Efficient lithium adsorbent regeneration and recovery method

Abstract

The invention belongs to the technical field of lithium extraction by an adsorption method, and discloses an efficient lithium adsorbent regeneration and recovery method, which comprises the following steps: performing regeneration recovery on a lithium adsorbent material by using a regeneration liquid, then feeding into a screening device for separation and recovery, and separating pollutants and a broken adsorbent out of a system along with the regeneration liquid to obtain a regenerated adsorbent, and leaching, drying and recovering the regenerated adsorbent. The method is mainly used for solving the problems of adsorbent pollution, crushing, hardening and the like caused by long-time operation of the salt lake lithium extraction adsorbent material, and the lithium adsorbent can be quickly and effectively regenerated and recycled by using the method, so that the production cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium extraction by adsorption method, and particularly relates to a method for regenerating and recycling high-efficiency lithium adsorbents. Background Art

[0002] Lithium is the metal element with the smallest atomic radius and the lightest density, known as the green energy metal and "white petroleum", and is widely used in electronic products, new energy vehicles, chemical industry, medicine, metallurgy and other fields. In the global lithium end-use market, 80% of lithium resources are used in the preparation of rechargeable lithium-ion batteries. Under the development trend of "green and low-carbon" in the global market, the demand for lithium resources in various application scenarios such as new energy vehicles, energy storage, electric bicycles, and power tools has increased rapidly, and the supply of lithium and its compounds has fallen short of demand.

[0003] The main technologies for extracting lithium from salt lakes include precipitation method, calcination method, extraction method, membrane separation method, adsorption method, etc. The adsorption method has good selectivity, simple process, economy and environmental protection, and is considered to be one of the most promising methods for extracting lithium from salt lake brine. High-performance adsorption materials are the key in this method. Currently, the most studied adsorbents mainly include aluminum-based adsorbents, manganese-based adsorbents and titanium-based adsorbents. Due to the complex chemical components of salt lake brine, the brine contains sediment, organic matter and trace elements that are likely to cause poisoning and pollution of lithium adsorbents. During long-term use, the lithium adsorbents will be poisoned and polluted, the adsorption performance will decline, the brine will scour, the adsorbents will be dissolved, damaged and broken, and some sediment will easily cause the adsorbents to agglomerate, thus greatly reducing the efficiency of lithium adsorbents and affecting industrial production. Summary of the Invention

[0004] The present invention provides a method for regenerating and recycling high-efficiency lithium adsorbents. This method is mainly used to solve the problems of adsorbent pollution, fragmentation, agglomeration, etc. of the lithium extraction adsorbent material from salt lakes during long-term operation. Using this method, regeneration can be carried out quickly and efficiently. The poisoned and polluted elements of the lithium adsorbent are washed out with the regeneration liquid, and the lithium adsorbent is recovered by screening technology for repeated use, saving production costs.

[0005] The present invention provides the following technical solutions:

[0006] A method for regenerating and recycling high-efficiency lithium adsorbents, comprising the following steps: regenerating and restoring the lithium adsorbent material with the regeneration liquid, and then sending it to a screening device for separation and recovery. The pollutants and broken adsorbents are separated from the system with the regeneration liquid to obtain the regenerated adsorbent, and the regenerated adsorbent is rinsed, dried and recovered.

[0007] Further, the lithium adsorbent material includes one or more of aluminum-based adsorbents, titanium-based adsorbents, and manganese-based adsorbents.

[0008] Further, the lithium adsorbent material includes one or more of spherical adsorbents, hollow cylindrical adsorbents, and strip-shaped adsorbents. Further, the lithium adsorbent material includes one or more of spherical adsorbents with a diameter of 0.1 - 0.5 cm, hollow cylindrical adsorbents with an inner diameter of 0.1 - 0.6 cm and an outer diameter of 0.5 - 2 cm, and strip-shaped adsorbents with a diameter of 0.1 - 0.5 cm and a length of 0.1 - 1 cm.

[0009] Further, the regeneration liquid is a bittern system, the pH of the bittern system is 1 - 7, the anion of the bittern system is chloride ion, the anion content is 80 - 180 g / L, and the cation of the bittern system is one or more of sodium ion, magnesium ion, and potassium ion.

