CN105251436A - Assembly line system in which service life of lithium ion sieve adsorbents is prolonged and operating method thereof - Google Patents

Abstract

The invention discloses an assembly line system and an operation method for improving the service life of a lithium ion sieve adsorbent. The system is composed of a number of adsorption towers connected in series and connected head to tail to form an adsorption-desorption assembly line. Each adsorption tower includes: loaded in the adsorption tower The lithium ion sieve adsorbent; the pump arranged at the inlet of the adsorption tower; the first valve controlling the inlet of the adsorption tower; and the second valve controlling the outlet of the adsorption tower. According to the adsorption saturation degree of the lithium ion sieve adsorbent, the assembly line system of the present invention uses the pipeline rotation mode to switch the working state of the lithium ion sieve adsorbent in time, and can prolong the service life of the adsorbent without improving the microstructure of the adsorbent , increase the total amount of lithium element adsorption and transfer in the whole life cycle, reduce production costs, and improve the cost-effectiveness ratio. The invention is beneficial to applying the lithium ion sieve adsorbent and its adsorption-desorption technology to occasions where the lithium element concentration is relatively low, and improves the resource utilization rate in the mining of lithium mineral resources and the recycling of waste lithium batteries.

Description

Pipeline system and operation method for improving service life of lithium ion sieve adsorbent

technical field

The invention belongs to the fields of mining of mineral resources and recycling of solid waste, and relates to a method for using a lithium ion sieve adsorbent on a lithium resource mining or recovery production line, specifically, to a method for improving the lithium ion sieve by rotating and switching the state of the assembly line. The method of adsorbent lifetime.

Background technique

With the advent of the digital information era and the new energy era, lithium secondary batteries have become the most comprehensive performance and the most widely used portable and mobile energy storage devices, especially in recent years for electric vehicles, hybrid vehicles and energy storage power stations. The demand for large-scale energy storage applications has exploded, and the output of lithium secondary batteries has doubled. Batteries have become the main consumption direction of lithium resources. The strategic significance of lithium resources in the new energy era is comparable to the strategic position of petroleum in the past 100 years. However, the current mining speed of lithium resources has been difficult to meet the rapidly growing demand of the lithium battery industry. There are three main countermeasures for this problem:

The first is to study and improve the technology of extracting lithium from liquid lithium mineral resources, because liquid forms account for more than half of the mineable lithium resources on the earth, and this proportion is as high as more than 80% in China.

The second is to develop technologies for recovering the lost lithium element from the tail liquid discharged from the existing lithium ore (including solid and liquid) mining and refining production lines, because the lithium element lost in the tail liquid discharged from the existing mining and refining production lines can be as high as 40% of the total.

The third is to develop technology for recovering lithium elements from waste lithium batteries. The existing waste lithium battery recovery technology is immature, and the main purpose is to recover cobalt elements in lithium cobalt oxide batteries. Recycling technology is still under study.

Lithium ion sieve adsorbents have broad application prospects in the above three lithium resource mining and recovery technologies. Among them, LMO (lithium metal oxide) type lithium ion sieve adsorbents have good selective adsorption capacity and can extract The two processes of lithium element and separation of impurities (refining) are solved together. Among them, manganese-based lithium-ion sieve adsorbents, which have been studied most deeply and have the best selective adsorption capacity, such as LiMnO _2.5 (usually also denoted as Li _1.6 Mn _1.6 O ₄ ), Li ₄ Mn ₅ O ₁₂ (commonly denoted as Li _1.33 Mn _1.67 O ₄ ), etc., but they have a common weakness, that is, they will slowly dissolve during the adsorption-desorption cycle.

Contents of the invention

The purpose of the present invention is to reduce the dissolution of the lithium ion sieve adsorbent during use, so that all lithium ion sieve adsorbents that have the characteristics of increased dissolution loss with the prolongation of the adsorption time or desorption time in actual use reduce the loss, and have Longer life, thereby reducing the cost of use and improving efficiency.

In order to achieve the above object, the present invention provides a pipeline system that improves the service life of the lithium-ion sieve adsorbent. The system is composed of a number of adsorption towers connected in series and head to tail to form an adsorption-desorption pipeline. Each adsorption tower includes:

Lithium ion sieve adsorbent packed in the adsorption tower;

A pump arranged at the inlet of the adsorption tower;

a first valve controlling the inlet to the adsorption column; and

The second valve controlling the outlet of the adsorption tower.

