Sulfating roasting smelting process of lepidolite

Abstract

The invention provides a sulfating roasting smelting process of lepidolite, and relates to the technical field of mineral processing. A sulfating roasting smelting process of lepidolite comprises the following steps that S1, low-temperature oxidizing roasting is conducted, specifically, the lepidolite and concentrated sulfuric acid are evenly mixed, and a mixed material A is obtained through low-temperature oxidizing roasting; s2, high-temperature reduction roasting: crushing the mixed material A, adding an auxiliary agent and a wave-absorbing agent, uniformly mixing, and performing high-temperature reduction roasting to obtain a mixed material B; s3, water leaching: carrying out water leaching reaction on the mixed material B, and filtering to obtain lithium slag and brine; s4, concentrating and cooling: concentrating and cooling the brine to obtain concentrated brine and potassium sulfate; s5, impurity removal: removing impurities from the concentrated brine, and filtering to obtain purified liquid; s6, lithium precipitation: adding sodium carbonate into the purified liquid to obtain lithium carbonate and lithium precipitation mother liquid; and S7, extraction and reverse extraction: performing multi-stage extraction and reverse extraction on the lithium precipitation mother liquor to obtain rubidium cesium salt. The smelting process provided by the invention is low in energy consumption and high in product yield.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, and in particular to a sulphate roasting and smelting process of lepidolite. Background Art

[0002] As lithium carbonate resources are the core component of lithium-ion batteries, the need for independent control and development of lithium resources and the research of efficient and environmentally friendly lithium extraction technology has become increasingly prominent. As the mainstream ore resource for lithium extraction in China, lithium mica has the characteristics of complexity, low content and difficulty in processing. Its smelting process research is a hot research topic in China. The traditional methods for extracting lithium from lithium mica mainly include limestone sintering method, pressure cooking method, chlorination roasting method, sulfate method and sulfuric acid method. Specifically: the principle of the sulfate method is the ion exchange reaction of the solid phase under high temperature conditions. The transformation process has less impurities dissolved and is currently the most widely used mica lithium extraction method; the sulfuric acid method is to extract valuable elements from the ore by decomposing it under acidic conditions. It can be divided into sulfuric acid leaching method and sulfuric acid roasting method according to its type. The sulfuric acid leaching method is to obtain a lithium-containing leachate through an acid hydrolysis reaction of mica in an acidic system. Since the acid leaching reaction is non-selective, a large amount of impurities such as aluminum and iron in the mica enter the water leachate. The water leachate is a complex strongly acidic sulfate solution with an aluminum concentration of more than 10g / L, resulting in a large amount of alkali consumption in the impurity removal process and the production of a large number of low-value by-products.

[0003] Sulfuric acid roasting is a roasting method that converts certain metal sulfides and other compounds in the charge into water-soluble sulfates under strict control of the furnace atmosphere and furnace temperature. Patent CN115522070A proposes a method for selectively extracting lithium from lithium aluminum silicate minerals. First, a low-temperature roasting is used to initially destroy the lithium mica structure, and then a two-stage high-temperature roasting is used to recover the residual acid, and the impurities such as aluminum sulfate and iron sulfate in the mineral are decomposed to convert them into water-insoluble iron oxide and aluminum oxide, and finally water leaching is used to achieve the purpose of selectively extracting valuable elements. However, practice shows that for the characteristic lithium mica ore in Yichun area, the lithium conversion rate of this method is low, and the high-temperature roasting process is to completely decompose impurities such as aluminum sulfate, and the roasting temperature and time need to be severely controlled, resulting in high process energy consumption. Therefore, it is urgent to develop a low-energy lithium mica sulfuric acid roasting smelting process, shorten the roasting time and roasting energy consumption, and improve the resource efficiency of lithium ore. Summary of the invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a sulphate roasting and smelting process of lepidolite.

[0005] The present invention provides a sulphate roasting and smelting process for lithium mica, comprising the following steps:

[0006] S1, low temperature oxidation roasting: lepidolite and concentrated sulfuric acid are mixed evenly, and low temperature oxidation roasting is performed to obtain a mixed material A;

[0007] S2, high temperature reduction roasting: after the mixed material A is crushed, an additive and a wave absorber are added, mixed evenly, and then high temperature reduction roasting is performed to obtain a mixed material B;

[0008] S3, water leaching: subjecting the mixed material B to water leaching reaction and filtering to obtain lithium slag and brine;

[0009] S4, concentration and cooling: concentrating and cooling the brine to obtain concentrated brine and potassium sulfate;

[0010] S5, impurity removal: remove impurities from the concentrated brine and filter it to obtain a purified liquid;

[0011] S6, lithium precipitation: adding sodium carbonate to the purified liquid to obtain lithium carbonate and lithium precipitation mother liquor;

[0012] S7, extraction and stripping: subjecting the lithium precipitated mother liquor to multi-stage extraction and stripping to obtain rubidium and cesium salts.

