CN222816826U

CN222816826U - Lithium hydroxide mother liquor lithium carbonate production system

Info

Publication number: CN222816826U
Application number: CN202421462679.1U
Authority: CN
Inventors: 黄鹏飞; 严小龙
Original assignee: Yinghai Fuxing Engineering Technology Chengdu Co ltd
Current assignee: Yinghai Fuxing Engineering Technology Chengdu Co ltd
Priority date: 2024-06-24
Filing date: 2024-06-24
Publication date: 2025-05-02
Anticipated expiration: 2034-06-24

Abstract

The utility model discloses a lithium hydroxide mother liquor precipitation lithium carbonate production system, including a pre-stage impurity removal system, a reactor, a centrifuge, a primary slurry mixing tank, a primary slurry washing tank, a primary centrifuge, a secondary slurry mixing tank, a secondary slurry washing tank, a secondary centrifuge and a dryer, the reactor is provided with a carbon dioxide inlet pipe, the carbon dioxide inlet pipe is provided with a flow meter and a regulating valve, the reactor is provided with an inlet pipe disc, and the inlet pipe disc is connected with the carbon dioxide inlet pipe. Compared with the prior art, the utility model uses a pre-stage impurity removal system to remove impurities from the lithium hydroxide mother liquor, reasonably controls the proportion of carbon dioxide, avoids excessive generation of lithium bicarbonate, adopts a suitable feed amount, temperature, and stirring rate, thereby controlling the reaction rate to obtain the target lithium carbonate crystal form, reduce impurity carryover, adopts a two-stage process operation of normal temperature reaction and high temperature pyrolysis, ensures complete pyrolysis of lithium bicarbonate, reduces the solubility of lithium carbonate, and improves the yield of lithium carbonate.

Description

Lithium hydroxide mother liquor lithium carbonate production system

Technical Field

The utility model relates to the field of chemical industry, in particular to a lithium hydroxide mother liquor lithium carbonate precipitation production system.

Background

At present, high-impurity mother liquor (the main component is 11% saturated concentration lithium hydroxide) generated in a lithium hydroxide process in the lithium chemical industry is recovered, and is usually treated by a carbon dioxide neutralization precipitation method. However, the mother solution has higher impurity content, contains impurities such as calcium, magnesium, sodium, potassium, iron and the like, has incomplete process impurity removal, has high impurity content of the product, is easy to carry impurities in the crystal form generation of the reaction link, influences the quality of the product, has certain solubility of lithium carbonate, has unsuitable operation parameters of the rinsing link, and can lead the liquid holdup of a rule system to be increased or the rinsing effect to be poor. When the reaction of lithium hydroxide and carbon dioxide is carried out, lithium bicarbonate is generated when the carbon dioxide is excessive, so that the yield is greatly reduced, and when the carbon dioxide is insufficient, the reaction is incomplete, the yield is low, lithium hydroxide is entrained, and the product quality is low. In the process of generating lithium carbonate reaction, the processes of pipe blockage and wall attachment are very easy to generate due to the characteristics of materials, and the phenomena of unsmooth system operation and system shutdown cleaning are often caused.

According to the situation, the technological parameters of each operation link of the lithium hydroxide mother solution lithium carbonate precipitation process are researched, and a series of reasonable process production systems are developed, so that the product quality is improved, and the project energy consumption is reduced.

Disclosure of utility model

The utility model aims to provide a lithium hydroxide mother solution precipitated lithium carbonate production system which solves the problems.

In order to achieve the purpose, the lithium hydroxide mother liquor lithium carbonate production system comprises a front-stage impurity removal system, a reaction kettle, a centrifugal machine, a primary pulp mixing tank, a primary pulp washing tank, a primary centrifugal machine, a secondary pulp mixing tank, a secondary pulp washing tank, a secondary centrifugal machine and a dryer, wherein the front-stage impurity removal system, the reaction kettle, the centrifugal machine, the primary pulp mixing tank, the primary pulp washing tank, the primary centrifugal machine, the secondary pulp mixing tank, the secondary pulp washing tank, the secondary centrifugal machine and the dryer are sequentially communicated through a lithium hydroxide conveying pipeline, a carbon dioxide air inlet pipe is arranged on the reaction kettle, a flow meter and a regulating valve are arranged on the carbon dioxide air inlet pipe, an air inlet pipe disc is arranged in the reaction kettle, a plurality of exhaust holes are formed in the air inlet pipe disc, and the air inlet pipe disc is communicated with the carbon dioxide air inlet pipe.