A buffer layer is reserved between the lithium ion sieve adsorbent and the top of the adsorption tower. The top of the adsorption tower is provided with a ventilation elbow to keep the adsorption tower open to the atmosphere.

The main components of the lithium ion sieve adsorbent have the characteristic of intensifying dissolution loss with the prolongation of the adsorption time or desorption time.

The present invention also provides an operation method for improving the service life of the lithium-ion sieve adsorbent by using the above-mentioned assembly line system. The method switches the state of the first valve and the second valve so that the adsorption towers connected in series are placed in the adsorption-desorption cycle in turn. stage or desorption stage; the switching valve state refers to controlling the valve through manual or automatic procedures, thereby changing the source of the solution flowing into the adsorption tower and the destination of the solution flowing out of the adsorption tower.

The described adsorption stage refers to that the Li ⁺ solution to be adsorbed is pumped in through the first valve of an adsorption tower, and after being adsorbed by the lithium ion sieve adsorbent in the tower, it flows through the second valve at the outlet of the tower into the subsequent series of A plurality of adsorption towers; until the Li ⁺ concentration in the outlet solution of the tower is higher than the first predetermined value, the adsorption phase of the tower ends. The Li ⁺ solution to be adsorbed must be pretreated, and the pretreatment refers to adjusting its pH value to 7-8.5, and then adding carbonate or bicarbonate, so that the amount of carbonate and bicarbonate substances therein is final. The sum of the concentrations is greater than 50% of the final concentration of lithium ions in the solution.

Described desorption phase refers to that after the adsorption phase of the tower ends, the acidic solution is pumped through its first valve, so that the Li ⁺ desorption of the lithium ion sieve adsorbent in the adsorption tower is dissolved in the acidic solution, by Its second valve discharges for standby; until the Li ⁺ concentration in the discharged liquid is lower than the second predetermined value, the desorption phase of the tower ends.

The first predetermined value is 50%~85% of the Li concentration in the solution at the inlet of the adsorption tower ^, preferably 50%~70%; the second predetermined value is 100~400ppm, preferably 100~200ppm .

After each adsorption tower reaches the first predetermined value of the outlet concentration, switch the valve state to enter the desorption stage, or change the control conditions and predetermined values to enter the next adsorption stage; after each adsorption tower reaches the second predetermined value of the outlet concentration, switch The valve state enters the adsorption stage, or changes the control conditions and predetermined values to enter the next desorption stage.

The method of the present invention effectively reduces the chemical dissolution of the lithium ion sieve adsorbent in use, prolongs the service life, reduces the use cost, and can also reduce the lithium element content in the final discharge tail liquid, so as to obtain as much economic benefit and environmental protection as possible. benefit.

Description of drawings

Fig. 1 is the flow state schematic diagram of the 4:1 distribution between the adsorption step and the washing-desorption step of the adsorption tower group arranged according to the present invention, wherein the first four towers are in the cascade adsorption steps connected in series, and the last tower is being connected with acid Circulation between storage tanks is the desorption step.

Fig. 2 is a graph showing the relationship between the lithium ion sieve adsorbent and the adsorption amount of Li ⁺ in the solution and the dissolution amount of Mn element relative to the adsorption time.

detailed description

The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, and are not intended to limit the protection scope of the present invention.

A pipeline system lithium ion recovery system for improving the service life of the lithium ion sieve adsorbent provided by the present invention, as shown in Figure 1, the system is a number of adsorption towers connected in series and end to end (adsorption towers A, B, C, D, E) To form an adsorption-desorption pipeline, each adsorption tower contains:

Lithium ion sieve adsorbent 1 packed in the adsorption tower;

A pump 2 arranged at the inlet of the adsorption tower;

a first valve 3 controlling the inlet of the adsorption tower; and

The second valve 4 controlling the outlet of the adsorption tower.

A buffer layer 5 is reserved between the lithium ion sieve adsorbent 1 and the top of the adsorption tower, and there is a ventilation elbow 6 at the top of the adsorption tower to keep the adsorption tower unblocked from the atmosphere.

The operating method of the assembly line system of the present invention comprises the following steps:

Step 1, loading adsorbent and desorption for the first time: set 5 adsorption towers as a group, numbered A, B, C, D, E, and the main component of them is LiMnO _2.5 (usually also recorded as Li _1.6 Mn _1.6 O ₄ ) lithium ion sieve adsorbent particles, pay attention to reserve about 1/10 of the buffer space at the top of the tower and keep it open to the atmosphere. Slowly pump 0.5 mol/L hydrochloric acid (or 0.25 mol/L sulfuric acid), and the effluent is sent to the subsequent process for preparing lithium carbonate for use. HMnO _2.5 in the desorbed state is obtained after acid washing and sufficient ion exchange treatment, and then enters the adsorption-desorption production cycle after passing through clean water for 10 minutes of rapid flow washing.