[0013] The sulfation roasting and smelting process of lithium mica proposed in the present invention converts lithium mica into lithium carbonate, potassium sulfate and rubidium-cesium salt through low-temperature oxidation roasting, high-temperature reduction roasting, water leaching, concentration cooling, impurity removal, lithium precipitation and extraction and stripping. The process has the advantages of high element yield and low energy consumption, and effectively improves the resource utilization efficiency of lithium ore.

[0014] Preferably, in S1, the mass ratio of concentrated sulfuric acid to lepidolite is (1.0-2.0):1.

[0015] Preferably, in the S1, the water content of the lepidolite is 10-25wt%.

[0016] Preferably, in S1, the low-temperature oxidation calcination comprises calcining at 150-320° C. for 0.5-5 h in an air atmosphere.

[0017] Since the boiling point of sulfuric acid is 340°C, by controlling the low-temperature roasting temperature range, sulfuric acid can be kept in liquid phase and generate strong oxidizing Lewis acid, which is beneficial to the reaction mass transfer process and promotes mineral decomposition; the purpose of low-temperature oxidation roasting is to promote the decomposition of sulfuric acid into sulfur trioxide, which has stronger oxidizing properties than sulfur dioxide, and then reacts with the ore in a gas-solid manner to promote ore decomposition; in addition, controlling the temperature and time of low-temperature oxidation roasting helps to reduce sulfuric acid consumption and increase the extraction rate of valuable metals such as lithium, rubidium and cesium.

[0018] Preferably, in said S2, the crushed particle size is less than 100 mesh.

[0019] Preferably, in S2, the auxiliary agent is selected from one or more of calcium sulfate, calcium oxide, calcium fluoride, calcium carbonate, calcium hydroxide and calcium carbide.

[0020] The additives are calcium-containing compounds, which promote the reaction of aluminum, silicon, iron and other oxides with the additives during the high-temperature roasting process, further destroying the organizational structure of the lithium mica mineral, thereby increasing the conversion rate of valuable elements. Most of the lithium mica structure has been destroyed in the sulfuric acid low-temperature oxidation roasting process. Therefore, only a small amount of additives is needed to further improve the resource utilization of lithium mica.

[0021] Preferably, in S2, the absorber is selected from one or more of iron powder and iron oxide.

[0022] The present invention introduces an iron-based wave absorbing agent to fully improve the conversion efficiency of the mixed material from absorbed microwave energy to internal energy, thereby further reducing energy consumption.

[0023] Preferably, in the S2, the mass ratio of the mixed material A, the auxiliary agent and the absorber is 100:(5-15):(0-10).

[0024] Preferably, in said S2, the high temperature reduction calcination comprises calcination at 700-1300° C. for 0.5-3 h in a reducing atmosphere.

[0025] In order to solve the problem that sulfates such as iron and aluminum in the sulfation roasting products of lithium mica are difficult to decompose, a reducing atmosphere is introduced. Compared with the traditional solid-solid reaction, the present invention improves the kinetic characteristics of the sulfate decomposition reaction by utilizing gas-solid reaction, greatly reduces the decomposition temperature and decomposition time of substances such as aluminum sulfate and iron sulfate, and significantly reduces energy consumption, thereby realizing "flash roasting" in the sulfate decomposition process.

[0026] More preferably, the reducing atmosphere is selected from one or more of carbon monoxide and hydrogen.

[0027] Preferably, in said S2, the roasting is carried out by microwave heating.

[0028] Microwave metallurgy technology is introduced into the sulfation high-temperature reduction roasting process. Compared with conventional heating, microwave metallurgy heating technology has the characteristics of high heating efficiency, fast rate, low reaction temperature, improved drying efficiency, selective heating, etc., which promotes consumption reduction of traditional metallurgical processes.

[0029] Preferably, in S3, the water immersion reaction comprises immersing the mixed material B in water at 60-90° C. and stirring at a rotation speed of 100-300 rpm for 0.5-2 h.

[0030] The role of water leaching reaction is to dissolve the soluble lithium, rubidium and cesium salts in the ore into the water phase, and then separate them from the aluminosilicate minerals, which is the basis for further separation, purification or preparation of related products.

[0031] More preferably, the mass ratio of water to mixed material B is (0.8-1.5):1.

[0032] Preferably, in S4, the brine is concentrated by 2 to 4 times.