[0010] Further, the step of regenerating and restoring the lithium adsorbent material with the regeneration liquid includes: mixing and stirring the lithium adsorbent material and the regeneration liquid, with a stirring speed of 10 - 300 r / min, a stirring time of 5 - 120 min, and a stirring temperature of 15 - 45 °C.

[0011] Further, ultrasonic treatment is carried out simultaneously during the mixing and stirring of the lithium adsorbent material and the regeneration liquid, with an ultrasonic power of 100 - 800 W.

[0012] Further, the screening device is one or more of a vibrating screen, a circular vibrating screen, a gyratory vibrating screen, and a shaking screen.

[0013] Further, the screen of the screening device has three layers, D1, D2, and D3. The aperture of D1 is 4 - 6 meshes, the aperture of D2 is 8 - 12 meshes, and the aperture of D3 is 25 - 35 meshes. The D1 layer removes large particle sediment, the D2 layer recovers the completed lithium adsorbent, the D3 layer recovers the broken adsorbent, the regenerated brine is recycled, and the broken adsorbent can be returned to the manufacturer for recycling.

[0014] Further, the rinsing water is one or more of pure water, tap water, and industrial fresh water.

[0015] Further, the drying is carried out by hot air drying at 40 - 80 °C.

[0016] Beneficial effects

[0017] The present invention provides a method for efficient regeneration and recycling of lithium adsorbents. Due to the complex chemical composition of salt lake brine, the brine contains sediment, organic matter, and trace elements that are likely to cause poisoning and pollution of lithium adsorbents. During long-term use, the lithium adsorbents will be poisoned and polluted, resulting in a decline in adsorption performance. At the same time, due to the flushing of the brine, the adsorbents are damaged and broken, and some sediment is likely to cause the adsorbents to agglomerate, resulting in an increase in operating pressure after long-term use of the adsorbent resin column, thus greatly reducing the efficiency of lithium adsorbents and affecting industrial production. By adopting the method provided by the present invention, the performance of lithium adsorbents can be efficiently and quickly restored. Through off-line regeneration, water washing, stirring, screening, lithium adsorbent materials with good performance can be recovered for reuse, which maximally saves production costs and improves adsorption efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the process for regeneration and recycling of lithium adsorbents;

[0019] Figure 2 is the schematic diagram of the principle of lithium adsorbent regeneration;

[0020] Figure 3 is the diagram of screening and recycling of lithium adsorbents;

[0021] Figure 4 is the comparison diagram of the contaminated adsorbent and the adsorbent after regeneration and recycling in Example 1;

[0022] Figure 5 is the XRD comparison diagram of the contaminated adsorbent and the regenerated adsorbent in Example 2. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to more clearly illustrate the technical solutions of the present invention, the present invention will be further described below; obviously, only a part of the embodiments are described below. For those of ordinary skill in the art, without creative efforts, the technical solutions described in the present invention can also be applied to other similar scenarios according to these; in order to more clearly illustrate the technical solutions of the present invention, the technical solutions of the present invention will be further described in detail below.

[0024] Example 1

[0025] In this example, an aluminum-based adsorbent contaminated after one year of industrial operation in a certain salt lake in Qinghai is used. The spherical aluminum-based adsorbent has a diameter of about 0.2 cm. At present, the performance of the adsorbent has declined. The adsorption capacity of the adsorbent is detected to be 2.51 g / L, and the adsorption capacity of the initial new adsorbent is 3.45 g / L. In addition, the surface of the adsorbent is wrapped with sediment and there is a phenomenon of agglomeration.

[0026] Load 100 L of contaminated lithium adsorbent into a resin column equipped with stirring, and add the regeneration solution. The regeneration solution is sodium chloride solution with a chloride ion content of 100 g / L. Control the stirring speed at 300 r / min, stir for 30 min, and keep the temperature at 25 °C. During the stirring process, ultrasound is applied simultaneously with a power of 500 W to allow the lithium adsorbent to fully regenerate with the sodium chloride solution.

[0027] After regeneration, open the valve at the bottom of the resin tower to let the lithium adsorbent flow into the multi-functional vibrating screen for screening by the principle of gravity. The sieve mesh of the multi-functional vibrating screen has three layers, D1, D2, and D3. The mesh number of the D1 layer sieve is 5 meshes, the mesh number of the D2 layer sieve is 10 meshes, and the mesh number of the D3 layer sieve is 30 meshes. The D2 layer sifts out the intact adsorbent after regeneration.

