阅读说明：本技术 一种以锂云母为原料制备电池级碳酸锂的方法 (Method for preparing battery-grade lithium carbonate by taking lepidolite as raw material ) 是由 南进喜 曾小毛 穆健书 吴进方 南天 苏婕 张国强 王玲珑 叶盛旗 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种以锂云母为原料制备电池级碳酸锂的方法,采用浓硫酸与锂云母在中低温下发生固相反应后用水浸出溶解硫酸碱金属盐；采用加入不同结晶诱导剂连续诱导结晶除杂的方法在不同的温度区间分别析出硫酸铝铷铯矾盐、硫酸铝钾矾盐等；采用氢氧化钾进行中和结晶除杂,得到的氢氧化铝和硫酸钾,将氢氧化铝用于中合过量硫酸,补加硫酸钾得到硫酸铝钾矾盐；最后将得到的氢氧化锂溶液与二氧化碳反应制备电池级碳酸锂。本发明使用氢氧化钾、氢氧化铝作为中和试剂和硫酸钾作为结晶除杂试剂,实现生产工艺不引入钙、镁等杂质离子,最后将得到的氢氧化锂溶液与二氧化碳反应制备电池级碳酸锂,实现了锂云母一步法制备电池级碳酸锂的技术重大突破。(The invention discloses a method for preparing battery-grade lithium carbonate by taking lepidolite as a raw material, which is characterized in that concentrated sulfuric acid and lepidolite are subjected to solid phase reaction at medium and low temperature and then are leached by water to dissolve alkali metal sulfate; adding different crystallization inducers to continuously induce crystallization and impurity removal to respectively separate out aluminum rubidium, cesium and aluminum potassium sulfate salts and the like in different temperature intervals; neutralizing, crystallizing and removing impurities by adopting potassium hydroxide to obtain aluminum hydroxide and potassium sulfate, using the aluminum hydroxide for neutralizing excessive sulfuric acid, and supplementing the potassium sulfate to obtain aluminum sulfate potassium alum salt; and finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare the battery-grade lithium carbonate. According to the invention, potassium hydroxide and aluminum hydroxide are used as a neutralization reagent, potassium sulfate is used as a crystallization impurity removal reagent, impurity ions such as calcium and magnesium are not introduced into the production process, and finally, the obtained lithium hydroxide solution reacts with carbon dioxide to prepare the battery-grade lithium carbonate, so that a technical breakthrough of preparing the battery-grade lithium carbonate by a lepidolite one-step method is realized.)

1. A method for preparing battery-grade lithium carbonate by taking lepidolite as a raw material is characterized by comprising the following steps:

s1, leaching and dissolving alkali metal sulfate by using water after solid phase reaction is carried out on concentrated sulfuric acid and lepidolite at medium and low temperature;

s2, adding different crystallization inducers to continuously induce crystallization and remove impurities to separate out aluminum rubidium, cesium and aluminum potassium sulfate salts at different temperature intervals;

s3, neutralizing, crystallizing and removing impurities by using potassium hydroxide to obtain aluminum hydroxide and potassium sulfate, using the aluminum hydroxide to neutralize excessive sulfuric acid, and supplementing the potassium sulfate to obtain aluminum sulfate potassium alum salt;

and S4, finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare the battery-grade lithium carbonate.

2. The method for preparing battery-grade lithium carbonate by using lepidolite as a raw material according to claim 1, wherein the step S1 is specifically as follows: adding concentrated sulfuric acid and lithium mica powder into the mixture according to a mass ratio of 1: 1-6, adding the mixture into a grinding device, mechanically grinding for 24-72 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground mixture of lithium mica powder and concentrated sulfuric acid into an extraction tank, adding water with the mass of 3-10 times of that of the mixture, soaking for 24-96 hours, leaching and dissolving alkali metal sulfate, and filtering and separating to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt.

3. The method for preparing battery-grade lithium carbonate by using lepidolite as a raw material according to claim 1, wherein the step S2 is specifically as follows: controlling the temperature of the leaching solution at 55-65 ℃, adding rubidium aluminum sulfate and cesium aluminum sulfate crystallization inducers to separate out rubidium aluminum sulfate and cesium aluminum sulfate, and filtering to obtain filtrate A; cooling the filtrate A to 5-15 ℃, adding an aluminum potassium sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain filtrate B.

4. The method for preparing battery-grade lithium carbonate by using lepidolite as a raw material according to claim 1, wherein the step S3 is specifically as follows: adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 5-15 ℃, adding a crystallization inducer into the filtrate C, crystallizing to obtain potassium sulfate, and filtering to obtain a filtrate D; and (3) using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain aluminum sulfate potassium alum salt, and filtering to obtain filtrate E, namely the lithium hydroxide solution.

