阅读说明：本技术 一种离子膜法制备高纯度碳酸锂工艺 (Process for preparing high-purity lithium carbonate by ion membrane method ) 是由 刘海松 于 2019-10-14 设计创作，主要内容包括：本发明公开了一种离子膜法制备高纯度碳酸锂工艺,涉及高纯度碳酸锂制备技术领域,为解决现有高纯度碳酸锂多采用沉淀法和重结晶法制备,流程长,且杂质较多,而采用电解法制备高纯度碳酸锂电耗大,故应用较少的问题。步骤1：使用过滤网对收集来的盐湖卤水进行过滤处理；步骤2：将过滤后的盐湖卤水静置在容器中,进行自然沉降处理；步骤3：在容器中添加絮凝剂,并充分搅拌反应,吸附微粒,加快聚沉；步骤4：在除杂后的盐湖卤水即Li<Sub>2</Sub>CO<Sub>3</Sub>中添加过量的碳酸钠和氢氧化钠,再次过滤后,添加少量HCL溶液,以去除其中的Ca、Mg等阳离子杂质,若采用粗Li<Sub>2</Sub>CO<Sub>3</Sub>作为原料可直接从该步骤开始；对除杂后的溶液进行电解处理,获得高纯度LiOH溶液。(2 3 2 3 the invention discloses a process for preparing high-purity lithium carbonate by an ion membrane method, which relates to the technical field of high-purity lithium carbonate preparation, and aims to solve the problems that the existing high-purity lithium carbonate is prepared by a precipitation method and a recrystallization method, the flow is long, and impurities are more, and the high-purity lithium carbonate prepared by an electrolysis method has high power consumption and is less in application.)

1. A process for preparing high-purity lithium carbonate by an ion membrane method is characterized by comprising the following steps: the method comprises the following steps:

Step 1: filtering the collected salt lake brine by using a filter screen;

Step 2: standing the filtered salt lake brine in a container, and performing natural sedimentation treatment;

And step 3: adding a flocculating agent into the container, fully stirring for reaction, adsorbing particles and accelerating coagulation;

Step 4, adding excessive sodium carbonate and sodium hydroxide into salt lake brine, namely Li ₂ CO ₃ after impurity removal, filtering again, adding a small amount of HCL solution to remove Ca, Mg and other cationic impurities, and starting from the step directly if crude Li ₂ CO ₃ is adopted as a raw material;

and 5: carrying out electrolytic treatment on the solution after impurity removal to obtain a high-purity LiOH solution;

And 6, introducing CO ₂ into the high-purity LiOH solution to carbonize the solution, thereby obtaining the high-purity Li ₂ CO ₃ solution.

2. the process for preparing high-purity lithium carbonate by the ion membrane method according to claim 1, which is characterized in that: in the step 1, a filter screen is adopted, so that suspended particles such as algae and rust in salt lake brine can be preliminarily filtered.

3. The process for preparing high-purity lithium carbonate by the ion membrane method according to claim 1, which is characterized in that: the step 2 and the step 3 can be carried out simultaneously, a flocculating agent is added and stirred while the sedimentation is carried out, so that particles are adsorbed, the coagulation is accelerated, the impurity removal time is saved, the impurity removal efficiency is improved, and the method can effectively remove heavy particles and colloidal substances in the salt lake brine.

4. The process for preparing high-purity lithium carbonate by the ion membrane method as claimed in claim 1, wherein in the step 4, sodium carbonate is added into Li ₂ CO ₃, and can react with Ca ²⁺ therein to generate calcium carbonate precipitate, and the chemical equation of the reaction is Ca ²⁺ + CO3 ^2- → CaCO3 ↓, and the overbased amount of the sodium carbonate is 200-400 mg/l.

5. the process for preparing high-purity lithium carbonate by the ion membrane method as claimed in claim 1, wherein in the step 4, sodium hydroxide is added into Li ₂ CO ₃ to react with Mg ²⁺ therein to generate insoluble Mg (OH)2 precipitate, and the reaction formula is Mg ²⁺ +2OH ^- → Mg (OH)2 ↓, and the excessive alkali amount of the sodium hydroxide is 100-300 Mg/l.

6. the process for preparing high-purity lithium carbonate by the ion membrane method according to claim 1, wherein the solution obtained after impurity removal in the step 5 is used as an anolyte of an electrolytic cell, a catholyte is LiOH solution, the LiOH solution and the catholyte are separated by an ion membrane, lithium ions enter the anolyte through the ion membrane during electrolysis, OH ^- cannot enter the anolyte through the ion membrane, and the high-purity LiOH solution can be obtained after the electrolysis process is finished.