[0028] Collect the lithium adsorbent in the D2 layer, wash it with pure water, dry it with hot air at 50 °C, and then recycle it. By detecting the performance of the recycled adsorbent, the adsorption capacity reaches 3.42 g / L, which is 36% higher than that before regeneration; the desorption capacity of the detected adsorbent reaches 3.26 g / L, which is 35% higher than that before regeneration and recycling.

[0029] Table 1 Comparison of adsorption performance of adsorbent before and after regeneration and recycling

[0030]

[0031] Example 2

[0032] In this example, an aluminum-based adsorbent contaminated after 2 years of industrial operation in a certain salt lake in Qinghai is used. The aluminum-based adsorbent is a hollow type with an outer diameter of about 0.5 cm. Currently, the performance of the adsorbent has declined. The detected adsorption capacity of the adsorbent is 1.81 g / L, and the surface of the adsorbent is covered with sediment and has a slightly yellow color.

[0033] Load 100 L of contaminated lithium adsorbent into a resin column equipped with stirring, and add the regeneration solution. The regeneration solution is magnesium chloride solution with a chloride ion content of 100 g / L. Control the stirring speed at 300 r / min, stir for 30 min, and keep the temperature at 25 °C to allow the lithium adsorbent to fully regenerate with the magnesium chloride solution.

[0034] After regeneration, open the valve at the bottom of the resin tower to let the lithium adsorbent flow into the multi-functional vibrating screen for screening by the principle of gravity. The sieve mesh of the multi-functional vibrating screen has three layers, D1, D2, and D3. The mesh number of the D1 layer sieve is 5 meshes, the mesh number of the D2 layer sieve is 10 meshes, and the mesh number of the D3 layer sieve is 30 meshes. The D2 layer sifts out the intact adsorbent after regeneration.

[0035] Collect the lithium adsorbent in the D2 layer, wash it with industrial fresh water, dry it with hot air at 40 °C, and then recycle it. By testing the performance of the recycled adsorbent, it is found that the adsorption capacity of the adsorbent reaches 2.85 g / L, and the performance is improved by 57% compared with that before the regeneration and recycling of the adsorbent.

[0036] Table 2 Comparison of Adsorption Performance of Adsorbent before and after Regeneration and Recycling

[0037]

[0038] Example 3

[0039] In this example, an aluminum-based adsorbent contaminated after 2 years of industrial operation in a certain salt lake in Qinghai is used. The hollow aluminum-based adsorbent has an outer diameter of about 0.5 cm. At present, the performance of the adsorbent has declined. The adsorption capacity of the adsorbent is detected to be 1.81 g / L, and the surface of the adsorbent is wrapped with sediment and the color is slightly yellow.

[0040] Load 100 L of contaminated lithium adsorbent into a resin column with stirring in the same proportion. Without adding the regeneration liquid, directly mix and stir with industrial fresh water, control the stirring speed at 300 r / min, stir for 30 min, and the temperature is at room temperature of 25 °C.

[0041] Then open the valve at the bottom of the resin tower to allow the lithium adsorbent to flow into the multi-functional vibrating screen for screening by the principle of gravity. The sieve meshes of the multi-functional vibrating screen are divided into three layers: D1, D2, and D3. Among them, the mesh number of the D1 layer sieve is 5 meshes, the mesh number of the D2 layer sieve is 10 meshes, and the mesh number of the D3 layer sieve is 30 meshes. The regenerated complete adsorbent is screened out by the D2 layer.

[0042] Collect the lithium adsorbent in the D2 layer, wash it with industrial fresh water, dry it with hot air at 40 °C, and then recycle it. By testing the performance of the recycled adsorbent, the adsorption capacity of the adsorbent is detected to be 1.88 g / L, and the performance is not improved compared with that before the regeneration and recycling of the adsorbent. The desorption capacity of the adsorbent is 1.76 g / L, and the performance is not improved compared with that before the regeneration and recycling of the adsorbent. It is found by comparison that without using the regeneration liquid, the performance of the adsorbent cannot be restored.