5. The method of claim 1, wherein the crystallization inducing agent is a precipitated material of 500nm to 5 um.

Technical Field

The invention relates to the technical field of non-ferrous metal smelting, in particular to a method for preparing battery-grade lithium carbonate by taking lepidolite as a raw material.

Background

Lepidolite is an important mineral resource and has a chemical composition of K { Li_2-xAl_1+x[Al_2xSi_4-2xO₁₀](OH,F)₂0-0.5, it is one of potassium and lithium based aluminosilicates, a mica mineral, which contains abundant rare metal materials, lithium, potassium, rubidium, cesium, aluminum, etc. With the increasing shortage of world energy, developing and utilizing new energy is a common topic in the world and is more and more emphasized by various countries; lithium and salts thereof such as lithium carbonate and lithium sulfate are basic raw material products of the lithium new energy industry, and since lepidolite contains lithium metal which is a basic material of the lithium new energy industry, the development and application of lepidolite become a popular problem at present.

The lithium tantalum-niobium ore in Yichun Jiangxi is the largest lithium tantalum-niobium ore in Asia at present, the lithium tantalum-niobium ore is rich in resources, the content of lithium dioxide in lepidolite reaches 4.5%, and the method has the advantage condition of extracting lithium carbonate resources. Therefore, the method for extracting lithium carbonate by using lepidolite as a raw material has wide market prospect and good economic benefit.

From the existing production process, the production yield of lithium carbonate is not ideal, the comprehensive production benefit is not high, the input-output ratio is insufficient, and the industrial production is difficult to realize. The existing preparation method of lithium carbonate adopts lepidolite as a raw material to carry out extraction, mainly comprises a sulfuric acid method or a potassium sulfate calcination method, and has the disadvantages of overhigh potassium sulfate consumption, high energy consumption, high material flow flux and low lithium recovery rate, so the product cost for preparing lithium carbonate and lithium sulfate is overhigh.

Moreover, when the existing lithium carbonate is prepared by using lepidolite as a raw material, a battery-grade lithium carbonate product is usually extracted through a process of firstly producing industrial-grade lithium carbonate and then through a corresponding refining process, but cannot be prepared through direct precipitation in a one-step method.

The patent CN201911421655.5 previously filed by the applicant discloses a method for preparing battery-grade lithium carbonate by using lepidolite as a raw material through one-step method, which is characterized in that the lepidolite is used as the raw material and is mixed with auxiliary materials, the raw material and the auxiliary materials are mixed and then are roasted in a rotary kiln device, the roasted material and water or dilute sulfuric acid solution are mixed to form solid-liquid mixed solution, the solid-liquid mixed solution is impregnated, the impregnation time is controlled to be 2-3 hours, and the solid-liquid mass ratio is controlled to be 1: 1.5-2, filtering to remove residues, washing filter residues with water, and recycling the washing liquid to obtain a leaching solution; selectively removing impurities from the leaching solution to obtain a refined lithium solution; filling high-purity carbon dioxide gas into the refined lithium solution with the adjusted pH value, and washing and filtering to obtain a battery-grade lithium carbonate product and a lithium precipitation mother solution; concentrating, cooling, crystallizing, drying and the like the lithium precipitation mother liquor, recovering potassium sodium salt, returning to recycle, and feeding the liquor after recovering potassium sodium salt into a rubidium-cesium extraction system to recover rubidium-cesium salt. The method introduces the compound salt and needs a more complex impurity removal process.

Disclosure of Invention

The invention aims to provide a method for preparing battery-grade lithium carbonate by taking lepidolite as a raw material, potassium hydroxide and aluminum hydroxide are used as a neutralization reagent, potassium sulfate is used as a crystallization impurity removal reagent, impurity ions such as calcium, magnesium and the like are not introduced into the production process, and finally, the obtained lithium hydroxide solution reacts with carbon dioxide to prepare battery-grade lithium carbonate, so that the technical breakthrough of preparing the battery-grade lithium carbonate by using a lepidolite one-step method is realized.

In order to achieve the purpose, the invention adopts the following technical scheme: a method for preparing battery-grade lithium carbonate by taking lepidolite as a raw material comprises the following steps:

s1, leaching and dissolving alkali metal sulfate by using water after solid phase reaction is carried out on concentrated sulfuric acid and lepidolite at medium and low temperature;

s2, adding different crystallization inducers to continuously induce crystallization and remove impurities to separate out aluminum rubidium, cesium and aluminum potassium sulfate salts and the like at different temperature intervals;

s3, neutralizing, crystallizing and removing impurities by using potassium hydroxide to obtain aluminum hydroxide and potassium sulfate, using the aluminum hydroxide to neutralize excessive sulfuric acid, and supplementing the potassium sulfate to obtain aluminum sulfate potassium alum salt;

and S4, finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare the battery-grade lithium carbonate.

