Method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue

Abstract

The present application belongs to the field of metallurgy, and particularly relates to a method for efficiently extracting lithium from spodumene and comprehensively utilizing waste residue. The method uses spodumene concentrate as raw material and sodium oxide or sodium salt as additive. After mixing and pelletizing, high-temperature calcination is performed to convert spodumene into nepheline or albite, decompose combined lithium oxide in spodumene, and then perform leaching with alkali liquor to dissolve lithium oxide in the form of lithium hydroxide into solution. After purification and concentration, sodium carbonate is added to the leaching solution, and lithium carbonate is obtained by sedimentation, filtration and separation. The leaching residue is mixed with aluminum powder, pelletized, and then subjected to aluminothermic vacuum reduction. The reduced residue is converted into a refractory material raw material mainly composed of alumina and silica. The metallic sodium obtained by vacuum reduction is further converted into sodium oxide by controlled combustion, and then into sodium salt as additive. The present application solves the problems of high energy consumption, large sulfuric acid consumption, and waste residue utilization in the prior art process of extracting lithium from spodumene concentrate by sulfuric acid method.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy, and particularly relates to a method for efficiently extracting lithium from spodumene and comprehensively utilizing waste residues. BACKGROUND

[0002] There are mainly three forms of lithium resources: salt lake brine lithium ore, pegmatite type hard rock lithium ore and sedimentary rock type clay lithium ore, wherein the salt lake brine lithium ore accounts for more than 60% of the total amount of global lithium resources and is the most common form of lithium resources, but its development degree is much lower than that of mine lithium. At present, domestic lithium salt is mainly extracted from spodumene and lepidolite. In the process of extracting lithium from spodumene, the sulfuric acid method is mostly adopted. The sulfuric acid method is to first convert alpha-spodumene contained in spodumene concentrate into beta-spodumene at high temperature, then mix the calcined beta-spodumene with concentrated sulfuric acid to perform sulfuric acid roasting, and after cooling, water leaching is performed to generate soluble lithium sulfate and insoluble gangue. The leaching solution is adjusted to pH by lime milk, and carbonates are added to remove impurities such as calcium, magnesium, iron and aluminum to obtain a purified lithium sulfate solution. Sodium carbonate is added to precipitate lithium carbonate, and the extraction rate of lithium can reach 90%. However, a large amount of insoluble gangue and neutralization residue cannot be utilized in the process of extracting lithium by the sulfuric acid method, and the energy consumption is large in the two roasting processes. A large amount of acid is consumed in the treatment process, and a large amount of sulfate salt cannot be utilized. The whole process has high energy consumption and large pollution. SUMMARY

[0003] The purpose of the present application is to provide a method for efficiently extracting lithium from spodumene and comprehensively utilizing waste residues, which solves the problems of high energy consumption, large sulfuric acid consumption and waste residue utilization in the process of extracting lithium from spodumene concentrate by the sulfuric acid method in the prior art.

[0004] The technical scheme of the present application is as follows:

[0005] A method for efficiently extracting lithium from spodumene and comprehensively utilizing waste residues, mainly comprising the following steps:

[0006] (1) Spodumene calcination conversion

[0007] First, the spodumene concentrate is ground to a particle size of less than 0.15 mm, and then mixed with sodium oxide or sodium salt as an additive. The particle size of the sodium salt is less than 0.15 mm. The content of lithium oxide in the spodumene concentrate is more than 5.0 wt%, and the mass mixing ratio of the spodumene concentrate and the additive is 1:(0.10-0.90). The mixed material is placed into a dry powder ball press to form a pellet, and the pelletizing pressure is 100-500 MPa. The pressed pellet is placed into a calcination device for calcination, and the calcination temperature is 1000-1250℃, and the calcination time is 1-20h.

