阅读说明：本技术 一种盐湖碳酸锂生产中高浓度氯化锂溶液中除硼的方法 (Method for removing boron from high-concentration lithium chloride solution in salt lake lithium carbonate production ) 是由 张生顺 朱红卫 马存彪 黄鹏贵 杜长岳 张青山 于 2021-02-03 设计创作，主要内容包括：本发明公开了一种盐湖碳酸锂生产中高浓度氯化锂溶液中除硼的方法,包括以下步骤：将N个吸附柱依次串联连接,形成流向相同且可循环运转的吸附除硼组、水顶料组、解析组和顶水组；分别将待处理料液、纯水、解析液、除硼合格料液输入至前述吸附柱组中,同时进行吸附除硼、水顶料、解析和顶水工序；然后通过切换吸附柱上的控制阀使完成吸附除硼的吸附柱进入水顶料工序,完成水顶料的吸附柱进入解析工序,完成解析的吸附柱进入顶水工序,完成顶水的吸附柱进入吸附除硼工序,每一吸附柱都顺序依次完成四个工序,循环进行；其中解析工序依次经过酸再生、碱转型和水洗碱。本方法能连续除硼,效率高,效果好,且避免了氯化锂溶液和水的浪费。(The invention discloses a method for removing boron from a high-concentration lithium chloride solution in the production of lithium carbonate in a salt lake, which comprises the following steps: sequentially connecting N adsorption columns in series to form an adsorption boron removal group, a water jacking group, an analysis group and a water jacking group which have the same flow direction and can run circularly; respectively inputting feed liquid to be treated, pure water, analytic liquid and qualified boron-removing feed liquid into the adsorption column group, and simultaneously carrying out processes of adsorption boron removal, water jacking, analysis and water jacking; then, switching a control valve on the adsorption column to enable the adsorption column which finishes adsorption and boron removal to enter a water liftout process, enabling the adsorption column which finishes water liftout to enter an analysis process, enabling the adsorption column which finishes analysis to enter a water-ejecting process, enabling the adsorption column which finishes water ejection to enter an adsorption and boron removal process, and sequentially completing four processes for each adsorption column in a circulating manner; wherein the resolving process sequentially comprises acid regeneration, alkali transformation and alkali washing. The method can continuously remove boron, has high efficiency and good effect, and avoids the waste of lithium chloride solution and water.)

1. A method for removing boron from a high-concentration lithium chloride solution in the production of lithium carbonate in a salt lake is characterized by comprising the following steps:

the method comprises the following steps: sequentially connecting N adsorption columns in series to form four groups of adsorption columns which have the same flow direction and rotate circularly, namely an adsorption boron removal group, a water jacking group, an analysis group and a water jacking group;

step two: introducing a feed liquid to be treated into an adsorption boron removal group, inputting pure water into a water jacking group, inputting a resolving liquid into a resolving group, inputting the qualified feed liquid after boron removal into a water jacking group, and respectively and simultaneously performing four procedures of adsorption boron removal, water jacking, resolving and water jacking;

step three: after the second step is finished, the adsorption column which finishes adsorbing and removing boron enters a water jacking process by switching a control valve on the adsorption column, the adsorption column which finishes water jacking enters an analysis process, the adsorption column which finishes analysis enters a water jacking process, the adsorption column which finishes water jacking enters an adsorption and boron removal process, and each adsorption column finishes four processes in sequence;

the resolving procedure comprises acid regeneration, alkali transformation and alkali washing.

2. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in salt lake as claimed in claim 1, wherein the feed solution to be treated is the high-concentration lithium chloride solution with the boron content of 200-1000ppm, and the qualified feed solution after boron removal is the high-concentration lithium chloride solution with the boron content of 2-10 ppm.

3. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in the salt lake, according to claim 1, characterized in that the feeding flow rate of the adsorption boron removal group is 7-15m³H, the temperature is 15-30 ℃.

4. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in the salt lake, according to claim 1, characterized in that the feeding flow rate of the water top material group is 0.8-2m³/h。

5. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in salt lake according to claim 1,

the acid regeneration is as follows: inputting dilute hydrochloric acid to eject water existing in the adsorption column after the water ejection is finished, resolving boron adsorbed in the adsorption column, and removing the boron adsorbed in the adsorption column;

the alkali transformation is as follows: inputting dilute alkali to neutralize dilute hydrochloric acid in the adsorption column, transforming the adsorption column and recovering the boron removal performance of the adsorption column to the original state;

the water washing alkali comprises the following components: pure water is fed in to lower the pH in the adsorption column.

6. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in salt lake according to claim 5,

the dilute hydrochloric acid has the mass fraction of 3-5 percent and the dosage of 0.04-0.08m³The feeding flow rate is 100-240L/h;

the diluted alkali accounts for 2 to 3 mass percent and is used in an amount of 0.015 to 0.04m³The feeding flow rate is 50-200L/h for one time;

the flow rate of the pure water in the alkali washing water is 1-3m³/h。

7. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in the salt lake, according to claim 1, characterized in that the feeding flow rate of the top water group is 0.5-1.5m³/h。

8. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in the salt lake, according to claim 1, is characterized in that the qualified high-concentration lithium chloride solution output by the adsorption boron removal group is conveyed to a back-end process stage to prepare lithium carbonate.

9. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in the salt lake, according to claim 1, is characterized in that the high-concentration lithium chloride solutions with different concentrations output by the water top material group are conveyed to different process stages at the front end.

10. The method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in salt lake, according to claim 1, characterized in that the number of adsorption columns of the adsorption boron removal group is N1, the number of adsorption columns of the water top group is N2, the number of adsorption columns of the desorption group is N3, and the number of adsorption columns of the top water group is N4, wherein N1+ N2+ N3+ N4, N1 is not less than 4, N2 is not less than 3, N3 is not less than 4, N4 is not less than 1, and the adsorption columns are special boron removal resins with macroporous structures.

Technical Field

The invention belongs to the technical field of chemical boron removal, and particularly relates to a method for removing boron from a high-concentration lithium chloride solution in the production of lithium carbonate in a salt lake.

Background

The salt lake is rich in main components such as sodium, potassium, magnesium and the like, and also rich in important minerals such as boron, lithium and the like. Salt lake resources in China are very rich in the world, and have advantages over the United states, Russia and other major countries, namely, the salt lake resources are large in quantity and large in scale, and the salt lake resources are buried shallowly. Therefore, the advantages of extracting lithium from the salt lake and producing lithium carbonate are obvious.

In the production process of lithium carbonate, lithium is required to be extracted from salt lake brine to form a lithium chloride solution, however, the lithium chloride solution contains a large amount of sodium, boron and other impurities due to the composition of the salt lake, so that the boron content in the produced lithium carbonate product exceeds the standard and cannot meet the requirement. Therefore, impurities such as sodium, boron and the like in the lithium chloride solution need to be removed in advance, but boron is difficult to be completely removed in the lithium chloride solution due to the characteristic of boron, the boron content in the lithium carbonate raw material can only be reduced, and the common method for removing the impurities of the boron in the production process of the lithium carbonate in the salt lake is membrane separation, but the boron content cannot be stably removed due to the characteristic of the membrane so as to effectively reduce the boron content.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for removing boron from a high-concentration lithium chloride solution in the production of lithium carbonate in a salt lake, so as to solve the problems in the background art.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a method for removing boron from a high-concentration lithium chloride solution in the production of lithium carbonate in a salt lake comprises the following steps:

the method comprises the following steps: sequentially connecting N adsorption columns in series to form four groups of adsorption columns which have the same flow direction and can circularly run, namely an adsorption boron removal group, a water jacking group, an analysis group and a water jacking group;

step two: introducing a feed liquid to be treated into an adsorption boron removal group, inputting pure water into a water jacking group, inputting a resolving liquid into a resolving group, inputting the qualified feed liquid after boron removal into a water jacking group, and respectively and simultaneously performing four procedures of adsorption boron removal, water jacking, resolving and water jacking;

step three: after the second step is finished, the adsorption column which finishes adsorbing and removing boron enters a water jacking process by switching a control valve on the adsorption column, the adsorption column which finishes water jacking enters an analysis process, the adsorption column which finishes analysis enters a water jacking process, the adsorption column which finishes water jacking enters an adsorption and boron removal process, and each adsorption column finishes four processes sequentially in turn;

the resolving procedure comprises acid regeneration, alkali transformation and alkali washing.

In the process, the boron adsorption and removal group is used for adsorbing boron in the high-concentration lithium chloride solution by utilizing the adsorption performance of the adsorption column so as to achieve the purposes of removing boron and efficiently reducing the boron content; the water ejection group utilizes water (the density is 1000 kg/m)³) With a high-concentration lithium chloride solution (density 1124 kg/m)³) The high-concentration lithium chloride solution is recycled according to the concentration of the lithium chloride solution due to different specific gravities, so that the waste of the high-concentration lithium chloride solution is avoided; the analysis group enables the boron removal performance of the adsorption column to be restored to the original state through acid regeneration and alkali transformation, specifically, the acid regeneration is used for replacing boron in the adsorption column, the alkali transformation is used for restoring the performance of the adsorption column, and the water-washing alkali is used for adjusting the pH value in the adsorption column, so that the pH value of lithium chloride solution passing through an inlet and an outlet of the adsorption column is consistent, and the quality of subsequent battery-grade lithium carbonate is not influenced; the top water group is used for ejecting and recovering pure water existing in the adsorption column after alkali washing by using a qualified high-concentration lithium chloride solution, so that the loss of the pure water is reduced, and the concentration difference of the adsorption column of the top water group after entering the adsorption boron removal group is reduced.

Further, the feed liquid to be treated is a high-concentration lithium chloride solution with boron content of 200-1000ppm, and the qualified feed liquid after boron removal is the high-concentration lithium chloride solution with boron content of 2-10 ppm.

Further, the feeding flow rate of the adsorption boron removal group is 7-15m³H, the temperature is 15-30 ℃.