Step 2, pretreatment of the solution to be adsorbed: In the pretreatment pool, adjust the pH of the lithium-containing salt lake brine to be adsorbed to 7~8 with NaOH or KOH, and then add a certain amount of NaHCO ₃ or NaHCO according to the required adsorption pH value ₃ + Na ₂ CO ₃ mixture, so that the sum of the final concentration of carbonate [CO ₃ ^2- ] + the final concentration of bicarbonate [HCO ₃ ^- ] (unit mol/L) is higher than the final concentration of lithium ions in the solution 50%; preferably, the final concentration of bicarbonate is 70% to 90% of the final concentration of lithium ions, and the final concentration of carbonate is 0.

Step 3, adsorption in towers A, B, C, and D: slowly and continuously pump the pretreated brine to be adsorbed into the adsorption tower group, making it pass through towers A, B, C, and D in series at an appropriate flow rate. Monitor the lithium ion concentration X _a of the solution at the entrance of tower A, and the lithium ion concentration X _b in the solution flowing out of tower A to tower B. When the lithium ion concentration X _b rises to X _a *50%~60%, the process is terminated. step.

Step 4: Adsorption in towers B, C, D, and E, and desorption in tower A: After step 3 is terminated, immediately switch the status of the pipeline valve (manual or automatic program control), so that the solution in the pretreatment pool is directly pumped into tower B, and then Flow through C, D, E towers in turn. At the same time, tower A enters the state of washing and desorption—wash tower A quickly with clean water for 5-10 minutes, and then slowly pump into the eluent containing 0.5mol/L hydrochloric acid or 0.25mol/L sulfuric acid (actually, it also contains a lower concentration Li ⁺ repeated use of acidic eluent), monitoring the lithium concentration or acid concentration at the outlet of the tower.

According to specific requirements, the eluent with higher lithium content (not reused) can be sent to the subsequent process step of preparing lithium carbonate; and when the lithium concentration at the outlet of tower A drops to a certain value, the outlet liquid is recovered to the acid The storage tank is reused for subsequent elution; and when the lithium concentration at the outlet continues to drop to a lower definite value such as 100-200ppm, the desorption step of tower A is terminated. Quickly wash the adsorption tower A with clean water for 10 minutes after the desorption is completed. At this time, the adsorption tower is in the state of ready for desorption and can re-enter the next adsorption step.

Step 5, adsorption in towers C, D, E, and A, and desorption in tower B: refer to step 4, after step 4 is terminated, switch the pipeline valve so that the solution to be adsorbed flows through towers C, D, E, and A in sequence for exchange adsorption , while Tower B enters the state of washing and desorption.

Step 6, towers D, E, A, and B are adsorbed, and tower C is desorbed: refer to step 4. After step 5 is terminated, towers D, E, A, and B enter the exchange adsorption step, and tower C enters the washing and desorption state at the same time .

Step 7, towers E, A, B, and C are adsorbed, tower D is desorbed: refer to step 4, after step 6 is terminated, towers E, A, B, and C enter the exchange adsorption step, and tower D enters the washing and desorption state at the same time .

Step 8, towers A, B, C, and D are adsorbed, tower E is desorbed: refer to step 4, after step 7 is terminated, towers A, B, C, and D enter the exchange adsorption step, and tower E enters the washing and desorption state at the same time . As shown in Figure 1, the E tower and the acid storage tank constitute a circulation loop. After this step is finished and washed quickly with clear water, the valve should be switched so that the pump-in and pump-out cycles between Tower A and the acid storage tank, while Tower E is connected in series to Tower D; the Li ⁺ solution to be adsorbed in the pretreatment pool is directly pumped Enter B tower, discharge through C, D, E tower successively, this is step 4. Repeat steps 4 to 8, and the entire adsorption-desorption cycle pipeline can be rotated and operated continuously.