Preferably, a secondary washing water recovery pipe is arranged between the secondary centrifugal machine and the primary pulp mixing tank, and a transfer tank and a solution pump are arranged on the secondary washing water recovery pipe.

Preferably, jackets are arranged on the reaction kettle, the primary pulp washing kettle and the secondary pulp washing kettle, a steam inlet pipe and a condensed water outlet pipe are arranged on the jackets, and the jackets on the reaction kettle are provided with the jackets.

Preferably, the jacket of the reaction kettle is also provided with a circulating cooling water inlet pipe and a circulating cooling water outlet pipe, the circulating cooling water inlet pipe and the circulating cooling water outlet pipe are communicated with the inside of the jacket, the circulating cooling water inlet pipe is positioned at the bottom of the jacket, and the circulating cooling water outlet pipe is positioned at the upper part of the jacket.

Preferably, an inert gas vent valve is further arranged at the top of the reaction kettle.

Preferably, a variable frequency stirring device is arranged in the reaction kettle.

Preferably, the impurity removal system comprises an impurity removal kettle, a microporous filter element filter, nano-filtration equipment and a resin adsorption filter, wherein the impurity removal kettle, the microporous filter element filter, the nano-filtration equipment and the resin adsorption filter are sequentially communicated through a lithium hydroxide conveying pipeline, the resin adsorption filter is communicated with the inside of the reaction kettle through the lithium hydroxide conveying pipeline, and a dosing box is arranged on the impurity removal kettle.

Preferably, a middle transfer groove is respectively arranged between the microporous filter element filter and the nano-filtration equipment and on the lithium hydroxide conveying pipeline between the resin adsorption filter and the secondary evaporation crystallization system.

Compared with the prior art, the utility model has the advantages that the technology has the following advantages:

1. The combination of chemical impurity removal, nanofiltration and resin adsorption impurity removal is applied, so that the lithium hydroxide mother solution is efficient and reliable in impurity removal.

2. According to the reaction molar ratio and in combination with engineering experiments, reasonable carbon dioxide ratio is adopted, so that excessive generation of lithium bicarbonate is avoided.

3. And the reaction rate is controlled by adopting proper feeding amount, temperature and stirring rate, so that the target lithium carbonate crystal form is obtained, and impurity carrying is reduced.

4. And a reaction kettle link adopts two-stage process operation of normal temperature reaction and high temperature pyrolysis. Ensure the complete pyrolysis of lithium bicarbonate.

5. Scientific theoretical calculation and material balance calculation are carried out, and secondary washing water is used as part of primary washing water, so that the use of system water is reduced, and the load of subsequent solution concentration is reduced. The water consumption of the rinsing link is better than 20% of the industry.

6. Reasonable rinsing temperature is adopted, so that the solubility of the lithium carbonate is reduced, and the yield of the lithium carbonate is improved.

7. The product meets the index of YS/T582-2013 battery grade lithium carbonate, and LiCO ₃ is more than or equal to 99.5.

Drawings

FIG. 1 is a schematic diagram of a system of the present utility model;

FIG. 2 is a schematic structural diagram of the reaction vessel of the present utility model.

In the figure, a medicine adding tank, a 2 part of a impurity removing kettle, a 3 part of a microporous filter element filter, a 4 part of a nano filtering device, a 5 part of a resin adsorption filter, a 6 part of a reaction kettle, a 7 part of a centrifugal machine, a 8 part of a primary pulp mixing tank, a 9 part of a primary pulp washing kettle, a10 part of a primary centrifugal machine, a11 part of a secondary pulp mixing tank, a 12 part of a secondary pulp washing kettle, a 13 part of a secondary centrifugal machine, a 14 part of a dryer, a 15 part of lithium hydroxide conveying pipeline, a 16 part of a middle rotary tank, a 17 part of a carbon dioxide air inlet pipe, a 18 part of a secondary washing water recycling pipe, a 19 part of a flowmeter, a 20 part of a regulating valve, a 21 part of an air inlet pipe, a 22 part of a jacket, a 23 part of a steam air inlet pipe, a 24 part of a condensed water outlet pipe, a 25 part of a circulating cooling water inlet pipe, a 26 part of a circulating cooling water outlet pipe and a 27 part of an inert gas discharging valve.