Further, the feeding flow rate of the water top material group is 0.8-2m³/h。

Further, the acid is regenerated as: inputting dilute hydrochloric acid to eject water existing in the adsorption column after the water liftout is completed, and resolving out all boron adsorbed in the adsorption column to remove the boron adsorbed in the adsorption column, wherein the ejected water can be recycled for the water liftout;

the alkali transformation is as follows: inputting dilute alkali to neutralize dilute hydrochloric acid in the adsorption column, transforming the adsorption column and recovering the boron removal performance of the adsorption column to the original state;

the water washing alkali comprises the following components: pure water is fed in to lower the pH in the adsorption column.

Furthermore, the diluted hydrochloric acid has the mass fraction of 3-5 percent and the using amount of 0.04-0.08m³The feeding flow rate is 100-240L/h;

the diluted alkali accounts for 2 to 3 mass percent and is used in an amount of 0.015 to 0.04m³The feeding flow rate is 50-200L/h for one time;

the flow rate of the pure water in the alkali washing water is 1-3m³/h。

Further, the feeding flow rate of the top water group is 0.5-1.5m³/h。

Further, the qualified high-concentration lithium chloride solution output by the adsorption boron removal group is conveyed to a back-end process stage to prepare lithium carbonate.

Further, high-concentration lithium chloride solutions with different concentrations output by the water top material group are conveyed to different process stages at the front end.

Furthermore, the number of the adsorption columns of the boron adsorption and removal group is N1, the number of the adsorption columns of the water topping group is N2, the number of the adsorption columns of the analysis group is N3, and the number of the adsorption columns of the water topping group is N4, wherein N is 1+ N2+ N3+ N4, N1 is more than or equal to 4, N2 is more than or equal to 3, N3 is more than or equal to 4, and N4 is more than or equal to 1.

Further, the control valve is a solenoid valve for periodically controlling the flow direction of the liquid.

Further, the adsorption column is special boron removal resin with a macroporous structure, and the type of the resin is LSC-800.

Specifically, the method of the present invention has the following specific operation process when applied:

adsorption boron removal group: n1 adsorption columns are connected in series for operation, and N1 is more than or equal to 4;

water liftout group: n2 adsorption columns are connected in series for operation, and N2 is more than or equal to 3;

analyzing the group: n3 adsorption columns are connected in series for operation, and N3 is more than or equal to 4;

a water-pushing group: n4 adsorption columns are connected in series for operation, and N4 is more than or equal to 1;

in the same time period, N1 adsorption columns adsorb and remove boron; carrying out water liftout on N2 adsorption columns, and recovering a high-concentration lithium chloride solution; resolving by using N3 adsorption columns, removing boron adsorbed by the adsorption columns and recovering the adsorption performance of the boron; and recovering pure water from the N4 adsorption columns. Each adsorption column is periodically and circularly alternated, namely, one adsorption column in the four groups is switched to the corresponding next group in each switching process, so that the continuous purpose is achieved.

High-concentration lithium chloride solution with the temperature of 15-30 ℃ and the boron content of 200-1000ppm is added into the solution in a proportion of 7-15m³The flow velocity of/h is input into the boron adsorption and removal group at a constant speed to carry out boron adsorption and removal. Specifically, a high-concentration lithium chloride solution flows in from the upper part of a first adsorption column, after the high-concentration lithium chloride solution is fully exchanged with resin, a part of boron is adsorbed by the first adsorption column, the high-concentration lithium chloride solution subjected to the first boron removal flows out from the lower part of the first adsorption column, then flows into a second adsorption column from the upper part of the second adsorption column, the boron is adsorbed for the second time, the high-concentration lithium chloride solution subjected to the second boron removal flows out from the lower part of the second adsorption column, sequentially flows through an N1 adsorption column and flows out from the lower part of an N1 adsorption column, and the high-concentration lithium chloride solution with the boron content of 2ppm-10ppm is collected or directly conveyed to a rear-end process stage to prepare lithium carbonate. When the boron is removed by adsorption, the first adsorption column is switched to a water top material group after the adsorption capacity of the first adsorption column is saturated, and specifically, a high-concentration lithium chloride solution flowing out of the adsorption column and a high-concentration lithium chloride solution flowing in the adsorption column are mixed togetherWhen the solution is consistent, the adsorption column reaches the saturated state of the adsorption capacity.

Adding pure water at a ratio of 0.8-2m³And inputting the flow velocity of the flow velocity/h into a water jacking group at a constant speed, and recovering the high-concentration lithium chloride solution. Specifically, pure water flows in from the upper part of a first adsorption column, the high-concentration lithium chloride solution in the first adsorption column is ejected out, then flows into a second adsorption column through the lower part of the first adsorption column and the upper part of the second adsorption column, the high-concentration lithium chloride solution in the second adsorption column is ejected out, the pure water sequentially flows through an N2 adsorption column and then flows out from the lower part of an N2 adsorption column, and the ejected high-concentration lithium chloride solutions with different concentrations are collected or directly conveyed to different process stages at the front end for recycling. During water jacking, the high-concentration lithium chloride solution in the first adsorption column is switched to an analysis group after being jacked.