[0008] (2) Dissolution of lithium oxide and purification of solution

[0009] The calcined material is ground to a particle size of less than 0.10 mm, and then is put into a sodium hydroxide aqueous solution with a temperature of 20-90℃ for leaching, the concentration of sodium hydroxide is 1-50g / L, the leaching time is 10-120min, and the liquid-solid ratio during the leaching process is (3-10):1; after the leaching, filtration is performed to obtain a first filtrate and a filter residue, which are a leaching solution and a leaching residue respectively; the filtrate is evaporated and concentrated to make the concentration of lithium hydroxide in the lithium hydroxide solution in the filtrate reach 100g / L or more, the concentrated filtrate is kept at a temperature of 40-80℃, and sodium carbonate is added to the concentrated filtrate, so that lithium hydroxide in the solution is converted into lithium carbonate precipitate, filtration is performed to obtain a second filtrate and a filter residue, and the filter residue is washed with deionized water and then is dried to obtain a lithium carbonate product;

[0010] (3) Comprehensive utilization of leaching residue

[0011] The obtained leaching residue is dried at a temperature of 100-150℃ for 2-10h, and then is ground to a particle size of less than 0.15 mm, and then is uniformly mixed with aluminum powder with a particle size of less than 0.15 mm to obtain a mixture, the mass ratio of the leaching residue to the aluminum powder is 100:(5-10); the mixture is pressed into a ball with a briquetting pressure of 100-200MPa, and then the briquetting material is put into a vacuum reduction tank, the vacuum reduction tank is placed in a reduction furnace, vacuum is drawn, and then the vacuum reduction tank is heated to 900-1200℃ for reduction; during the reduction, the residual pressure in the vacuum reduction tank is 0.1-30Pa, and the vacuum reduction time is 3-8h, and after the reduction, crystalline sodium and a reduction residue are obtained.

[0012] In step (1) of the method, the sodium salt is sodium carbonate, sodium hydroxide or sodium bicarbonate, the mass ratio of the spodumene concentrate to sodium oxide is 1:(0.10-0.30), the mass ratio of the spodumene concentrate to sodium hydroxide is 1:(0.20-0.50), the mass ratio of the spodumene concentrate to sodium carbonate is 1:(0.25-0.60), and the mass ratio of the spodumene concentrate to sodium bicarbonate is 1:(0.45-0.90).

[0013] In step (1) of the method, the reactions occurring during the calcination are as follows:

[0014] Li2O·Al2O3·4SiO2+2Na2O=Na2O·Al2O3·2SiO2+Na2O·Al2O3·6SiO2+2Li2O (1)

[0015] Li2O·Al2O3·4SiO2+4NaOH=Na2O·Al2O3·2SiO2+Na2O·Al2O3·6SiO2+2H2O+2Li2O (2)

[0016] Li2O AI2O3 4SiO2 + 2Na2CO3 = Na2O AI2O3 2SiO2 + Na2O AI2O3 6SiO2 + 2CO2 + 2Li2O (3)

[0017] Li2O AI2O3 4SiO2 + 4NaHCO3 = Na2O AI2O3 2SiO2 + Na2O AI2O3 6SiO2 + 2CO2 + H2O + 2Li2O (4).

[0018] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (1), the calcination device of the mixture of spodumene concentrate and sodium oxide or sodium salt is a rotary kiln, a tunnel kiln or a muffle furnace.

[0019] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (2), the drying temperature is 150-350°C, and the drying time is 1-10h.

[0020] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (2), the secondary filtrate and the washing liquid after washing the filter residue are mixed, the concentration of sodium hydroxide is adjusted, and then returned to the calcination material leaching process as a leaching solution.

[0021] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (3), the reaction occurring during the reduction process is as follows:

[0022] 9Na2O AI2O3 2SiO2 (s) + 4Al (l) = 12Na (g) + 8Al2O3 (s) + 3Na2O AI2O3 6SiO2 (s) (5)

[0023] 3Na2O AI2O3 2SiO2 (s) + 2Al (l) = 6Na (g) + 4Al2O3 (s) + 6SiO2 (s) (6)

[0024] 3Na2O AI2O3 6SiO2 (s) + 2Al (l) = 6Na (g) + 4Al2O3 (s) + 18SiO2 (s) (7).

[0025] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (3), the main components of the reduction residue obtained after reduction are alumina and silicon oxide, which are used as raw materials for silicon-aluminum refractory materials; the crystalline sodium is converted into sodium oxide through controllable combustion, and the sodium oxide is returned to the spodumene calcination conversion process as an additive for raw materials.

[0026] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (3), the vacuum reduction tank is divided into a crystallization zone and a reduction zone, and the length ratio of the crystallization zone to the reduction zone is 1:3-1:5.

[0027] The lithium extraction and waste residue comprehensive utilization method of spodumene, in step (3), the reduction furnace adopts electric heating, or the reduction furnace adopts water gas or natural gas as a heat source.