[0033] Preferably, in said S4, the cooling temperature is -5 to 0°C.

[0034] Preferably, in S5, impurity removal includes primary impurity removal and secondary impurity removal; the primary impurity removal uses calcium oxide to adjust the pH of the concentrated brine, and the secondary impurity removal uses sodium carbonate to remove calcium.

[0035] The purpose of primary impurity removal is to remove multivalent cations; the purpose of secondary impurity removal is to remove calcium ions.

[0036] More preferably, the primary impurity removal uses calcium oxide to adjust the pH of the concentrated brine to 10-12 to remove multivalent cations.

[0037] More preferably, the molar ratio of sodium carbonate to calcium in the concentrated brine in the secondary impurity removal is 1.1:1.

[0038] More preferably, the impurity removal process temperature is 30°C.

[0039] Preferably, in the S6, the concentration of sodium carbonate is 200 g / L to 300 g / L; the molar ratio of sodium carbonate to lithium oxide in the purified liquid is (1.0 to 1.3):1, the lithium precipitation temperature is 80 to 100° C., and the aging time is 0.5 to 2 h.

[0040] Controlling the conditions during lithium precipitation helps reduce reagent consumption, lower the lithium concentration in lithium precipitation mother liquor, and effectively improve the efficiency and purity of primary lithium precipitation.

[0041] Preferably, in the S7, the extractant concentration is 0.5-1.0 mol / L, the O / A ratio is 1-4, the extraction time is 0-20 min, and the temperature is 15-50° C.; the stripping agent is sulfuric acid, the concentration is 0.5-2 mol / L, and the stripping A / O ratio is 2-5.

[0042] The beneficial effects of the present invention are:

[0043] The invention adds an auxiliary agent in the high-temperature reduction roasting stage to improve the conversion rate of valuable elements; and by adopting microwave roasting and adding an absorber, aluminum sulfate, iron sulfate and other substances are decomposed in a reducing atmosphere, which greatly shortens the roasting time and roasting energy consumption. Compared with the traditional method, the whole process has the advantages of high element yield and low energy consumption, and effectively improves the resource efficiency of lithium mica ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The figure is a schematic diagram of the process flow of the sulphate roasting and smelting process of lepidolite proposed in the present invention. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is described in detail through specific embodiments.

[0046] Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial sources.

[0047] The lithium mica is lithium mica from Yichun area in China, with a water content of 17%. Its chemical composition is shown in Table 1.

[0048] Table 1

[0049]

[0050] Example 1

[0051] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0052] S1, low temperature oxidation roasting: lepidolite and concentrated sulfuric acid were mixed in a mass ratio of 1:1.5 and placed in a roasting furnace, the reaction temperature was controlled to be 270°C, air was introduced to maintain an oxidizing atmosphere, and low temperature roasting was performed for 1 hour to obtain a mixed material A;

[0053] S2, high-temperature reduction roasting: crush the mixed material A into 120 meshes, add 5% calcium sulfate and 3% iron oxide accounting for the mass of the mixed material A, mix them evenly, put them in a roasting furnace, introduce carbon monoxide to maintain a reducing atmosphere, use microwave heating and control the roasting temperature to be 850°C, the reaction time is 2h, and obtain the mixed material B;

[0054] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0055] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0056] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0057] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0058] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0059] Example 2

[0060] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0061] S1, low-temperature oxidation roasting: lepidolite and concentrated sulfuric acid were mixed uniformly in a mass ratio of 1:1.8 and placed in a roasting furnace, the reaction temperature was controlled to be 270°C, air was introduced to maintain an oxidizing atmosphere, and low-temperature roasting was performed for 1 hour to obtain a mixed material A;

[0062] S2, high-temperature reduction roasting: crush the mixed material A into 120 meshes, add 10% of calcium sulfate and 3% of iron oxide, which account for the mass of the mixed material A, mix them evenly, put them in a roasting furnace, introduce carbon monoxide to maintain a reducing atmosphere, use microwave heating and control the roasting temperature to be 850°C, the reaction time is 1h, and obtain the mixed material B;

[0063] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0064] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0065] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0066] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0067] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0068] Example 3

[0069] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0070] S1, low-temperature oxidation roasting: lepidolite and concentrated sulfuric acid were mixed uniformly in a mass ratio of 1:1.8 and placed in a roasting furnace, the reaction temperature was controlled to be 270°C, air was introduced to maintain an oxidizing atmosphere, and low-temperature roasting was performed for 1 hour to obtain a mixed material A;

