CN115011798B

CN115011798B - Method for recovering lithium from lithium-containing aluminum electrolyte

Info

Publication number: CN115011798B
Application number: CN202210692501.5A
Authority: CN
Inventors: 雷在荣; 刘霞; 赖正莲; 雷谦程
Original assignee: Panzhihua Jiuxing Vanadium And Titanium Co ltd
Current assignee: Panzhihua Jiuxing Vanadium And Titanium Co ltd
Priority date: 2022-06-17
Filing date: 2022-06-17
Publication date: 2023-05-30
Anticipated expiration: 2042-06-17
Also published as: CN115011798A

Abstract

The invention provides a method for recovering lithium from lithium-containing aluminum electrolyte, which adopts a roasting and leaching process and a multi-stage solution purifying and impurity removing process, on one hand solves the problem of low lithium leaching rate caused by wrapping lithium salt due to direct soaking of the aluminum electrolyte with strong acid, improves the lithium leaching rate, simultaneously avoids corrosion of equipment caused by corrosive concentrated acid, and on the other hand improves the purity and yield of products and the quality of lithium salt through the multi-stage impurity removing process.

Description

Method for recovering lithium from lithium-containing aluminum electrolyte

Technical Field

The invention belongs to the field of industrial aluminum electrolyte waste recycling, and particularly relates to a method for recycling lithium from lithium-containing aluminum electrolyte. The recovery raw materials aimed by the invention are collectively called lithium-containing aluminum electrolyte, and are mainly derived from industrial aluminum electrolyte waste, namely complex aluminum electrolyte or aluminum electrolyte solid waste and the like at present.

Background

Lithium carbonate or lithium hydroxide is a basic lithium compound, is a basic material for producing other lithium compounds and metallic lithium products, and is widely applied to the fields of ceramic manufacture, metallurgy, glass, medicine, food, rubber and the like. In recent years, with the rapid development of the lithium battery industry, the demand for high-purity lithium salts has been rapidly expanding, and lithium salts have been widely used for manufacturing LiCoO ₂ 、LiMnO ₄ 、LiFePO ₄ And a positive electrode material of a ternary lithium battery, an electrolyte thereof, and a negative electrode material such as lithium meta-titanate.

The manufacture of lithium carbonate or lithium hydroxide generally derives from four types of raw materials: a) Liquid ore, namely salt lake brine; b) Spodumene; c) Lepidolite; b) Lithium-containing waste. Among them, the preparation of lithium salt from lithium-containing waste is advantageous for the recovery and recycling of resources, and is one of the directions of intensive research in recent years.

In the case of lithium-containing waste, waste aluminum electrolyte is waste produced in the industry when aluminum is produced by cryolite-alumina fused salt electrolysis, and the waste aluminum electrolyte generally contains a relatively high content of lithium element because the alumina as the raw material for electrolytic aluminum contains Li to a varying extent ₂ O, in the electrolytic process, lithium element enters the electrolyte in an ion form, and is continuously enriched along with the continuous growth of the age of the electrolytic tank, and when the lithium element in the aluminum electrolyte reaches 2-3% by mass percent in terms of LiF, the initial crystal temperature of the electrolyte is reduced, and the energy consumption is reduced; however, when the content of lithium element in the aluminum electrolyte is too high, the electrolyte system not only can reduce the solubility of aluminum oxide in the electrolyte, but also can cause the increase of the superheat degree of the electrolyte, so that the energy consumption is increased, the service life of the electrolytic tank is shortened, and the economic benefit of the electrolytic aluminum is influenced. Therefore, when the content of lithium element in the aluminum electrolyte is too high, the aluminum electrolyte needs to be replaced periodically, and the replaced aluminum electrolyte is waste aluminum electrolyte, wherein the content of lithium element in the waste aluminum electrolyte can be as high as 6-10% (mass percent) in terms of LiF, millions of tons of waste aluminum electrolyte are produced in the electrolytic aluminum industry every year, and therefore, the recovery of lithium from the waste aluminum electrolyte becomes an important lithium compound source.

The related research on preparing lithium salt by adopting waste aluminum electrolyte is still immature, and a plurality of technical problems to be solved still exist, wherein two problems at the very core are how to solve the problems of low leaching rate and low yield of lithium; and how to solve the environmental pollution problem caused by HF.

The prior art developed a number of different lithium extraction processes, for example CN10993017B, CN105349786B, CN111115665a, etc., using the following processes: grinding, washing or not washing, high-concentration acid liquor soaking reaction, defluorination reaction, reaction with carbonate to produce lithium carbonate crude product, and refining. Namely, after the aluminum electrolyte is crushed, washing with water or without water, then soaking with high-concentration acid, leaching LiF, and then adding alkaline earth metal salt or aluminum salt and fluorine to form precipitate for removing fluorine. Finally, liF is converted into other lithium salts, such as lithium carbonate. Of such processesThe method has the advantages of simple flow, but the defects are very prominent: firstly, the concentrated acid soaking can cause serious corrosion to production equipment, so that the service life of the production equipment is shortened; secondly, the leaching rate of lithium is very low in mass production, and it is widely believed in the industry that lithium element usually exists in the aluminum electrolyte in the form of LiF, liF is difficult to dissolve in water but is easy to dissolve in acid, so that the above process adopts a high-concentration acid solution soaking mode to leach LiF in the aluminum electrolyte, but in fact, the existence form of lithium element in the aluminum electrolyte is very complex, and besides the existence form of LiF, the lithium element is likely to exist in the form of Li ₃ AlF ₆ 、Li ₂ NaAlF ₆ 、LiNa ₂ AlF ₆ In the form of equal, when Na is present in the electrolytic process ₃ AlF ₆ 、Li ₃ AlF ₆ 、Li ₂ NaAlF ₆ 、LiNa ₂ AlF ₆ Upon encountering strong acids (such as dilute sulfuric or nitric acid), the various salt species, including soluble sodium and/or lithium salts, and insoluble AlF, are immediately decomposed ₃ In this process, the lithium salt is entrapped in the insoluble AlF ₃ During the process or in the thick slurry formed by the method, so that the lithium leaching rate is reduced, the production cost of extracting lithium is high, and the method does not have the practical feasibility of large-scale industrial production; thirdly, defluorination and conversion of LiF from acid liquor are easy to generate various impurities, and more difficulties are caused to subsequent purification, and the production cost is increased by adding a purification step of lithium carbonate, and the yield of the lithium carbonate is seriously affected; fourthly, a large amount of HF is generated in the reaction, and the fluorine content in the aluminum electrolyte is extremely high (up to 80 percent), because the main component of cryolite required for electrolysis is sodium hexafluoroaluminate (Na ₃ AlF ₆ ) Various fluorine-containing salts, such as lithium fluoride (LiF), aluminum fluoride (AlF), are derived during electrolysis ₃ ) Sodium fluoride (NaF), undegraded Na ₃ AlF ₆ And possibly Li ₃ AlF ₆ 、Li ₂ NaAlF ₆ 、LiNa ₂ AlF ₆ And the like, the composition of the fluoride is also very complex. Fluorine is generally not harmful to the environment when present in the form of a stable salt, but when added to high concentration acid soak the milled aluminum electrolyte, a significant amount of sodium fluoride is carried into the solution and acid Reacting to generate HF; na (Na) ₃ AlF ₆ May also decompose to produce HF; the difficult fluoride salt can also react with high-concentration acid to generate a certain amount of HF, and high temperature is often required when the concentrated acid is soaked, so that the overflow of HF gas is aggravated, and the problems of serious HF pollution and difficult treatment are caused. The inability to effectively treat HF is a major reason why aluminum electrolyte recovery of lithium has not been possible to scale up to date.

