Method for extracting lithium by adsorbing original brine of magnesium sulfate subtype salt lake

Abstract

The invention relates to the field of adsorption lithium extraction, and discloses a method for adsorbing lithium from magnesium sulfate subtype salt lake original brine. The method comprises the following steps: (1) evaporating and concentrating original brine of the magnesium sulfate subtype salt lake to obtain lithium-rich brine, and adsorbing the lithium-rich brine by using an adsorbent to extract lithium so as to obtain adsorption tail liquid in which the lithium content is 0.1-0.2 g / L and the magnesium content is 60-80 g / L; (2) regenerating the inactivated layered aluminum adsorbent by using the adsorption tail liquid obtained in the step (1) to obtain a regenerated layered aluminum adsorbent; and (3) carrying out adsorption lithium extraction on the magnesium sulfate subtype salt lake original brine by using the regenerated layered aluminum adsorbent. According to the method, the inactivated adsorbent is regenerated through the high-magnesium lithium-containing old brine adsorption tail liquid, meanwhile, lithium resources in the high-magnesium old brine adsorption tail liquid can be recycled in the regeneration process, and the lithium yield is increased.

Description

Technical Field

[0001] The invention relates to the technical field of lithium extraction by adsorption, and in particular to a method for extracting lithium by adsorption from original brine of a magnesium sulfate subtype salt lake. Background Art

[0002] At present, the main methods for extracting lithium from salt lakes include membrane method, adsorption method, solar pond method, solvent extraction method and electrochemical method. Among them, some methods have been successfully applied to the industrial production of lithium extraction from salt lake brine. Since the adsorption method mainly uses the electrostatic effect on the surface of the adsorbent or the "size effect" of the crystal structure to achieve the goal of selective separation of target ions, it has the advantages of high lithium selectivity, low cost, low environmental pressure, and high recycling rate. It has great development potential in the application of lithium extraction from low-grade salt lake brine with high magnesium-lithium ratio. The adsorbents that can be used for lithium extraction from salt lake brine mainly include layered aluminum and titanium, spinel manganese and titanium adsorbents. So far, only layered aluminum adsorbents have been industrialized, and manganese and titanium adsorbents are still in the pilot and laboratory research stage. However, aluminum adsorbents still have problems such as extremely low dynamic adsorption capacity and severe pulverization when applied on a large scale.

[0003] Based on the structure-activity relationship between the adsorption performance and crystal structure of aluminum-based adsorbents, aluminum-based adsorbents utilize the Li + The spatial confinement effect of vacancies can realize the Li + Selective screening and adsorption are performed. During the adsorption process, Li + Occupy Al 3+ The vacancies in the (OH)6 layer and the accompanying anions remain in the interlayer gap to maintain electrical neutrality. The structure of aluminum-based adsorbents is sensitive and the adsorption performance is easily attenuated after excessive desorption. + In the process, its structure gradually transforms into one without Li + The adsorption capacity of gibbsite is greatly reduced, which leads to a rapid decrease in the adsorption capacity of the adsorbent. In the process of adsorption and lithium extraction from the original brine of magnesium sulfate subtype salt lake, the intercalated SO4 2- The interlayer spacing of the adsorbent material is enlarged and the stacking structure of the aluminum-based adsorbent is significantly changed, resulting in fluctuations in adsorption performance. 2- The negative effects of competitive adsorption and electrostatic repulsion caused by the increase in ionic strength increase, resulting in a decrease in the adsorption performance of aluminum-based adsorbents in sulfate salt lakes. In the actual production process, the sulfate ions in the original brine can be completely removed, or the ratio of chloride ions to sulfate ions in the original brine can be adjusted, and the high magnesium solution can be used to pass through Li +The intercalation reaction in gibbsite improves the performance of the adsorbent by deactivating the adsorbent. The above methods require pretreatment of the original brine or preparation of a high-magnesium solution before the adsorption and lithium extraction process. Other impurity ions will be introduced into the system, and the operation process is complicated, the work efficiency is low, and the cost is high.

[0004] In the traditional process of lithium extraction from salt lakes, lithium-rich old brine after potassium precipitation is used as raw material, and lithium is extracted through an "adsorption + membrane method" process in which the front-end process is adsorption and the back-end process is membrane method. During the front-end old brine adsorption and lithium extraction process, the adsorption tail liquid of the lithium-containing and high-magnesium old brine after lithium extraction is generally discharged to the evaporation salt field for further evaporation and concentration. During the evaporation and concentration process of the adsorption tail liquid of the lithium-containing and high-magnesium old brine, due to the solubility of various salts in the tail liquid system, sodium, magnesium and other salts are crystallized and precipitated in sequence. A large amount of lithium resources are entrained in the crystallization process and are difficult to be efficiently recovered, resulting in the loss of high-quality lithium resources. In addition, the low lithium recovery rate of the original brine in the early salt field evaporation and concentration process reduces the utilization rate of salt lake lithium resources again. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of lithium resource loss in the adsorption and lithium extraction process of the prior art, easy introduction of impurities in adsorbent regeneration and complicated operation, and provide a method for extracting lithium by adsorption of original brine from magnesium sulfate subtype salt lake. The method regenerates the adsorbent deactivated in the original brine adsorption process by adsorbing the tail liquid of high-magnesium lithium-containing old brine to restore its performance. At the same time, the regeneration process can recover the lithium resources in the adsorption tail liquid of high-magnesium old brine, thereby improving the lithium yield.