[0028] The design idea of the present application is:

[0029] The current lithium ore lithium extraction process needs two times of calcination, and the whole process has high energy consumption, large acid consumption, and the waste residue cannot be utilized. The present application adds a small amount of alkali to spodumene, and high-temperature calcination converts the spodumene phase into a sodium feldspar or nepheline phase, so that the lithium oxide existing in the spodumene phase is converted into free lithium oxide, and then the free lithium oxide is dissolved into the solution by water solution leaching, so as to realize the extraction of lithium. The method has low alkali consumption, only needs one time of calcination, has low energy consumption, the alkali in the waste residue can be recycled and reused, the treated waste residue can be utilized, and compared with the traditional acid treatment, the method is energy-saving and environmentally friendly, and has low cost.

[0030] The advantages and beneficial effects of the present application are:

[0031] The high-efficiency lithium extraction and waste residue comprehensive utilization method of the present application has the advantages of simple process, low cost, low sodium salt consumption, most of the sodium salt can be returned for reuse, the treated waste residue can be used as a silicon-aluminum refractory material, the whole process does not produce waste, and is pollution-free. The method is an energy-saving and environmentally friendly production method of lithium carbonate, and has good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The present application is a high-efficiency lithium extraction and waste residue comprehensive utilization process flow diagram. DETAILED DESCRIPTION

[0033] As shown in Figure 1 The high-efficiency lithium extraction and waste residue comprehensive utilization process flow of the present application is as follows:

[0034] Using spodumene concentrate as raw material and sodium oxide or sodium salts (such as sodium carbonate, sodium hydroxide, or sodium bicarbonate) as additives, the mixture is mixed, formed into pellets, and then calcined at high temperature to convert spodumene into nepheline or albite. This process decomposes the combined lithium oxide in spodumene. Then, alkaline leaching is performed to dissolve the lithium oxide into the solution as lithium hydroxide. After purification and concentration, sodium carbonate is added to the leachate, and the mixture is separated by sedimentation and filtration to obtain lithium carbonate. The secondary filtrate after filtration is adjusted as needed to meet the requirements for alkaline solution use. The leaching residue (mainly albite and nepheline) is mixed with aluminum powder, formed into pellets, and then subjected to aluminothermic vacuum reduction. The reduction residue obtained from vacuum reduction is converted into a silica-alumina refractory material raw material with alumina and silicon oxide as the main components. The metallic sodium obtained from vacuum reduction is then subjected to controlled combustion to obtain sodium oxide, which is further converted into sodium salts for use as additives.

[0035] The present invention will now be described in further detail with reference to the embodiments.

[0036] Example 1

[0037] like Figure 1 As shown in the figure, this embodiment proposes a method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue, which mainly includes the following steps:

[0038] (1) Calcination and conversion of spodumene

[0039] First, spodumene concentrate is ground to a particle size of less than 0.15 mm. Then, it is mixed with sodium oxide as an additive, with a sodium oxide particle size of less than 0.15 mm. The lithium oxide content in the spodumene concentrate is 6.5 wt%, and the mass ratio of spodumene concentrate to sodium oxide is 1:0.20. The uniformly mixed material is then placed in a dry powder briquetting machine and pressed into pellets at a pressure of 300 MPa. The pressed pellets are then placed in a rotary kiln for calcination at 1150℃ for 10 hours.

[0040] (2) Lithium oxide leaching and solution purification

[0041] The calcined material was ground to a particle size of less than 0.10 mm, and then leached in a sodium hydroxide aqueous solution at 50°C (30 g / L) for 50 min at a liquid-to-solid ratio of 6:1. After leaching, the solution was filtered to obtain a primary filtrate and a leaching residue, respectively. The filtrate was then evaporated and concentrated to achieve a lithium hydroxide concentration of over 100 g / L in the lithium hydroxide aqueous solution. The concentrated filtrate was kept at 60°C, and sodium carbonate was added. The lithium hydroxide in the solution was converted into lithium carbonate precipitate, which was then filtered to obtain a secondary filtrate and a filter residue. The filter residue was washed with deionized water and dried to obtain the lithium carbonate product at 280°C for 4 h.

[0042] The secondary filtrate and the washing solution are mixed, the concentration of sodium hydroxide is adjusted, and the mixture is returned to the leaching process of the calcined material as a leaching solution.