7. The process for preparing high-purity lithium carbonate by the ion membrane method according to claim 1, which is characterized in that: the electrolytic cell in the step 5 adopts the photocell as an electric energy source, the photocell is also called as a solar cell, is a semiconductor element which generates electromotive force under the illumination condition, and is an element which can generate electromotive force under the illumination of light.

8. the process for preparing high-purity lithium carbonate by the ion membrane method according to claim 1, wherein the chemical equation of the carbonization reaction of the high-purity LiOH solution and the CO ₂ in the step 6 is 2LiOH + CO ₂ ═ Li ₂ CO ₃ + H ₂ O.

Technical Field

The invention relates to the technical field of high-purity lithium carbonate preparation, in particular to a process for preparing high-purity lithium carbonate by an ion membrane method.

Background

Lithium carbonate, an inorganic compound, has a chemical formula of Li ₂ CO ₃, is colorless monoclinic crystal system crystals or white powder, and has a density of 2.11g/cm ³. because the main raw material for producing the lithium carbonate is salt lake brine (the ore method has low global capacity due to high cost), enterprises for producing the lithium carbonate on a large scale must have the exploitation right of salt lake resources with rich lithium resource reserves, so the industry has higher resource barriers, and on the other hand, because most resources of the salt lake on the world are high-magnesium low-lithium types, the technical difficulty of the process for purifying and separating the lithium carbonate from high-magnesium low-lithium old brine is very large, the technologies are only mastered in a few foreign companies, so the lithium carbonate industry has technical barriers.

However, the existing high-purity lithium carbonate is mostly prepared by a precipitation method and a recrystallization method, the flow is long, and more impurities exist, while the high-purity lithium carbonate prepared by an electrolysis method has large power consumption and less application; therefore, the existing requirements are not met, and a process for preparing high-purity lithium carbonate by an ion membrane method is provided for the lithium carbonate.

disclosure of Invention

the invention aims to provide a process for preparing high-purity lithium carbonate by an ion membrane method, which aims to solve the problems that the existing high-purity lithium carbonate in the background art is mostly prepared by a precipitation method and a recrystallization method, has long flow and more impurities, and the high-purity lithium carbonate prepared by an electrolysis method has high power consumption and less application.

In order to achieve the purpose, the invention provides the following technical scheme: a process for preparing high-purity lithium carbonate by an ion membrane method comprises the following steps:

Step 1: filtering the collected salt lake brine by using a filter screen;

Step 2: standing the filtered salt lake brine in a container, and performing natural sedimentation treatment;

and step 3: adding a flocculating agent into the container, fully stirring for reaction, adsorbing particles and accelerating coagulation;

Step 4, adding excessive sodium carbonate and sodium hydroxide into salt lake brine, namely Li ₂ CO ₃ after impurity removal, filtering again, adding a small amount of HCL solution to remove Ca, Mg and other cationic impurities, and starting from the step directly if crude Li ₂ CO ₃ is adopted as a raw material;

And 5: carrying out electrolytic treatment on the solution after impurity removal to obtain a high-purity LiOH solution;

And 6, introducing CO ₂ into the high-purity LiOH solution to carbonize the solution, thereby obtaining the high-purity Li ₂ CO ₃ solution.

preferably, a filter screen is adopted in the step 1, so that suspended particles such as algae and iron rust in the salt lake brine can be filtered primarily.

Preferably, the step 2 and the step 3 can be carried out simultaneously, a flocculating agent is added and stirred while the sedimentation is carried out, so that particles are adsorbed, the coagulation is accelerated, the impurity removal time is saved, the impurity removal efficiency is improved, and the method can effectively remove heavy particles and colloidal substances in the salt lake brine.

preferably, the addition of sodium carbonate in Li ₂ CO ₃ in step 4 can react with Ca ²⁺ therein to generate calcium carbonate precipitate, and the reaction formula is Ca ²⁺ + CO3 ^2- → CaCO3 ↓, and the overbased amount of sodium carbonate is 200-.