The lithium ion sieve adsorbent is abbreviated as "LMO", and the metal element "M" can be one of Al, Sn, Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Mo and other elements or more; "L" is Li, but it can also contain a mixture of other alkali metals and alkaline earth metal ions (non-proportional compounds such as Li _x Mg _1.33-x Mn _1.67 O ₄ ), "O" is an oxygen atom. The proportions of "L", "M" and "O" are variable and need not be integers. In addition to the LMO type lithium ion sieve adsorbent, this method is also applicable to other types of lithium ion sieve adsorbents for recycling lithium-containing solutions, as long as the main components have increased dissolution loss with the extension of adsorption time or desorption time characteristics.

As shown in Figure 2, when a single adsorption column is used to adsorb the above-mentioned pretreated lithium-containing (700ppm) brine, the decrease in the concentration of lithium in the effluent Δ[Li] gradually decreases from close to 700ppm, that is to say, the adsorption column from the solution The ability to adsorb lithium gradually decreases from close to complete adsorption; at the same time, the content of Mn dissolved in the solution by the adsorbent material in the column gradually increases from below the detection limit of the instrument. Although the dissolution concentration is less than 0.3ppm, hundreds of times Cumulative dissolution losses over cyclic use can be severe. Relevant tests have shown that chemical dissolution is closely related to the degree of adsorption saturation of the adsorbent. In the "unadsorbed" state where the adsorption saturation is almost 0, even if soaked for a long time, the chemical dissolution of the adsorbent is still very slight. It can be considered that the adsorption saturation The equivalent adsorption time is shorter in a very low state.

Therefore, using the above scheme to switch the state of the pipeline can make the adsorbent contact with the solution that has been absorbed by the front tower for a long time and the lithium concentration is reduced, so it stays in a state with a low degree of adsorption saturation for a long time; only in series adsorption In the final stage of the step, the first column is exposed to a higher concentration of raw liquid for a short period of time, and quickly reaches the near adsorption saturation state under given control conditions, and then is quickly replaced by the rotation of the adsorption column group to switch to the desorption step. This process flow arrangement not only reduces the (equivalent) time that the adsorbent stays in the adsorption saturation state, it actually shortens the actual time each column spends in the adsorption step due to forward rotation. On the other hand, the adsorption saturation degree of the adsorbent that has just been desorbed is the lowest, and when it is replaced by rotation into the adsorption tower group, it is used as the last tower of series adsorption, which can extract the residual lithium element in the solution to the maximum extent, and reduce the amount of lithium that is discharged from the tail liquid as much as possible. Lost lithium resources.

In the above-mentioned process, the pipeline is divided into five adsorption towers connected in series, and the number of segmented devices (such as the number of adsorption towers) on the actual adsorption-desorption pipeline can be two or more, and the way each segment forms the pipeline can be series, Parallel, mixed. In the above-mentioned process, each section only switches between the two state conditions of adsorption condition and desorption condition. During production, each section can also be set at different pH values, temperatures, auxiliary ion concentrations and other multi-parameters according to actual needs. Toggle between conditional states.

Example 1

Set 5 adsorption towers as a group, numbered A, B, C, D, E, all of which are filled with lithium ion sieve adsorbent particles whose main component is LiMnO _2.5 (Li _1.6 Mn _1.6 O ₄ ). Reserve about 1/10 of the buffer space and keep it open to the atmosphere. Slowly pump in 0.25mol/L dilute sulfuric acid, and the effluent contains desorbed lithium, which is sent to the subsequent process for preparing lithium carbonate for use. HMnO _2.5 in the desorbed state is obtained after acid washing and sufficient ion exchange treatment, and is washed with clean water for 10 to 15 minutes.

In the pretreatment pool, adjust the pH of the lithium-containing salt lake brine to be adsorbed to 7~8 with carbonate or NaOH, and then add a certain amount of NaHCO ₃ according to the lithium content—for example, this example uses a solution containing 700ppm lithium, then add NaHCO ₃ to make the final concentration [HCO ₃ ^- ]=0.075mol/L; because the price of saturated lithium carbonate solution and dilute sulfuric acid solution in the practical factory is much lower than that of sodium bicarbonate, the actual process on the production line is based on the ratio of the amount of substance to 2 :1 Add Li ₂ CO ₃ and H ₂ SO ₄ so that the final concentration [HCO ₃ ^- ]=0.07~0.075mol/L.