[0006] In order to achieve the above object, the present invention provides a method for extracting lithium by adsorption from raw brine of magnesium sulfate subtype salt lake, the method comprising the following steps:

[0007] (1) evaporating and concentrating the original brine of the magnesium sulfate subtype salt lake to obtain lithium-rich brine, and using an adsorbent to adsorb and extract lithium from the lithium-rich brine to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.1-0.2 g / L and the magnesium content is 60-80 g / L;

[0008] (2) regenerating the deactivated layered aluminum adsorbent using the adsorption tail liquid obtained in step (1) to obtain a regenerated layered aluminum adsorbent;

[0009] (3) Using the regenerated layered aluminum adsorbent to adsorb and extract lithium from the original brine of magnesium sulfate subtype salt lake.

[0010] Preferably, in steps (1) and (3), the density of the magnesium sulfate subtype salt lake original brine is 1-1.4 g / mL, the lithium content is 100-200 ppm, and the magnesium content is 20000-30000 ppm.

[0011] Preferably, in step (1), the adsorbent is at least one of a layered aluminum-based adsorbent, a layered titanium-based adsorbent, a spinel-structured manganese-based adsorbent and a spinel-structured titanium-based adsorbent.

[0012] Preferably, in step (2), the regeneration process comprises: using the adsorption tail liquid obtained in step (1) to elute the deactivated layered aluminum adsorbent for 8-15 minutes.

[0013] Preferably, in step (2), the layered aluminum adsorbent has an adsorption capacity of 1-5 g / L, a sphericity of 50-100% after grinding, a physical strength of 90-100%, and an apparent density of 0.4-0.9 g / mL.

[0014] Preferably, in step (3), the process of adsorption and lithium extraction is implemented in a continuous ion exchange device, which includes an adsorption zone, a leaching zone, a desorption zone and a top water zone arranged in sequence, and a plurality of adsorption columns formed by layered aluminum adsorbents are continuously circulated in the adsorption zone, the leaching zone, the desorption zone and the top water zone.

[0015] Preferably, in the adsorption zone, the magnesium sulfate subtype salt lake original brine enters the adsorption column through the upper feeding method for adsorption, and discharges low-lithium tail liquid, and the lithium content of the low-lithium tail liquid is 65-69ppm;

[0016] In the desorption zone, pure water is used to desorb the adsorption column after being treated in the elution zone to obtain a high-lithium qualified solution, wherein the lithium content of the high-lithium qualified solution is 442-452 ppm;

[0017] In the elution zone, the high-lithium qualified solution obtained in the desorption zone is used to elute the adsorption column saturated with adsorption in the adsorption zone;

[0018] In the top water zone, the low-lithium tail liquid obtained in the adsorption zone is used to perform a top water reverse operation on the adsorption column after desorption in the desorption zone.

[0019] Preferably, in the elution zone, the high-lithium qualified solution is used to elute the adsorption column by upper feeding;

[0020] In the desorption zone, pure water desorbs the adsorption column by upper feeding;

[0021] In the top water zone, the low-lithium tail liquid is top watered to the adsorption column by a bottom feeding method.

[0022] Preferably, the number of adsorption columns configured in the continuous ion exchange device is 30, and during continuous operation, the adsorption zone has 16 adsorption columns, which are connected in an eight-in-two series manner; the elution zone has 5 adsorption columns, which are connected in a five-column series manner; the desorption zone has 8 adsorption columns, which are connected in a two-in-four series manner; and the top water zone has 1 adsorption column.

[0023] Preferably, the continuous ion exchange device is also equipped with a regeneration zone. After the adsorption column is deactivated, the adsorption tail liquid obtained in step (1) is used in the regeneration zone to regenerate the deactivated adsorption column, and the regenerated adsorption column is returned to the adsorption zone for recycling.

[0024] The method for extracting lithium by adsorption of raw brine from magnesium sulfate subtype salt lakes of the present invention regenerates the lithium-extracting adsorbent by adsorbing tail liquid of high-magnesium old brine, thereby avoiding the intercalation of SO4 in the adsorbent during the lithium extraction process. 2- At the same time, the regeneration process can effectively recover the high-quality lithium resources that would have been discharged from the old brine adsorption tail liquid, thereby improving the comprehensive recovery rate of lithium resources from salt lakes, extending the service life of resources, and improving the utilization rate of salt fields, achieving the effect of green closed-loop production and promoting the healthy and stable development of the new energy industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of the method for extracting lithium by adsorption from raw brine of magnesium sulfate subtype salt lake. DETAILED DESCRIPTION

[0026] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The method for extracting lithium by adsorption from raw brine of magnesium sulfate subtype salt lake of the present invention comprises the following steps:

[0029] (1) evaporating and concentrating the original brine of the magnesium sulfate subtype salt lake to obtain lithium-rich brine, and using an adsorbent to adsorb and extract lithium from the lithium-rich brine to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.1-0.2 g / L and the magnesium content is 60-80 g / L;

[0030] (2) regenerating the deactivated layered aluminum adsorbent using the adsorption tail liquid obtained in step (1) to obtain a regenerated layered aluminum adsorbent;

[0031] (3) Using the regenerated layered aluminum adsorbent to adsorb and extract lithium from the original brine of magnesium sulfate subtype salt lake.