Inputting 3-5% dilute hydrochloric acid into the analysis group at a constant speed of 240L/h and 100-; 2-3% dilute alkali is input into the analysis group at a constant speed at a feeding flow rate of 50-200L/h for alkali transformation, and pure water is input at a flow rate of 1-3m³And inputting the feed flow velocity of the/h into the analysis group at a constant speed, and washing alkali with water to finally recover the boron removal performance of the adsorption column. Specifically, the pure water is added at a ratio of 1-3m³The flow velocity of the flow velocity/h flows in from the upper part of the first adsorption column at a constant speed, flows out from the lower part to the upper part of the second adsorption column, flows out from the lower part of the second adsorption column, sequentially flows through the Nth 3 adsorption columns, and flows out from the lower part of the Nth 3 adsorption column. Meanwhile, part of the pure water is delivered to a pipeline connected with the upper part of the N3 th adsorption column and is mixed with concentrated hydrochloric acid which is input into the pipeline at a constant speed of 100-240L/h, and the pure water dilutes the concentrated hydrochloric acid to 3% -5% in the pipeline. Meanwhile, part of the pure water is conveyed into a pipeline connected with the upper part of the second adsorption column and is mixed with concentrated alkali which is input into the pipeline at a constant speed of 50-200L/h, and the concentrated alkali is diluted to 2% -3% by the pure water in the pipeline. The concentrated acid or the concentrated alkali is mixed and diluted in the pipeline, so that the operation is simple, safe and easy to control. During acid regeneration, dilute hydrochloric acid flows into the pure water tank from the upper part of the N3 th adsorption column at a constant speed at a feeding flow rate of 100-240L/h, and pure water in the N3 th adsorption column is ejected and recoveredWhen the ejected water contains dilute hydrochloric acid, the N3 th adsorption column begins to analyze the adsorbed boron, the analyzed boron flows out from the lower part of the N3 th adsorption column and is discharged to the trench, when the boron concentration in the dilute hydrochloric acid is reduced, the acid regeneration of the N3 th adsorption column is completed, and the operation is switched to the alkali transformation process, so that the N3-1 st adsorption column is subjected to alkali transformation. And during alkali transformation, dilute alkali flows in from the upper part of the second adsorption column at a constant speed at a feeding flow rate of 50-200L/h, flows out from the lower part of the second adsorption column to the upper part of the third adsorption column, flows out from the lower part of the third adsorption column, passes through the N3-1 adsorption columns to neutralize dilute hydrochloric acid in the flowing adsorption columns, and when the dilute alkali flows out from the lower part of the N3-1 adsorption columns, the alkali transformation of the second adsorption column is completed, and the alkali transformation process is switched to an alkali washing process to become the first adsorption column for alkali washing. Adding pure water at a volume of 1-3m³Inputting the flow velocity of/h into a first adsorption column at a constant speed, flushing out the dilute alkali in the first adsorption column, reducing the pH value in the first adsorption column, enabling the pure water to flow out from the lower part of the first adsorption column, flowing into a second adsorption column through the upper part of the second adsorption column, flushing out the dilute alkali in the second adsorption column, reducing the pH value in the second adsorption column, and carrying out the process until the dilute alkali flows out from the lower part of the N3 adsorption columns. During the analysis, the pH in the first adsorption column was lowered to a certain value, and then the column was switched to the top water group.

The high-concentration lithium chloride solution with boron removed qualified is added by 0.5-1.5m³The flow velocity of the flow velocity per hour is input into the top water group at a constant speed, and water recovery and concentration difference reduction are carried out. Specifically, the qualified high-concentration lithium chloride solution without boron flows in from the lower part of the first adsorption column, pure water in the first adsorption column is ejected out, the qualified high-concentration lithium chloride solution without boron flows out from the upper part of the first adsorption column, flows into the second adsorption column through the lower part of the second adsorption column, and the pure water in the second adsorption column is ejected out, the qualified high-concentration lithium chloride solution without boron sequentially flows through the N4 adsorption columns and flows out from the upper parts of the N4 adsorption columns, and the ejected pure water is recovered to a recovery water tank for reuse. And when the water is topped, switching the pure water in the first adsorption column to an adsorption boron removal group after the pure water is topped up so as to continue adsorption.

The working processes of the adsorption boron removal group, the water jacking group, the analysis group and the water jacking group are synchronously developed, and the control valves are periodically switched. Each adsorption column completes all the steps after a cycle of one cycle (the cycle of one cycle is defined as that for one adsorption column, the whole process of adsorbing and removing boron groups, water top material groups, analysis groups and top water groups is completely carried out, for example, twelve adsorption columns are totally used, four adsorption and removing boron groups, three water top material groups, four analysis groups and one top water group are illustrated, and one cycle refers to that one adsorption column in the adsorption and removing boron groups respectively carries out four stages of adsorbing and removing boron groups, three stages of the water top material groups, four stages of the analysis groups and one stage of the top water groups). Wherein all the feeding media of the boron adsorption and removal group, the water jacking group and the analysis group enter from the upper part of the adsorption column, and the feeding media of the water jacking group enter from the lower part of the adsorption column, so that the phenomenon that the continuous adsorption is not facilitated due to overhigh pressure difference is avoided.