Another type of method provided by the prior art is to introduce a high temperature roasting process, such as CN114314625a, into the lithium extraction process, which is: mixing aluminum electrolyte and auxiliary aluminum sulfate, roasting at high temperature, pickling and/or washing the roasted material, and adding water-soluble carbonate into the filtrate to prepare lithium carbonate. The process has the advantages that the lithium salt in the aluminum electrolyte can be converted into the soluble lithium salt through a high-temperature roasting process, and the dissolution of the lithium salt during acid washing or water washing is facilitated. However, since the patent application focuses on recovery of fluoride (aluminum fluoride/cryolite/sodium fluoride) from waste aluminum electrolyte, the whole process flow does not take lithium extraction as a final goal, so that the research of the lithium extraction process is insufficient, and there are many disadvantages in recovery of lithium, namely, the auxiliary material added during roasting is aluminum sulfate, and insoluble AlF is generated during roasting ₃ The lithium salt is wrapped in insoluble AlF ₃ Among them, the leaching rate of lithium is lowered at the time of acid washing; and secondly, when lithium is recovered, no impurity removal operation is performed on the filtrate after acid washing, sodium carbonate is directly added to precipitate lithium, so that a plurality of impurities exist in the product, high-purity lithium carbonate cannot be obtained, and the yield of lithium is also reduced. 3. Aluminum fluoride generated during roasting of the process reacts with water molecules when the temperature reaches 300-400 ℃ to generate aluminum oxide and hydrogen fluoride, and the aluminum fluoride and the hydrogen fluoride can cause the problem of HF pollution control. Therefore, the process still has a great room for improvement, and the process has no practical feasibility of industrial application.

For this reason, it is an object of the art to develop a method for recovering lithium that is effective in extracting lithium from lithium-containing aluminum electrolytes and effective in reducing HF contamination.

Disclosure of Invention

The invention aims at solving the technical problems in the prior art, and provides a method for recovering lithium from lithium-containing aluminum electrolyte, which has high lithium leaching rate and can effectively avoid HF pollution.

In order to achieve the purpose of the invention, the invention provides a method for recovering lithium from lithium-containing aluminum electrolyte, which comprises a roasting leaching lithium extraction section and a solution purification lithium extraction section, and is characterized in that: the roasting leaching lithium extraction working section comprises a roasting working procedure of aluminum electrolyte and a dilute acid leaching working procedure after roasting, wherein auxiliary materials are added in the roasting working procedure, and the aluminum electrolyte and the auxiliary materials are uniformly mixed and then roasted; the solution purifying and lithium extracting working section comprises multi-step impurity removing operation.

Further, the roasting leaching lithium extraction working section comprises the following steps:

(1) Mixing the aluminum electrolyte and auxiliary materials, and then placing the mixture into a roasting furnace for roasting at the temperature of 200-1000 ℃ for the time of: converting the material into clinker after 0.5-20 hours;

(2) Mixing clinker with 0.05-10mol/L dilute acid solution, controlling the mass ratio of the dilute acid solution to the clinker to be 1:1-10:1, and stirring and reacting for 0.5-12 hours at the temperature of 10-100 ℃;

(3) Filtering the mixed solution after the step (2) of dilute acid leaching reaction is finished to obtain primary filtrate and primary filter residues, judging the concentration of lithium elements in the primary filtrate, if the concentration of the lithium elements in the primary filtrate cannot meet the requirement of a solution purification and lithium extraction working section, introducing the primary filtrate into the step (2), and circularly leaching to realize the enrichment of the lithium elements until the concentration of the lithium elements in the primary filtrate meets the requirement of the solution purification and lithium extraction working section, and allowing the primary filtrate to enter the solution purification and lithium extraction working section;

Further, the solution purification and lithium extraction section comprises the following steps (before numbering):

(4) Adding alkaline substances into the primary filtrate to adjust the pH to 3-7, precipitating impurity elements in the solution, and filtering to obtain secondary filtrate and secondary filter residue;

(5) Adding a calcium-containing compound into the secondary filtrate to remove fluoride ions in the solution, and filtering to obtain tertiary filtrate and tertiary filter residue;

(6) Adding carbonate, oxalic acid or oxalate into the tertiary filtrate, precipitating to remove excessive calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue;

(7) Adding carbonate or hydroxide into the four filtrates to recover lithium, adjusting pH to 8-14, and filtering after the reaction to obtain five filtrates and five filter residues, wherein the five filter residues are the target lithium-containing compounds.

Preferably, in the step (1), the aluminum electrolyte is crushed and sieved by 0-250 meshes, and then mixed with auxiliary materials.

Preferably, the mass ratio of the aluminum electrolyte powder to the auxiliary materials in the step (1) is 9:1 to 1:9.

According to one embodiment of the present invention, the auxiliary material added in the step (1) is selected from a salt or an oxide containing an alkali metal element (such as Na, K, etc.), or a salt or an oxide containing a transition metal element (such as Ti, V, fe, mn, zn, etc.). Preferably, the auxiliary material is selected from NaCl and Na ₂ SO ₄ 、NaHSO ₄ 、Na ₂ O、NaOH、Na ₂ CO ₃ 、NaHCO ₃ 、KCl、K ₂ SO ₄ 、KHSO ₄ 、K ₂ O、KOH、K ₂ CO ₃ 、KHCO ₃ 、Fe ₂ O ₃ 、FeSO ₄ 、MnO ₂ Or ores containing these substances and production residues, such as steelmaking residues, etc. The auxiliary materials can be singly used or mixed for use when mixedWhen used, it is preferably a salt or oxide containing Na, K, fe or Mn.

The aluminum electrolyte is mixed with the auxiliary materials and then baked, so that the transformation of the lithium-containing compound is promoted, the lithium-containing compound, especially lithium fluoride, is transformed into lithium oxide, and the lithium element is leached more conveniently in the subsequent dilute acid soaking process. The fluorine element and metal cations in the auxiliary materials form soluble salts, so that the wrapping of the lithium element is greatly reduced, and the yield of the lithium element is further improved. The reaction mechanism mainly involved in this step is as follows:

the addition of an auxiliary material in the firing step is one of the aspects of the present invention. LiF and other possible Li ₃ AlF ₆ 、Li ₂ NaAlF ₆ 、LiNa ₂ AlF ₆ The lithium-containing compounds are converted into lithium oxides and NaF/KF under the action of auxiliary materials, such as sodium carbonate/potassium carbonate/sodium oxide/potassium oxide;

the non-decomposed cryolite is converted into soluble sodium salt, aluminum salt and metal fluoride under the action of auxiliary materials, such as metal salt; or to sodium oxide, aluminum oxide and metal fluoride by the action of metal oxides.