Specifically, S1, adding concentrated sulfuric acid and lithium mica powder together according to a mass ratio of 1: 1-6, adding the mixture into a grinding device, mechanically grinding for 24-72 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground mixture of lithium mica powder and concentrated sulfuric acid into an extraction tank, adding water with the mass of 3-10 times of that of the mixture, soaking for 24-96 hours, leaching and dissolving alkali metal sulfate, and filtering and separating to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt.

Specifically, S2, controlling the temperature of the leaching solution at 55-65 ℃, adding rubidium aluminum sulfate and cesium aluminum sulfate crystallization inducers, separating out rubidium aluminum sulfate alum salt and cesium aluminum sulfate alum salt, and filtering to obtain filtrate A; cooling the filtrate A to 5-15 ℃, adding an aluminum potassium sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain filtrate B.

Specifically, S3, adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 5-15 ℃, adding a crystallization inducer into the filtrate C, crystallizing to obtain potassium sulfate, and filtering to obtain a filtrate D; and (3) using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain aluminum sulfate potassium alum salt, and filtering to obtain filtrate E, namely the lithium hydroxide solution.

Specifically, the crystallization inducer of the present invention is a precipitation substance, preferably a homoacidic precipitation substance, which can exist in the current system at 500nm to 5 um.

The invention has the beneficial effects that: different crystallization inducers are added to continuously induce crystallization and impurity removal, and aluminum rubidium, cesium and aluminum potassium sulfate salts and the like are respectively precipitated in different temperature ranges. The potassium hydroxide is adopted for neutralization, crystallization and impurity removal, the obtained byproducts such as the aluminum hydroxide and the potassium sulfate can be recycled in a green way, the aluminum hydroxide is used for neutralizing excessive sulfuric acid, the potassium sulfate is supplemented to obtain aluminum sulfate potassium alum salt, the consumption of alkali such as the potassium hydroxide required in the neutralization process can be reduced, energy conservation and emission reduction are realized, the aluminum sulfate potassium alum salt with higher purity can be prepared through the process, and the comprehensive utilization of aluminum, potassium and sulfate radicals in the lepidolite is realized. According to the invention, potassium hydroxide and aluminum hydroxide are used as a neutralization reagent, potassium sulfate is used as a crystallization impurity removal reagent, impurity ions such as calcium and magnesium are not introduced into the production process, and finally, the obtained lithium hydroxide solution reacts with carbon dioxide to prepare the battery-grade lithium carbonate, so that a technical breakthrough of preparing the battery-grade lithium carbonate by a lepidolite one-step method is realized.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

A method for preparing battery-grade lithium carbonate by taking lepidolite as a raw material comprises the following steps:

s1, adding concentrated sulfuric acid and lithium mica powder together according to a mass ratio of 1: 1-6, adding the mixture into a grinding device, mechanically grinding the mixture for 24-72 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground mixture of lithium mica powder and concentrated sulfuric acid into an extraction tank, adding water with the mass of 3-10 times of that of the mixture, soaking the mixture for 24-96 hours, leaching and dissolving alkali metal sulfate, and filtering and separating the mixture to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt;

s2, controlling the temperature of the leaching solution at 55-65 ℃, adding aluminum rubidium sulfate and aluminum cesium sulfate crystallization inducers to separate out aluminum rubidium sulfate alum salt and aluminum cesium sulfate alum salt, and filtering to obtain filtrate A; cooling the filtrate A to 5-15 ℃, adding a potassium aluminum sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain a filtrate B, wherein the crystallization inducer is a precipitate with the particle size of 500nm to-5 um;

s3, adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 5-15 deg.C, adding crystallization inducer which is potassium sulfate particle or insoluble precipitate under the condition, the particle size is 500 nm-5 um, crystallizing to obtain potassium sulfate, and filtering to obtain filtrate D; using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain potassium aluminum sulfate alum salt, and filtering to obtain filtrate E, namely lithium hydroxide solution;

and S4, finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare the battery-grade lithium carbonate.