[0032] In the method of the present invention, in steps (1) and (3), the density of the original brine of the magnesium sulfate subtype salt lake is 1-1.4 g / mL, the content of lithium ions is above 150 mg / L, the content of magnesium ions is 20-30 g / L, the content of sodium ions is 75-95 g / L, the content of potassium ions is 9-10 g / L, the content of boron ions is 250-350 mg / L, the content of chloride ions is 170-200 g / L, and the content of sulfate ions is 9-13 g / L.

[0033] In the method described in the present invention, in step (1), the evaporation concentration is carried out in a solar pond to precipitate sodium and potassium.

[0034] In some embodiments, in step (1), the adsorption and lithium extraction can be carried out in an ion exchange resin adsorption device and / or an adsorbent fixed bed device, and the conditions for the adsorption and lithium extraction may include: a temperature of -10-30°C, preferably -5-25°C; a flow rate of the lithium-rich brine of 0.5-3.5BV / h, preferably 1.5-2.5BV / h; and the adsorbent is at least one of a layered aluminum adsorbent, a layered titanium adsorbent, a spinel structured manganese adsorbent, and a spinel structured titanium adsorbent.

[0035] In the present invention, in step (1), a portion of the adsorption tail liquid is discharged into the salt pan for evaporation and concentration, and the other portion is used for regenerating the deactivated layered aluminum adsorbent in subsequent operations.

[0036] In the method of the present invention, in step (2), the adsorbent may be at least one of a layered aluminum adsorbent, a layered titanium adsorbent, a spinel structure manganese adsorbent and a spinel structure titanium adsorbent, preferably a layered aluminum adsorbent. In the present invention, the layered aluminum adsorbent can effectively adsorb and extract lithium ions from low-quality, high magnesium-to-lithium ratio brine.

[0037] In the present invention, in step (2), the adsorption capacity of the layered aluminum adsorbent can be 1-5 g / L, the ball rate after grinding can be 50-100%, the physical strength can be 90-100%, and the apparent density can be 0.4-0.9 g / mL. In the present invention, when the performance of the layered aluminum adsorbent is within the above range, the layered aluminum adsorbent has a better ability to adsorb lithium ions.

[0038] In the method described in the present invention, in step (2), the regeneration process may include: using the adsorption tail liquid obtained in step (1) to elute the deactivated layered aluminum adsorbent; the time is 5-20 minutes, preferably 8-15 minutes.

[0039] In the method described in the present invention, in step (2), the adsorption tail liquid after regeneration of the deactivated layered aluminum adsorption is discharged into the original brine of the magnesium sulfate subtype salt lake for recycling.

[0040] In some embodiments, in step (3), the process of adsorption and lithium extraction can be implemented in a continuous ion exchange device, which may include an adsorption zone, a leaching zone, a desorption zone and a top water zone arranged in sequence, and a plurality of adsorption columns formed by layered aluminum adsorbents are continuously circulated in the adsorption zone, the leaching zone, the desorption zone and the top water zone.

[0041] In a more preferred embodiment, in step (3), the continuous ion exchange device further comprises a valve assembly, wherein the valve assembly connects the adsorption zone, the elution zone, the desorption zone and the top water zone, and the column is cut by rotating the valve assembly during operation of the continuous ion exchange device.

[0042] In some embodiments, in the adsorption zone, the magnesium sulfate subtype salt lake original brine enters the adsorption column through the upper feeding method for adsorption, and discharges low-lithium tail liquid, and the lithium content of the low-lithium tail liquid is 65-69ppm. In a more preferred embodiment, the adsorption conditions include: a temperature of -5-25°C and a flow rate of 6.6-8.3BV / h. In these embodiments, when the adsorption conditions are within the above range, the adsorbent has a higher efficiency in adsorbing lithium ions.

[0043] In some embodiments, in the desorption zone, pure water is used to desorb the adsorption column after being treated in the elution zone to obtain a high-lithium qualified solution, and the lithium content of the high-lithium qualified solution is 442-452ppm. In a more preferred embodiment, the desorption conditions include: a temperature of -5-25°C and a flow rate of 3-4BV / h. In these embodiments, when the desorption conditions are within the above range, the adsorbent has a higher desorption efficiency and is not easily deactivated.

[0044] In the method described in the present invention, in step (3), a part of the high-lithium qualified solution obtained by the desorption is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product, and the other part is used to rinse the adsorption column that is saturated with adsorption in the adsorption zone.

[0045] In some embodiments, in the elution zone, the high-lithium qualified solution obtained in the desorption zone is used to elute the adsorption column saturated with adsorption in the adsorption zone. In a more preferred embodiment, the elution conditions include: a temperature of -5-25°C and a flow rate of 0.5-1.1 BV / h. In these embodiments, when the elution conditions are within the above range, impurity ions such as magnesium ions, sodium ions, potassium ions, boron ions and calcium ions in the adsorption column are removed more thoroughly.