Detailed Description

The present utility model will be further described below

The utility model relates to a lithium hydroxide mother liquor precipitated lithium carbonate production system, which is shown in fig. 1-2 and comprises a pre-stage impurity removal system, a reaction kettle 6, a centrifugal machine 7, a primary pulp mixing tank 8, a primary pulp washing kettle 9, a primary centrifugal machine 10, a secondary pulp mixing tank 11, a secondary pulp washing kettle 12, a secondary centrifugal machine 13 and a dryer 14, wherein the pre-stage impurity removal system, the reaction kettle 6, the centrifugal machine 7, the primary pulp mixing tank 8, the primary pulp washing kettle 9, the primary centrifugal machine 10, the secondary pulp mixing tank 11, the secondary pulp washing kettle 12, the secondary centrifugal machine 13 and the dryer 14 are sequentially communicated through a lithium hydroxide conveying pipeline 15.

In the reaction kettle 6, carbon dioxide (gas) is introduced into the lithium hydroxide solution to react, and lithium carbonate precipitate is generated. And circulating water is introduced during the reaction, so that the generation rate of the crystal forms is controlled. After the reaction is completed, the temperature is raised to 90 ℃ to completely decompose the excessive lithium bicarbonate generated by the side reaction into lithium carbonate.

Equation of reaction 2LiOH+CO ₂＝Li₂CO₃↓+H₂ 0

Side reactions Li ₂CO₃ (poorly soluble) +H ₂0+CO₂＝2LiHCO₃ (soluble)

Pyrolysis reaction 2LiHCO ₃＝Li₂CO₃↓+H₂0+CO₂ ≡

When lithium hydroxide reacts with carbon dioxide, lithium bicarbonate is generated when the carbon dioxide is excessive, so that the yield is greatly reduced, when the carbon dioxide is insufficient, the reaction is incomplete, the yield is low, lithium hydroxide is entrained, the product quality is low, and when the reaction is too fast, the crystal formation is uneven, and impurities are entrained. The stirring rate and temperature also have a direct effect on the crystal morphology.

The reaction kettle 6 is provided with a carbon dioxide air inlet pipe 17, the carbon dioxide air inlet pipe 17 is provided with a flowmeter 19 and a regulating valve 20, the rate and the total amount of carbon dioxide addition can be controlled through the arranged flowmeter 19 and the regulating valve 20 of carbon dioxide, the situation that excessive generation and over-fast reaction of lithium bicarbonate are avoided, and the reaction kettle 6 is internally provided with variable frequency stirring equipment which can control the size of lithium carbonate crystals through variable frequency stirring.

The reaction kettle 6, the primary pulp washing kettle 9 and the secondary pulp washing kettle 12 are provided with jackets 22, the jackets 22 are provided with steam inlet pipes 23 and condensate water outlet pipes 24, and the jackets 22 on the reaction kettle 6 are provided with jackets 22. The jacket 22 can be temperature-raising controlled to ensure complete decomposition of lithium bicarbonate.

The jacket 22 of the reaction kettle 6 is also provided with a circulating cooling water inlet pipe 25 and a circulating cooling water outlet pipe 26, the circulating cooling water inlet pipe 25 and the circulating cooling water outlet pipe 26 are communicated with the inside of the jacket 22, the circulating cooling water inlet pipe 25 is positioned at the bottom of the jacket 22, and the circulating cooling water outlet pipe 26 is positioned at the upper part of the jacket 22. The jacket 22 is additionally provided with a circulating cooling water inlet pipe 25 and a circulating cooling water outlet pipe 26, circulating cooling water is introduced, and the jacket 22 can be used for timely cooling control of the reaction kettle 6 so as to ensure the stability of lithium carbonate crystallization in the reaction kettle 6.

Through practical production test experience, the carbon dioxide lithium hydroxide=1.4:1 is controlled, so that the reaction can be carried out thoroughly, excessive hydrogenation is avoided, and the method is an ideal balance point.

With respect to pyrolysis temperature. Lithium bicarbonate starts to decompose at 60 ℃, whereas thorough decomposition requires 85 ℃. The pyrolysis is carried out in a non-boiling state at 90 ℃, so that the current situation that the pipe is not completely blocked due to the decomposition of lithium bicarbonate can be effectively prevented, the yield is ensured, and the steam consumption is not excessively wasted.

