阅读说明：本技术 一种氯化锂生产工艺及其系统 (Lithium chloride production process and system ) 是由 刘发贵 祝旭甲 邢红 杨建育 张成胜 王文海 张荣子 张成勇 孙海东 马成功 谢 于 2021-01-07 设计创作，主要内容包括：本发明公开一种氯化锂生产工艺,包括：吸附：卤水进入吸附塔中进行锂的吸附,所述吸附塔中的吸附剂吸附锂离子、镁离子；锂洗：锂洗液进入所述吸附塔中将所述镁离子进行清洗去除,酸调节所述锂洗液的PH使得锂洗在酸性环境下进行；脱析：脱析液进入所述吸附塔中将所述锂离子洗涤下来,得到氯化锂合格液。本发明在锂洗的时候加酸调节锂洗液的PH使得锂洗在酸性环境下进行,可以去除锂洗时硼酸根产生的氢氧根离子,减少氢氧化镁的生成,一方面,控制吸附剂的失活速度,抑制吸附剂失活现象的产生,不影响吸附性能,另一方面去除的镁盐量更多,保证了氯化锂合格液的质量。(The invention discloses a lithium chloride production process, which comprises the following steps: adsorption: the brine enters an adsorption tower to be adsorbed by lithium, and an adsorbent in the adsorption tower adsorbs lithium ions and magnesium ions; lithium washing: the lithium washing liquid enters the adsorption tower to clean and remove the magnesium ions, and the pH of the lithium washing liquid is adjusted by acid to ensure that the lithium washing is carried out in an acidic environment; desorption: and (4) enabling the desorption solution to enter the adsorption tower to wash the lithium ions to obtain qualified lithium chloride solution. According to the invention, acid is added to adjust the pH of the lithium washing liquid during lithium washing so that the lithium washing is carried out in an acidic environment, hydroxide ions generated by borate during the lithium washing can be removed, and the generation of magnesium hydroxide is reduced.)

1. A process for producing lithium chloride, wherein the process for producing lithium chloride comprises:

step S1, adsorption: the brine enters an adsorption tower (1) to be adsorbed with lithium, and an adsorbent in the adsorption tower (1) adsorbs lithium ions and magnesium ions;

step S2, lithium washing: lithium washing liquid enters the adsorption tower (1) to clean and remove the magnesium ions, and the pH of the lithium washing liquid is adjusted by acid to ensure that the lithium washing is carried out in an acidic environment;

step S3, desorption: and (4) enabling the desorption solution to enter the adsorption tower (1) to wash the lithium ions to obtain qualified lithium chloride solution.

2. The lithium chloride production process according to claim 1, wherein the step S2 lithium washing includes:

step S21, feeding a section of lithium washing liquid into the adsorption tower (1) from a section of lithium washing tank (21), and feeding the cleaned section of lithium washing liquid into a old brine tank (3) for recycling; the one-section lithium washing solution at least comprises 300-400mg/L lithium ions and 50-60g/L magnesium ions;

step S22, feeding a secondary lithium washing solution into the adsorption tower (1) from a secondary lithium washing tank (22), and feeding the washed secondary lithium washing solution into the primary lithium washing tank (21); the second-stage lithium washing solution at least comprises 500-800mg/L lithium ions and 15-30g/L magnesium ions;

s23, feeding three lithium washing solutions into the adsorption tower (1) from a three lithium washing tank (23), feeding the washed three lithium washing solutions into the first lithium washing tank (21), and adjusting the pH value of the three lithium washing solutions to 4-7 by acid; the three-stage lithium washing solution at least comprises 100-200mg/L lithium ions and 4-7g/L magnesium ions;

and S24, feeding the four-section lithium washing liquid into the adsorption tower (1) from a four-section lithium washing tank (24), feeding the four-section lithium washing liquid after washing into the two-section lithium washing tank (22), wherein the four-section lithium washing liquid is water, and adjusting the pH value of the four-section lithium washing liquid to be 5-7 by acid.