[0043] Table 3 Comparison of Adsorption Performance of Adsorbent before and after Recycling

[0044]

[0045] Example 4

[0046] In this example, an aluminum-based adsorbent contaminated after 2 years of industrial operation in a certain salt lake in Qinghai is used. The hollow aluminum-based adsorbent has an outer diameter of about 0.5 cm. At present, the performance of the adsorbent has declined. The adsorption capacity of the adsorbent is detected to be 1.81 g / L, and the surface of the adsorbent is wrapped with sediment and the color is slightly yellow.

[0047] Load 100 L of contaminated lithium adsorbent into a resin column equipped with stirring, and add a regeneration solution, which is a magnesium chloride solution with a chloride ion content of 100 g / L. Control the stirring speed at 300 r / min, stir for 30 min, and keep the temperature at 25 °C to allow the lithium adsorbent to fully regenerate with the magnesium chloride solution.

[0048] After regeneration, open the valve at the bottom of the resin tower to allow the lithium adsorbent to flow to a centrifuge by gravity for dehydration and centrifugation.

[0049] Collect the centrifuged adsorbent, wash it with industrial fresh water, dry it with hot air at 40 °C, and then recycle it. It is found that the recycled adsorbents are of different sizes and still contain sediment particles. By simple screening, normal adsorbents are recovered, and the proportion of normal adsorbents is 85%. Correspondingly, if screening is not carried out directly and the adsorbents are recycled and loaded into the adsorption device in the later stage, the true effective component of the adsorbent will be reduced by 15%. Although the screened adsorbents are tested and the adsorption capacity of the adsorbents reaches 2.75 g / L, the performance is improved by 52% compared with that before the regeneration and recycling of the adsorbents.

[0050] Table 4 Comparison of adsorption performance before and after the regeneration and recycling of the adsorbent

[0051]

[0052] Therefore, contaminated adsorbents need to be regenerated with a professional regeneration solution. After regeneration, the adsorbents need to be screened by a suitable screening process to remove sediment, large particle impurities, and broken adsorbents, and then the normal and suitable adsorbents are recycled for use. Otherwise, it will greatly affect the industrial adsorption performance.

[0053] Example 5

[0054] In this example, a contaminated titanium-based adsorbent from a certain project, which is a spherical adsorbent with an outer diameter of about 0.5 cm, is used. Currently, the performance of the adsorbent has declined. The adsorption capacity of the tested adsorbent is 1.31 g / L, while that of the initial new adsorbent reaches 3.85 g / L. Moreover, the surface of the adsorbent is covered with sediment and shows a slightly yellow color. By testing, it is found that the surface of the adsorbent contains iron elements.

[0055] Load 100 L of contaminated lithium adsorbent into a resin column equipped with stirring, add a sodium chloride regeneration solution, adjust the pH of the regeneration solution to 2 by adding hydrochloric acid, with a chloride ion content of 100 g / L in the solution. Control the stirring speed at 300 r / min, stir for 25 min, and keep the temperature at 25 °C. Add ultrasonic waves during the stirring process, with an ultrasonic power of 500 W, to allow the lithium adsorbent to fully regenerate with the regeneration solution.

[0056] After regeneration, open the valve at the bottom of the resin tower, and let the lithium adsorbent flow into the multi-functional vibrating screen by gravity for screening. The sieve meshes of the multi-functional vibrating screen are divided into three layers: D1, D2, and D3. Among them, the mesh number of the D1 layer sieve is 5 meshes, the mesh number of the D2 layer sieve is 10 meshes, and the mesh number of the D3 layer sieve is 30 meshes. The intact adsorbent after regeneration is screened out by the D2 layer.

[0057] Collect the lithium adsorbent in the D2 layer, wash it with pure water, dry it with hot air at 50 °C, and then recycle it. By detecting the performance of the recycled adsorbent, the adsorption capacity reaches 3.55 g / L, which is 170% higher than that before regeneration; the desorption capacity of the detected adsorbent reaches 3.61 g / L, which is 173% higher than that before regeneration and recycling.

[0058] Table 5 Comparison of adsorption performance of adsorbent before and after regeneration and recycling

[0059]

[0060] Example 6

[0061] In this example, a contaminated manganese-based adsorbent, a granular adsorbent with an outer diameter of about 0.3 cm, is used. The performance of the adsorbent has decreased and there is a caking phenomenon. The adsorption capacity of the detected adsorbent is 2.31 g / L, while the initial new adsorbent has an adsorption capacity of 3.12 g / L.