According to another embodiment of the present invention, the auxiliary materials added in the step (1) are selected from the following components:

a) Salts or oxides containing alkaline earth metal elements (beryllium, magnesium, calcium, strontium, barium, radium), for example: magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium sulfate, magnesia, magnesium chloride, calcium oxide, calcium hydroxide, calcium carbonate, calcium chloride, calcium oxalate, calcium sulfate, limestone, lime, barium oxide, barium hydroxide, barium carbonate, barium sulfate, barium chloride; b) Salts or oxides containing lanthanide metal elements (e.g., la, sc, ce, sm, etc.); c) Salts or oxides containing silicon (Si) and lead (Pb) elements, for example: silica, sodium silicate, silica; d) Ores containing one or more of the above elements, production residues or wastes, and the like.

Further preferably, the auxiliary materials are salts or oxides containing magnesium, calcium, barium and silicon, or ores and production residues or wastes containing alkaline earth metal elements, si or Pb.

Further preferably, the auxiliary material is MgO, mgCO ₃ 、MgSO ₄ 、CaO、CaCO ₃ 、CaSO ₄ 、BaO、BaCO ₃ 、BaSO ₄ 、SiO ₂ As well as magnesia, silica, limestone, lime, and the like.

The auxiliary materials can be singly used or mixed.

Mixing an aluminum electrolyte and auxiliary materials, and then roasting for reaction, wherein lithium-containing compounds in the aluminum electrolyte, especially lithium fluoride, are converted into soluble lithium salts under the action of auxiliary material metal salts or are converted into lithium oxides under the action of auxiliary material metal oxides, so that the dissolution rate of lithium in a dilute acid reaction is improved; while the fluorine element is transferred and reacts with the metal element in the auxiliary material to form indissolvable metal fluoride, such as MgF ₂ 、CaF ₂ 、BaF ₂ 、SiF ₄ 、PbF ₂ And/or LaF ₃ Etc., thereby realizing the effect of fixing fluorine. It is worth noting that these fluorides are compared with AlF ₃ Higher thermal stability, e.g. AlF ₃ Can react with water molecules at 300-400 ℃ and is suitable for MgF ₂ Compared with other auxiliary materials including aluminum sulfate and the like, the auxiliary materials added with substances including alkaline earth metal element salts or oxides and the like have obvious advantages in reducing HF release, and have more excellent curing effect in the roasting stage; in the subsequent dilute acid stripping reaction, these metal fluorides have low solubility, allowing the fluorine element to solidify throughout the precipitate. Therefore, the lithium leaching rate can be improved, the generation of HF gas can be obviously reduced, and the environmental treatment cost is reduced.

Preferably, the dilute acid in the step (2) is selected from hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, oxalic acid and the like, and may be one or two or more. After the reaction of the clinker and the dilute acid is finished, the lithium-containing compound in the clinker is dissolved into the dilute acid solution, so that preparation is made for purifying and extracting lithium from the solution.

Preferably, in the step (3), the mixed solution after the reaction in the step (2) is filtered to obtain primary filtrate and primary filter residue, the primary filter residue is washed to be neutral and is dried, and the lithium content of the filter residue is less than 0.4%; the concentration of lithium in the primary filtrate is judged to be a certain value, and the next operation is performed, so that the effect is better, and the concentration of lithium in the primary filtrate is preferably not lower than 5g/L, more preferably not lower than 7g/L. When the judgment standard of the concentration of lithium in the primary filtrate is set to be not lower than 7g/L, if the concentration of lithium element in the primary filtrate is lower than 7g/L, introducing the primary filtrate into the step (2), and circularly leaching to realize enrichment of the lithium element;

In terms of the process of the solution purification and lithium extraction section,

preferably, the alkaline substance added in the step (4) is at least one of sodium carbonate, sodium hydroxide, potassium carbonate, potassium hydroxide, ammonia water, lime, limestone and the like; the main component of the secondary filter residue produced in the step (4) is iron/aluminum precipitate.

Preferably, the calcium-containing compound added in the step (5) is calcium sulfate, calcium chloride, calcium hydroxide or calcium oxide, and the main components of the tertiary filter residue generated in the step (5) are calcium fluoride precipitate and magnesium-manganese precipitate;

preferably, the carbonate added in the step (6) is sodium carbonate or potassium carbonate, the oxalate added is sodium oxalate or potassium oxalate, and the main component of the fourth filter residue generated in the step (6) is calcium carbonate or calcium oxalate.

Preferably, the carbonate added in step (7) is sodium carbonate or potassium carbonate; the added hydroxide is sodium hydroxide and potassium hydroxide; when carbonate is added, the composition of the five filter residues, namely the target lithium compound, is lithium carbonate. When the hydroxide is added, the composition of the five filter residues, namely the target lithium compound, is lithium hydroxide.

Preferably, the five filtrates obtained in the step (7) enter an evaporation concentration system, and the product after concentration and crystallization is sodium sulfate; and (5) returning the concentrated liquid to the step (5) again for purifying and extracting lithium.

According to the method of the invention, in order to avoid the HF gas entering the environment as much as possible, an air draft system and an alkali liquor treatment system are arranged in the acid leaching reaction step of the step (2) so as to extract the HF gas generated by the reaction and treat the HF gas by alkali liquor, thereby eliminating the pollution of HF to the environment.

Compared with the prior art, the method provided by the invention has the following technical advantages:

(1) On one hand, the lithium-containing compound, especially lithium fluoride, is converted into a soluble lithium compound by mixing and roasting the aluminum electrolyte and auxiliary materials, and the leaching effect of lithium element can be greatly improved after the dilute acid leaching reaction; the auxiliary material provided by the invention can be used for further dissolving out the lithium element coated by the product in the reaction, thereby further contributing to the improvement of the yield of the lithium element. Experimental results show that when the salt or oxide containing alkali metal elements or the salt or oxide containing transition metal elements is adopted as auxiliary materials, the leaching rate of lithium is greatly improved by mixing and roasting the aluminum electrolyte and the auxiliary materials, and the leaching rate is more than 80 percent; when the salt or oxide containing alkaline earth metal elements, the salt or oxide containing lanthanide series metal elements and the salt or oxide containing silicon or lead elements are adopted as auxiliary materials, the leaching rate of lithium is about 70% or more than 70%, which is far superior to 40-50% of the leaching rate of the prior art (see comparative examples 1 and 2), particularly when the auxiliary materials are alkaline earth metals or contain a considerable amount of alkaline earth metals, fluorine is better solidified due to the more stable fluoride salt of the alkaline earth metals, and only a small amount of HF is brought into solution during the subsequent treatment, so that the difficulty of HF treatment is greatly reduced, and the effect is very remarkable;

(2) In the solution purification and lithium extraction stage, the impurity content in the target product is reduced to the greatest extent through a plurality of impurity removal procedures, and the high-purity lithium-containing compound can be obtained;

(3) Concentrated acid is not needed in the whole lithium extraction process, so that corrosiveness is greatly reduced, and equipment requirements are also reduced;

(4) Auxiliary materials adopted in the roasting leaching lithium extraction working section are utilized and the defluorination operation of the solution purification lithium extraction working section is combined, so that the generation and emission of HF gas are reduced to the greatest extent, and the environmental protection and the health protection of production personnel are facilitated;

(5) The whole process is simple, the lithium recovery is high, the method is suitable for large-scale production, and the feasibility of large-scale popularization is realized.