3. The process for producing lithium chloride according to claim 2, wherein the acid is hydrochloric acid.

4. The lithium chloride production process according to claim 2, wherein the step S3 desorption includes:

step S31, feeding the first-stage desorption liquid into the adsorption tower (1) from the first-stage desorption tank (51), feeding part of the washed first-stage desorption liquid into the three-stage lithium washing tank (23), and taking part of the washed first-stage desorption liquid as qualified lithium chloride liquid; the primary desorption liquid at least comprises 300-500mg/L lithium ions and 1-1.7g/L magnesium ions;

step S32, feeding the second-stage desorption liquid into the adsorption tower (1) from a second-stage desorption tank (52), feeding part of the washed second-stage desorption liquid into the first-stage desorption tank (51), and taking part of the washed second-stage desorption liquid as qualified lithium chloride liquid; the secondary desorption liquid at least comprises 300-500mg/L lithium ions and 0.3-0.6g/L magnesium ions;

step S33, feeding the three-section desorption liquid into the adsorption tower (1) from the three-section desorption tank (53), feeding a part of the washed three-section desorption liquid into the first-section desorption tank (51), and feeding a part of the washed three-section desorption liquid into the second-section desorption tank (52); the third-stage desorption liquid is water.

5. The lithium chloride production process of claim 1, wherein the adsorbent is an aluminum-based adsorbent.

6. The lithium chloride production process according to claim 4, wherein the lithium chloride production process further comprises step S4 of: and (3) allowing brine to enter the adsorption tower (1) to replace desorption liquid in the adsorption tower, and allowing the desorption liquid to enter the second-stage desorption tank (52).

7. A lithium chloride production system comprises an adsorption tower (1), a lithium washing tank (2), an acid liquor storage tank (4), a desorption tank (5) and a qualified liquid storage tank (6), wherein the adsorption tower (1) is respectively connected with the lithium washing tank (2), the desorption tank (5) and the qualified liquid storage tank (6), and the lithium washing tank (2) is respectively connected with the acid liquor storage tank (4) and the desorption tank (5);

the brine enters the adsorption tower (1) to be adsorbed with lithium, and the adsorbent in the adsorption tower (1) adsorbs lithium ions and magnesium ions; lithium washing liquid in the lithium washing tank (2) enters the adsorption tower (1) to wash and remove the magnesium ions, and acid in the acid liquid storage tank (4) adjusts the pH value of the lithium washing liquid to enable the lithium washing to be carried out in an acidic environment; and the desorption liquid in the desorption tank (5) enters the adsorption tower (1) to wash the lithium ions, and the qualified lithium chloride liquid is obtained and stored in the qualified liquid storage tank (6).

8. The lithium chloride production system according to claim 7, wherein the lithium washing tank (2) comprises a first lithium washing tank (21), a second lithium washing tank (22), a third lithium washing tank (23) and a fourth lithium washing tank (24) which are arranged at intervals, and the adsorption tower (1) is respectively connected with the first lithium washing tank (21), the second lithium washing tank (22), the third lithium washing tank (23) and the fourth lithium washing tank (24).

9. The lithium chloride production system according to claim 7, wherein the desorption tank (5) comprises a first desorption tank (51), a second desorption tank (52) and a third desorption tank (53) which are arranged at intervals, and the adsorption tower (1) is respectively connected with the first desorption tank (51), the second desorption tank (52) and the third desorption tank (53).

10. The lithium chloride production system of claim 7, wherein the adsorbent is an aluminum-based adsorbent.

Technical Field

The invention relates to the technical field of lithium chloride production, in particular to a process for producing a lithium chloride solution by adsorbing and extracting lithium.

Background

At present, the production method of lithium chloride mainly comprises various methods such as a conversion method, a solvent extraction method, an adsorption method, a salting-out method, a freezing method and the like, wherein the adsorption method is to use an adsorbent with high selectivity on lithium to adsorb lithium in salt lake brine and then elute the lithium so as to achieve the purpose of separating the lithium from other impurity ions. The adsorption method has the advantages of simple process, high recovery rate and good selectivity, and can be deeply applied.

Because the salt lake brine is usually the brine with ultrahigh magnesium-lithium ratio (the magnesium-lithium ratio is more than 500:1), a large amount of magnesium salt is generated in the lithium adsorption process, and the adsorbent is inactivated at a high speed, so that the adsorbent inactivation phenomenon is easy to generate, the adsorption performance is influenced, and the adsorption efficiency is reduced.

Disclosure of Invention

The invention aims to provide a lithium chloride production process and a lithium chloride production system, which are used for solving the problems that in the prior art, an adsorbent is high in inactivation speed and easy to generate inactivation phenomenon.