[0046] In the method described in the present invention, in step (3), the high-lithium qualified solution is used to rinse the adsorption column that is saturated with adsorption in the adsorption zone and then discharged for refining, lithium precipitation and other operations to obtain a lithium salt product.

[0047] In some embodiments, in the top water zone, the low-lithium tail liquid obtained in the adsorption zone is used to perform a top water reverse operation on the adsorption column after desorption in the desorption zone.

[0048] In a more preferred embodiment, in the elution zone, the high-lithium qualified solution is used to elute the adsorption column by upper feeding;

[0049] In the desorption zone, pure water desorbs the adsorption column by upper feeding;

[0050] In the top water zone, the low-lithium tail liquid is top watered to the adsorption column by a bottom feeding method.

[0051] In a more preferred embodiment, the number of adsorption columns configured in the continuous ion exchange device is 30, and during continuous operation, the adsorption zone has 16 adsorption columns, which are connected in an eight-in-two series manner; the elution zone has 5 adsorption columns, which are connected in a five-column series manner; the desorption zone has 8 adsorption columns, which are connected in a two-in-four series manner; and the top water zone has 1 adsorption column.

[0052] In some embodiments, the continuous ion exchange device is further configured with a regeneration zone. After the adsorption column is deactivated, the adsorption tail liquid obtained in step (1) is used in the regeneration zone to regenerate the deactivated adsorption column, and the regenerated adsorption column is returned to the adsorption zone for recycling.

[0053] In a more preferred embodiment, the deactivated adsorption column is switched to the regeneration zone by rotating the valve assembly and connected to the feed pipe of the adsorption tail liquid. After the adsorbent is regenerated, it is returned to the adsorption zone through the valve assembly for recycling.

[0054] In a more preferred embodiment, after the continuous ion exchange device has been running for 30 cycles, it is connected to the regeneration zone and runs for 30 cycles continuously to regenerate the adsorbent. After the regeneration is completed, the continuous ion exchange device is cut out of the regeneration zone and continues to circulate.

[0055] like Figure 1 As shown, the method for extracting lithium by adsorption from the original brine of magnesium sulfate subtype salt lake of the present invention specifically comprises the following steps:

[0056] (1) Using layered aluminum adsorbents to extract lithium from magnesium sulfate subtype salt lake brine:

[0057] S1. Close the valves related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method and is homogeneously adsorbed with the layered aluminum adsorbent to discharge the low-lithium tail liquid, wherein a part of the low-lithium tail liquid is discharged to the solar pond for further beach drying and concentration, and the other part of the low-lithium tail liquid is used to perform a reverse top water operation on the adsorption column after desorption in the desorption zone in the top water zone;

[0058] S2. In the desorption zone, pure water is used to desorb the adsorption column treated in the elution zone by upper feeding to obtain a high-lithium qualified liquid, wherein a part of the high-lithium qualified liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product, and the other part is used to elute the adsorption column saturated with adsorption in the adsorption zone;

[0059] S3, in the elution zone, using the high-lithium qualified solution obtained in the desorption zone to elute the adsorption column saturated with adsorption in the adsorption zone by upper feeding to remove impurity ions, and refining and precipitating lithium on the liquid product discharged from the elution to obtain a lithium salt product;

[0060] S4, in the top water zone, using the low-lithium tail liquid obtained in S1 to perform a top water reverse operation on the adsorption column after desorption in the desorption zone by a bottom feeding method, discharge the pure water remaining in the desorption process in S3, and discharge the liquid product obtained by the top water reverse operation to a solar pond for further beach concentration;

[0061] S5. New magnesium sulfate subtype salt lake original brine is introduced to circulate the above steps, and after 30 cycles, a deactivated layered aluminum adsorbent is obtained, and the valve circuit related to the regeneration process is switched.

[0062] (2) The original brine of the magnesium sulfate subtype salt lake is evaporated and concentrated in a solar pond to obtain lithium-rich brine, and the lithium-rich brine is adsorbed and extracted with an adsorbent to obtain an adsorption tail liquid, wherein a portion of the adsorption tail liquid is discharged into a salt pan for evaporation and concentration, another portion is used to regenerate the layered aluminum adsorbent deactivated in step (1), and the remaining portion of the adsorption tail liquid is refined, lithium is precipitated, and the like to obtain a lithium salt product.

[0063] (3) Regenerating the deactivated layered aluminum adsorbent and simultaneously adsorbing and extracting lithium:

[0064] S6. Open the valve circuit related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method to be homogeneously adsorbed with the deactivated layered aluminum adsorbent, and the low-lithium tail liquid is discharged. Part of the low-lithium tail liquid is discharged to the solar pond for further sun exposure and concentration. The deactivated layered aluminum adsorbent is eluted and regenerated using the adsorption tail liquid obtained in step (2) to obtain a regenerated layered aluminum adsorbent, and the liquid product obtained by elution is discharged into the original brine of the magnesium sulfate subtype salt lake for recycling;

[0065] S7, cyclically run step S2, step S3, step S4 and step S6, and cut out the valve path related to the regeneration process after 30 cycles.