The invention has the beneficial effects that:

according to the method for removing boron from the high-concentration lithium chloride solution in the salt lake lithium carbonate production, provided by the invention, the impurity boron in the high-concentration lithium chloride solution is adsorbed by series adsorption columns by adopting a continuous adsorption method, and the boron adsorption and removal efficiency of the adsorption columns is improved to the maximum extent by reasonably distributing the number of the adsorption columns in each group and the flow rate. The boron content in the high-concentration lithium chloride solution is reduced from 200ppm to 1000ppm to 2ppm to 10ppm, so that the aim of removing boron in the high-concentration lithium chloride solution is fulfilled, the boron content in the high-concentration lithium chloride solution is far lower than the quality requirement of battery-grade lithium carbonate by less than 200ppm, the preparation of lithium carbonate is carried out by using the low-boron lithium chloride solution with the concentration of 2ppm to 10ppm, and the quality of lithium carbonate products is further improved. The boron adsorbed in the series adsorption columns is removed by using 3% -5% of dilute hydrochloric acid and 2% -3% of dilute alkali, and the boron adsorption and removal performance of the series adsorption columns is recovered, so that the boron is adsorbed and removed again, and the effect of continuously and stably removing the boron can be achieved. In addition, the waste of lithium chloride solution and water is effectively avoided through the water jacking and water jacking process, so that the lithium recovery rate can reach 98-100%, and the water recovery rate can reach more than 85%.

Drawings

Fig. 1 is a schematic flow chart before handover in embodiment 1 of the present invention;

fig. 2 is a schematic flow chart of embodiment 1 of the present invention after handover.

Number in the figure:

1. a first adsorption column; 2. a second adsorption column; 3. a third adsorption column; 4. a fourth adsorption column; 5. a fifth adsorption column; 6. a sixth adsorption column; 7. a seventh adsorption column; 8. an eighth adsorption column; 9. a ninth adsorption column; 10. a tenth adsorption column; 11. an eleventh adsorption column; 12. a twelfth adsorption column;

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to 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. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a method for removing boron from a high-concentration lithium chloride solution in the production of lithium carbonate in a salt lake, which comprises the following steps:

the method comprises the following steps: sequentially connecting N adsorption columns in series to form four groups of adsorption columns which have the same flow direction and can circularly run, namely an adsorption boron removal group, a water jacking group, an analysis group and a water jacking group;

step two: introducing a feed liquid to be treated into an adsorption boron removal group, inputting pure water into a water jacking group, inputting a resolving liquid into a resolving group, inputting the qualified feed liquid after boron removal into a water jacking group, and respectively and simultaneously performing four procedures of adsorption boron removal, water jacking, resolving and water jacking;

step three: after the second step is finished, the adsorption column which finishes adsorbing and removing boron enters a water jacking process by switching a control valve on the adsorption column, the adsorption column which finishes water jacking enters an analysis process, the adsorption column which finishes analysis enters a water jacking process, the adsorption column which finishes water jacking enters an adsorption and boron removal process, and each adsorption column finishes four processes sequentially in turn;

the resolving procedure comprises acid regeneration, alkali transformation and alkali washing.

Specifically, the feed liquid to be treated is a high-concentration lithium chloride solution with boron content of 200-1000ppm, and the feed liquid qualified after boron removal is the high-concentration lithium chloride solution with boron content of 2-10 ppm.

Specifically, the feeding flow rate of the adsorption boron removal group is 7-15m³H, the temperature is 15-30 ℃.

Specifically, the feeding flow rate of the water top material group is 0.8-2m³/h。

Specifically, the acid regeneration is: inputting dilute hydrochloric acid to eject water existing in the adsorption column after the water liftout is completed, and resolving out all boron adsorbed in the adsorption column to remove the boron adsorbed in the adsorption column, wherein the ejected water can be recycled for the water liftout; the alkali transformation is as follows: inputting dilute alkali to neutralize dilute hydrochloric acid in the adsorption column, transforming the adsorption column and recovering the boron removal performance of the adsorption column to the original state; the water washing alkali is as follows: pure water is fed in to lower the pH in the adsorption column.

Specifically, the diluted hydrochloric acid has the mass fraction of 3-5% and the using amount of 0.04-0.08m³The feeding flow rate is 100-240L/h; 2 to 3 percent of dilute alkali, and the dosage of the dilute alkali is 0.015 to 0.04m³The feeding flow rate is 50-200L/h for one time; washing pure water in alkali with water at a feed flow rate of 1-3m³/h。

Specifically, the feeding flow rate of the top water group is 0.5-1.5m³/h。

Specifically, the qualified high-concentration lithium chloride solution output by the adsorption boron removal group is conveyed to the back-end process stage to prepare lithium carbonate. High-concentration lithium chloride solutions with different concentrations output by the water liftout group are conveyed to different process stages at the front end.

Specifically, the adsorption columns of the boron adsorption and removal group are N1, the adsorption columns of the water topping group are N2, the adsorption columns of the analysis group are N3, and the adsorption columns of the water topping group are N4, wherein N is 1+ N2+ N3+ N4, N1 is more than or equal to 4, N2 is more than or equal to 3, N3 is more than or equal to 4, N4 is more than or equal to 1

In particular, the control valve is a solenoid valve for periodically controlling the liquid flow direction.

Specifically, the adsorption column is special boron removal resin with a macroporous structure, and the resin is LSC-800.