In order to achieve the above purpose, the invention provides the following technical scheme: a process for producing lithium chloride, comprising:

step S1, adsorption: the brine enters an adsorption tower to be adsorbed by lithium, and an adsorbent in the adsorption tower adsorbs lithium ions and magnesium ions;

step S2, lithium washing: the lithium washing liquid enters the adsorption tower to clean and remove the magnesium ions, and the pH of the lithium washing liquid is adjusted by acid to ensure that the lithium washing is carried out in an acidic environment;

step S3, desorption: and (4) enabling the desorption solution to enter the adsorption tower to wash the lithium ions to obtain qualified lithium chloride solution.

According to an embodiment of the present invention, the step S2 of lithium washing includes:

step S21, feeding a section of lithium washing liquid into the adsorption tower from a section of lithium washing tank, and feeding the cleaned section of lithium washing liquid into a old brine tank for recycling; the one-section lithium washing solution at least comprises 300-400mg/L lithium ions and 50-60g/L magnesium ions;

step S22, feeding a second-stage lithium washing liquid into the adsorption tower from a second-stage lithium washing tank, and feeding the washed second-stage lithium washing liquid into the first-stage lithium washing tank; the second-stage lithium washing solution at least comprises 500-800mg/L lithium ions and 15-30g/L magnesium ions;

step S23, feeding three lithium washing solutions into the adsorption tower from three lithium washing tanks, feeding the three lithium washing solutions into the first lithium washing tank after washing, and adjusting the pH value of the three lithium washing solutions to 4-7 by acid; the three-stage lithium washing solution at least comprises 100-200mg/L lithium ions and 4-7g/L magnesium ions;

and S24, feeding the four-section lithium washing liquid into the adsorption tower from a four-section lithium washing tank, feeding the four-section lithium washing liquid after washing into the two-section lithium washing tank, wherein the four-section lithium washing liquid is water, and adjusting the pH of the four-section lithium washing liquid to be 5-7 by acid.

According to one embodiment of the invention, the acid is hydrochloric acid.

According to an embodiment of the present invention, the step S3 of desorbing includes:

step S31, feeding the first-stage desorption liquid into the adsorption tower from the first-stage desorption tank, feeding part of the washed first-stage desorption liquid into the three-stage lithium washing tank, and taking part of the washed first-stage desorption liquid as qualified lithium chloride liquid; the primary desorption liquid at least comprises 300-500mg/L lithium ions and 1-1.7g/L magnesium ions;

step S32, feeding the second-stage desorption liquid into the adsorption tower from a second-stage desorption tank, feeding a part of the washed second-stage desorption liquid into the first-stage desorption tank, and taking a part of the washed second-stage desorption liquid as a qualified lithium chloride liquid; the secondary desorption liquid at least comprises 300-500mg/L lithium ions and 0.3-0.6g/L magnesium ions;

step S33, enabling the three-section desorption liquid to enter the adsorption tower from the three-section desorption tank, enabling a part of the washed three-section desorption liquid to enter the first-section desorption tank and a part of the washed three-section desorption liquid to enter the second-section desorption tank; the third-stage desorption liquid is water.

According to one embodiment of the invention, the adsorbent is an aluminium-based adsorbent.

According to one embodiment of the present invention, the lithium chloride production process further comprises step S4, topping solution: and (3) allowing brine to enter the adsorption tower to replace desorption liquid in the adsorption tower, and allowing the desorption liquid to enter the second-stage desorption tank.

The invention also provides a lithium chloride production system which comprises an adsorption tower, a lithium washing tank, an acid liquor storage tank, a desorption tank and a qualified liquor storage tank, wherein the adsorption tower is respectively connected with the lithium washing tank, the desorption tank and the qualified liquor storage tank;

the brine enters the adsorption tower to be adsorbed by lithium, and an adsorbent in the adsorption tower adsorbs lithium ions and magnesium ions; the lithium washing liquid in the lithium washing tank enters the adsorption tower to wash and remove the magnesium ions, and the acid in the acid liquid storage tank adjusts the pH value of the lithium washing liquid so that the lithium washing is carried out in an acidic environment; and the desorption liquid in the desorption tank enters the adsorption tower to wash the lithium ions, and the qualified lithium chloride liquid is obtained and stored in the qualified liquid storage tank.

According to one embodiment of the invention, the lithium washing tank comprises a first-section lithium washing tank, a second-section lithium washing tank, a third-section lithium washing tank and a fourth-section lithium washing tank which are arranged at intervals, and the adsorption tower is respectively connected with the first-section lithium washing tank, the second-section lithium washing tank, the third-section lithium washing tank and the fourth-section lithium washing tank.