[0071] S2, high-temperature reduction roasting: crush the mixed material A into 120 meshes, add 14% of calcium sulfate and 5% of iron oxide, which account for the mass of the mixed material A, mix them evenly, put them in a roasting furnace, introduce carbon monoxide to maintain a reducing atmosphere, use microwave heating and control the roasting temperature to 900°C, the reaction time is 0.5h, and obtain a mixed material B;

[0072] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0073] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0074] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0075] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0076] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0077] Example 4

[0078] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0079] S1, low-temperature oxidation roasting: lepidolite and concentrated sulfuric acid were mixed uniformly in a mass ratio of 1:1.8 and placed in a roasting furnace, the reaction temperature was controlled to be 270°C, air was introduced to maintain an oxidizing atmosphere, and low-temperature roasting was performed for 1 hour to obtain a mixed material A;

[0080] S2, high-temperature reduction roasting: crush the mixed material A into 120 meshes, add 14% of calcium sulfate and 3% of iron oxide, which account for the mass of the mixed material A, mix them evenly, put them in a roasting furnace, introduce carbon monoxide to maintain a reducing atmosphere, use microwave heating and control the roasting temperature to be 1000°C, the reaction time is 0.2h, and obtain the mixed material B;

[0081] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0082] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0083] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0084] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0085] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0086] Comparative Example 1

[0087] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0088] S1, low temperature roasting: lepidolite and concentrated sulfuric acid were mixed in a mass ratio of 1:1.5 and placed in a roasting furnace, the reaction temperature was controlled to 270°C, and low temperature roasting was performed for 2h to obtain a mixed material A;

[0089] S2, high temperature roasting: crush the mixed material A into 120 mesh, place it in a roasting furnace, use combustion heating and control the roasting temperature to be 850°C, the reaction time is 3h, and obtain the mixed material B;

[0090] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0091] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0092] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0093] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0094] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0095] Comparative Example 2

[0096] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0097] S1, low temperature oxidation roasting: lepidolite and concentrated sulfuric acid were mixed in a mass ratio of 1:1.5 and placed in a roasting furnace, the reaction temperature was controlled to be 270°C, air was introduced to maintain an oxidizing atmosphere, and low temperature roasting was performed for 1 hour to obtain a mixed material A;

[0098] S2, high temperature reduction roasting: the mixed material A is crushed into 120 mesh and placed in a roasting furnace, carbon monoxide is introduced to maintain a reducing atmosphere, microwave heating is used and the roasting temperature is controlled to be 850°C, and the reaction time is 2h to obtain a mixed material B;

[0099] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0100] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0101] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0102] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0103] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0104] Comparative Example 3

[0105] A sulphate roasting and smelting process for lepidolite comprises the following steps:

[0106] S1, low temperature oxidation roasting: lepidolite and concentrated sulfuric acid were mixed in a mass ratio of 1:1.5 and placed in a roasting furnace, the reaction temperature was controlled to be 270°C, air was introduced to maintain an oxidizing atmosphere, and low temperature roasting was performed for 1 hour to obtain a mixed material A;

[0107] S2, high temperature roasting: crush the mixed material A into 120 mesh and place it in a roasting furnace, add 5% calcium sulfate and 3% iron oxide accounting for the mass of the mixed material A, mix them evenly and place them in a roasting furnace, use microwave heating and control the roasting temperature to be 850°C, the reaction time is 2h, and obtain the mixed material B;

[0108] S3, water leaching: Mix material B and water in a mass ratio of 1:1.2, stir at 80°C and 120 rpm for 1 hour for water leaching reaction, and filter to obtain lithium slag and brine;

[0109] S4, concentration and cooling: concentrate the brine by 3 times, cool it to -3°C, stir it at 30 rpm, and react it for 0.2h to obtain concentrated brine and potassium sulfate;

[0110] S5. Impurity removal: The concentrated brine is impurity-removed. The pH of the concentrated brine is adjusted to 12.0 by calcium oxide for the first impurity removal to remove multivalent cations. The second impurity removal is calcium removal by sodium carbonate. The molar ratio of sodium carbonate to calcium in the concentrated brine is 1.1:1. The impurity removal process temperature is 30°C. The purified liquid is filtered to obtain;

[0111] S6, lithium precipitation: lithium precipitation is carried out by the reverse addition method of 300g / L sodium carbonate solution, sodium carbonate is added to the purified liquid, the temperature is maintained at 95°C, the aging time is 0.6h, the liquid obtained is the lithium precipitation mother liquor, and the solid is washed three times with water to obtain lithium carbonate; wherein the molar ratio of sodium carbonate to lithium oxide in the purified liquid is 1.2:1;

[0112] S7, extraction and stripping: the lithium precipitate mother liquor is extracted with t-BAMBP, the extractant concentration is 0.8 mol / L, the O / A ratio is 3, the extraction time is 5 min, and the temperature is 25°C; the stripping agent is sulfuric acid, the concentration is 1 mol / L, and the stripping A / O ratio is 3.