The reaction kettle 6 is internally provided with an air inlet pipe plate 21, the air inlet pipe plate 21 is provided with a plurality of exhaust holes, the air inlet pipe plate 21 is communicated with the carbon dioxide air inlet pipe 17, and uniform air inlet of carbon dioxide can be realized through the air inlet pipe plate 21 and fully reacts with lithium hydroxide.

The centrifuge 7 separates the reacted lithium carbonate slurry. And (3) delivering the lithium carbonate solid to a lower link for size mixing, and returning the liquid (containing lithium) to a system for use.

Delivering the lithium carbonate solid separated by the centrifugal machine 7 into a pulp mixing tank, mixing pulp by secondary washing water, delivering into a pulp washing kettle for stirring and washing, wherein the stirring and washing temperature is 80 ℃. Because the separated lithium carbonate solid can entrain certain soluble impurities, such as Na ⁺、K⁺、cl^-、SO₄ ^2-, slurry mixing washing is needed, when the solution temperature is higher, the solubility of the lithium carbonate is lower, and the solid adopts a high-temperature rinsing mode, so that the product yield can be improved.

After primary slurry washing kettle is stirred and washed once, the primary centrifugal machine 10 is used for separation, primary stirring and washing liquid (containing lithium) is returned to the system for use, the primary stirring and washing lithium carbonate solid is sent to the secondary slurry mixing tank 11 for slurry mixing, pure water is used for slurry mixing, and the secondary slurry washing kettle is sent for stirring and washing, and the stirring and washing temperature is 80 ℃.

After secondary stirring and washing, the lithium carbonate solid is sent to dry by using a secondary centrifugal machine 13, and the secondary stirring and washing liquid has less impurities and can be used as primary stirring and washing pulp, so that a secondary washing water recovery pipe 18 is arranged between the secondary centrifugal machine 13 and the primary pulp mixing tank 8, and a transfer tank 16 and a solution pump are arranged on the secondary washing water recovery pipe 18, so that the recycling of secondary washing water can be realized.

The secondary centrifuge 13 sends the wet lithium carbonate crystals to a dryer 14, and the wet lithium carbonate crystals are dried until the water content is less than or equal to 0.25 percent and are packaged and sold. The product meets the index of YS/T582-2013 battery grade lithium carbonate, and LiCO3 is more than or equal to 99.5

The top of the reaction kettle 6 is also provided with an inert gas vent valve 27 which can be used for discharging inert gas in the reaction kettle 6.

The impurity removal system comprises an impurity removal kettle 2, a microporous filter element filter 3, nano-filtration equipment 4 and a resin adsorption filter 5, wherein the impurity removal kettle 2, the microporous filter element filter 3, the nano-filtration equipment 4 and the resin adsorption filter 5 are sequentially communicated through a lithium hydroxide conveying pipeline 15, the resin adsorption filter 5 is communicated with the inside of a reaction kettle 6 through the lithium hydroxide conveying pipeline 15, and a dosing box 1 is arranged on the impurity removal kettle 2.

The lithium hydroxide mother liquor raw material with high impurity is subjected to chemical impurity removal, physical impurity removal, nanofiltration and resin adsorption through an impurity removal system.

Chemical impurity removal, namely, the lithium hydroxide mother liquor is the liquid recycled in the system in the concentration process of the lithium hydroxide device, various impurities in the mother liquor are gradually enriched along with the time, and finally, the product quality requirement cannot be met, and the lithium hydroxide mother liquor needs to be discharged out of the system for recovery.

The lithium hydroxide mother solution contains more soluble impurities such as Ca ²⁺、Mg²⁺、Na⁺、K⁺、Fe³⁺ and some insoluble impurities. Firstly, adding an impurity removing agent such as sodium carbonate and oxalic acid into an impurity removing kettle 2 through a dosing tank 1, reacting with Ca ²⁺、Mg²⁺、Fe³⁺, and precipitating high-valence metal ions.

And (3) physical impurity removal, namely, pumping carbonate/oxalate precipitate generated by chemical impurity removal into a microporous filter element filter 3 along with slurry, and filtering in a 0.5 mu m high-precision filter to remove sediment and insoluble particles in the solution.

Nanofiltration, namely delivering the lithium hydroxide solution filtered by the microporous filter element into nanofiltration equipment 4. The aperture of the nanofiltration membrane is a few nanometers, so the nanofiltration membrane is called nanofiltration, can intercept organic matters and multivalent soluble ions, and allows small molecular organic matters and monovalent ions to permeate. The equipment can deeply remove impurities from the part where oxalic acid is not thoroughly removed, and has an excellent removal effect on high-valence ions such as Ca²⁺、Mg²⁺、Fe³ ⁺、Mn⁴⁺、Al³⁺、SI⁴⁺、SO₄ ^2- through feedback of test effects.