The pretreated brine to be adsorbed is slowly and continuously pumped into the adsorption tower group, making it pass through A, B, C, and D towers in series at an appropriate flow rate. The lithium ion concentration of the solution at the entrance of tower A is about 700ppm, so when the lithium ion concentration X _b in the solution flowing out of tower A to tower B rises to >400ppm, this step is terminated. Switch the state of the pipeline valve so that the solution in the pretreatment tank is directly pumped into tower B, and then flows through towers C, D, and E in sequence. At the same time, tower A enters the state of washing and desorption—wash tower A with clean water for 10 minutes, and then slowly pump 0.25mol/L sulfuric acid eluent (in actual production, it is a reusable acidic eluent containing lower concentration Li ⁺ ).

According to specific requirements, the eluent with higher lithium content (not reused) can be sent to the subsequent process step of preparing lithium carbonate; and when the lithium concentration at the outlet of tower A drops to a certain value—for example, lithium in this example When the content drops to 300-350ppm, the outlet liquid is recovered to the acid storage tank for reuse in subsequent elution; and then the desorption step is terminated when the lithium content continues to drop to 100ppm. Quickly wash the adsorption tower A with clean water for 10 minutes after the desorption is completed. At this time, the adsorption tower is in the state of ready for desorption and can re-enter the next adsorption step.

According to the following table 1, the rotation switching of each tower on the pipeline is carried out. The judgment standard of switching is still >400ppm to stop the adsorption step, and <100ppm to stop the desorption step.

Table 1: The status table of the rotation switching status of each tower on the pipeline

This scheme is a dynamic method used in actual industrial production. Compared with the method of using five adsorption towers in parallel, this scheme only needs about 1/2 of the time to make each adsorption column (in turn) reach adsorption saturation, and the adsorbent The time spent near adsorption saturation is shorter, so the chemical dissolution loss is significantly reduced. Preliminary calculations show that under the premise of achieving the same total amount of lithium element adsorption-desorption transfer, this method reduces the dissolution loss of the adsorbent by more than 60% compared with the method of parallel connection of multiple towers and switching the adsorption and desorption steps at the same time, so it can be extended. service life, reduce the cost of use and improve efficiency.

Example 2

Refer to the steps of Example 1, but only adjust the pH of the lithium-containing brine to be adsorbed to about 8.5 with Ca(OH) ₂ or NaOH in the pretreatment tank, without adding carbonate and bicarbonate buffer such as NaHCO ₃ . This method is suitable for production conditions where cheap carbonate (bi)carbonate cannot be obtained. Since there is no buffer, the adsorption rate drops rapidly at the beginning, so it is necessary to replenish alkali before each tower and reuse the liquid to be adsorbed until the lithium content in it is reduced to A certain value.

In this example, the initial brine to be adsorbed containing 700ppm of lithium is slowly pumped into adsorption tower groups A, B, C, and D after pretreatment, and the lithium concentration in the effluent of tower D is monitored. When the value rises rapidly to >300ppm, the effluent Drain back to the pretreatment tank, and at the same time use the automatic adjustment device to supplement Ca(OH) ₂ or NaOH to the pretreatment tank, so that the solution in the pretreatment tank is always maintained at a pH of about 8.5. In addition to adding lye to the pretreatment tank, lye should be supplemented online according to the pH value before each tower (except the first tower), so that the pH value of the solution flowing into each tower is maintained at about 8.5. Let the brine to be adsorbed circulate repeatedly until the lithium content of the outlet liquid drops to <300ppm, then discharge the outlet liquid directly without returning to the pretreatment tank, and replace the new brine in the pretreatment tank.

Monitor the lithium ion concentration of the outlet liquid of the first tower. When the lithium concentration difference between the outlet of the first tower and the inlet is less than 20ppm, this step is terminated, and the tower A of the first tower is cleaned and desorbed off-line (refer to Example 1), while B, C, The adsorption step of group D and E starts. The arrangement table of each group of rotation switching adsorption step and desorption step is carried out with reference to Example 1, and the judgment standard of the switching step is that the difference between the lithium concentration at the outlet and the inlet of the first tower is <20ppm.

This method is an alternative method to Example 1 under the production conditions where cheap (bi)carbonate cannot be obtained, and its adsorption rate is much lower than that of Example 1, so the time-consuming increase of each adsorption-desorption cycle is relatively large . The dissolution loss of the adsorbent in this method is also significantly reduced compared with the traditional process, and the service life is prolonged.