According to one embodiment of the invention, the desorption tank comprises a first-stage desorption tank, a second-stage desorption tank and a third-stage desorption tank which are arranged at intervals, and the adsorption tower is respectively connected with the first-stage desorption tank, the second-stage desorption tank and the third-stage desorption tank.

According to one embodiment of the invention, the adsorbent is an aluminium-based adsorbent.

Compared with the prior art, the lithium chloride production process and the lithium chloride production system provided by the invention have the following advantages:

this application adds the PH of acid regulation lithium lotion when lithium is washed and makes lithium wash and go on under acid environment, can get rid of the hydroxide ion that the borate produced when lithium was washed, reduces the formation of magnesium hydrate, and on the one hand, the deactivation speed of control adsorbent inhibits the production of adsorbent deactivation phenomenon, does not influence adsorption performance, and the magnesium salt volume that on the other hand was got rid of is more, has guaranteed the quality of the qualified liquid of lithium chloride.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. In the drawings:

FIG. 1 is a schematic structural diagram of a lithium chloride production system according to a preferred embodiment of the present invention;

FIG. 2 is a flow chart of the steps of a lithium chloride production process based on the lithium chloride production system shown in FIG. 1;

FIG. 3 is a flow chart based on the step of lithium washing in the lithium chloride production process shown in FIG. 2;

FIG. 4 is a flow chart based on the step of desorption in the lithium chloride production process shown in FIG. 2.

Reference numerals:

the device comprises an adsorption tower 1, a lithium washing tank 2, a first-section lithium washing tank 21, a second-section lithium washing tank 22, a third-section lithium washing tank 23, a fourth-section lithium washing tank 24, a old brine tank 3, an acid liquor storage tank 4, a desorption tank 5, a first-section desorption tank 51, a second-section desorption tank 52, a third-section desorption tank 53 and a qualified liquid storage tank 6.

Detailed Description

The present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific examples described in the following embodiments of the present invention are merely illustrative of specific embodiments of the present invention and do not limit the scope of the invention.

The invention is further described with reference to the following figures and detailed description of embodiments.

As shown in fig. 1 and fig. 2, wherein fig. 1 is a schematic structural diagram of a lithium chloride production system according to a preferred embodiment of the present invention; fig. 2 is a flow chart showing steps of a lithium chloride production process based on the lithium chloride production system shown in fig. 1. It should be noted that the arrows in fig. 1 only represent the connection relationship, and do not represent the feeding and discharging positions.

The embodiment is a lithium chloride production process, which comprises the following steps:

step S1, adsorption: the brine enters an adsorption tower 1 to be adsorbed by lithium, and an adsorbent in the adsorption tower 1 adsorbs lithium ions and magnesium ions;

step S2, lithium washing: lithium washing liquid enters the adsorption tower 1 to clean and remove the magnesium ions, and the pH of the lithium washing liquid is adjusted by acid to ensure that the lithium washing is carried out in an acidic environment;

step S3, desorption: and (4) enabling the desorption solution to enter the adsorption tower 1 to wash the lithium ions to obtain qualified lithium chloride solution.

The brine adopted in the application is salt lake brine and belongs to brine with an ultrahigh magnesium-lithium ratio (the magnesium-lithium ratio is more than or equal to 500:1), researches show that the brine contains sodium borate, boric acid can be partially hydrolyzed to generate boric acid molecules and hydroxyl ions after the sodium borate is ionized in water, so that the alkaline environment condition is adopted during lithium washing, the hydroxyl ions generated by the boric acid during lithium washing can react with the magnesium ions in a lithium washing solution to form magnesium hydroxide, and on one hand, the magnesium hydroxide is attached to an adsorbent, so that the adsorbent is high in inactivation speed, the adsorbent is easy to inactivate, the adsorption performance is influenced, on the other hand, the content of magnesium salts in the lithium washing solution is greatly reduced, the removal effect of the magnesium salts is poor, the pH value of the lithium washing solution and the content of the lithium washing solution are detected, and experimental results are shown in table 1. As is clear from table 1, the higher the PH of the lithium washing solution, the lower the content of magnesium salt, which means that the more hydroxide in the lithium washing solution, the lower the content of magnesium salt eluted, and a large amount of magnesium ions formed magnesium hydroxide and adhered to the adsorbent.