[0066] The following examples further illustrate the method for extracting lithium from magnesium sulfate subtype salt lake raw brine by adsorption. The examples are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0067] The experimental methods in the following examples and comparative examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0068] In the following embodiments and comparative examples, the process of regenerated adsorbent adsorbing and extracting lithium from magnesium sulfate subtype salt lake original brine is operated in a continuous ion exchange device, which includes: an adsorption zone, a leaching zone, a desorption zone and a top water zone configured in sequence, and a plurality of adsorption columns formed by layered aluminum adsorbents are continuously circulated in the adsorption zone, the leaching zone, the desorption zone and the top water zone connected by a valve assembly, wherein the number of adsorption columns configured in the continuous ion exchange device is 30, and during the continuous operation, the adsorption zone has 16 adsorption columns, which are connected in an eight-in-two series manner; the leaching zone has 5 adsorption columns, which are connected in a five-column series manner; the desorption zone has 8 adsorption columns, which are connected in a two-in-four series manner; the top water zone has 1 adsorption column;

[0069] The continuous ion exchange device is also provided with a regeneration zone, and the regeneration zone can be flexibly switched in the elution zone to effectively operate the adsorbent regeneration process.

[0070] Example 1

[0071] The density of the magnesium sulfate subtype salt lake original brine used in this embodiment is 1.21 g / mL, the content of lithium ions is 100 mg / L, and the content of magnesium ions is 20 g / L.

[0072] (1) Using layered aluminum adsorbents to extract lithium from magnesium sulfate subtype salt lake brine:

[0073] S1. Close the valves related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method and is homogeneously adsorbed with the layered aluminum adsorbent to discharge the low-lithium tail liquid, wherein a part of the low-lithium tail liquid is discharged to the solar pool for further beach drying and concentration, and the other part of the low-lithium tail liquid is used to perform a reverse top water operation on the adsorption column after desorption in the desorption zone in the top water zone. The adsorption capacity of the layered aluminum adsorbent is 2.33 g / L, the ball rate after grinding is 53.3%, the physical strength is 96.25%, and the apparent density is 0.59 g / mL;

[0074] S2. In the desorption zone, pure water is used to desorb the adsorption column treated in the elution zone by upper feeding to obtain a high-lithium qualified liquid, wherein a part of the high-lithium qualified liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product, and the other part is used to elute the adsorption column saturated with adsorption in the adsorption zone;

[0075] S3, in the elution zone, using the high-lithium qualified liquid obtained in the desorption zone to elute the adsorption column saturated with adsorption in the adsorption zone by upper feeding to remove impurity ions such as magnesium ions, sodium ions, potassium ions, boron ions and calcium ions, and refining and precipitating lithium on the liquid product discharged from the elution to obtain a lithium salt product;

[0076] S4, in the top water zone, using the low-lithium tail liquid obtained in S1 to perform a top water reverse operation on the adsorption column after desorption in the desorption zone by a bottom feeding method, discharge the pure water remaining in the desorption process in S3, and discharge the liquid product obtained by the top water reverse operation to a solar pond for further beach concentration;

[0077] S5. New magnesium sulfate subtype salt lake original brine is introduced to circulate the above steps, and after 30 cycles, a deactivated layered aluminum adsorbent is obtained, and the valve circuit related to the regeneration process is switched.

[0078] (2) The original brine of the magnesium sulfate subtype salt lake is evaporated and concentrated in a solar pond to obtain lithium-rich brine, and the lithium-rich brine is adsorbed and extracted with an aluminum-based adsorbent to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.1 g / L and the magnesium content is 60 g / L, wherein a portion of the adsorption tail liquid is discharged into a salt pan for evaporation and concentration, a portion is used to regenerate the layered aluminum-based adsorbent deactivated in step (1), and the remaining portion of the adsorption tail liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product.

[0079] (3) Regenerating the deactivated layered aluminum adsorbent and simultaneously adsorbing and extracting lithium:

[0080] S6. Open the valve circuit related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method to be homogeneously adsorbed with the deactivated layered aluminum adsorbent, and the low-lithium tail liquid is discharged. Part of the low-lithium tail liquid is discharged to the solar pond for further sun exposure and concentration. The deactivated layered aluminum adsorbent is eluted and regenerated using the adsorption tail liquid obtained in step (2) to obtain a regenerated layered aluminum adsorbent, and the liquid product obtained by elution is discharged into the original brine of the magnesium sulfate subtype salt lake for recycling;

[0081] S7, cyclically run step S2, step S3, step S4 and step S6, and cut out the valve path related to the regeneration process after 30 cycles.

[0082] Example 2

[0083] The density of the magnesium sulfate subtype salt lake original brine used in this embodiment is 1.22 g / mL, the content of lithium ions is 130 mg / L, and the content of magnesium ions is 23 g / L.