Preferably, the addition of sodium hydroxide in Li ₂ CO ₃ in step 4 can react with Mg ²⁺ therein to form insoluble Mg (OH)2 precipitate, and the reaction formula is Mg ²⁺ +2OH ^- → Mg (OH)2 ↓, and the amount of sodium hydroxide excess base is 100-300 Mg/l.

preferably, the solution after impurity removal in the step 5 is used as an anolyte of an electrolytic cell, a catholyte is a LiOH solution, the two solutions are isolated by an ionic membrane, lithium ions can enter the anolyte through the ionic membrane in the electrolytic process, OH ^- cannot enter the anolyte through the ionic membrane, and the high-purity LiOH solution can be obtained after the electrolytic process is finished.

preferably, the electrolytic cell in the step 5 uses a photovoltaic cell as an electric energy source, the photovoltaic cell is also called a solar cell, is a semiconductor element which generates electromotive force under the illumination condition, and is an element which can generate electromotive force under the illumination condition of light, and because the electric energy consumption of electrolysis is large, and solar energy is inexhaustible, the energy consumption can be effectively reduced by using the photovoltaic cell as the electric energy source of the electrolytic cell, and the cost required by production can be reduced.

Preferably, the chemical equation of the carbonization reaction of the high-purity LiOH solution and the CO ₂ in the step 6 is 2LiOH + CO ₂ ═ Li ₂ CO ₃ + H ₂ O.

compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, salt lake brine or crude lithium carbonate is adopted as a raw material, when the salt lake brine is adopted, impurity removal treatment is required, and ion impurities in the salt lake brine or crude lithium carbonate after impurity removal can be removed in an electrolytic manner, so that the high-purity lithium carbonate is prepared.

2. The photovoltaic cell is used as an electric energy source of the electrolytic cell, and is also called as a solar cell, and is a semiconductor element which generates electromotive force under the illumination condition, the electromotive force can be generated under the illumination condition of light, and the conventional electrolysis consumes too much electric energy, and the solar energy is inexhaustible, so that the energy consumption can be effectively reduced by using the photovoltaic cell as the electric energy source of the electrolytic cell, and the cost required by production is reduced.

Drawings

FIG. 1 is a flow chart of the present invention;

Detailed Description

the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

Referring to fig. 1, an embodiment of the present invention: a process for preparing high-purity lithium carbonate by an ion membrane method comprises the following steps:

Step 1: filtering the collected salt lake brine by using a filter screen;

Step 2: standing the filtered salt lake brine in a container, and performing natural sedimentation treatment;

And step 3: adding a flocculating agent into the container, fully stirring for reaction, adsorbing particles and accelerating coagulation;

Step 4, adding excessive sodium carbonate and sodium hydroxide into salt lake brine, namely Li ₂ CO ₃ after impurity removal, filtering again, adding a small amount of HCL solution to remove Ca, Mg and other cationic impurities, and starting from the step directly if crude Li ₂ CO ₃ is adopted as a raw material;

And 5: carrying out electrolytic treatment on the solution after impurity removal to obtain a high-purity LiOH solution;

And 6, introducing CO ₂ into the high-purity LiOH solution to carbonize the solution, thereby obtaining the high-purity Li ₂ CO ₃ solution.

furthermore, a filter screen is adopted in the step 1, so that suspended particles such as algae and iron rust in the salt lake brine can be preliminarily filtered.

Further, the step 2 and the step 3 can be carried out simultaneously, a flocculating agent is added and stirred while the sedimentation is carried out, so that particles are adsorbed, the coagulation is accelerated, the impurity removal time is saved, the impurity removal efficiency is improved, and the method can effectively remove heavy particles and colloid substances in the salt lake brine.

Further, in step 4, the addition of sodium carbonate in Li ₂ CO ₃ can react with Ca ²⁺ therein to generate calcium carbonate precipitate, and the reaction formula is Ca ²⁺ + CO3 ^2- → CaCO3 ↓, and the overbased amount of sodium carbonate is 200-400 mg/l.

Further, in step 4, the addition of sodium hydroxide in Li ₂ CO ₃ can react with Mg ²⁺ therein to form insoluble Mg (OH)2 precipitate, which has the chemical formula of Mg ²⁺ +2OH ^- → Mg (OH)2 ↓, and the amount of sodium hydroxide overbase is 100-300 Mg/l.

Further, the solution after impurity removal in the step 5 is used as an anolyte of the electrolytic cell, a LiOH solution is selected as a catholyte, the LiOH solution and the anolyte are isolated by an ionic membrane, lithium ions can enter the anolyte through the ionic membrane in the electrolytic process, OH ^- cannot enter the anolyte through the ionic membrane, and the high-purity LiOH solution can be obtained after the electrolytic process is finished.

Furthermore, the electrolytic cell in step 5 uses a photocell as an electric energy source, and the photocell is also called a solar cell, is a semiconductor element which generates electromotive force under the illumination condition, and is an element which can generate electromotive force under the illumination condition of light.

Further, the chemical equation of the carbonization reaction of the high-purity LiOH solution and the CO ₂ in the step 6 is 2LiOH + CO ₂ ═ Li ₂ CO ₃ + H ₂ O.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.