TABLE 1 magnesium salt content and pH of lithium wash

pH value	9.2	9.1	8.96	8.74	8.36	7.3
							Magnesium salt content g/l	14.4	28.7	35.9	47.9	71.85	143.7

Therefore, the PH of the lithium washing liquid is adjusted by adding acid when lithium is washed, so that lithium washing is carried out in an acidic environment, hydroxide ions generated by borate during lithium washing can be removed, and generation of magnesium hydroxide is reduced.

The steps are explained in detail below.

In step S1, the adsorption tower 1 is used to complete the processes of lithium adsorption-lithium elution-desorption, and is a device for packing a solid adsorbent in a tower so that some components in a gas or liquid entering the tower are adsorbed by the porous structure of the adsorbent, thereby realizing component separation. The adsorption temperature is 18-22 ℃.

The adsorbent is an aluminum-based adsorbent. The aluminum-based adsorbent is industrially applied when lithium is extracted from brine by adopting an adsorption method, and has moderate adsorption rate and adsorption capacity, good selectivity and recycling performance and low preparation cost.

The step S2 of lithium washing includes: and the lithium washing liquid in the lithium washing tank 2 enters the adsorption tower 1 to wash and remove the magnesium ions, and the acid in the acid liquid storage tank 3 adjusts the pH value of the lithium washing liquid so that the lithium washing is carried out in an acidic environment. The lithium washing temperature is 18-22 ℃.

Specifically, the lithium washing tank 2 is used for providing lithium washing liquid, and includes a first lithium washing tank 21, a second lithium washing tank 22, a third lithium washing tank 23, and a fourth lithium washing tank 24, which are arranged at intervals, and the adsorption tower 1 is connected to the first lithium washing tank 21, the second lithium washing tank 22, the third lithium washing tank 23, and the fourth lithium washing tank 24, respectively.

As shown in fig. 3, fig. 3 is a flow chart based on the lithium washing step in the lithium chloride production process shown in fig. 2.

The step S2 of lithium washing includes:

step S21, feeding a section of lithium washing liquid into the adsorption tower 1 from the section of lithium washing tank 21, and feeding the section of cleaned lithium washing liquid into the old brine tank 3 for recycling; the one-section lithium washing solution at least comprises 300-400mg/L lithium ions and 50-60g/L magnesium ions;

step S22, feeding a secondary lithium washing solution into the adsorption tower 1 from the secondary lithium washing tank 22, and feeding the washed secondary lithium washing solution into the primary lithium washing tank 21; the second-stage lithium washing solution at least comprises 500-800mg/L lithium ions and 15-30g/L magnesium ions;

step S23, feeding three lithium washing solutions into the adsorption tower 1 from the three lithium washing tanks 23, feeding the three lithium washing solutions into the first lithium washing tank 21 after washing, and adjusting the pH value of the three lithium washing solutions to 4-7 by acid in the acid solution storage tank 4; the three-stage lithium washing solution at least comprises 100-200mg/L lithium ions and 4-7g/L magnesium ions;

and S24, feeding the four-section lithium washing solution into the adsorption tower 1 from the four-section lithium washing tank 24, feeding the washed four-section lithium washing solution into the two-section lithium washing tank 22, wherein the four-section lithium washing solution is water, and adjusting the pH of the four-section lithium washing solution to 5-7 by acid in the acid solution storage tank 4. Specifically, the four-stage lithium washing liquid is industrial water.

The PH values of the three-stage lithium washing solution and the four-stage lithium washing solution are adjusted by acid, and meanwhile, the PH values of the first-stage lithium washing solution and the second-stage lithium washing solution can also be influenced, specifically, in this embodiment, the PH value of the three-stage lithium washing solution is adjusted to be 4 to 7 by acid, and the PH value of the four-stage lithium washing solution is adjusted to be 5 to 7, so that the PH value of the first-stage lithium washing solution is 4 to 7, and the PH value of the second-stage lithium washing solution is 4 to 7. The whole lithium washing process is carried out under an acidic environment, so that the formation of magnesium hydroxide is greatly reduced, and the adsorption effect of the adsorbent is ensured.

The acid is hydrochloric acid, so that impurities can be prevented from being introduced, and the concentration can be adjusted according to actual conditions.

The step S3 desorption includes: and (3) feeding the desorption liquid in the desorption tank 5 into the adsorption tower 1 to wash the lithium ions to obtain qualified lithium chloride liquid.

Specifically, the desorption tank 5 is used for providing desorption liquid, and includes a first-stage desorption tank 51, a second-stage desorption tank 52, and a third-stage desorption tank 53, and the adsorption tower 1 is connected to the first-stage desorption tank 51, the second-stage desorption tank 52, and the third-stage desorption tank 53, respectively.