[0084] (1) Using layered aluminum adsorbents to extract lithium from magnesium sulfate subtype salt lake brine:

[0085] S1. Close the valves related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method and is homogeneously adsorbed with the layered aluminum adsorbent to discharge the low-lithium tail liquid, wherein a part of the low-lithium tail liquid is discharged to the solar pool for further sun exposure and concentration, and the other part of the low-lithium tail liquid is used to perform a reverse top water operation on the adsorption column after desorption in the desorption zone in the top water zone. The adsorption capacity of the layered aluminum adsorbent is 3.23 g / L, the ball rate after grinding is 65.2%, the physical strength is 97.3%, and the apparent density is 0.52 g / mL;

[0086] S2. In the desorption zone, pure water is used to desorb the adsorption column treated in the elution zone by upper feeding to obtain a high-lithium qualified liquid, wherein a part of the high-lithium qualified liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product, and the other part is used to elute the adsorption column saturated with adsorption in the adsorption zone;

[0087] S3, in the elution zone, using the high-lithium qualified liquid obtained in the desorption zone to elute the adsorption column saturated with adsorption in the adsorption zone by upper feeding to remove impurity ions such as magnesium ions, sodium ions, potassium ions, boron ions and calcium ions, and refining and precipitating lithium on the liquid product discharged from the elution to obtain a lithium salt product;

[0088] S4, in the top water zone, using the low-lithium tail liquid obtained in S1 to perform a top water reverse operation on the adsorption column after desorption in the desorption zone by a bottom feeding method, discharge the pure water remaining in the desorption process in S3, and discharge the liquid product obtained by the top water reverse operation to a solar pond for further beach concentration;

[0089] S5. New magnesium sulfate subtype salt lake original brine is introduced to circulate the above steps, and after 30 cycles, a deactivated layered aluminum adsorbent is obtained, and the valve circuit related to the regeneration process is switched.

[0090] (2) The original brine of the magnesium sulfate subtype salt lake is evaporated and concentrated in a solar pond to obtain lithium-rich brine, and the lithium-rich brine is adsorbed and extracted with an aluminum-based adsorbent to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.13 g / L and the magnesium content is 65 g / L, wherein a portion of the adsorption tail liquid is discharged into a salt pan for evaporation and concentration, another portion is used to regenerate the layered aluminum-based adsorbent deactivated in step (1), and the remaining portion of the adsorption tail liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product.

[0091] (3) Regenerating the deactivated layered aluminum adsorbent and simultaneously adsorbing and extracting lithium:

[0092] S6. Open the valve circuit related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method to be homogeneously adsorbed with the deactivated layered aluminum adsorbent, and the low-lithium tail liquid is discharged. Part of the low-lithium tail liquid is discharged to the solar pond for further sun exposure and concentration. The deactivated layered aluminum adsorbent is eluted and regenerated using the adsorption tail liquid obtained in step (2) to obtain a regenerated layered aluminum adsorbent, and the liquid product obtained by elution is discharged into the original brine of the magnesium sulfate subtype salt lake for recycling;

[0093] S7, cyclically run step S2, step S3, step S4 and step S6, and cut out the valve path related to the regeneration process after 30 cycles.

[0094] Example 3

[0095] The density of the magnesium sulfate subtype salt lake original brine used in this embodiment is 1.23 g / mL, the content of lithium ions is 160 mg / L, and the content of magnesium ions is 26 g / L.

[0096] (1) Using layered aluminum adsorbents to extract lithium from magnesium sulfate subtype salt lake brine:

[0097] S1. Close the valves related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method and is homogeneously adsorbed with the layered aluminum adsorbent to discharge the low-lithium tail liquid, wherein a part of the low-lithium tail liquid is discharged to the solar pool for further sun exposure and concentration, and the other part of the low-lithium tail liquid is used to perform a reverse top water operation on the adsorption column after desorption in the desorption zone in the top water zone. The adsorption capacity of the layered aluminum adsorbent is 1.5g / L, the ball rate after grinding is 77.6%, the physical strength is 98%, and the apparent density is 0.72g / mL;

[0098] S2. In the desorption zone, pure water is used to desorb the adsorption column treated in the elution zone by upper feeding to obtain a high-lithium qualified liquid, wherein a part of the high-lithium qualified liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product, and the other part is used to elute the adsorption column saturated with adsorption in the adsorption zone;

[0099] S3, in the elution zone, using the high-lithium qualified liquid obtained in the desorption zone to elute the adsorption column saturated with adsorption in the adsorption zone by upper feeding to remove impurity ions such as magnesium ions, sodium ions, potassium ions, boron ions and calcium ions, and refining and precipitating lithium on the liquid product discharged from the elution to obtain a lithium salt product;

[0100] S4, in the top water zone, using the low-lithium tail liquid obtained in S1 to perform a top water reverse operation on the adsorption column after desorption in the desorption zone by a bottom feeding method, discharge the pure water remaining in the desorption process in S3, and discharge the liquid product obtained by the top water reverse operation to a solar pond for further beach concentration;

[0101] S5. New magnesium sulfate subtype salt lake original brine is introduced to circulate the above steps, and after 30 cycles, a deactivated layered aluminum adsorbent is obtained, and the valve circuit related to the regeneration process is switched.