Example 3

The steps of Example 1 were followed, but the adsorbent was replaced by Li _1.33 Mn _1.67 O ₄ -PVC particles. This adsorbent also has the characteristic of intensifying the dissolution loss with the prolongation of staying in the state near adsorption saturation. Therefore, this method can also achieve the same total amount of lithium element adsorption-desorption transfer, and the adsorption-desorption steps can be reduced by about 40%. In Example 1, the lithium ion adsorption saturation capacity of the adsorbent is relatively low, so it approaches adsorption saturation quickly, and the degree of dissolution reduction is not as obvious as in Example 1.

The present invention aims at the common weakness of various lithium ion sieve adsorbents, that is, in actual use, there is a characteristic that the dissolution loss increases with the prolongation of the adsorption time or desorption time, and adopts a strategy: multiple adsorption towers are cascaded to form an adsorption-desorption Attached assembly line, through program control, different adsorption towers (and thus the adsorbents in the corresponding towers) are placed in different stages of the adsorption-desorption cycle in turn, so as to switch the working state of the adsorbent in time, so that the microscopic adsorption of the adsorbent can be improved. On the premise of the structure, the service life of the adsorbent is extended, and the total amount of lithium element adsorption and transfer in the whole life cycle is increased.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the above disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. improve the pipeline system in lithium ion sieve adsorbant service life, it is characterized in that, this system is some series connection and the adsorption tower that head and the tail are communicated with forms adsorption-desorption streamline, and each adsorption tower comprises:

Be seated in the lithium ion sieve adsorbant (1) in adsorption tower;

Be arranged on the pump (2) at adsorption column inlet place;

Control first valve (3) of adsorption column inlet; And

Control second valve (4) of adsorption column outlet.

2. the pipeline system improving lithium ion sieve adsorbant service life as claimed in claim 1, it is characterized in that, be reserved with cushion (5) between described lithium ion sieve adsorbant (1) and adsorption tower top, and adsorption tower top have ventilating bent-tube (6) with keep adsorption tower and air unimpeded.

3. the pipeline system improving lithium ion sieve adsorbant service life as claimed in claim 1, is characterized in that, described lithium ion sieve adsorbant (1) key component has aggravation to dissolve the characteristic of loss with the prolongation of adsorption time or desorption time.

4. the method for operating utilizing the pipeline system described in claim 1 to improve lithium ion sieve adsorbant service life, it is characterized in that, the method, by switching first valve (3), the second valve (4) state, makes the adsorption tower of connecting be placed in absorption phase or the desorption stage of adsorption-desorption cycle in turn; Described switch valve state, refers to manually or automatic program control valve, thus changes the solution source flowing into adsorption tower and the solution whereabouts flowing out adsorption tower.

5. method of operating as claimed in claim 4, is characterized in that described absorption phase refers to Li upon adsorption ⁺solution pumps into through first valve (3) of an adsorption tower, and after the lithium ion sieve adsorbant absorption in tower, the second valve (4) exported by tower flows into some adsorption towers of order series connection thereafter; Until Li in this tower outlet solution ⁺concentration terminates higher than the absorption phase of this tower during the first predetermined value.

6. method of operating as claimed in claim 5, is characterized in that, described Li upon adsorption ⁺solution must through pretreatment, and this pretreatment refers to and regulates its pH value to be 7 ~ 8.5, then adds carbonate or bicarbonate, makes carbonate wherein and bicarbonate radical amount of substance final concentration sum be greater than 50% of lithium ion final concentration in this solution.

7. method of operating as claimed in claim 5, it is characterized in that, the first described predetermined value is Li in the solution of this adsorption column inlet ⁺50% ~ 85% of concentration.

8. method of operating as claimed in claim 4, is characterized in that, described desorption stage, after referring to that the absorption phase of this tower terminates, pumps into acid solution, make the Li of lithium ion sieve adsorbant in adsorption tower by its first valve (3) ⁺desorption, is added in acid solution, discharges for subsequent use by its second valve (4); Until Li in exudate ⁺concentration terminates lower than the desorption stage of this tower during the second predetermined value.

9. method of operating as claimed in claim 8, it is characterized in that, the second described predetermined value is 100 ~ 400ppm.

10. method of operating as claimed in claim 4, is characterized in that, each adsorption tower is not limited to carry out adsorption and desorption under the restriction of single controlled condition and exit concentration predetermined value; Each adsorption tower is after reaching exit concentration first predetermined value, and switch valve state enters desorption stage, or changes controlled condition and predetermined value and enter next absorption phase; Each adsorption tower is after reaching exit concentration second predetermined value, and switch valve state enters absorption phase, or changes controlled condition and predetermined value and enter next desorption stage.