[0062] Load 100 L of contaminated lithium adsorbent into a resin column with stirring, add sodium chloride regeneration solution, adjust the pH of the regeneration solution to 2 by adding hydrochloric acid, the chloride ion content in the solution is 100 g / L, control the stirring speed at 300 r / min, stir for 25 min, and the temperature is 25 °C. Add ultrasound during the stirring process, and the ultrasound power is 500 W, so that the lithium adsorbent can be fully regenerated with the regeneration solution.

[0063] After regeneration, open the valve at the bottom of the resin tower, and let the lithium adsorbent flow into the multi-functional vibrating screen by gravity for screening. The sieve meshes of the multi-functional vibrating screen are divided into three layers: D1, D2, and D3. Among them, the mesh number of the D1 layer sieve is 5 meshes, the mesh number of the D2 layer sieve is 10 meshes, and the mesh number of the D3 layer sieve is 30 meshes. The intact adsorbent after regeneration is screened out by the D2 layer.

[0064] Collect the lithium adsorbent in the D2 layer, wash it with pure water, dry it with hot air at 50 °C, and then recycle it. By detecting the performance of the recycled adsorbent, the adsorption capacity reaches 3.05 g / L, which is 32% higher than that before regeneration; the desorption capacity of the detected adsorbent reaches 3.01 g / L, which is 30% higher than that before regeneration and recycling.

[0065] Table 6 Comparison of adsorption performance of adsorbent before and after regeneration and recycling

[0066]

Claims

1. A method for regenerating and recycling an efficient lithium adsorbent, characterized in that, It includes the following steps: The lithium adsorbent material is regenerated and restored using the regeneration liquid, and then sent to a screening device for separation and recovery. The pollutants and crushed adsorbent are separated from the system along with the regeneration liquid to obtain the regenerated adsorbent, and the regenerated adsorbent is rinsed, dried and recovered.

2. The efficient lithium adsorbent regeneration and recovery method according to claim 1, wherein The lithium adsorbent material includes one or more of aluminum-based adsorbents, titanium-based adsorbents, and manganese-based adsorbents.

3. The method for efficient regeneration and recycling of lithium adsorbent according to claim 1, characterized in that, The lithium adsorbent material includes one or more of spherical adsorbents, hollow cylindrical adsorbents, and strip-shaped adsorbents.

4. The method for regenerating and recycling the high-efficiency lithium adsorbent according to claim 1, characterized in that, The regeneration liquid is a brine system. The pH of the brine system is 1 to 7. The anion of the brine system is chloride ion, and the anion content is 80 to 180 g / L. The cation of the brine system is one or more of sodium ion, magnesium ion, and potassium ion.

5. The method for efficient regeneration and recovery of lithium adsorbent according to claim 1, wherein The step of regenerating and restoring the lithium adsorbent material using the regeneration liquid includes: mixing and stirring the lithium adsorbent material and the regeneration liquid, with a stirring speed of 10 to 300 r / min, a stirring time of 5 to 120 min, and a stirring temperature of 15 to 45 °C.

6. The method for regenerating and recycling the high-efficiency lithium adsorbent according to claim 1, wherein During the mixing and stirring of the lithium adsorbent material and the regeneration liquid, ultrasonic treatment is carried out simultaneously, and the ultrasonic power is 100 to 800 W.

7. The high-efficiency lithium adsorbent regeneration and recovery method according to claim 1, characterized in that, The screening device is one or more of a vibrating screen, a circular vibrating screen, a rotary vibrating screen, and a shaking screen.

8. The method for regenerating and recycling the high-efficiency lithium adsorbent according to claim 1, wherein The screen of the screening device has three layers of D1, D2, and D3. The aperture of D1 is 4 to 6 meshes, the aperture of D2 is 8 to 12 meshes, and the aperture of D3 is 25 to 35 meshes.

9. The method for regenerating and recycling the high-efficiency lithium adsorbent according to claim 1, wherein The rinsing water is one or more of pure water, tap water, and industrial fresh water.

10. The high-efficiency lithium adsorbent regeneration and recovery method according to claim 1, wherein The drying is carried out by blowing hot air at 40 to 80 °C.

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