The invention is suitable for recovering lithium from lithium-containing aluminum electrolyte, the recovery raw materials aimed at by the invention are mainly derived from industrial aluminum electrolyte waste at present, and the invention can also be aimed at extracting lithium elements of other aluminum electrolytes containing lithium elements.

Drawings

Fig. 1: the flow chart of the method for recovering lithium from lithium-containing aluminum electrolyte is shown in the specification.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the matters related to the present invention are shown in the accompanying drawings.

Example 1

A method for recovering lithium from a lithium-containing aluminum electrolyte, comprising the steps of:

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage content of lithium fluoride is 3.88%, and the lithium fluoride is sieved by 60 meshes;

(2) Weighing 80g of aluminum electrolyte subjected to ball milling and screening, adding 20g of sodium carbonate, uniformly mixing, and roasting in a roasting furnace at 900 ℃ for 6 hours to convert into clinker;

(3) Crushing and screening the clinker again, weighing 80g of crushed clinker with 200 meshes, mixing with 600ml of dilute sulfuric acid with the concentration of 5mol/l, and stirring and leaching for 10 hours at the temperature of 80 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, wherein the weight of the primary filter residue is 54g, the lithium content in the primary filter residue is 0.28%, the volume of the primary filtrate is 510ml, and the lithium leaching rate is 82%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements; when the mass concentration of the enriched lithium element in the primary filtrate reaches 9.88g/l, the solution enters a solution purifying and lithium extracting section;

2. solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, wherein the lithium concentration is 9.88g/l, adding sodium hydroxide to adjust the pH value to be 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.7g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions in the solution, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the primary filter residues of the tertiary filter residues are calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.4g after drying;

(7) Adding 1.5g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 33g of sodium carbonate into the four-time filtrate, reacting for 30min at pH value of 12, filtering to obtain five-time filter residues and five-time filtrate, wherein the five-time filter residues are the target product lithium carbonate, and washing and drying to obtain 20g of lithium carbonate with purity of 99.63%; the concentration of lithium element in the five-time filtrate is 1.9g/L;

(9) Taking 500ml of five times filtrate to enter an evaporation concentration system, cooling, filtering, drying filter residues to obtain 89 sodium sulfate, and returning 120ml of filtrate to the step (6) for further carrying out lithium extraction operation.

Example 2

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage content of lithium fluoride is 3.88%, and the lithium fluoride is sieved by a 50-mesh sieve;

(2) Weighing 50g of aluminum electrolyte subjected to ball milling and screening, adding 50g of sodium oxide, uniformly mixing, and roasting in a roasting furnace at 850 ℃ for 5 hours to convert into clinker;

(3) Crushing and screening the clinker again, weighing 80g of crushed 120-mesh clinker, mixing with 400ml of dilute sulfuric acid with the concentration of 3mol/l, and stirring and leaching for 10 hours at 50 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, weighing 62g of the residue, wherein the lithium content in the primary filter residue is 0.24%, and the lithium leaching rate is 81%; the volume of the primary filtrate is 550ml, the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 8.6g/l, the primary filtrate enters a solution purification and lithium extraction working section;

2. solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide with the lithium concentration of 8.6g/l, and regulating the pH value to be 5.5 to obtain secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.1g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions in the solution, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 1.6g after drying;

(7) Adding 1.2g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) 26g of sodium carbonate is added into the four filtrates, the pH value is 11, the reaction is carried out for 30min, five times of filtrate and five times of filter residues are obtained, the five times of filter residues are the target product lithium carbonate, and 16g of lithium carbonate is obtained after washing and drying, and the purity is 99.66%; the concentration of lithium element in the five-time filtrate is 2.0g/L;

(9) Taking 500ml of five times filtrate to enter an evaporation concentration system, cooling, filtering, drying filter residues to obtain 83 sodium sulfate, and returning 120ml of filtrate to the step (6) for further carrying out lithium extraction operation.

Example 3

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage content of lithium fluoride is 5.62%, and the lithium fluoride is 80 meshes;

(2) Weighing 70g of ball-milled and screened aluminum electrolyte, adding 30g of potassium carbonate, uniformly mixing, roasting in a roasting furnace at 900 ℃ for 7 hours, and converting into clinker;

(3) Crushing the clinker again, weighing 80g of crushed 200-mesh clinker, mixing with 500ml of dilute sulfuric acid with the concentration of 1.8mol/l, and stirring and leaching for 8 hours at 70 ℃;

(4) Filtering the mixed slurry after the reaction is finished, and washing the filter residue for a small amount for multiple times until the PH value of the filter residue is 6-7 to obtain primary filtrate and primary filter residue, drying the primary filter residue, wherein the weight of the primary filter residue is 56g, the lithium content in the primary filter residue is 0.25%, and the lithium leaching rate is 87%; the volume of the primary filtrate is 630ml, and the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements; when the mass concentration of the enriched lithium element in the primary filtrate reaches 12.1g/l of lithium concentration, the solution enters a solution purifying and lithium extracting section;

2. solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide to regulate the PH=5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.8g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.1g after drying;

(7) Adding 1.7g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 41g of sodium carbonate into the four-time filtrate, reacting for 30min at the pH value of 12, filtering to obtain five-time filtrate and five-time filter residue, and washing and drying the precipitate obtained by the five-time filter residue to obtain 25g of lithium carbonate with the purity of 99.65%; the concentration of lithium in the five filtrates is 2.3g/l;

(9) Taking 500ml of five times filtrate to enter an evaporation concentration system, cooling, filtering, drying filter residues to obtain 79 sodium sulfate and potassium sulfate mixed salt, and returning 115ml of filtrate to the step (6) for further carrying out lithium extraction operation.