Example 1

S1, adding 100g of concentrated sulfuric acid and 100g of lithium mica powder into a ball milling tank for mechanical grinding for 24 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground lithium mica powder-concentrated sulfuric acid mixture into an extraction tank, adding 2000g of water, soaking for 24 hours, leaching and dissolving alkali metal sulfate, filtering and separating to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt;

s2, controlling the temperature of the leaching solution at 65 ℃, adding rubidium aluminum sulfate crystals as crystal seeds serving as crystallization inducers, separating out rubidium aluminum sulfate alum salt and cesium aluminum sulfate alum salt, and filtering to obtain filtrate A; cooling the filtrate A to 15 ℃, adding an aluminum potassium sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain filtrate B;

s3, adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 15 ℃, adding a crystallization inducer into the filtrate C, crystallizing to obtain potassium sulfate, and filtering to obtain a filtrate D; using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain potassium aluminum sulfate alum salt, and filtering to obtain filtrate E, namely lithium hydroxide solution;

s4, and finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare 9.05g of battery-grade lithium carbonate.

Example 2

S1, adding 100g of concentrated sulfuric acid and 200g of lithium mica powder into a ball milling tank for mechanical grinding for 36 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground lithium mica powder-concentrated sulfuric acid mixture into an extraction tank, adding 2000g of water, soaking for 36 hours, leaching and dissolving alkali metal sulfate, filtering and separating to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt;

s2, controlling the temperature of the leaching solution at 60 ℃, adding rubidium aluminum sulfate and cesium aluminum sulfate crystallization inducers to separate out rubidium aluminum sulfate alum salt and cesium aluminum sulfate alum salt, and filtering to obtain filtrate A; cooling the filtrate A to 10 ℃, adding an aluminum potassium sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain filtrate B;

s3, adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 10 ℃, adding a crystallization inducer into the filtrate C, crystallizing to obtain potassium sulfate, and filtering to obtain a filtrate D; using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain potassium aluminum sulfate alum salt, and filtering to obtain filtrate E, namely lithium hydroxide solution;

s4, and finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare 18.22g of battery-grade lithium carbonate.

Example 3

S1, adding 100g of concentrated sulfuric acid and 400g of lithium mica powder into a ball milling tank for mechanical grinding for 36 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground lithium mica powder-concentrated sulfuric acid mixture into an extraction tank, adding 2000g of water, soaking for 24 hours, leaching and dissolving alkali metal sulfate, filtering and separating to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt;

s2, controlling the temperature of the leaching solution at 55 ℃, adding rubidium aluminum sulfate and cesium aluminum sulfate crystallization inducers to separate out rubidium aluminum sulfate alum salt and cesium aluminum sulfate alum salt, and filtering to obtain filtrate A; cooling the filtrate A to 15 ℃, adding an aluminum potassium sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain filtrate B;

s3, adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 15 ℃, adding a crystallization inducer into the filtrate C, crystallizing to obtain potassium sulfate, and filtering to obtain a filtrate D; using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain potassium aluminum sulfate alum salt, and filtering to obtain filtrate E, namely lithium hydroxide solution;

s4, and finally, reacting the obtained lithium hydroxide solution with carbon dioxide to prepare 36.04g of battery-grade lithium carbonate.

Example 4

S1, adding 100g of concentrated sulfuric acid and 600g of lithium mica powder into a ball milling tank for mechanical grinding for 48 hours, carrying out solid-phase reaction in the mixing process, transferring the mechanically ground lithium mica powder-concentrated sulfuric acid mixture into an extraction tank, adding 2100g of water, soaking for 24 hours, leaching and dissolving alkali metal sulfate, filtering and separating to obtain a leachate, wherein the leachate mainly contains potassium salt, aluminum salt, lithium salt, rubidium salt and cesium salt;

s2, controlling the temperature of the leaching solution at 55 ℃, adding rubidium aluminum sulfate and cesium aluminum sulfate crystallization inducers to separate out rubidium aluminum sulfate alum salt and cesium aluminum sulfate alum salt, and filtering to obtain filtrate A; cooling the filtrate A to 5 ℃, adding an aluminum potassium sulfate crystallization inducer to separate out potassium aluminum sulfate salt, and filtering to obtain filtrate B;

s3, adding potassium hydroxide into the filtrate B for neutralization until no precipitate is generated, and filtering the precipitate after neutralization to obtain aluminum hydroxide and filtrate C; cooling the filtrate C to 5 ℃, adding a crystallization inducer into the filtrate C, crystallizing to obtain potassium sulfate, and filtering to obtain a filtrate D; using aluminum hydroxide to neutralize excessive sulfuric acid, supplementing potassium sulfate according to the addition amount of the aluminum hydroxide, crystallizing to obtain potassium aluminum sulfate alum salt, and filtering to obtain filtrate E, namely lithium hydroxide solution;

s4, and finally reacting the obtained lithium hydroxide solution with carbon dioxide to prepare 54.61g of battery-grade lithium carbonate.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.