is purified.

[0125] Lithium-rich brine was introduced into an aeration tank, and CO2 was continuously introduced into the bottom aeration disc and liquid alkali was pumped in to maintain the pH of the system between 9 and 11. A large amount of precipitate appeared. The precipitate was separated, rinsed and dried to obtain carbon fixation material rich in carbonate ions.

[0126] The filtrate was tested and found to contain no aluminum or iron ions, but contained small amounts of calcium and magnesium ions. The pH was adjusted to 12 with liquid alkali to precipitate and separate the remaining calcium, magnesium, and other impurities in the solution. After filtration, the pH was adjusted to neutral with sulfuric acid, and the purified solution was evaporated and concentrated to achieve a lithium ion concentration of over 10 g / L. Sodium carbonate (15% of the mass of the concentrated brine) was added to the concentrated brine at a temperature above 95°C. The high-temperature brine was then centrifuged to obtain crude lithium carbonate and lithium precipitation mother liquor. The crude lithium carbonate and lithium precipitation mother liquor were further processed according to a known procedure to obtain refined lithium carbonate, sodium sulfate, evaporation condensate, and evaporation mother liquor. The evaporation mother liquor was returned to the front end and mixed with recycled water for reuse.

[0127] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the resource utilization of lithium-containing materials, characterized in that, Includes the following steps: The lithium-containing material is pulped, and the resulting pulp is preheated to obtain a preheated pulp. The preheated slurry is mixed with sulfuric acid and leached under the action of steam to obtain leaching residue and brine. The brine and hydrogen peroxide are mixed and oxidized under aeration and acidic conditions to remove iron and thallium, resulting in brine with impurities and thallium removed. The thallium-removed brine is cooled and crystallized to obtain aluminum sulfate alum salt and purified solution; The purified liquid undergoes carbonate precipitation under aeration and alkaline conditions to obtain purified residue and lithium-rich brine. The lithium-rich brine is purified under alkaline conditions, and the purified solution is evaporated and concentrated under neutral conditions to obtain concentrated brine. The concentrated brine and sodium carbonate are mixed and filtered at high temperature to obtain crude lithium carbonate and lithium precipitation mother liquor. The lithium precipitation mother liquor was evaporated and crystallized to obtain sodium sulfate; The lithium-containing materials include lithium-containing tailings and / or lithium-containing raw ore.

2. The resource recovery method according to claim 1, characterized in that, The slurry has a solid content of 20-50%, and the preheating temperature is above 60°C.

3. The resource recovery method according to claim 1, characterized in that, The sulfuric acid is concentrated sulfuric acid, and the ratio of the concentrated sulfuric acid to the lithium-containing material is 300-700 mL: 1000 g. The pressure of the water vapor is 0.4–0.8 MPa.

4. The resource recovery method according to claim 1 or 3, characterized in that, The leaching temperature is above 120°C, and the leaching time is 0.3 to 4 hours.

5. The resource recovery method according to claim 1, characterized in that, The concentration of the hydrogen peroxide is 20-30%, and the amount of hydrogen peroxide added is 0.1-1% of the volume of the brine. During the oxidation process to remove thallium iron, the aeration gas is air, the aeration amount is 2 to 4 times the volume of the brine, the aeration time is more than 4 hours, and the acidic pH value is 2 to 3.

5.

6. The resource recovery method according to claim 1, characterized in that, The cooling crystallization temperature is 5°C.

7. The resource recovery method according to claim 1, characterized in that, During the carbonate precipitation process, the aeration gas is CO2, and the alkaline pH value is 8-11.

8. The resource recovery method according to claim 1, characterized in that, During the impurity removal process, the alkaline pH value is 12.

9. The resource recovery method according to claim 1, characterized in that, The concentration of lithium ions in the concentrated brine is ≥5 g / L.

10. The resource recovery method according to claim 1 or 9, characterized in that, The concentrated brine and sodium carbonate are mixed at a temperature above 95°C, and the amount of sodium carbonate added is 5-15% of the mass of the concentrated brine.

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