[0043] (3) Comprehensive utilization of leaching residue

[0044] The obtained leaching residue is dried at a temperature of 120°C for 7h, and then the dried leaching residue is ground to a particle size of less than 0.15mm, and then mixed uniformly with aluminum powder with a particle size of less than 0.15mm to obtain a mixture, the mass ratio of the leaching residue to the aluminum powder being 100:8; the mixture is pressed into a ball, the briquetting pressure being 160MPa, and then the briquetting material is placed into a vacuum reduction tank, the vacuum reduction tank being placed in a reduction furnace, vacuum is drawn, and then the reduction tank is heated to 1000°C for reduction; the residual pressure in the reduction tank during the reduction is 10Pa, the vacuum reduction time is 6 hours, and crystalline sodium and reduction residue are obtained after reduction.

[0045] The main components of the reduction residue obtained after reduction are aluminum oxide and silicon oxide, which are used as raw materials for silico-alumina refractory materials. The crystalline sodium is converted into sodium oxide by controlled combustion, and the sodium oxide is returned to the lithium spar calcination conversion process as an additive for raw materials.

[0046] The vacuum reduction tank is placed in the reduction furnace, the reduction furnace is similar to the reduction furnace for the Pidgeon process for magnesium smelting, and the reduction tank is similar to the reduction tank for the Pidgeon process for magnesium smelting, which is divided into a crystallization zone and a reduction zone, and the length ratio of the crystallization zone to the reduction zone is 1:4.

[0047] Example 2

[0048] As shown in Figure 1 , the present embodiment proposes a method for efficient lithium extraction from lithium spar and comprehensive utilization of waste residue, which mainly includes the following steps:

[0049] (1) Calcination conversion of lithium spar

[0050] First, the lithium spar concentrate is ground to a particle size of less than 0.15mm, and then mixed with sodium hydroxide as an additive, the particle size of the sodium salt being less than 0.15mm, wherein the lithium oxide content in the lithium spar concentrate is 6.5wt%, and the mass ratio of the lithium spar concentrate to the sodium hydroxide is 1:0.35. The uniformly mixed material is placed into a dry powder ball press to be pressed into a briquetting material, the briquetting pressure being 200MPa. The pressed briquetting material is placed into a tunnel kiln for calcination, the calcination temperature being 1000°C, and the calcination time being 20h.

[0051] (2) Dissolution of lithium oxide and purification of the solution

[0052] The calcined material is ground to a particle size of less than 0.10 mm, and then is put into a sodium hydroxide aqueous solution at a temperature of 60°C for leaching. The concentration of the sodium hydroxide is 20 g / L, the leaching time is 60 min, and the liquid-solid ratio during the leaching process is 8:1. After leaching, filtration is performed to obtain a first filtrate and a filter residue, which are a leaching solution and a leaching residue, respectively. The filtrate is evaporated and concentrated to make the concentration of lithium hydroxide in the lithium hydroxide aqueous solution in the filtrate reach more than 100 g / L. The concentrated filtrate is kept at a temperature of 50°C, and sodium carbonate is added to the concentrated filtrate. Lithium hydroxide in the solution is converted into lithium carbonate precipitate, which is separated by filtration to obtain a second filtrate and a filter residue. The filter residue is washed with deionized water and then is dried to obtain a lithium carbonate product. The drying temperature is 240°C, and the drying time is 6 h.

[0053] The second filtrate and the washing solution are mixed, and the concentration of sodium hydroxide is adjusted. The mixture is returned to the leaching process of the calcined material as a leaching solution.

[0054] (3) Comprehensive utilization of leaching residue

[0055] The obtained leaching residue is dried at a temperature of 130°C for 5 h, and then is ground to a particle size of less than 0.15 mm. The ground leaching residue is uniformly mixed with aluminum powder having a particle size of less than 0.15 mm to obtain a mixture. The mass ratio of the leaching residue to the aluminum powder is 100:7. The mixture is pressed into a ball at a briquetting pressure of 180 MPa. The briquetted material is put into a vacuum reduction pot, which is placed in a reduction furnace. The vacuum reduction pot is heated to 1100°C for reduction after being vacuumized. The residual pressure in the vacuum reduction pot during the reduction is 15 Pa, and the vacuum reduction time is 5 h. Crystalline sodium and a reduction residue are obtained after the reduction.