Example 4

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage content of lithium fluoride is 5.62%, and the lithium fluoride is 200 meshes;

(2) Weighing 40g of ball-milled and sieved aluminum electrolyte, adding 60g of potassium oxide, uniformly mixing, roasting in a roasting furnace for 6 hours at 950 ℃, and converting into clinker;

(3) Crushing the clinker again, weighing 80g of crushed 200-mesh clinker, mixing with 400ml of dilute sulfuric acid with the concentration of 2.5mol/l, and stirring and leaching for 6 hours at 90 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7 to obtain primary filtrate and primary filter residue, drying the primary filter residue, weighing 54g of the residue, wherein the lithium content in the primary filter residue is 0.22%, and the lithium leaching rate is 89.7%; the volume of the primary filtrate is 580ml, the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 11.8g/l, the primary filtrate enters a solution purification and lithium extraction working section;

2. Solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide to adjust the pH to 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.6g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.9g after drying;

(7) Adding 2.3g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) 39g of sodium carbonate is added into the four-time filtrate, the pH value is 12, the reaction is carried out for 30min, the five-time filtrate and five-time filter residue are obtained, the precipitate obtained by the five-time filter residue is washed and dried, and 23g of lithium carbonate with the purity of 99.63 percent is obtained; the lithium concentration in the five times of filtrate is 2.12g/l;

(9) And (3) evaporating and concentrating 500ml of the five-time filtrate, cooling, filtering, drying filter residues to obtain 72 sodium sulfate and potassium sulfate mixed salt, and returning 128ml of the filtrate to the step (6) for further carrying out lithium extraction operation.

Example 5

1. Roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 5.62%, and the lithium fluoride is 200 meshes;

(3) Crushing the clinker again, weighing 80g of crushed 200-mesh clinker, mixing with 400ml of dilute nitric acid with the concentration of 2mol/l, and stirring and leaching for 6 hours at 90 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, weighing 52g of the residue, wherein the lithium content in the primary filter residue is 0.18%, and the lithium leaching rate is 90.3%; the volume of the primary filtrate is 530ml, the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 9.7g/l, the primary filtrate enters a solution purification and lithium extraction working section;

2. solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide to regulate the pH value to 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates.

(6) Adding 1.4g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 1.9g after drying;

(8) Adding 31g of sodium carbonate into the four-time filter residue, reacting for 30min at the pH value of 12, filtering to obtain five-time filtrate and five-time filter residue, and washing and drying the precipitate obtained by the five-time filter residue to obtain 19.5g of lithium carbonate with the purity of 99.71%; the lithium concentration of the five times filtrate is 2.09g/l;

(9) And (3) taking 500ml of five-time filtrate, evaporating and concentrating, cooling, filtering, and drying filter residues to obtain 74 sodium sulfate and potassium sulfate mixed salt. 118ml of filtrate is returned to the step (6) to further carry out the lithium extraction operation.

Example 6

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage content of lithium fluoride is 5.62%, and the lithium fluoride passes through 120 meshes;

(2) Weighing 40g of aluminum electrolyte subjected to ball milling and screening, adding 60g of magnesia, uniformly mixing, roasting in a roasting furnace for 3 hours at 550 ℃, and converting into clinker;

(3) Crushing the clinker again, weighing 80g of crushed 200-mesh clinker, mixing with 400ml of dilute sulfuric acid with the concentration of 0.6mol/l, and stirring and leaching for 6 hours at 80 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, wherein the weight of the primary filter residue is 76.4g, the lithium content in the primary filter residue is 0.38%, the volume of the primary filtrate is 510ml, and the lithium leaching rate is 69%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 8.95g/l, the primary filtrate enters a solution purification and lithium extraction section;

2. solution purification and lithium extraction working section:

(6) Adding 1.5g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 1.86g after drying;

(7) Adding 1.65g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 26.5g of sodium carbonate into the four filtrates, reacting for 30min at pH value of 11, filtering to obtain five filtrates and five filter residues, washing and drying the precipitate obtained from the five filter residues to obtain 18g of lithium carbonate with purity of 99.65%; the lithium concentration in the five times of filtrate is 2.12g/l;

(9) And (3) evaporating and concentrating 500ml of the five-time filtrate, cooling, filtering, drying filter residues to obtain 58.5 sodium sulfate, and returning 145ml of the filtrate to the step (6) to further carry out lithium extraction operation.

Example 7

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 3.8%, and the lithium fluoride passes through 80 meshes;

(2) Weighing 80g of aluminum electrolyte, adding 20g of silica, uniformly mixing, roasting at 800 ℃ for 3 hours, and converting into clinker;

(3) Crushing the clinker again, weighing 70g of crushed 80-mesh clinker, mixing with 560ml of (1.5+1.5) mol/l hydrochloric acid and nitric acid, and stirring and leaching for 10 hours at 35 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, wherein the weight of the primary filter residue is 55.5g, the lithium content in the primary filter residue is 0.18%, the volume of the primary filtrate is 640ml, and the lithium leaching rate is 80.3%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 10.3g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction working section;

2. Solution purifying and lithium extracting section

(6) Adding 1.35g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 1.56g after drying;

(7) Adding 1.45g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 33.7g of sodium carbonate into the four filtrates, reacting for 30min, filtering to obtain five filtrates and five filter residues, washing and drying the precipitate obtained from the five filter residues to obtain 20.1g of lithium carbonate with the purity of 99.7%; the lithium concentration in the five times of filtrate is 1.58g/l;

(9) Taking 500ml of five times of filtrate, evaporating and concentrating, cooling, filtering, 150ml of filtrate, further extracting lithium by the filtrate in a impurity removal system, and drying filter residues to obtain 71.6 sodium sulfate; and (3) returning the filtrate to the step (6) to further carry out lithium extraction operation.

Example 8

1. Roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 2.6%, and the lithium fluoride is sieved by a sieve of 50 meshes;

(2) Weighing 50g of aluminum electrolyte, adding 50g of limestone, roasting at 950 ℃ for 11 hours, and converting into clinker;

(3) Crushing clinker, weighing 80g of crushed 180-mesh clinker, mixing with 800ml of dilute sulfuric acid with the concentration of 1.1mol/l, and stirring and leaching for 10 hours at 65 ℃;

(4) The mixed slurry after the reaction is finished is filtered, and the filter residue is washed for a small amount for a plurality of times until the pH value of the filter residue is 6-7, so that primary filtrate and primary filter residue are obtained, the volume of the primary filtrate is 960ml, the primary filter residue is dried, the weight of the residue is 64g, the lithium content in the primary filter residue is 0.14%, and the lithium leaching rate is 82.6%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 9.9g/l, the primary filtrate enters a solution purification and lithium extraction section;

2. solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide, and regulating the pH value to 5.5 to obtain secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.89g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.25g after drying;

(7) Adding 1.77g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 24g of sodium carbonate into the four filtrates, reacting for 30min at pH value of 11, filtering to obtain five filtrates and five filter residues, washing and drying the precipitate obtained from the five filter residues to obtain 16g of lithium carbonate with purity of 99.55%; the lithium concentration in the five filtrates is 1.9g/l;

(9) Taking 500ml of five times filtrate, evaporating and concentrating, cooling, filtering, 136ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 68 sodium sulfate.