The above boron removal method is applied by way of specific examples below.

Example 1

When the invention is applied specifically, the specific operation process is as follows, and the flow before switching is as shown in fig. 1:

adsorption boron removal group: the first adsorption column 1, the second adsorption column 2, the third adsorption column 3 and the fourth adsorption column 4 are connected in series for operation, and the boron content is gradually reduced in the whole adsorption and boron removal process after the high-concentration lithium chloride solution is subjected to four-stage resin adsorption and separation;

water liftout group: the fifth adsorption column 5, the sixth adsorption column 6 and the seventh adsorption column 7 are connected in series;

analyzing the group: the eighth adsorption column 8, the ninth adsorption column 9, the tenth adsorption column 10 and the eleventh adsorption column 11 are connected in series;

a water-pushing group: a twelfth adsorption column 12;

in the same time period, the first adsorption column 1, the second adsorption column 2, the third adsorption column 3 and the fourth adsorption column 4 are used for adsorbing and removing boron; three adsorption column water lifters including a fifth adsorption column 5, a sixth adsorption column 6 and a seventh adsorption column 7 are used for recovering a high-concentration lithium chloride solution; the eighth adsorption column 8, the ninth adsorption column 9, the tenth adsorption column 10 and the eleventh adsorption column 11 are analyzed, so that boron adsorbed by the adsorption columns is removed and the adsorption performance is recovered; the twelfth adsorption column 12 ejects water to recover pure water. Each adsorption column is periodically and circularly alternated, namely, one adsorption column in the four groups is switched to the corresponding next group in each switching process, so that the continuous purpose is achieved.

The high-concentration lithium chloride solution with the temperature of 25 ℃ and the boron content of 200ppm-1000ppm is added into 10m³The flow velocity of/h is input into the boron adsorption and removal group at a constant speed to carry out boron adsorption and removal. Specifically, the high-concentration lithium chloride solution flows in from the upper part of the first adsorption column 1, and after sufficient exchange with the resin, a part of boron is adsorbed by the first adsorption column 1, and the high-concentration lithium chloride solution from which boron is removed for the 1 st time is adsorbed from the lower part of the first adsorption column 1And the high-concentration lithium chloride solution with boron content of 4ppm flows out from the lower part of the fourth adsorption column 4, and is collected or directly conveyed to a rear-end process stage to prepare lithium carbonate. In the adsorption removal of boron, when the adsorption capacity of the first adsorption column 1 is saturated and then switched to the water top group (as shown in fig. 2), specifically, when the high concentration lithium chloride solution flowing out of the adsorption column is identical to the high concentration lithium chloride solution flowing in, the adsorption column reaches an adsorption capacity saturation state.

Adding pure water at a volume of 1.5m³And inputting the flow velocity of the flow velocity/h into a water jacking group at a constant speed, and recovering the high-concentration lithium chloride solution. Specifically, pure water flows in from the upper part of the fifth adsorption column 5, the high-concentration lithium chloride solution in the fifth adsorption column 5 is ejected, then flows into the sixth adsorption column 6 through the lower part of the fifth adsorption column 5 and the upper part of the sixth adsorption column 6, the high-concentration lithium chloride solution in the sixth adsorption column 6 is ejected, the pure water sequentially flows through the seventh adsorption column 7 and then flows out from the lower part of the seventh adsorption column 7, and the ejected high-concentration lithium chloride solutions with different concentrations are collected or directly conveyed to different process stages at the front end for recycling. During the water jacking, the high-concentration lithium chloride solution in the fifth adsorption column 5 is switched to the analysis group after being jacked up (as shown in fig. 2).