[0056] The main components of the reduction residue obtained after the reduction are aluminum oxide and silicon oxide, which are used as raw materials for silico-alumina refractory materials. The crystalline sodium is converted into sodium oxide by controllable combustion, and the sodium oxide is returned to the lithium spodumene calcination conversion process as an additive for raw materials.

[0057] The vacuum reduction pot is placed in the reduction furnace, which is similar to a reduction furnace for the Pidgeon process for magnesium smelting. The vacuum reduction pot is similar to a reduction pot for the Pidgeon process for magnesium smelting, and is divided into a crystallization zone and a reduction zone. The length ratio of the crystallization zone to the reduction zone is 1:4.

[0058] Example 3

[0059] As shown in Figure 1 , the present embodiment proposes a method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue, which mainly includes the following steps:

[0060] (1) Spodumene calcination conversion

[0061] Firstly, the spodumene concentrate is ground to a particle size of less than 0.15 mm, and then is dosed with sodium carbonate as an additive, the particle size of sodium salt is less than 0.15 mm, wherein the lithium oxide content in the spodumene concentrate is 6.5wt%, the mass ratio of spodumene concentrate to sodium carbonate is 1:0.42. The mixed material is put into a dry powder ball press to press into pellets, the pelletizing pressure is 150 MPa. The pressed pellet material is put into a muffle furnace for calcination, the calcination temperature is 1200℃, and the calcination time is 5h.

[0062] (2) Dissolution of lithium oxide and purification of solution

[0063] The calcined material is ground to a particle size of less than 0.10 mm, and then is put into a sodium hydroxide aqueous solution at a temperature of 40℃ for leaching, the concentration of sodium hydroxide is 40g / L, the leaching time is 20min, and the liquid-solid ratio during leaching is 10:1; after leaching, filtration is performed to obtain a first filtrate and a filter residue, which are leaching solution and leaching residue respectively; the filtrate is evaporated and concentrated to make the concentration of lithium hydroxide in the lithium hydroxide aqueous solution in the filtrate reach more than 100g / L, the temperature of the concentrated filtrate is maintained at 40℃, and sodium carbonate is added to the concentrated filtrate, the lithium hydroxide in the solution is converted into lithium carbonate precipitate, and a second filtrate and a filter residue are obtained by filtration. The filter residue is dried after washing with deionized water to obtain a lithium carbonate product, the drying temperature is 180℃, and the drying time is 9h.

[0064] The second filtrate and the washing solution are mixed and adjusted to a sodium hydroxide concentration, and then are returned to the leaching process of the calcined material as a leaching solution.

[0065] (3) Comprehensive utilization of leaching residue

[0066] The obtained leaching residue is dried at a temperature of 110℃ for 9h, and then is ground to a particle size of less than 0.15 mm, and then is mixed with aluminum powder having a particle size of less than 0.15 mm to obtain a mixture, the mass ratio of leaching residue to aluminum powder is 100:9; the mixture is pressed into balls, the pelletizing pressure is 180 MPa, and then the pellet material is put into a vacuum reduction pot, the vacuum reduction pot is placed in a reduction furnace, vacuum is drawn, and then the reduction pot is heated to 1200℃ for reduction; the residual pressure in the reduction pot during reduction is 5Pa, the vacuum reduction time is 4 hours, and crystalline sodium and reduction residue are obtained after reduction.

[0067] The reduction residue obtained after reduction mainly contains aluminum oxide and silicon oxide, which can be used as raw materials for silicon-aluminum refractory materials. The crystalline sodium is converted into sodium oxide by controlled combustion, and the sodium oxide is returned to the spodumene calcination conversion process as an additive for raw materials.

[0068] The vacuum reduction tank is placed in a reduction furnace, the reduction furnace is similar to a reduction furnace for the Pidgeon process of magnesium smelting, the reduction tank is similar to a reduction tank for the Pidgeon process of magnesium smelting, and the reduction tank is divided into a crystallization zone and a reduction zone, wherein the length ratio of the crystallization zone to the reduction zone is 1:4.