[0113] After the above-mentioned sulfuric acid roasting and smelting process of lithium mica, the transformation rate of each element based on the slag is shown in Table 2.

[0114] Table 2

[0115]

[0116] The energy consumption and product of the above-mentioned sulfuric acid roasting and smelting process of lithium mica are shown in Table 3 based on the unit ton of lithium mica.

[0117] Table 3

[0118]

[0119]

[0120] It can be seen from the data in Table 2 that the sulfation roasting and smelting process of the lithium mica of the present invention can increase the amount of sulfuric acid in the low-temperature oxidation roasting process and add additives in the high-temperature reduction roasting stage to improve the leaching rate of valuable elements such as lithium, rubidium and cesium. In the high-temperature roasting process, introducing reducing gas, increasing the roasting temperature and increasing the roasting time can reduce the leaching rate of impurities such as aluminum and iron.

[0121] It can be seen from the data in Table 3 that the sulfation roasting and smelting process of lithium mica of the present invention can significantly reduce energy consumption by microwave roasting, and the additional addition of a wave absorber can further reduce energy consumption; the higher the lithium rubidium cesium leaching rate, the higher the yield of related products. At the same time, the leachate contains more aluminum and iron impurities, which will reduce the yield of salt products such as lithium rubidium cesium.

[0122] It can be seen from the data of Comparative Example 1 and the embodiment that microwave roasting significantly reduces roasting energy consumption, and reduction roasting and adding additives can reduce impurity leaching and improve product yield; it can be seen from the data of Comparative Example 2 and the embodiment that additives can improve the leaching rate and yield of lithium, rubidium and cesium, and the absorbing material is beneficial to further reduce energy consumption; it can be seen from the data of Comparative Example 3 and the embodiment that high-temperature roasting and the introduction of reducing gas help decompose impurities such as aluminum sulfate / iron, inhibit the water leaching and dissolution of iron / aluminum elements, and improve the product yield.

[0123] In summary, the sulphate roasting and smelting process of lepidolite provided by the present invention has low energy consumption and high yield of the obtained product.

[0124] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A sulphate roasting and smelting process of lepidolite, characterized in that: The following steps are involved: S1, low temperature oxidation roasting: lepidolite and concentrated sulfuric acid are mixed evenly, and low temperature oxidation roasting is performed to obtain a mixed material A; S2, high temperature reduction roasting: after the mixed material A is crushed, an additive and a wave absorber are added, mixed evenly, and then high temperature reduction roasting is performed to obtain a mixed material B; S3, water leaching: subjecting the mixed material B to water leaching reaction and filtering to obtain lithium slag and brine; S4, concentration and cooling: concentrating and cooling the brine to obtain concentrated brine and potassium sulfate; S5, impurity removal: remove impurities from the concentrated brine and filter it to obtain a purified liquid; S6, lithium precipitation: adding sodium carbonate to the purified liquid to obtain lithium carbonate and lithium precipitation mother liquor; S7, extraction and stripping: subjecting the lithium precipitated mother liquor to multi-stage extraction and stripping to obtain rubidium and cesium salts.

2. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the above-mentioned S1, the low-temperature oxidation calcination includes calcination at 150-320° C. for 0.5-5 h in an air atmosphere.

3. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the S2, the auxiliary agent is selected from one or more of calcium sulfate, calcium oxide, calcium fluoride, calcium carbonate, calcium hydroxide, and calcium carbide.

4. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the above-mentioned S2, the wave absorbing agent is selected from one or more of iron powder and iron oxide.

5. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the above-mentioned S2, the high-temperature reduction calcination includes calcination at 700-1300° C. for 0.5-3 h in a reducing atmosphere.

6. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the above-mentioned S3, the water immersion reaction comprises immersing the mixed material B in water at 60-90° C. and stirring at a rotation speed of 100-300 rpm for 0.5-2 hours.

7. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the above-mentioned S5, impurity removal includes primary impurity removal and secondary impurity removal; the primary impurity removal uses calcium oxide to adjust the pH of the concentrated brine, and the secondary impurity removal uses sodium carbonate to remove calcium.

8. The sulphation roasting and smelting process of lepidolite according to claim 1, characterized in that: In the S6, the concentration of sodium carbonate is 200g / L to 300g / L; the molar ratio of sodium carbonate to lithium oxide in the purified liquid is (1.0 to 1.3):1.

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