4% dilute hydrochloric acid is input into an analysis group at a constant speed at a flow rate of 180L/h for acid regeneration; 2.5% diluted alkali is input into the analysis group at a constant speed at a feeding flow rate of 140L/h for alkali transformation, and pure water is added at a flow rate of 2m³And inputting the feed flow velocity of the/h into the analysis group at a constant speed, and washing alkali with water to finally recover the boron removal performance of the adsorption column. Specifically, pure water was added at 2m³The flow velocity of the flow velocity/h flows in from the upper part of the eighth adsorption column 8 at a constant speed, flows out from the lower part to the upper part of the ninth adsorption column 9, flows out from the lower part of the ninth adsorption column 9, sequentially flows through the eleventh adsorption column 11, and then flows out from the lower part of the eleventh adsorption column 11. At the same time, part of the purified water is fed into the pipe connected to the upper part of the eleventh adsorption column 11 and is 180L/greater or equal in volumeh, uniformly inputting the concentrated hydrochloric acid into the pipeline at a constant flow rate, and diluting the concentrated hydrochloric acid to 4% by pure water in the pipeline. Meanwhile, part of the pure water is conveyed into a pipeline connected with the upper part of the ninth adsorption column 9 and is mixed with concentrated alkali which is input into the pipeline at a constant speed of 140L/h, and the pure water dilutes the concentrated alkali to 2.5 percent in the pipeline. The concentrated acid or the concentrated alkali is mixed and diluted in the pipeline, so that the operation is simple, safe and easy to control. In the acid regeneration, dilute hydrochloric acid is flowed into the pure water tank from the upper part of the eleventh adsorption column 11 at a constant feed flow rate of 180L/h to eject and recover pure water in the eleventh adsorption column 11, when the ejected water contains dilute hydrochloric acid, the eleventh adsorption column 11 starts to analyze the adsorbed boron, the analyzed boron flows out from the lower part of the eleventh adsorption column 11 and is discharged to the trench, and after the boron concentration in the dilute hydrochloric acid is reduced, the acid regeneration of the eleventh adsorption column 11 is completed, and the process is switched to the alkali conversion process (as shown in fig. 2). During alkali transformation, dilute alkali flows in from the upper part of the ninth adsorption column 9 at a constant speed at a feeding flow rate of 140L/h, flows out from the lower part of the ninth adsorption column 9 to the upper part of the tenth adsorption column 10, and then flows out from the lower part of the tenth adsorption column 10, and neutralizes the dilute hydrochloric acid in the ninth adsorption column 9 and the tenth adsorption column 10 flowing through, and when the dilute alkali flows out from the lower part of the tenth adsorption column 10, the alkali transformation of the ninth adsorption column 9 is completed, and the alkali washing process is switched to (as shown in fig. 2). Pure water still 2m³Inputting the flow velocity of/h into the eighth adsorption column 8 at a constant speed, flushing out the dilute alkali in the eighth adsorption column 8, reducing the pH in the eighth adsorption column 8, enabling the pure water to flow out from the lower part of the eighth adsorption column 8, flowing into the ninth adsorption column 9 through the upper part of the ninth adsorption column 9, flushing out the dilute alkali in the ninth adsorption column 9, reducing the pH in the ninth adsorption column 9, and carrying out the process until the dilute alkali flows out from the lower part of the eleventh adsorption column 11. In the analysis, the pH in the eighth adsorption column 8 was lowered to a certain value, and then the column was switched to the top water group (as shown in fig. 2).

The high-concentration lithium chloride solution with qualified boron removal is added by 1m³The flow velocity of the flow velocity per hour is input into the top water group at a constant speed, and water recovery and concentration difference reduction are carried out. Specifically, the qualified boron-removed high-concentration lithium chloride solution flows in from the lower part of the twelfth adsorption column 12, pure water existing in the twelfth adsorption column 12 is pushed out, and qualified boron-removed high-concentration chlorine is obtainedThe lithium ion solution flows out from the upper part of the twelfth adsorption column 12, and the pushed-out pure water is recovered to the recovery water tank for reuse. In the water-topping period, after the pure water in the twelfth adsorption column 12 is topped up, the column is switched to the boron-removal adsorption group for further adsorption (as shown in fig. 2).

The working processes of the adsorption boron removal group, the water jacking group, the analysis group and the water jacking group are synchronously developed, the control valves are periodically switched, and the schematic flow chart after switching is shown in fig. 2. And (4) completing all the steps by circulating each adsorption column for one period. The cycle in this period is defined as: aiming at one adsorption column, the whole process of the boron adsorption removal group, the water jacking group, the analysis group and the water jacking group is completely finished. That is, there are twelve adsorption columns in total, four adsorption boron removal groups, three water liftout groups, four desorption groups, and one water liftout group. One period refers to that one adsorption column in the adsorption boron removal group respectively carries out four stages of adsorption boron removal group, three stages of water ejection group, four stages of analysis group and one stage of water ejection group.

The temperature of the feed for the adsorption boron removal groups for examples 2-4 was varied from that of example 1 and is detailed in table 1.

The feed flow rates for the adsorptive boron removal groups of examples 5-7 are different from example 1 and are detailed in table 1.

The water topping set feed flow rates of examples 8-10 are different from example 1 and are detailed in table 1.

The process parameters and boron removal results, lithium recovery results, and water recovery results for examples 1-10 are detailed in Table 1 below.

TABLE 1 summary of the process parameters and test results for examples 1-10

As can be seen from Table 1, after the high-concentration lithium chloride solution in examples 1-10 is subjected to the boron removal method of the present invention, the final boron content is reduced to less than 200ppm and far less than 200ppm of the quality requirement of battery-grade lithium carbonate, which meets the requirement of preparing lithium carbonate battery products. Of course, the parameters of the feeding temperature of the adsorption boron removal group, the feeding flow rate of the adsorption boron removal group and the feeding flow rate of the water top group mentioned in the boron removal method according to the present invention are not limited to those exemplified in the above examples. In general, when the feeding temperature of the adsorption boron removal group is in the range of the active adsorption boron removal temperature of the resin, the boron removal effect is better; the feeding flow rate of the adsorption boron removal group can be adjusted according to the resin amount in the adsorption column and the boron content in the feeding solution, and the feeding flow rate is properly slowed down to increase the adsorption time so that boron removal is more sufficient; the feeding flow rate of the water top material group can be adjusted according to the quantity of the adsorption columns and the feeding flow rate of the boron removal group through adsorption, and the feeding flow rate is properly accelerated to enable lithium to be recovered more fully.

The mass fractions of dilute hydrochloric acid and dilute base in the resolved sets of examples 11-12 are different from those in example 1 and are detailed in Table 2.