[0069] Example 4

[0070] As Figure 1 shown, the present embodiment proposes a method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue, mainly comprising the following steps:

[0071] (1) Spodumene calcination conversion

[0072] First, the spodumene concentrate is ground to a particle size of less than 0.15 mm, then mixed with sodium bicarbonate as an additive, the particle size of the sodium salt is less than 0.15 mm, wherein the lithium oxide content in the spodumene concentrate is 6.5wt%, the mass ratio of the spodumene concentrate to sodium bicarbonate is 1:0.78. The mixed material is put into a dry powder ball press to press into a pellet, the pelletizing pressure is 350MPa. The pressed pellet is placed in a muffle furnace for calcination, the calcination temperature is 1050℃, and the calcination time is 13h.

[0073] (2) Dissolution of lithium oxide and purification of solution

[0074] The calcined material is ground to a particle size of less than 0.10 mm, then immersed in a sodium hydroxide aqueous solution at a temperature of 70℃, the concentration of sodium hydroxide is 10g / L, the dissolution time is 80min, and the liquid-solid ratio during dissolution is 3:1; after dissolution, filtration is performed to obtain a first filtrate and a filter residue, which are leaching solution and leaching residue respectively; the filtrate is evaporated and concentrated to make the concentration of lithium hydroxide in the lithium hydroxide aqueous solution in the filtrate reach more than 100g / L, the concentrated filtrate is kept at a temperature of 80℃, and sodium carbonate is added to the concentrated filtrate, the lithium hydroxide in the solution is converted into lithium carbonate precipitate, and a second filtrate and a filter residue are obtained by filtration. The filter residue is washed with deionized water and then dried to obtain a lithium carbonate product, the drying temperature is 320℃, and the drying time is 2h.

[0075] The second filtrate and the washing solution are mixed, the concentration of sodium hydroxide is adjusted, and then returned to the leaching process of the calcined material as a leaching solution.

[0076] (3) Comprehensive utilization of leaching residue

[0077] The obtained leaching residue is dried at a temperature of 140℃ for 3h, then the dried leaching residue is ground to below 0.15mm, then mixed with aluminum powder with a particle size of less than 0.15mm to obtain a mixture, the mass ratio of leaching residue to aluminum powder is 100:6; the mixture is pressed into a ball, the balling pressure is 120MPa, then the balling material is put into a vacuum reduction tank, the vacuum reduction tank is placed in a reduction furnace, vacuum is extracted, then the reduction tank is heated to 900℃ for reduction; the residual pressure in the reduction tank during reduction is 20Pa, the vacuum reduction time is 7 hours, after reduction, crystalline sodium and reduction residue are obtained.

[0078] The main components of the reduction residue obtained after reduction are alumina and silica, which are used as raw materials for silico-alumina refractory materials. The crystalline sodium is converted into sodium oxide by controlled combustion, and the sodium oxide is returned to the spodumene calcination conversion process as an additive for raw materials.

[0079] The vacuum reduction tank is placed in the reduction furnace, the reduction furnace is similar to the Pidgeon method magnesium reduction furnace, and the reduction tank is similar to the Pidgeon method magnesium reduction tank, which is divided into two parts of crystallization zone and reduction zone, and the length ratio of the crystallization zone to the reduction zone is 1:4.