[0102] (2) The original brine of the magnesium sulfate subtype salt lake is evaporated and concentrated in a solar pond to obtain lithium-rich brine, and the lithium-rich brine is adsorbed and extracted with an aluminum-based adsorbent to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.16 g / L and the magnesium content is 75 g / L, wherein a portion of the adsorption tail liquid is discharged into a salt pan for evaporation and concentration, another portion is used to regenerate the layered aluminum-based adsorbent deactivated in step (1), and the remaining portion of the adsorption tail liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product.

[0103] (3) Regenerating the deactivated layered aluminum adsorbent and simultaneously adsorbing and extracting lithium:

[0104] S6. Open the valve circuit related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method to be homogeneously adsorbed with the deactivated layered aluminum adsorbent, and the low-lithium tail liquid is discharged. Part of the low-lithium tail liquid is discharged to the solar pond for further sun exposure and concentration. The deactivated layered aluminum adsorbent is eluted and regenerated using the adsorption tail liquid obtained in step (2) to obtain a regenerated layered aluminum adsorbent, and the liquid product obtained by elution is discharged into the original brine of the magnesium sulfate subtype salt lake for recycling;

[0105] S7, cyclically run step S2, step S3, step S4 and step S6, and cut out the valve path related to the regeneration process after 30 cycles.

[0106] Example 4

[0107] The density of the magnesium sulfate subtype salt lake original brine used in this embodiment is 1.24 g / mL, the content of lithium ions is 200 mg / L, and the content of magnesium ions is 30 g / L.

[0108] (1) Using layered aluminum adsorbents to extract lithium from magnesium sulfate subtype salt lake brine:

[0109] S1. Close the valves related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method and is homogeneously adsorbed with the layered aluminum adsorbent to discharge the low-lithium tail liquid, wherein a part of the low-lithium tail liquid is discharged to the solar pool for further beach drying and concentration, and the other part of the low-lithium tail liquid is used to perform a reverse top water operation on the adsorption column after desorption in the desorption zone in the top water zone. The layered aluminum adsorption capacity is 2.26g / L, the ball rate after grinding is 91.45%, the physical strength is 99.2%, and the apparent density is 0.81g / mL;

[0110] S2. In the desorption zone, pure water is used to desorb the adsorption column treated in the elution zone by upper feeding to obtain a high-lithium qualified liquid, wherein a part of the high-lithium qualified liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product, and the other part is used to elute the adsorption column saturated with adsorption in the adsorption zone;

[0111] S3, in the elution zone, using the high-lithium qualified liquid obtained in the desorption zone to elute the adsorption column saturated with adsorption in the adsorption zone by upper feeding to remove impurity ions such as magnesium ions, sodium ions, potassium ions, boron ions and calcium ions, and refining and precipitating lithium on the liquid product discharged from the elution to obtain a lithium salt product;

[0112] S4, in the top water zone, using the low-lithium tail liquid obtained in S1 to perform a top water reverse operation on the adsorption column after desorption in the desorption zone by a bottom feeding method, discharge the pure water remaining in the desorption process in S3, and discharge the liquid product obtained by the top water reverse operation to a solar pond for further beach concentration;

[0113] S5. New magnesium sulfate subtype salt lake original brine is introduced to circulate the above steps to obtain a deactivated layered aluminum adsorbent after 30 cycles, and the valve circuit related to the regeneration process is switched, wherein a part of the adsorption tail liquid is discharged into the salt pan for evaporation and concentration, and the other part is used to regenerate the layered aluminum adsorbent deactivated in step (1).

[0114] (2) The original brine of the magnesium sulfate subtype salt lake is evaporated and concentrated in a solar pond to obtain lithium-rich brine, and the lithium-rich brine is adsorbed and extracted with an aluminum-based adsorbent to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.2 g / L and the magnesium content is 80 g / L, wherein a portion of the adsorption tail liquid is discharged into a salt pan for evaporation and concentration, another portion is used to regenerate the layered aluminum-based adsorbent deactivated in step (1), and the remaining portion of the adsorption tail liquid is subjected to refining, lithium precipitation and other operations to obtain a lithium salt product.

[0115] (3) Regenerating the deactivated layered aluminum adsorbent and simultaneously adsorbing and extracting lithium:

[0116] S6. Open the valve circuit related to the regeneration process. In the adsorption zone, the original brine of the magnesium sulfate subtype salt lake enters the adsorption column through the upper feeding method to be homogeneously adsorbed with the deactivated layered aluminum adsorbent, and the low-lithium tail liquid is discharged. Part of the low-lithium tail liquid is discharged to the solar pond for further sun exposure and concentration. The deactivated layered aluminum adsorbent is eluted and regenerated using the adsorption tail liquid obtained in step (2) to obtain a regenerated layered aluminum adsorbent, and the liquid product obtained by elution is discharged into the original brine of the magnesium sulfate subtype salt lake for recycling;

[0117] S7, cyclically run step S2, step S3, step S4 and step S6, and cut out the valve path related to the regeneration process after 30 cycles.

[0118] Comparative Example 1

[0119] This comparative example was implemented according to the method of Example 1, except that in step (2), the lithium content was 3 g / L and the magnesium content was 120 g / L.

[0120] Comparative Example 2

[0121] This comparative example was implemented according to the method of Example 1, except that in step (2), the lithium content was 0.01 g / L and the magnesium content was 20 g / L.