Resin adsorption, namely, finally, through the resin adsorption filter 5, adsorption groups (such as-COOH, -NH ₂ and the like) on the surface of the resin can be combined with certain molecules in the solution to form specific organic chemical substances, so that certain substances in the solution are adsorbed on the surface of the resin and are not dissolved.

And transfer grooves 16 are respectively arranged on lithium hydroxide conveying pipelines 15 between the microporous filter element filter 3 and the nano-filtration equipment 4 and between the resin adsorption filter 5 and the secondary evaporation crystallization system, and the filtered lithium hydroxide solution is transferred and buffered through the transfer grooves 16 so as to control the filtration time and the filtration effect.

The utility model uses the high impurity lithium hydroxide mother liquor as raw material, and obtains a production technology of battery grade lithium carbonate by a series of means of impurity removal, reaction, rinsing and the like, and the product accords with the index of YS/T582-2013 battery grade lithium carbonate, and LiCO ₃ is more than or equal to 99.5. Compared with the traditional production method, the production efficiency is improved, the product quality is improved, and the production energy consumption is reduced.

While the present utility model has been described in detail in connection with the specific examples thereof, which are set forth to illustrate the principles and embodiments of the utility model, it should be understood that the utility model is not limited thereto, but is susceptible to modification and variation in form and range of application by one of ordinary skill in the art, depending on the teachings of the utility model.

Claims

1. A lithium hydroxide mother liquor precipitation lithium carbonate production system, characterized in that: it includes: a front-stage impurity removal system, a reactor, a centrifuge, a primary slurry mixing tank, a primary slurry washing tank, a primary centrifuge, a secondary slurry mixing tank, a secondary slurry washing tank, a secondary centrifuge and a dryer, the front-stage impurity removal system, the reactor, the centrifuge, the primary slurry mixing tank, the primary slurry washing tank, the primary centrifuge, the secondary slurry mixing tank, the secondary slurry washing tank, the secondary centrifuge and the dryer are sequentially connected through a lithium hydroxide delivery pipeline, the reactor is provided with a carbon dioxide inlet pipe, the carbon dioxide inlet pipe is provided with a flow meter and a regulating valve, the reactor is provided with an inlet pipe disc, the inlet pipe disc is provided with a plurality of exhaust holes, and the inlet pipe disc is connected with the carbon dioxide inlet pipe.

2. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 1, characterized in that: a secondary wash water recovery pipe is provided between the secondary centrifuge and the primary slurry mixing tank, and a transfer tank and a solution pump are provided on the secondary wash water recovery pipe.

3. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 1, characterized in that: the reaction kettle, the first-level pulp washing kettle and the second-level pulp washing kettle are provided with a jacket, and the jacket is provided with a steam inlet pipe and a condensed water outlet pipe.

4. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 3, characterized in that: the jacket of the reactor is also provided with a circulating cooling water inlet pipe and a circulating cooling water outlet pipe, the circulating cooling water inlet pipe and the circulating cooling water outlet pipe are both connected to the inside of the jacket, the circulating cooling water inlet pipe is located at the bottom of the jacket, and the circulating cooling water outlet pipe is located at the upper part of the jacket.

5. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 1, characterized in that: an inert gas vent valve is also provided on the top of the reactor.

6. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 1, characterized in that: a variable frequency stirring device is provided in the reactor.

7. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 1, characterized in that: the impurity removal system consists of an impurity removal kettle, a microporous filter element filter, a nanofiltration device and a resin adsorption filter, the impurity removal kettle, the microporous filter element filter, the nanofiltration device and the resin adsorption filter are connected in sequence through a lithium hydroxide delivery pipeline, the resin adsorption filter is connected to the inside of the reactor through the lithium hydroxide delivery pipeline, and the impurity removal kettle is provided with a drug adding box.

8. A lithium hydroxide mother liquor precipitation lithium carbonate production system according to claim 7, characterized in that: a transfer tank is respectively provided on the lithium hydroxide delivery pipeline between the microporous filter element filter and the nanofiltration equipment, and between the resin adsorption filter and the secondary evaporation crystallization system.