Example 9

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 7.2%, and the lithium fluoride is sieved by 160 meshes;

(2) Weighing 50g of aluminum electrolyte, adding 25+25g of magnesia and silica, roasting for 8 hours at 950 ℃ and converting into clinker;

(3) Crushing the clinker again, weighing 76g of crushed 160-mesh clinker, mixing with 530ml of dilute hydrochloric acid with the concentration of 4mol/l, and stirring and leaching for 12 hours at the temperature of 60 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, wherein the weight of the primary filter residue is 74g, the lithium content in the primary filter residue is 0.32%, the volume of the primary filtrate is 700ml, and the lithium leaching rate is 80.7%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 7.9g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction working section;

2. Solution purification and lithium extraction working section:

(5) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide with pH of 5.5 to obtain secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.89g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.75g after drying;

(7) Adding 1.27g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 24g of sodium carbonate into the four filtrates, reacting for 30min at pH value of 11, filtering to obtain five filtrates and five filter residues, washing and drying the precipitate obtained from the five filter residues to obtain 16g of lithium carbonate with purity of 99.55%; the lithium concentration in the five times filtrate is 1.9g/l,

(9) Taking 500ml of five times filtrate, evaporating and concentrating, cooling, filtering, 146ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 46g of sodium sulfate.

Example 10

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 4.6%, and the lithium fluoride is sieved by a 50-mesh sieve;

(2) Weighing 50g of aluminum electrolyte, adding 25+25g of calcium carbonate and calcium oxide, and roasting at 800 ℃ for 5 hours to convert into clinker;

(3) Crushing the clinker again, weighing 70g of crushed 100-mesh clinker, mixing with 300ml of sulfuric acid with the concentration of 1+0.05mol/L and perchloric acid, and stirring and leaching for 8 hours at 70 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, weighing 56g of the residue, wherein the lithium content in the primary filter residue is 0.22%, the volume of the primary filtrate is 420ml, and the lithium leaching rate is 80%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 9.5g/l, the primary filtrate enters a solution purification and lithium extraction section;

2. solution purification and lithium extraction working section:

(5) Taking 400ml of a primary filtrate enrichment solution, adding sodium hydroxide, and regulating the pH value to 5.5 to obtain secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.9g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.5g after drying;

(7) Adding sodium carbonate 1.1 into the tertiary filtrate, precipitating excessive calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 22g of sodium carbonate into the four-time filtrate, reacting for 30min at the pH value of 12, filtering to obtain five-time filtrate and five-time filter residue, and washing and drying the precipitate obtained by the five-time filter residue to obtain 16.3g of lithium carbonate with the purity of 99.63%; the lithium concentration in the five times filtrate is 2.1g/l;

(9) Taking 400ml of five times filtrate, evaporating and concentrating, cooling, filtering, taking 105ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 53g of sodium sulfate.

Example 11

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 3.88%, and the lithium fluoride is sieved by 160 meshes;

(2) Weighing 80g of aluminum electrolyte, adding 20g of barium carbonate, and roasting at 750 ℃ for 5 hours to produce clinker;

(3) Crushing clinker again, weighing 80g of crushed 160-mesh clinker, mixing with 400ml of hydrochloric acid and perchloric acid with the concentration of 2+0.01mol/l, and stirring and leaching for 10 hours at 40 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, drying the primary filter residue, wherein the weight of the primary filter residue is 71.5g, the lithium content in the primary filter residue is 0.2%, the volume of the primary filtrate is 490ml, and the lithium leaching rate is 82.3%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 8.1g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction working section;

2. Solution purification and lithium extraction working section:

(5) Taking 400ml of a primary filtrate enrichment solution, adding sodium hydroxide to regulate the pH value to 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 1.1g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 1.3g after drying;

(8) Adding 20.5g of sodium carbonate into the four filtrates, reacting for 30min at pH value of 11, filtering to obtain five filtrates and five filter residues, washing and drying the precipitate obtained from the five filter residues to obtain 12.7g of lithium carbonate with purity of 99.65%; the lithium concentration in the five filtrates is 1.9g/l;

(9) Taking 400ml of five times filtrate, evaporating and concentrating, cooling, filtering, 110ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 51g of sodium sulfate.

Example 12

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 6.2%, and the lithium-containing aluminum electrolyte passes through 60 meshes;

(2) Weighing 60g of aluminum electrolyte, adding 20+20g of barium carbonate and alum, and roasting at 850 ℃ for 4 hours to produce clinker;

(3) Crushing the clinker again, weighing 80g of crushed 100-mesh clinker, mixing with 500ml of nitric acid and perchloric acid with the concentration of 1.5+0.01mol/l, and stirring and leaching for 8 hours at room temperature;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, wherein the volume of the primary filtrate is 605ml, the primary filter residue is dried, the weight of the residue is 73.5g, the lithium content in the primary filter residue is 0.22%, and the lithium leaching rate is 83.6%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 13.5g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction working section;

2. solution purifying and lithium extracting section

(6) Adding 3.5g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 5.1g after drying;

(7) Adding 2.15g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary filter residue, wherein the quaternary filter residue is mainly calcium carbonate precipitation;

(8) Adding 48g of sodium carbonate into the four-time filtrate, reacting for 30min at the pH value of 13, filtering to obtain five-time filtrate and five-time filter residue, washing and drying the precipitate obtained by the five-time filter residue to obtain 30g of lithium carbonate with the purity of 99.77%; the lithium concentration in the five times of filtrate is 2.1g/l;

(9) Taking 500ml of five times filtrate, evaporating, concentrating, cooling, filtering, 140ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 66g of sodium sulfate.

Example 13

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 4.6%, and the lithium-containing aluminum electrolyte passes through 120 meshes;

(2) Weighing 60g of aluminum electrolyte, adding 20+20g of limestone+silica, and roasting at 850 ℃ for 6 hours to produce clinker;

(3) Crushing the clinker again, weighing 70g of crushed 100-mesh clinker, mixing with 420ml of sulfuric acid and oxalic acid with the concentration of 0.2+0.4mol/l, and stirring and leaching for 11 hours at 60 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, wherein the volume of the primary filtrate is 570ml, the primary filter residue is dried, the weight of the residue is 64g, the lithium content in the primary filter residue is 0.19%, and the lithium leaching rate is 83.5%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 15.6g/l, the primary filtrate enters a solution purification and lithium extraction section;

2. Solution purification and lithium extraction working section:

(5) Taking 1000ml of a primary filtrate enrichment solution, adding sodium hydroxide to regulate the pH value to 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(6) Adding 2.7g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain tertiary filtrate and tertiary filter residues, wherein the tertiary filter residues mainly comprise calcium fluoride precipitation and magnesium-manganese precipitation, and weighing 2.9g after drying;

(7) Adding 3.55g of sodium carbonate into the tertiary filtrate to precipitate redundant calcium ions, and filtering to obtain a quaternary filtrate and calcium carbonate precipitate;

(8) Adding 115g of sodium carbonate into the fourth precipitation, reacting for 30min at the pH value of 14, filtering to obtain five times of filtrate and filter residue, washing and drying the obtained precipitation to obtain 70.3g of lithium carbonate with the purity of 99.69%; the lithium concentration of the five times filtrate is 1.89g/l;

(9) Taking 1000ml of five times filtrate, evaporating and concentrating, cooling, filtering, 270ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 165g of sodium sulfate.

Example 14

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass content of lithium fluoride is 5.62%, and passing through a 100-mesh sieve;

(2) Weighing 40g of aluminum electrolyte, adding 20+40g of sodium sulfate and calcium sulfate, and roasting at 850 ℃ for 8 hours to produce clinker;

(3) Crushing the clinker again, weighing 80g of crushed 100-mesh clinker, mixing with 560ml of sulfuric acid with the concentration of 2mol/l, and stirring and leaching for 8 hours at the temperature of 70 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, wherein the volume of the primary filtrate is 700ml, the primary filter residue is dried, the weight of the primary filter residue is 66g, the lithium content in the primary filter residue is 0.39%, and the lithium leaching rate is 71.4%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 11.8g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction working section;

2. solution purification and lithium extraction working section:

(6) Adding 2.2g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain a tertiary filtrate, a tertiary filter residue calcium fluoride precipitate and a magnesium-manganese precipitate, and drying to obtain 3.11g of the secondary filtrate;

(7) Adding 2.8g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary residue calcium carbonate precipitate;

(8) Adding 41g of sodium carbonate into the four-time filtrate, reacting for 30min at the pH value of 13, filtering to obtain five-time filtrate and five-time filter residue, washing and drying the precipitate obtained by the five-time filter residue to obtain 26g of lithium carbonate with the purity of 99.73%; the lithium concentration in the five times of filtrate is 2g/l;

(9) Taking 500ml of five times filtrate, evaporating and concentrating, cooling, filtering, 170ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 67g of sodium sulfate.

Example 15

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 5.62%, and the lithium-containing aluminum electrolyte passes through 120 meshes;

(2) Weighing 50g of aluminum electrolyte, adding 20+30g of sodium sulfate and ferric sulfate, and roasting at 700 ℃ for 6 hours to produce clinker;

(3) Crushing the clinker again, weighing 80g of crushed 200-mesh clinker, mixing with 500ml of sulfuric acid with the concentration of 1.2mol/l, and stirring and leaching for 8 hours at 70 ℃;

(4) Filtering the mixed slurry after the reaction is finished, washing the filter residue for a small amount for multiple times until the pH value of the filter residue is 6-7, obtaining primary filtrate and primary filter residue, wherein the volume of the primary filtrate is 680ml, the primary filter residue is dried, the weight of the primary filter residue is 71g, the lithium content in the primary filter residue is 0.27%, and the lithium leaching rate is 74.4%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 9.5g/l, the primary filtrate enters a solution purification and lithium extraction section;

2. Solution purification and lithium extraction working section:

(5) Taking 600ml of a primary filtrate enriched solution, adding sodium hydroxide to regulate the pH value to 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates.

(6) Adding 3g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain a tertiary filtrate, a tertiary filter residue calcium fluoride precipitate and a magnesium-manganese precipitate, and drying to obtain 4.3g of the secondary filtrate;

(7) Adding 1.9g of sodium carbonate into the tertiary filtrate, precipitating redundant calcium ions, and filtering to obtain a quaternary filtrate and a quaternary residue calcium carbonate precipitate;

(8) Adding 37.5g of sodium carbonate into the four-time filtrate, reacting for 30min at the pH value of 12, filtering to obtain five-time filtrate and five-time filter residue, washing and drying the precipitate obtained by the five-time filter residue to obtain 23.5g of lithium carbonate with the purity of 99.75%; the lithium concentration in the five times filtrate is 2.1g/l;

(9) Taking 600ml of five times filtrate, evaporating and concentrating, cooling, filtering, 170ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 91g of sodium sulfate.

Comparative example 1

1. roasting leaching lithium extraction working section:

(1) Ball milling and crushing lithium-containing aluminum electrolyte, wherein the mass percentage of lithium fluoride is 4.62%, and the lithium fluoride passes through 120 meshes;

(2) Uniformly mixing the crushed aluminum electrolyte with aluminum sulfate, and performing a roasting reaction to obtain roasting clinker; the mass ratio of the aluminum electrolyte to the aluminum sulfate is 1:0.5, the roasting temperature is 400 ℃, and the roasting time is 60min;

(3) Washing 85g of the roasting material obtained in the step (1) with acid, wherein the acid used for washing is dilute sulfuric acid, and the concentration of the dilute sulfuric acid is 0.53mol/l; washing in the water washing process until the pH value of the water washing liquid is 7;

(4) Step (3) slurry filtration to obtain primary filtrate and primary filter residue, wherein the volume of the primary filtrate is 620ml, the primary filter residue is dried, the weight of the residue is 71g, the lithium content in the primary filter residue is 0.67%, and the lithium leaching rate is 44.8%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 7g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction section;

(5) A large amount of alkaline water is consumed during flue gas treatment;

2. solution purification and lithium extraction working section:

(6) 13g of calcium oxide is added into the primary filtrate, stirring reaction is carried out for 1.5 hours, fluoride ions are removed, secondary filtrate, secondary filter residue calcium fluoride precipitate and magnesium-manganese precipitate are obtained through filtration, and 15.2g of the secondary filtrate (the fluoride ion content is high, the calcium oxide consumption is high, and the lithium loss reaches 9%) is obtained after drying;

(7) Adding 1.9g of sodium carbonate into the secondary filtrate, precipitating excessive calcium ions, and filtering to obtain tertiary filtrate and tertiary filter residue calcium carbonate precipitate;

(8) Adding 27g of sodium carbonate into the tertiary filtrate, reacting for 30min at the pH value of 12, filtering to obtain a quaternary filtrate and a quaternary filter residue, washing and drying a precipitate obtained by the quaternary filter residue to obtain 18g of lithium carbonate with the purity of 98.15%; the lithium concentration in the four filtrates is 2.1g/l;

(9) Taking 600ml of four times of filtrate, evaporating and concentrating, cooling, filtering, 170ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 71g of sodium sulfate.

Comparative example 2

1. roasting leaching lithium extraction working section:

(3) And (3) carrying out acid washing and water washing on the roasting material 85 obtained in the step (1), wherein the acid used for acid washing is dilute sulfuric acid, and the concentration of the dilute sulfuric acid is 1.09mol/l.

(4) Step (3) slurry filtration to obtain primary filtrate and primary filter residue, wherein the volume of the primary filtrate is 570ml, the primary filter residue is dried, the weight of the residue is 67g, the lithium content in the primary filter residue is 0.64%, and the lithium leaching rate is 50.3%; the primary filtrate returns to the leaching operation of the step (3) to continuously enrich and leach lithium elements, and when the mass concentration of the lithium elements in the primary filtrate after enrichment reaches 7.4g/l of lithium concentration, the primary filtrate enters a solution purification and lithium extraction working section;

(5) A large amount of alkaline water is consumed during flue gas treatment;

2. solution purification and lithium extraction working section:

(6) Taking 500ml of a primary filtrate enriched solution, adding sodium hydroxide to adjust the pH to 5.5, and obtaining secondary filter residues and secondary filtrate, wherein the secondary filter residues mainly comprise iron and aluminum precipitates;

(7) Adding 16g of calcium oxide into the secondary filtrate, stirring and reacting for 1.5 hours, removing fluoride ions, filtering to obtain three-time filtrate, three-time filter residue calcium fluoride precipitation and magnesium-manganese precipitation, and drying to obtain 18.9g (the fluoride ion content is high, the calcium oxide consumption is high, and the lithium loss reaches 11.7%);

(8) Adding 2.3g of sodium carbonate into the tertiary filtrate, precipitating excessive calcium ions, and filtering to obtain a quaternary filtrate and a quaternary residue calcium carbonate precipitate;

(9) Adding 27.5g of sodium carbonate into the four-time filtrate, reacting for 30min at the pH value of 12, filtering to obtain five-time filtrate and five-time filter residue, washing and drying the precipitate obtained by the five-time filter residue to obtain 18.2g of lithium carbonate with the purity of 97.8%; lithium concentration in five filtrates

1.95g/l；

(10) Taking 500ml of five times filtrate, evaporating and concentrating, cooling, filtering, 150ml of filtrate, further extracting lithium from the filtrate in the step (6), and drying filter residues to obtain 65g of sodium sulfate.

Comparative examples 1 and 2 are cases where lithium is extracted by the prior art (i.e., mixed roasting is performed by adding aluminum sulfate auxiliary material and aluminum electrolyte), and as shown by experimental results, the main technical problems are low lithium leaching rate, high loss rate when fluorine is leached out in a large amount, and low total recovery rate when solution is removed.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims

1. A method for recovering lithium from lithium-containing aluminum electrolyte comprises a roasting leaching lithium extraction section and a solution purifying lithium extraction section, and is characterized in that,

The roasting leaching lithium extraction working section comprises a roasting working procedure of aluminum electrolyte and a dilute acid leaching working procedure after roasting; auxiliary materials are added in the roasting procedure, and the aluminum electrolyte and the auxiliary materials are uniformly mixed and then roasted;

the solution purifying and lithium extracting working section comprises multi-step impurity removing operation;

the roasting leaching lithium extraction working section comprises the following operations:

(1) Mixing aluminum electrolyte and adjuvants, and roasting in a roasting furnace at 200-1000 deg.C ^o And C, roasting for the following time: converting the material into clinker after 0.5-20 hours;

(2) Mixing clinker and 0.05-10mol/L dilute acid solution, controlling the mass ratio of the dilute acid solution to the clinker to be 1:1-10:1, and stirring and reacting for 0.5-12 hours at the temperature of 10-100 ℃;

(3) After the reaction in the step (2) is finished, filtering the reacted mixed solution to obtain primary filtrate and primary filter residues, judging the concentration of lithium elements in the primary filtrate, if the concentration of the lithium elements in the primary filtrate cannot meet the requirement of a solution purification and lithium extraction working section, introducing the primary filtrate into the step (2), and circularly leaching to realize the enrichment of the lithium elements until the concentration of the lithium elements in the primary filtrate meets the requirement of the solution purification and lithium extraction working section, so that the primary filtrate enters the solution purification and lithium extraction working section;

The auxiliary materials added in the step (1) are selected from the following components: a) Salts or oxides containing alkaline earth metal elements; b) Salts or oxides containing lanthanide metal elements; c) Salts or oxides containing elemental silicon or lead; d) Ores containing one or more of the above elements and production residues or scraps; the auxiliary materials can be singly used or mixed.

2. The method of claim 1, wherein:

the solution purification and lithium extraction working section comprises the following operations (before numbering):

(7) Adding carbonate or hydroxide into the four filtrates to recover lithium, adjusting pH to 8-14, and filtering to obtain five filtrates and five residues after the reaction is finished, wherein the precipitate obtained by the five residues is the target lithium-containing compound.

3. The method of claim 1, wherein: in the step (1), the aluminum electrolyte is crushed and sieved by 0-250 meshes, and then is mixed with auxiliary materials.

4. The method of claim 1, wherein the mass ratio of the aluminum electrolyte to the auxiliary material in the step (1) is 9:1 to 1:9.

5. The method of claim 1, wherein the auxiliary material added in the step (1) is a salt or oxide containing magnesium, calcium, barium, silicon or lead, or an ore containing alkaline earth metal element, si or Pb and production residues or scraps.

6. The method according to claim 5, wherein the auxiliary materials added in the step (1) are MgO and MgCO ₃ 、MgSO ₄ 、CaO、CaCO ₃ 、CaSO ₄ 、BaO、BaCO ₃ 、BaSO ₄ 、SiO ₂ One or more of magnesia, silica, limestone or lime.

7. The method of claim 1, wherein the dilute acid solution employed in step (2) is selected from one or more of hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, or oxalic acid.

8. The method according to claim 1, wherein the primary filter residue is washed to neutrality in step (3) and dried.

9. The method of claim 2, wherein the alkaline substance added in step (4) is at least one of sodium carbonate, sodium hydroxide, potassium carbonate, potassium hydroxide, ammonia, lime or limestone.

10. The method of claim 2, wherein the calcium-containing compound added in step (5) is calcium sulfate, calcium chloride, calcium hydroxide, or calcium oxide.

11. The method of claim 2, wherein the carbonate added in step (6) is sodium carbonate or potassium carbonate and the oxalate added is sodium oxalate or potassium oxalate.

12. The method of claim 2, wherein the carbonate added in step (7) is sodium carbonate or potassium carbonate; the added hydroxide is sodium hydroxide or potassium hydroxide.

13. The method of claim 2, wherein the five filtrates obtained in step (7) are fed into an evaporation concentration system, and the product after concentration and crystallization is sodium sulfate; and (5) returning the concentrated liquid to the step (5) again for purifying and extracting lithium.

14. The method according to claim 1, wherein in the acid leaching reaction step of step (2), an air draft system and an alkali liquor treatment system are provided, and the HF gas generated by the reaction is extracted and treated with alkali liquor.

15. The method according to claim 1, wherein when the concentration of the enriched lithium element in the primary filtrate is not lower than 7g/L, the primary filtrate is fed into a solution purification and lithium extraction section.

16. The method of claim 9, wherein the primary component of the secondary filter residue produced in step (4) is iron/aluminum precipitate.

17. The method of claim 10, wherein the tertiary filter residue produced in step (5) comprises calcium fluoride precipitates and magnesium manganese precipitates as the major components.

18. The method of claim 11, wherein the primary component of the fourth residue produced in step (6) is calcium carbonate or calcium oxalate.