Claims

1. A method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue, characterized in that, The method mainly comprises the following steps: (1) Calcination conversion of spodumene Firstly, the spodumene concentrate is ground to a particle size of less than 0.15 mm, and then is mixed with sodium oxide, sodium carbonate, sodium hydroxide or sodium bicarbonate as additives, the particle size of sodium carbonate, sodium hydroxide or sodium bicarbonate is less than 0.15 mm, wherein the lithium oxide content in the spodumene concentrate is more than 5.0 wt%, the mass mixing ratio of the spodumene concentrate and the additives is 1:(0.10-0.90), the mixed material is put into a dry powder ball press to be pressed into a ball, and the balling pressure is 100-500 MPa; the pressed ball material is put into a calcination device to be calcined, the calcination temperature is 1000-1250℃, and the calcination time is 1-20 h; (2) Dissolution of lithium oxide and purification of solution The calcined material is ground to a particle size of less than 0.10 mm, and then is put into a sodium hydroxide aqueous solution with a temperature of 20-90℃ to be leached, the concentration of the sodium hydroxide is 1-50 g / L, the dissolution time is 10-120 min, and the liquid-solid ratio in the dissolution process is (3-10):1; after the dissolution, filtration is performed to obtain a first filtrate and a filter residue, which are a leaching solution and a leaching residue respectively; the filtrate is evaporated and concentrated, so that the concentration of lithium hydroxide in the lithium hydroxide aqueous solution in the filtrate reaches more than 100 g / L, the temperature of the concentrated filtrate is maintained at 40-80℃, sodium carbonate is added to the concentrated filtrate, lithium hydroxide in the solution is converted into lithium carbonate precipitate, a second filtrate and a filter residue are obtained by filtration, and the filter residue is dried after being washed by deionized water to obtain a lithium carbonate product; (3) Comprehensive utilization of leaching residue The obtained leaching residue is dried at a temperature of 100-150℃ for 2-10 h, then is ground to a particle size of less than 0.15 mm, and then is uniformly mixed with aluminum powder with a particle size of less than 0.15 mm to obtain a mixture, the mass ratio of the leaching residue and the aluminum powder is 100:(5-10); the mixture is pressed into a ball with a balling pressure of 100-200 MPa, and then the ball material is put into a vacuum reduction tank, the vacuum reduction tank is placed in a reduction furnace, vacuum is drawn, and then the vacuum reduction tank is heated to 900-1200℃ for reduction; during the reduction, the residual pressure in the vacuum reduction tank is 0.1-30 Pa, and the vacuum reduction time is 3-8 hours; and crystalline sodium and a reduction residue are obtained after the reduction.

2. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (1), the mass mixing ratio of the spodumene concentrate and sodium oxide is 1:(0.10-0.30), the mass mixing ratio of the spodumene concentrate and sodium hydroxide is 1:(0.20-0.50), the mass mixing ratio of the spodumene concentrate and sodium carbonate is 1:(0.25-0.60), and the mass mixing ratio of the spodumene concentrate and sodium bicarbonate is 1:(0.45-0.90).

3. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (1), the reaction occurring during the calcination is as follows: 2Li2O·Al2O3·4SiO2+2Na2O=Na2O·Al2O3·2SiO2+Na2O·Al2O3·6SiO2+2Li2O (1) 2Li2O-Al2O3-4SiO2+4NaOH=Na2O-Al2O3-2SiO2+Na2O-Al2O3-6SiO2+2H2O+2Li2O (2) 2Li2O-Al2O3-4SiO2+2Na2CO3=Na2O-Al2O3-2SiO2+Na2O-Al2O3-6SiO2+2CO2+2Li2O (3) 2Li2O-Al2O3-4SiO2+4NaHCO3=Na2O-Al2O3-2SiO2+Na2O-Al2O3-6SiO2+4CO2+2H2O+2Li2O (4).

4. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (1), the calcination device for mixing lithium spodumene concentrate with sodium oxide, sodium carbonate, sodium hydroxide or sodium bicarbonate mixture is a rotary kiln, a tunnel kiln or a muffle furnace.

5. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (2), the drying temperature is 150-350°C, and the drying time is 1-10h.

6. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (2), the secondary filtrate and the washing liquid after washing the filter residue are mixed, the concentration of sodium hydroxide is adjusted, and then returned to the calcination material leaching process as a leaching solution.

7. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (3), the reactions occurring during the reduction process are as follows: 9 Na2O-Al2O3-2SiO2(s)+4Al(l)=12Na(g)+8Al2O3(s)+3Na2O-Al2O3-6SiO2(s) (5) 3 Na2O-Al2O3-2SiO2(s)+2Al(l)=6Na(g)+4Al2O3(s)+6SiO2(s) (6) 3Na2O-Al2O3-6SiO2(s)+2Al(l)=6Na(g)+4Al2O3(s)+18SiO2(s) (7).

8. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (3), the main components of the reduction slag obtained after reduction are alumina and silica, which are used as raw materials for silico-alumina refractory materials; the crystalline sodium is converted into sodium oxide by controllable combustion, and the sodium oxide is returned to the lithium spodumene calcination conversion process as an additive for raw materials.

9. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (3), the vacuum reduction tank is divided into a crystallization zone and a reduction zone, and the length ratio of the crystallization zone to the reduction zone is 1:3-1:

5.

10. The method for efficient lithium extraction from spodumene and comprehensive utilization of waste residue according to claim 1, characterized in that, In step (3), the reduction furnace uses electric heating; or, the reduction furnace uses water gas or natural gas as a heat source.

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