The amounts of dilute hydrochloric acid and dilute base used in the resolved sets of examples 13-14 are different from those used in example 1 and are detailed in Table 2.

The flow rates of the dilute hydrochloric acid and the dilute base in the resolved sets of examples 15-18 are different from those in example 1 and are detailed in Table 2.

The process parameters and boron removal results, lithium recovery results, and water recovery results for examples 11-18 are detailed in Table 2 below.

TABLE 2 summary of the process parameters and test results for examples 1, 11-18

As can be seen from Table 2, in examples 11-18, after the high-concentration lithium chloride solution is subjected to the boron removal method of the present invention, the final boron content is reduced to below 200ppm and far below 200ppm of the quality requirement of battery-grade lithium carbonate, which meets the requirement of preparing lithium carbonate battery products. Of course, the parameters of the mass fraction, the amount, the flow rate, etc. of the dilute hydrochloric acid and the dilute alkali in the analysis group mentioned in the boron removal method according to the present invention are not limited to those listed in the above examples. In general, the amount of the dilute hydrochloric acid can be adjusted according to the amount of the resin in the adsorption column and the number of the adsorption columns; the amount of the dilute alkali is matched with that of the dilute hydrochloric acid, and the amount of the dilute alkali is slightly higher than that of the dilute hydrochloric acid, so that the acid is fully neutralized, and the adsorption column is transformed; when the mass fraction of the dilute hydrochloric acid is higher, the dosage is larger, and the flow rate is slower, the boron removal effect of the adsorption column treated by the dilute hydrochloric acid is better.

The flow rates of pure water in the resolved sets of examples 19-20 are different from those in example 1 and are detailed in Table 3.

The head water group feed flow rates for examples 21-22 were different from those of example 1 and are detailed in Table 3.

The number of columns in each group of examples 23-26 was different from that of example 1 and is detailed in Table 3.

The process parameters and boron removal results, lithium recovery results, and water recovery results for examples 19-26 are detailed in Table 3 below.

TABLE 3 summary of the process parameters and test results for examples 1, 19-26

As can be seen from Table 3, in examples 19-26, after the high-concentration lithium chloride solution is subjected to the boron removal method of the present invention, the final boron content is reduced to below 200ppm and far below 200ppm of the quality requirement of battery-grade lithium carbonate, which meets the requirement of preparing lithium carbonate battery products. Of course, the parameters of the flow rate of pure water in the desorption group, the feed flow rate of the top water group, the number of adsorption columns in each group, and the like, which are mentioned in the boron removal method according to the present invention, are not limited to those exemplified in the above examples. Generally, the flow speed of the pure water in the analysis group is properly reduced, so that the retention time of the pure water in the adsorption column can be prolonged, the pure water is fully contacted with the adsorption column and is fully washed, and the pH value in the adsorption column tends to be neutral; the feeding flow rate of the top water group can be adjusted according to the number of the adsorption columns in the top water group, the higher the flow rate is, the more the inlet amount in a short time is, the more the water is ejected out, the higher the water recovery efficiency is, the slower the flow rate is, the more the adsorption columns are contacted, and the better the effect of reducing the feeding concentration difference with the boron adsorption removal group is; the quantity of the adsorption columns in each group is set according to the feeding flow rate, the feeding boron content, the boron removal requirement and the like of each group, when the feeding boron content is higher, the quantity of the adsorption columns for adsorbing the boron removal group is properly increased, and when the pH value of the analytic group effluent liquid does not reach the standard, the quantity of the adsorption columns for analyzing the group is properly increased. On the basis that the indexes can meet the requirements, the number of the adsorption columns is reduced as much as possible, and the flow velocity is increased as much as possible, so that the boron adsorption and removal efficiency of the adsorption columns is improved as much as possible.

In summary, according to the method for removing boron from the high-concentration lithium chloride solution in the production of lithium carbonate in salt lake, provided by the invention, the impurity boron in the high-concentration lithium chloride solution is adsorbed by the adsorption columns connected in series by adopting the continuous adsorption method, and the boron adsorption and removal efficiency of the adsorption columns is improved to the maximum extent by reasonably distributing the number of the adsorption columns in each group and the flow rate. The boron content in the high-concentration lithium chloride solution is reduced from 200ppm to 1000ppm to 2ppm to 10ppm, so that the aim of removing boron in the high-concentration lithium chloride solution is fulfilled, the boron content in the high-concentration lithium chloride solution is far lower than the quality requirement of battery-grade lithium carbonate by less than 200ppm, the preparation of lithium carbonate is carried out by using the low-boron lithium chloride solution with the concentration of 2ppm to 10ppm, and the quality of lithium carbonate products is further improved. The boron adsorbed in the series adsorption columns is removed by using 3% -5% of dilute hydrochloric acid and 2% -3% of dilute alkali, and the boron adsorption and removal performance of the series adsorption columns is recovered, so that the boron is adsorbed and removed again, and the effect of continuously and stably removing the boron can be achieved. In addition, the waste of lithium chloride solution and water is effectively avoided through the water jacking and water jacking process, so that the lithium recovery rate can reach 98-100%, and the water recovery rate can reach more than 85%.

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.