[0122] Comparative Example 3

[0123] This comparative example is implemented according to the method of Example 1, except that step (2) is not performed. In step (3), a high concentration of chlorides such as sodium chloride, magnesium chloride, potassium chloride, etc. is used to regenerate the deactivated layered aluminum adsorbent to obtain a regenerated layered aluminum adsorbent.

[0124] Comparative Example 4

[0125] This comparative example was carried out according to the method of Example 1, except that step (3) was not performed.

[0126] Test Case

[0127] Respectively detecting and calculating the average lithium content in the low-lithium tail solution and the high-lithium qualified solution obtained in step (1) and step (3) of Example 1-4 and Comparative Example 1-4 in 60 cycles, and the average process lithium yield of Example 1-4 and Comparative Example 1-4;

[0128] In the present invention, the process lithium yield is the ratio of the total amount of lithium obtained in each cycle of the recovery process described in Examples 1-4 and Comparative Examples 1-4 to the total amount of lithium in the original brine of the magnesium sulfate subtype salt lake consumed in each cycle.

[0129] The results are shown in Table 1.

[0130] Table 1

[0131]

[0132] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for extracting lithium by adsorption from raw brine of magnesium sulfate subtype salt lake, characterized in that: The method comprises the following steps: (1) evaporating and concentrating the original brine of the magnesium sulfate subtype salt lake to obtain lithium-rich brine, and using an adsorbent to adsorb and extract lithium from the lithium-rich brine to obtain an adsorption tail liquid, wherein the lithium content of the adsorption tail liquid is 0.1-0.2 g / L and the magnesium content is 60-80 g / L; (2) regenerating the deactivated layered aluminum adsorbent using the adsorption tail liquid obtained in step (1) to obtain a regenerated layered aluminum adsorbent; (3) Using the regenerated layered aluminum adsorbent to adsorb and extract lithium from the original brine of magnesium sulfate subtype salt lake.

2. The method according to claim 1, characterized in that In steps (1) and (3), the density of the magnesium sulfate subtype salt lake original brine is 1-1.4 g / mL, the lithium content is 100-200 ppm, and the magnesium content is 20000-30000 ppm.

3. The method according to claim 1, characterized in that In step (1), the adsorbent is at least one of a layered aluminum-based adsorbent, a layered titanium-based adsorbent, a spinel-structured manganese-based adsorbent, and a spinel-structured titanium-based adsorbent.

4. The method according to claim 1, characterized in that In step (2), the regeneration process includes: using the adsorption tail liquid obtained in step (1) to elute the deactivated layered aluminum adsorbent for 8-15 minutes.

5. The method according to claim 1 or 4, characterized in that: In step (2), the layered aluminum adsorbent has an adsorption capacity of 1-5 g / L, a sphericity of 50-100% after grinding, a physical strength of 90-100%, and an apparent density of 0.4-0.9 g / mL.

6. The method according to any one of claims 1 to 5, characterized in that: In step (3), the process of adsorption and lithium extraction is implemented in a continuous ion exchange device, which includes an adsorption zone, a leaching zone, a desorption zone and a top water zone arranged in sequence, and a plurality of adsorption columns formed by layered aluminum adsorbents are continuously circulated in the adsorption zone, the leaching zone, the desorption zone and the top water zone.

7. The method according to claim 6, characterized in that In the adsorption zone, the magnesium sulfate subtype salt lake original brine enters the adsorption column through the upper feeding method for adsorption, and discharges low-lithium tail liquid, the lithium content of the low-lithium tail liquid is 65-69ppm; In the desorption zone, pure water is used to desorb the adsorption column after being treated in the elution zone to obtain a high-lithium qualified solution, wherein the lithium content of the high-lithium qualified solution is 442-452 ppm; In the elution zone, the high-lithium qualified solution obtained in the desorption zone is used to elute the adsorption column saturated with adsorption in the adsorption zone; In the top water zone, the low-lithium tail liquid obtained in the adsorption zone is used to perform a top water reverse operation on the adsorption column after desorption in the desorption zone.

8. The method according to claim 6, characterized in that In the elution zone, the high-lithium qualified solution is used to elute the adsorption column by upper feeding method; In the desorption zone, pure water desorbs the adsorption column by upper feeding; In the top water zone, the low-lithium tail liquid is top watered to the adsorption column by a bottom feeding method.

9. The method according to any one of claims 6 to 8, characterized in that: The number of adsorption columns configured in the continuous ion exchange device is 30, and during continuous operation, the adsorption zone has 16 adsorption columns, which are connected in an eight-in-two series manner; the elution zone has 5 adsorption columns, which are connected in a five-column series manner; the desorption zone has 8 adsorption columns, which are connected in a two-in-four series manner; and the top water zone has 1 adsorption column.

10. The method according to any one of claims 6 to 9, characterized in that: The continuous ion exchange device is also equipped with a regeneration zone. After the adsorption column is deactivated, the adsorption tail liquid obtained in step (1) is used in the regeneration zone to regenerate the deactivated adsorption column, and the regenerated adsorption column is returned to the adsorption zone for recycling.

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