And the qualified lithium chloride liquid is stored in a qualified liquid storage tank 6.

As shown in fig. 4, fig. 4 is a flow chart based on the desorption step in the lithium chloride production process shown in fig. 2.

The step S3 desorption includes:

step S31, feeding the first-stage desorption liquid into the adsorption tower 1 from the first-stage desorption tank 51, feeding part of the washed first-stage desorption liquid into the three-stage lithium washing tank 23, and feeding part of the washed first-stage desorption liquid serving as qualified lithium chloride liquid into the qualified liquid storage tank 6; the primary desorption liquid at least comprises 300-500mg/L lithium ions and 1-1.7g/L magnesium ions; the desorption temperature is 20-25 ℃.

Step S32, feeding the second-stage desorption liquid into the adsorption tower 1 from the second-stage desorption tank 52, feeding a part of the washed second-stage desorption liquid into the first-stage desorption tank 51, and feeding a part of the washed second-stage desorption liquid into a qualified liquid storage tank 6 as a qualified lithium chloride liquid; the secondary desorption liquid at least comprises 300-500mg/L lithium ions and 0.3-0.6g/L magnesium ions; the desorption temperature is 20-25 ℃.

Step S33, feeding the three-stage desorption liquid into the adsorption tower 1 from the three-stage desorption tank 53, feeding a part of the washed three-stage desorption liquid into the first-stage desorption tank 51, and feeding a part of the washed three-stage desorption liquid into the second-stage desorption tank 52; the third-stage desorption liquid is water. Specifically, the three-stage desorption liquid is industrial water, and the desorption temperature is 38-42 ℃. .

Because the magnesium content in the washed first-stage desorption liquid is higher, one part of the first-stage desorption liquid enters the three-stage lithium washing tank 23, and the other part of the first-stage desorption liquid serving as qualified lithium chloride liquid enters the qualified liquid storage tank 6; because the lithium content in the washed second-stage desorption liquid is low, one part of the second-stage desorption liquid enters the first-stage desorption tank 51, and the other part of the second-stage desorption liquid enters the qualified liquid storage tank 6 as qualified lithium chloride liquid; since the three-stage desorption liquid is water, a part of the three-stage desorption liquid enters the first-stage desorption tank 51, and a part of the three-stage desorption liquid enters the second-stage desorption tank 52, and hot water recovery is performed, so that lithium loss is reduced, and water consumption is reduced.

The division ratio of the first-stage desorption liquid and the division ratio of the second-stage desorption liquid are determined by actual production, and a middle equilibrium point for ensuring the quality and the yield is taken as a demarcation point.

The lithium chloride production process further comprises a step S4 of: the brine enters the adsorption tower 1 to replace the desorption liquid in the adsorption tower 1, and the desorption liquid enters the two-section desorption tank 52, namely, the desorbed industrial water is ejected out, so that the next circulation is facilitated.

As shown in fig. 1, the present invention further provides a lithium chloride production system, where the lithium chloride production system includes an adsorption tower 1, a lithium washing tank 2, an acid liquor storage tank 4, a desorption tank 5, and a qualified liquid storage tank 6, the adsorption tower 1 is connected to the lithium washing tank 2, the desorption tank 5, and the qualified liquid storage tank 6, respectively, and the lithium washing tank 2 is connected to the acid liquor storage tank 4 and the desorption tank 5, respectively;

the brine enters the adsorption tower 1 to be adsorbed by lithium, and the adsorbent in the adsorption tower 1 adsorbs lithium ions and magnesium ions; the lithium washing liquid in the lithium washing tank 2 enters the adsorption tower 1 to wash and remove the magnesium ions, and the acid in the acid liquid storage tank 4 adjusts the pH value of the lithium washing liquid to enable the lithium washing to be carried out in an acidic environment; and the desorption liquid in the desorption tank 5 enters the adsorption tower 1 to wash the lithium ions, and the qualified lithium chloride liquid is obtained and stored in the qualified liquid storage tank 6.

The structure and function of each device are described in detail in the lithium chloride production process, and are not described in detail herein.

Data of the specific examples are shown in Table 2

TABLE 2 specific examples

As can be seen from Table 2, when the pH of the four-stage lithium washing solution was adjusted to 6 and the pH of the three-stage lithium washing solution was adjusted to about 5, the pH of the first and second-stage lithium washing solutions was between 6 and 7.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim.