Continuous separation and exchange of lithium from chlorinated halogen

Abstract

The present invention provides a kind of chlorinated halogen continuous separation and exchange lithium extraction process, which includes filtering, adsorption, leaching, desorption and top liquid treatment of chlorinated halogen in sequence, wherein leaching uses desorption to obtain the desorption liquid. The chlorinated halogen continuous separation and exchange lithium extraction process provided by the present application is relative to old halogen for lithium extraction, and the original halogen can be extracted without sodium salt pond beach exposure after mining, thereby avoiding the lithium loss of 60wt% in salt fields, and the lithium extraction cycle is shortened from 1-2 years to 2 months, and the tail halogen and top salt solution after lithium extraction can all be recycled. In addition, the present application adopts desorption liquid for leaching, and the lithium ions in the desorption liquid suppress the desorption of lithium chloride in the adsorbent bed, and will not cause excessive desorption during desorption, while also saving energy consumption, and most of the sodium, potassium and magnesium ions in the adsorption bed can be eluted, and the Li / (Na+K) ratio in the desorption liquid is improved.

Description

Technical Field

[0001] The invention relates to the technical field of lithium extraction from lithium-containing brine, and in particular to a process for continuous lithium extraction from chlorinated raw brine. Background Art

[0002] Chaerhan Salt Lake belongs to Na + , K + Mg 2+ / / Cl-—H2O quaternary water-salt system, its process technology route is: raw brine mining - sodium salt pond beach sun-drying to remove sodium - brine stone beach sun-drying to extract potassium - old brine to extract lithium - tailings return to the mining area - solid ore to liquid ore, and so on. The traditional salt lake lithium extraction technology route needs to go through a relatively long salt field evaporation and concentration cycle (production cycle is more than 1 to 2 years), and the lithium recovery rate of the salt field section (brine mining and transportation, salt field step-by-step beach sun-drying) is only about 40%, which is the link with the largest entrainment loss. Therefore, trying to move the lithium extraction link forward has become the focus of the current industry.

[0003] Since the adsorption method conforms to the industry trend of "low-grade, low-cost, green lithium extraction technology", the mainstream salt lake lithium extraction process is still the coupling of adsorption + membrane. Compared with the old brine lithium extraction with "magnesium and lithium separation" as the core, the sodium chloride content in the original brine of the Qarhan Salt Lake is 20 to 30 times that of the old brine, the potassium chloride content is 10 to 15 times that of the old brine, and the magnesium chloride content is only 0.3 to 0.5 times that of the old brine. The process of lithium extraction from raw halides is similar to that of lithium extraction from old halides, but the details are different. If the sodium and potassium ions in the qualified liquid (product liquid) after lithium extraction are high, the following results will occur: First, sodium and potassium cannot be removed in the subsequent process (divalent calcium and magnesium can be removed at the back end), affecting the entire lithium carbonate production; second, the high TDS salt content leads to high operating pressure of the back-end reverse osmosis membrane and short membrane life; third, the lithium concentration of the electrodialysis product liquid will not be able to reach more than 18g / L (the lithium migration rate is lower than that of sodium); fourth, the lithium concentration multiple of the MVR high-lithium solution is low (sodium and potassium concentrations are too high, resulting in sodium chloride precipitation during evaporation); fifth, the sodium chloride concentration is too high during lithium precipitation, resulting in lithium carbonate wrapping sodium chloride ions during the crystallization nucleation process, affecting its product purity, and the large amount of washing water leads to a large amount of lithium precipitation mother liquor, which ultimately affects the overall yield of lithium carbonate. Therefore, the more important thing for raw halides to extract lithium is the separation of sodium and lithium, and the separation of potassium and lithium. The technical indicators of the qualified liquid are changed from Mg / Li to Li / (Na+K), and it is required not to affect the potassium extraction of the final lithium extraction tail liquid.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The main purpose of the present invention is to provide a continuous separation and exchange process for lithium extraction of chlorinated raw brine, so as to solve the problem that the mainstream lithium extraction process of salt lakes in the prior art is still the old brine lithium extraction with "magnesium-lithium separation" as the core, and the raw brine adopts a similar process for lithium extraction of old brine to extract lithium, which has the problems of sodium-lithium separation, potassium-lithium separation, product purity and low overall yield of lithium carbonate.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a continuous deionization and exchange process for lithium extraction of chlorinated raw brine is provided, and the continuous deionization and exchange process for lithium extraction comprises: step S1, filtering the chlorinated raw brine to remove large particles of sediment and impurities to obtain pretreated raw brine; step S2, using an adsorbent bed to adsorb the pretreated raw brine to obtain tail brine; step S3, rinsing the adsorbent bed that has been adsorbed with water to obtain a rinsing liquid; step S4, introducing desalted water into the rinsing adsorbent bed to perform desorption treatment to obtain a desorption liquid; returning the desorption liquid to step S3 to replace water for rinsing; step S5, using the tail brine to perform top liquid treatment on the desorbed adsorbent bed to obtain a top salt liquid, and recovering the top salt liquid.

[0007] Furthermore, in step S1, the SS value of the chlorinated raw brine is 250-2100 mg / L, and the SS value of the pretreated raw brine is ≤50 mg / L.

[0008] Furthermore, the filtering equipment used in the filtering process includes one of a plate and frame filter press, a bag filter, and a multi-media filter.

[0009] Furthermore, in step S2, the adsorbent contained in the adsorbent bed is an aluminum-based adsorbent, and the adsorption capacity of the aluminum-based adsorbent is ≥2.5 g / L.

[0010] Furthermore, the concentration of the pre-treated raw halogen is: Li + :0.18~0.24g / L,Mg 2+ :48.11~63.80g / L,Ca 2 + :0.33~0.44g / L,Na + :36.5~40.5g / L,K + :7.5~10.10g / L, B: 0.14~0.18g / L, SO4 2- : 9.96~12.92g / L, Cl-: 171.3-232.2g / L. Further, the concentration of tail halogen Li + ≤0.018g / L.

[0011] Further, in step S3, the elution treatment includes a first elution and a second elution, and the desorption liquid includes a first desorption liquid and a second desorption liquid; the first elution includes: eluting the adsorption bed layer treated with the first desorption liquid to obtain a first elution adsorption bed layer and a first elution liquid, wherein the temperature of the first desorption liquid is 23-33°C; the second elution includes: eluting the first elution bed layer with the second desorption liquid to obtain a second elution adsorption bed layer and a second elution liquid, wherein the temperature of the second desorption liquid is 45-55°C.

[0012] Furthermore, the concentration of the combined solution of the primary eluent and the secondary eluent is: Li + :0.40~0.6g / L,Na + :34.66~39.64g / L,K + :8.25~8.45g / L,Mg 2+ :51.25~53.99g / L,Ca 2+ : 0.44~0.63g / L, B: 0.141~0.197g / L.

[0013] Further, in step S4, the conductivity of the desalted water is ≤200 μs / cm, the temperature is 25-30°C; the concentration of the desorption solution is Li + :1.0~1.3g / L,Mg 2+ :0.4~0.8g / L,Ca 2+ :0.006~0.020g / L,Na + :0.050~0.140g / L,K + :0.020~0.050g / L, B: 0.015~0.020g / L, SO4 2- : 0.004~0.012g / L, Cl-: 10.3-15.2g / L; the conductivity of the desorption solution is 15-22ms / cm.

[0014] Further, in step S5, if the conductivity of the top salt solution is ≤3000 μs / cm, it is recovered to the desalted water tank; if the conductivity of the top salt solution is >3000 μs / cm, the top salt solution is discharged to the sodium salt pool.

[0015] Furthermore, in step S2, the tail brine is introduced into a sodium salt pool for beach drying, and then evaporated and concentrated to be used as a raw material for potassium extraction.

[0016] Further, in step S3, the primary eluent is returned to the original brine tank, and the secondary eluent is returned to the original brine tank after heat exchange treatment with desalted water.

[0017] Furthermore, a continuous ion-exchange lithium extraction system is used to carry out continuous ion-exchange lithium extraction of chloride-type raw brine. The continuous ion-exchange lithium extraction system includes a support plate, an adsorption area, a elution area, a desorption area and a top liquid area. The adsorption area, the elution area, the desorption area and the top liquid area are arranged in sequence around the axis of the support plate. A plurality of ion exchange columns are arranged on the support plate. The plurality of ion exchange columns are distributed in the adsorption area, the elution area, the desorption area and the top liquid area in sequence around the axis of the support plate. The support plate is rotatably arranged around its own axis so that any one of the plurality of ion exchange columns can enter the adsorption area, the elution area, the desorption area and the top liquid area in sequence.

[0018] Furthermore, the adsorption area includes a first adsorption area, a second adsorption area and a third adsorption area arranged in series, and the first adsorption area, the second adsorption area and the third adsorption area are respectively provided with 6 ion exchange columns in parallel, wherein the liquid inlet method of the first adsorption area is bottom-in and top-out, the liquid inlet method of the second adsorption area is bottom-in and bottom-out, and the liquid inlet method of the third adsorption area is top-in and bottom-out; the elution area includes a low-temperature elution area and a high-temperature elution area arranged in series, the low-temperature elution area is provided with 2 ion exchange columns in series, the liquid inlet method is top-in and bottom-out, and the high-temperature elution area is provided with 3 ion exchange columns in series, and the liquid inlet method is top-in and bottom-out; the desorption area includes a first desorption area and a second desorption area arranged in series, the first desorption area is provided with 3 ion exchange columns in parallel, the liquid inlet method is top-in and bottom-out, and the second desorption area is provided with 3 ion exchange columns in parallel, and the liquid inlet method is bottom-in and top-out; the top liquid area is provided with 1 ion exchange column, and the liquid inlet method is top-in and bottom-out.

[0019] The technical solution provided by this application has at least the following beneficial effects:

[0020] (1) Compared with the old brine method, the raw brine can be used to extract lithium without drying in the sodium salt pond, thus avoiding the loss of 60wt% of lithium in the salt field. At the same time, the lithium extraction cycle is shortened from 1-2 years to 2 months. The tail brine and top salt liquid after lithium extraction can all be recycled and processed. As the raw brine for the production of carnallite in potash fertilizer, the potassium loss is negligible.

[0021] (2) The most important qualified index of the eluent for lithium extraction from raw brine is Li / (Na+K). Referring to the industry technical index of lithium extraction from old brine of 3:1, the qualified index of the desorption liquid in this application, Li / (Na+K), is 2-4 times better than the industry technical index, and better than the technical index of lithium / sodium ratio for lithium extraction from old brine in salt lakes; the (Ca+Mg) / Li ratio is only 0.4-0.7, which is better than the technical index of lithium extraction from salt lakes of 3:1 for magnesium-lithium ratio, and the lithium concentration in the qualified index of the desorption liquid is high (greater than 0.9g / L), which greatly reduces the water consumption of lithium carbonate.

[0022] (3) The desorption liquid is used for elution treatment. The lithium ions in the desorption liquid inhibit the desorption of lithium chloride in the adsorbent bed, which will not cause excessive desorption during the desorption process. At the same time, it saves energy consumption and can elute most of the sodium, potassium and magnesium ions in the adsorption bed, thereby improving the Li / (Na+K) ratio in the desorption liquid and surpassing the industry technical indicators. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1A schematic flow chart of the continuous separation and extraction of lithium from chlorinated halogen provided in Example 1 of the present application is shown. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0026] As analyzed in the background technology of this application, the mainstream of the existing salt lake lithium extraction process is still the old brine lithium extraction with "magnesium-lithium separation" as the core, while the raw brine using a similar process of old brine lithium extraction has the problems of sodium-lithium separation, potassium-lithium separation, product purity and low overall yield of lithium carbonate. In order to solve this problem, this application provides a chlorination-type raw brine continuous separation and exchange lithium extraction process.

[0027] In a typical embodiment of the present application, a continuous separation and exchange process for lithium extraction of chlorinated raw brine is provided, which comprises the following steps: step S1, filtering the chlorinated raw brine to remove large particles of sediment and impurities to obtain pretreated raw brine; step S2, subjecting the pretreated raw brine to adsorption treatment using an adsorbent bed to obtain tail brine; step S3, rinsing the adsorbent bed that has been adsorbed with water to obtain a rinsing liquid; step S4, introducing desalted water into the rinsing adsorbent bed to perform desorption treatment to obtain a desorbent liquid; returning the desorbent liquid to step S3 to replace water for rinsing treatment; step S5, subjecting the desorbent bed that has been desorbed to top liquid treatment using the tail brine to obtain a top salt liquid, and recovering the top salt liquid.

[0028] The technical solution provided by this application has at least the following beneficial effects:

[0029] (1) Compared with the old brine method, the raw brine can be used to extract lithium without drying in the sodium salt pond, thus avoiding the loss of 60wt% of lithium in the salt field. At the same time, the lithium extraction cycle is shortened from 1-2 years to 2 months. The tail brine and top salt liquid after lithium extraction can all be recycled and processed. As the raw brine for the production of carnallite in potash fertilizer, the potassium loss is negligible.

[0030] (2) The most important qualified index of the desorption liquid for lithium extraction from raw brine is Li / (Na+K). Referring to the industry technical index of lithium extraction from old brine of 3:1, the qualified index of the eluent in this application, Li / (Na+K), is 2-4 times better than the industry technical index, and better than the technical index of lithium / sodium ratio of lithium extraction from old brine of salt lake; the magnesium-lithium ratio is only 0.4-0.7, which is better than the technical index of magnesium-lithium ratio of 3:1 in lithium extraction from salt lake, and the lithium concentration in the qualified index of the desorption liquid is high (greater than 1g / L), which greatly reduces the water consumption of lithium carbonate.

[0031] (3) The desorption liquid is used for elution treatment. The lithium ions in the desorption liquid inhibit the desorption of lithium chloride in the adsorbent bed, which will not cause excessive desorption during the desorption process. At the same time, it saves energy consumption and can elute most of the sodium, potassium and magnesium ions in the adsorption bed, thereby improving the Li / (Na+K) ratio in the desorption liquid and surpassing the industry technical indicators.

[0032] In some embodiments, in the above step S1, the SS value of the chlorinated raw brine that has not been filtered is 250-2100 mg / L (such as 250 mg / L, 300 mg / L, 500 mg / L, 700 mg / L, 800 mg / L, 1000 mg / L, 1500 mg / L, 2000 mg / L, 2100 mg / L), and the SS value of the pretreated raw brine obtained after filtration is preferably ≤50 mg / L to avoid clogging the adsorption column during the subsequent adsorption treatment and causing a decrease in adsorption capacity.

[0033] The above SS refers to suspended solids, which is a general term for suspended solids in water environment research and management. Suspended solids refer to solid substances suspended in water, including inorganic and organic substances insoluble in water, mud, clay, microorganisms, etc. The SS value refers to the concentration of suspended solids, which is usually determined by vacuum filtration pump plus nitrocellulose filter membrane method.

[0034] The concentration of each ion in the above-mentioned pretreated raw halogen is not limited. For example, in some embodiments, the concentration of the pretreated raw halogen is: Li + :0.18~0.24g / L,Mg 2+ :48.11~63.80g / L,Ca 2+ :0.33~0.44g / L,Na + :36.5~40.5g / L,K + :7.5~10.10g / L, B: 0.14~0.18g / L, SO4 2- :9.96~12.92g / L, Cl-:171.3-232.2g / L;

[0035] The filtering equipment used in the above-mentioned filtering treatment is commonly used equipment in the field, including but not limited to one of a plate filter press, a bag filter, and a multi-media filter.

[0036] In other embodiments, in the above step S2, the adsorbent in the adsorbent bed is an aluminum-based adsorbent, and the adsorption capacity of the aluminum-based adsorbent is ≥2.5 g / L, so as to further improve the adsorption performance of the adsorbent bed and improve the adsorption rate of potassium, sodium and lithium in the raw brine.

[0037] After the above adsorption treatment by the adsorbent bed, the Li + ≤0.018g / L to further improve the recovery rate of lithium.

[0038] In order to further improve the overall utilization rate of energy, the above step S2 is preferred, where part of the tail brine that has not been treated with top liquid is introduced into the sodium salt pool for beach drying, and then used as a raw material for potassium extraction after evaporation and concentration treatment.

[0039] In order to further improve the desorption efficiency of various metal ions, it is preferred that two stages of desorption liquids with different temperatures are used for elution in the above step S3. Specifically, in the above step S3, the elution treatment includes one stage elution and two stages elution, and the desorption liquid includes a first desorption liquid and a second desorption liquid. The first stage elution includes: eluting the adsorption bed layer after adsorption treatment with the first desorption liquid to obtain a primary elution adsorption bed layer and a primary elution liquid, wherein the temperature of the first desorption liquid is 23 to 33°C; the second stage elution includes: eluting the primary elution adsorption bed layer with the second desorption liquid to obtain a secondary elution adsorption bed layer and a secondary elution liquid, wherein the temperature of the second desorption liquid is 45 to 55°C.

[0040] By using two stages of desorption liquid with different temperatures for elution, the lithium ions in the desorption liquid are used to inhibit the desorption of lithium chloride in the adsorption bed, which will not cause excessive desorption during the desorption process. Secondly, two stages of elution at different temperatures are used to save energy consumption, and most of the sodium, potassium, and magnesium ions in the adsorption bed can be eluted, thereby improving the (Na+K) / Li ratio in the desorption liquid and exceeding the industry technical indicators.

[0041] In order to further reduce energy consumption, in some embodiments, the primary eluent is preferably returned to the original brine tank, and the secondary eluent is subjected to heat exchange treatment with desalted water and then returned to the original brine tank, thereby recovering part of the heat.

[0042] In some specific embodiments, the concentration of the combined solution of the primary eluent and the secondary eluent is: Li + :0.40~0.6g / L,Na + :34.66~39.64g / L,K + :8.25~8.45g / L,Mg 2+ :51.25~53.99g / L,Ca 2+ : 0.44~0.63g / L, B: 0.141~0.197g / L.

[0043] In order to further improve the desalination efficiency, in step S4, the conductivity of the desalted water is preferably ≤200 μs / cm, and the temperature is 25-30°C (such as 25°C, 28°C, 30°C). The concentration of the desorption solution is: Li + :1.0~1.3g / L,Mg 2+:0.4~0.8g / L,Ca 2 + :0.006~0.020g / L,Na + :0.050~0.140g / L,K + :0.020~0.050g / L, B: 0.015~0.020g / L, SO4 2- :0.004~0.012g / L,Cl - : 10.3-15.2g / L; the conductivity of the desorption solution is 15-22ms / cm (such as 15ms / cm, 17ms / cm, 18ms / cm, 20ms / cm, 22ms / cm).

[0044] In order to further improve the energy utilization rate of the top brine, in some embodiments, in the above step S5, if the conductivity of the top brine is ≤3000μs / cm, it is recovered to the desalted water tank for recycling; if the conductivity of the top brine is >3000μs / cm, the top brine is discharged to the sodium salt pool for recycling.

[0045] In order to facilitate the implementation of the above-mentioned continuous deionization and lithium extraction process of chloride-type raw brine, in some embodiments, a continuous deionization and lithium extraction system is used for continuous deionization and lithium extraction of chloride-type raw brine, and the continuous deionization and lithium extraction system includes a support plate, an adsorption area, a elution area, a desorption area and a top liquid area, and the adsorption area, the elution area, the desorption area and the top liquid area are arranged in sequence around the axis of the support plate, and a plurality of ion exchange columns are arranged on the support plate, and the plurality of ion exchange columns are distributed in the adsorption area, the elution area, the desorption area and the top liquid area in sequence around the axis of the support plate, and the support plate is rotatably arranged around its own axis so that any one of the plurality of ion exchange columns can enter the adsorption area, the elution area, the desorption area and the top liquid area in sequence.

[0046] The continuous ion-exchange lithium extraction system is used to continuously ion-exchange lithium from chloride-type raw halides, which is more conducive to improving the lithium extraction efficiency.

[0047] In some specific embodiments, in the above-mentioned continuous lithium extraction system, the adsorption area includes a first adsorption area, a second adsorption area and a third adsorption area arranged in series, and the first adsorption area, the second adsorption area and the third adsorption area are each provided with 6 ion exchange columns in parallel, wherein the liquid inlet mode of the first adsorption area is bottom-in and top-out, the liquid inlet mode of the second adsorption area is bottom-in and top-out, and the liquid inlet mode of the third adsorption area is top-in and bottom-out; the elution area includes a low-temperature elution area and a high-temperature elution area arranged in series, the low-temperature elution area is provided with 2 ion exchange columns in series, the liquid inlet mode is top-in and bottom-out, and the high-temperature elution area is provided with 3 ion exchange columns in series, and the liquid inlet mode is bottom-in and top-out; the desorption area includes a first desorption area and a second desorption area arranged in series, the first desorption area is provided with 3 ion exchange columns in parallel, the liquid inlet mode is top-in and bottom-out, and the second desorption area is provided with 3 ion exchange columns in parallel, and the liquid inlet mode is bottom-in and top-out; the top liquid area is provided with 1 ion exchange column, and the liquid inlet mode is top-in and bottom-out.

[0048] By adopting the bottom-in and top-out liquid inlet method for the ion exchange columns in the second adsorption zone, the second desorption zone and the top liquid zone, and adopting the top-in and bottom-out liquid inlet method for other zones, the adsorbent bed can be made fluffy and not compacted, which is beneficial to the adsorption and desorption of lithium chloride molecules, thereby further simplifying the process.

[0049] The beneficial effects of the present application will be further illustrated below in combination with embodiments and comparative examples.

[0050] Example 1

[0051] This embodiment provides a process for continuous separation and extraction of lithium from chlorinated halogen. The composition of the chlorinated halogen is shown in Table 1 below:

[0052] Table 1

[0053]

[0054] The continuous ion exchange and lithium extraction process steps (2) to (5) are all carried out in a continuous ion exchange and lithium extraction system. Figure 1As shown, the continuous ion exchange lithium extraction system includes a support disk, an adsorption area, an elution area, a desorption area and a top liquid area, the adsorption area, the elution area, the desorption area and the top liquid area are arranged in sequence around the axis of the disk, a plurality of ion exchange columns are arranged on the support disk, and the plurality of ion exchange columns are distributed in the adsorption area, the elution area, the desorption area and the top liquid area in sequence around the axis of the support disk, and the support disk is rotatably arranged around its own axis so that any one of the plurality of ion exchange columns can enter the adsorption area, the elution area, the desorption area and the top liquid area in sequence; wherein the adsorption area includes a series arrangement The invention comprises a first adsorption zone, a second adsorption zone and a third adsorption zone, and each of the three adsorption zones is provided with 6 ion exchange columns connected in parallel; the elution zone comprises a low-temperature elution zone and a high-temperature elution zone arranged in series, the low-temperature elution zone is provided with 2 ion exchange columns connected in series, and the high-temperature elution zone is provided with 3 ion exchange columns connected in series; the desorption zone comprises a first desorption zone and a second desorption zone arranged in series, the first desorption zone is provided with 3 ion exchange columns connected in parallel, and the second desorption zone is provided with 3 ion exchange columns connected in parallel; the second desorption zone is provided with 3 ion exchange columns connected in parallel; and the top liquid zone is provided with 1 ion exchange column.

[0055] The continuous ion exchange lithium extraction process specifically comprises the following steps:

[0056] (1) Pretreatment: pre-treat the chlorinated raw brine mined from the mining area, filter and separate the large particles of sand and other large impurities in the raw brine to prevent large particles from clogging the adsorbent pores and causing a decrease in adsorption capacity. The SS value of the pre-treated raw brine obtained after filtration treatment is ≤50mg / L; wherein the filtration treatment is carried out in a bag filter;

[0057] (2) Adsorption treatment: The pretreated raw brine is pumped into the adsorption area for adsorption treatment. The first adsorption area is provided with 1#-6# columns (each column is connected in parallel), and the liquid inlet method is top-in and bottom-out. The second adsorption area is provided with 7#-12# columns (each column is connected in parallel), and the liquid inlet method is bottom-in and top-out. The third adsorption area is provided with 13#-18# columns (each column is connected in parallel), and the liquid inlet method is bottom-in and top-out. The above 1#-12# columns are all filled with aluminum-based adsorbents, and the adsorption capacity of the aluminum-based adsorbent is ≥2.5g / L; wherein, the pretreated raw brine is pumped into the adsorption area at 87.8BV / h for adsorption treatment, and the average liquid inlet flow rate of each column is 14.6BV / h. The tail brine obtained after adsorption treatment flows out of 13#-18# columns and is discharged to the sodium salt pool at 14BV / h. Each column rotates for 10min to enter the next stage. The total adsorption time is 180min, and the temperature of the pretreated raw brine is 12°C.

[0058] (3) Elution treatment: The above-mentioned adsorption area ion exchange columns are transferred to the elution area in turn for elution treatment. The elution treatment includes two stages of elution. The first stage of elution is low-temperature (28°C) elution, which is carried out in the low-temperature elution area. The low-temperature elution area is provided with 29#-30# columns (each column is connected in series), the liquid inlet method is up-in and down-out, and the liquid inlet flow rate is 2.28BV / h (accounting for 40% of the total amount of the elution liquid), and a first-stage elution liquid is obtained. The second stage of high-temperature (50°C) elution is carried out in the high-temperature elution area. The high-temperature elution area is provided with 26#-27#-28# columns (each column is connected in series), the liquid inlet method is up-in and down-out, and the liquid inlet flow rate is 3.42BV / h (accounting for 60% of the total amount of the elution liquid), and a second-stage elution liquid is obtained. The two-stage elution time is 50min. After the elution is completed, the second-stage elution liquid is heat exchanged with fresh desalted water, and the two-stage elution liquid is collected and introduced into the filtered pre-treatment raw brine tank for recycling. Among them, when the elution treatment is started for the first time, deionized water at 28°C is used for the first elution, and water at 50°C is used for the second elution. Subsequently, the desorption liquid (with a conductivity of 18 ms / cm) obtained in step (4) can be used for elution treatment. The temperature of the first desorption liquid for the first elution is 28°C, and the temperature of the second desorption liquid for the second elution is 50°C (by external heating).

[0059] (4) Desorption treatment: The ion exchange columns in the elution area are transferred to the desorption area in turn for desorption treatment. The first desorption area is provided with 20#-21#-22# columns (each column is connected in parallel), and the liquid inlet method is top-in and bottom-out. The second analytical desorption area is provided with 23#-24#-25# columns (each column is connected in parallel), and the liquid inlet method is bottom-in and top-out. 25°C desalted water (conductivity 45μs / cm) is pumped into the first desorption area and the second desorption area in turn at 16.5BV / h. The average liquid inlet flow rate of each column is 5.5BV / h (3 columns in total). The generated desorption liquid is introduced into the desorption liquid storage tank. Each column rotates for 10min before entering the next stage. The total desorption time is 60min.

[0060] (5) Top liquid treatment: The ion exchange columns in the above-mentioned elution area are transferred to the top liquid area in turn for top liquid treatment. The top liquid area is provided with a 19# column. The liquid inlet method is top-in and bottom-out. The desalted water in the top liquid area is recovered using tail brine. The liquid inlet flow rate is 4.4 BV / h. The top salt liquid discharged from the top is recovered and treated (if the conductivity of the top salt liquid is ≤3000μs / cm, it is recovered to the desalted water tank; if the conductivity of the top salt liquid is >3000μs / cm, the top salt liquid is discharged to the sodium salt pool). The rotation time is 10min to enter the next stage. The top liquid time is 10min, the top liquid water temperature is 12℃, and the whole cycle is 300min.

[0061] Example 2

[0062] The difference between this embodiment and embodiment 1 is that the temperature of the desalted water subjected to desorption treatment in step (4) is 30°C.

[0063] Example 3

[0064] The difference between this embodiment and embodiment 1 is that in step (3), the temperature of the second desorption liquid in the second stage of elution is 45°C, and the temperature of the desalted water for desorption treatment in step (4) is 30°C.

[0065] Example 4

[0066] The difference between this embodiment and embodiment 1 is that the temperature of the second desorption liquid in the second stage of elution is 45°C, and the temperature of the desalted water for desorption treatment in step (4) is 25°C.

[0067] Example 5

[0068] The difference between this embodiment and embodiment 1 is that the temperature of the first desorption liquid in the first stage of elution is 33°C, and the temperature of the second desorption liquid in the second stage of elution is 55°C.

[0069] Example 6

[0070] The difference between this embodiment and embodiment 1 is that the temperature of the first desorption liquid in the first stage of elution is 23°C, and the temperature of the second desorption liquid in the second stage of elution is 45°C.

[0071] Example 7

[0072] The difference between this embodiment and embodiment 1 is that in step (3), the conductivity of the first desorption liquid and the conductivity of the second desorption liquid are both 15 ms / cm.

[0073] Example 8

[0074] The difference between this embodiment and embodiment 1 is that in step (3), the conductivity of the first desorption liquid and the conductivity of the second desorption liquid are both 22 ms / cm.

[0075] Example 9

[0076] The difference between this embodiment and embodiment 1 is that in step (3), the conductivity of the first desorption liquid and the conductivity of the second desorption liquid are both 35 ms / cm.

[0077] Example 10

[0078] The difference between this embodiment and embodiment 1 is that in step (3), the temperature of the first desorption liquid in the first stage of elution and the temperature of the second desorption liquid in the second stage of elution are both 27°C.

[0079] Embodiment 11

[0080] The difference between this embodiment and embodiment 1 is that in step (3), the temperature of the first desorption liquid in the first stage of elution and the temperature of the second desorption liquid in the second stage of elution are both 22°C.

[0081] Test example

[0082] The main ion contents of the desorbed solutions obtained in step (4) of each embodiment were measured respectively, and are shown in Table 2 below.

[0083] Table 2

[0084]

[0085]

[0086] Note: The units of the above ion concentrations are all mg / L.

[0087] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0088] (1) Compared with the old brine method, the raw brine can be used to extract lithium without drying in the sodium salt pond, thus avoiding the loss of 60wt% of lithium in the salt field. At the same time, the lithium extraction cycle is shortened from 1-2 years to 2 months. The tail brine and top salt liquid after lithium extraction can all be recycled and processed. As the raw brine for the production of carnallite in potash fertilizer, the potassium loss is negligible.

[0089] (2) The most important qualified index of the eluent for lithium extraction from raw brine is Li / (Na+K). Referring to the industry technical index of lithium extraction from old brine of 3:1, the qualified index of the desorption liquid in this application, Li / (Na+K), is 2-4 times better than the industry technical index, and better than the technical index of lithium / sodium ratio for lithium extraction from old brine in salt lakes; the (Ca+Mg) / Li ratio is only 0.4-0.7, which is better than the technical index of lithium extraction from salt lakes of 3:1 for magnesium-lithium ratio, and the lithium concentration in the qualified index of the desorption liquid is high (greater than 0.9g / L), which greatly reduces the water consumption of lithium carbonate.

[0090] (3) The desorption liquid is used for elution treatment. The lithium ions in the desorption liquid inhibit the desorption of lithium chloride in the adsorbent bed, which will not cause excessive desorption during the desorption process. At the same time, it saves energy consumption and can elute most of the sodium, potassium and magnesium ions in the adsorption bed, thereby improving the Li / (Na+K) ratio in the desorption liquid and surpassing the industry technical indicators.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for continuous separation and exchange of chlorinated halogen for lithium extraction, characterized in that: The continuous ion exchange lithium extraction process comprises: Step S1, filtering the chlorinated raw brine to remove large particles of sand and impurities to obtain pretreated raw brine; Step S2, subjecting the pretreated raw halogen to adsorption treatment using an adsorbent bed to obtain tail halogen; Step S3, washing the adsorbent bed after the adsorption treatment with water to obtain a washing liquid; Step S4, introducing the desalted water into the adsorbent bed that has undergone the elution treatment to perform desorption treatment to obtain a desorbed liquid; Returning the desorption liquid to step S3 to replace the water for the elution treatment; Step S5, using the tail brine to perform top liquid treatment on the adsorbent bed that has undergone the desorption treatment to obtain top salt solution, and the top salt solution is recovered for treatment; In step S3, the elution treatment includes a first elution and a second elution, and the desorption liquid includes a first desorption liquid and a second desorption liquid; The first stage elution comprises: eluting the adsorption bed layer subjected to adsorption treatment with the first desorption liquid to obtain a first elution adsorption bed layer and a first elution liquid, wherein the temperature of the first desorption liquid is 23-33° C.; The second stage elution comprises: eluting the first elution adsorption bed with the second desorption liquid to obtain a second elution adsorption bed and a second elution liquid, wherein the temperature of the second desorption liquid is 45-55° C.; The concentration of the desorption solution is: Li + :1.0~1.3g / L,Mg 2+ :0.4~0.8g / L,Ca 2+ :0.006~0.020g / L, Na + :0.050~0.140g / L,K + :0.020~0.050g / L,B:0.015~0.020g / L,SO4 2- :0.004~0.012g / L, Cl - :10.3-15.2g / L。 2. The process for continuous separation and extraction of lithium from chlorinated halogen according to claim 1, characterized in that: In step S1, the SS value of the chlorinated raw halogen is 250-2100 mg / L, and the SS value of the pretreated raw halogen is ≤50 mg / L; And / or, the filtering equipment used in the filtering process includes one of a plate and frame filter press, a bag filter, and a multi-media filter.

3. The process for continuous separation and exchange of chlorinated halogen for lithium extraction according to claim 1, characterized in that: In step S2, the adsorbent contained in the adsorbent bed is an aluminum-based adsorbent, and the adsorption capacity of the aluminum-based adsorbent is ≥ 2.5 g / L; And / or, the concentration of the pre-treated raw halogen is: Li + :0.18~0.24g / L,Mg 2+ :48.11~63.80g / L,Ca 2+ :0.33~0.44g / L,Na + :36.5~40.5g / L,K + :7.5~10.10g / L, B: 0.14~0.18g / L, SO4 2- :9.96~12.92g / L,Cl - : 171.3-232.2g / L; And / or, the concentration of tail halogen Li + ≤0.018g / L.

4. The process for continuous separation and exchange of chlorinated halogen for lithium extraction according to claim 1, characterized in that: The concentration of the combined solution of the primary eluent and the secondary eluent is: Li + :0.40~0.6g / L,Na + :34.66~39.64g / L,K + :8.25~8.45g / L,Mg 2+ :51.25~53.99g / L,Ca 2+ :0.44~0.63g / L, B: 0.141~0.197g / L.

5. The process for continuous separation and extraction of lithium from chlorinated halogen according to claim 1, characterized in that: In step S4, the conductivity of the desalted water is ≤200 μs / cm and the temperature is 25-30° C.; The conductivity of the desorption liquid is 15-22 ms / cm.

6. The process for continuous separation and exchange of chlorinated halogen for lithium extraction according to claim 1, characterized in that: In step S5, if the conductivity of the top salt solution is ≤3000 μs / cm, the top salt solution is recovered to the desalted water tank; if the conductivity of the top salt solution is >3000 μs / cm, the top salt solution is discharged to the sodium salt pool.

7. The process for continuous separation and extraction of lithium from chlorinated halogen according to claim 1, characterized in that: In step S2, the tail brine is introduced into a sodium salt pool for beach drying, and then evaporated and concentrated to serve as a raw material for potassium extraction.

8. The process for continuous separation and exchange of chlorinated halogen for lithium extraction according to claim 4, characterized in that: In step S3, the primary eluent is returned to the original brine tank, and the secondary eluent is returned to the original brine tank after heat exchange with the desalted water.

9. The process for continuous separation and extraction of lithium from chlorinated halogen according to any one of claims 1 to 8, characterized in that: A continuous ion exchange and lithium extraction system is used to carry out continuous ion exchange and lithium extraction of the chlorinated raw brine. The continuous ion exchange and lithium extraction system comprises a support plate, an adsorption area, a leaching area, a desorption area and a top liquid area. The adsorption area, the leaching area, the desorption area and the top liquid area are arranged in sequence around the axis of the support plate. A plurality of ion exchange columns are arranged on the support plate. The plurality of ion exchange columns are distributed in the adsorption area, the leaching area, the desorption area and the top liquid area in sequence around the axis of the support plate. The support plate is rotatably arranged around its own axis so that any one of the plurality of ion exchange columns can enter the adsorption area, the leaching area, the desorption area and the top liquid area in sequence.

10. The process for continuous separation and exchange of chlorinated halogen for lithium extraction according to claim 9, characterized in that: The adsorption area comprises a first adsorption area, a second adsorption area and a third adsorption area which are arranged in series, and each of the first adsorption area, the second adsorption area and the third adsorption area is provided with 6 ion exchange columns connected in parallel, wherein the liquid inlet mode of the first adsorption area is bottom-in and top-out, the liquid inlet mode of the second adsorption area is bottom-in and top-out, and the liquid inlet mode of the third adsorption area is top-in and bottom-out; The elution area includes a low-temperature elution area and a high-temperature elution area arranged in series, wherein the low-temperature elution area is provided with two ion exchange columns in series, and the liquid inlet mode is top-in and bottom-out, and the high-temperature elution area is provided with three ion exchange columns in series, and the liquid inlet mode is top-in and bottom-out; The desorption area includes a first desorption zone and a second desorption zone arranged in series, wherein the first desorption zone is provided with three ion exchange columns connected in parallel, and the liquid inlet mode is top-in and bottom-out, and the second desorption zone is provided with three ion exchange columns connected in parallel, and the liquid inlet mode is bottom-in and top-out; The top liquid area is provided with an ion exchange column, and the liquid inlet mode is top-in and bottom-out.

Images