Lithium adsorbent and preparation method therefor

Abstract

Disclosed in the present disclosure are a lithium adsorbent and a preparation method therefor. The lithium adsorbent has a porous structure, and includes an aluminum-based lithium adsorbent active material and a hydrophilic binder; and the lithium adsorbent has an average pore diameter ranging from 1 nm to 10 nm, a pore volume ranging from 0.65 ml/g to 0.8 ml/g, and a specific surface area ranging from 400 m.sup.2/g to 600 m.sup.2/g. The lithium adsorbent of the present disclosure has a specific average pore size ranging from 1 nm to 10 nm, lithium ions have a diameter of 0.3 nm, and the pore size of the lithium adsorbent of the present disclosure is three times or more greater than the diameter of the ions so that the lithium ions can quickly enter and exit pores. Therefore, the structure can ensure high adsorption efficiency and high desorption efficiency at a high flow rate, and allows desorption to be more concentrated than that of a general lithium adsorbent to reduce tailing, and can effectively improve the lithium production efficiency. Moreover, the product of the present disclosure has a pore size of less than 10 nm, allowing the lithium adsorbent to have a low dissolution loss rate and a long service life, and the lithium adsorbent of the present disclosure still has high adsorption efficiency and high desorption efficiency after 1000 cycles of adsorption and desorption.

Claims

1. A method for preparing a lithium adsorbent, comprising the steps of: uniformly mixing raw materials comprising a lithium compound, an aluminum compound, a pore-forming agent, a hydrophilic binder and water, and carrying out a reaction at a temperature ranging from 60? C. to 100? C. for 2 h to 4 h so that the lithium compound reacts with the aluminum compound to form an aluminum-based lithium adsorbent active material; wherein a ratio of a total weight of the lithium compound, the aluminum compound and the hydrophilic binder to a weight of the pore-forming agent is 100:(0.6 to 20); and curing the hydrophilic binder in the raw material mixture, and performing granulating and drying to obtain the lithium adsorbent.

2. The method of claim 1, wherein the aluminum compound is at least one of aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum carbonate, aluminum hydroxide, aluminum oxide and alumina sol.

3. The method of claim 1, wherein the lithium compound is at least one of lithium chloride, lithium carbonate and lithium hydroxide.

4. The method of claim 1, wherein the pore-forming agent is an organic pore-forming agent selected from at least one of polyvinylpyrrolidone, polyethylene glycol, a Span emulsifier and a Tween emulsifier.

5. The method of claim 1, wherein the raw materials further comprise a filler, wherein a ratio of the total weight of the lithium compound, the aluminum compound and the hydrophilic binder to a weight of the filler is 100:(0 to 20); and a ratio of a total weight of the lithium compound, the aluminum compound, the hydrophilic binder and the filler to the weight of the pore-forming agent is 100:(0.6 to 20).

6. The method of claim 5, wherein the filler is at least one of lithium ore, aluminum ore and a lithium adsorbent secondary recycling material; and the filler has a particle size of less than 0.15 mm.

7. The method of claim 1, wherein the hydrophilic binder is at least one of polyacrylamide, polyacrylate, dextran, agarose, polyvinyl alcohol and phenolic resin.

8. The method of claim 1, wherein the raw materials further comprise a curing agent, wherein the curing agent is selected from at least one of azobisisobutyronitrile, potassium persulfate, ammonium persulfate, sulfuric acid, hydrochloric acid, sodium hydroxide, a dialdehyde compound and epichlorohydrin.

9. The method of claim 8, wherein the dialdehyde compound comprises at least one of glyoxal, malondialdehyde, succinaldehyde, glutaraldehyde and adipaldehyde.

10. The method of claim 1, wherein a molar ratio of the lithium compound to the aluminum compound is 1:(2 to 6).

11. The method of claim 1, wherein a ratio of a total weight of the lithium compound and the aluminum compound to a weight of the hydrophilic binder is 100:(5 to 25).

12. The method of claim 1, wherein a ratio of a total weight of the lithium compound and the aluminum compound to a weight of the water in the raw materials is 1:(1 to 2.5).

13. The method of claim 1, wherein the drying is performed at a temperature ranging from 80? C. to 150? C.

Description

DETAILED DESCRIPTION

(1) The following examples are provided for a better further understanding of the present disclosure, are not limited to the best embodiments, and do not limit the contents and scope of protection of the present disclosure. Any product identical to or similar to the present disclosure obtained by anyone under the inspiration of the present disclosure or by combining the present disclosure with other features in the prior art falls within the scope of protection of the present disclosure.

(2) Specific experimental steps or conditions are not specified in the examples, they can be performed according to the operations or conditions of conventional experimental steps described in the literature in the field. The used reagents or instruments of which a manufacturer is not indicated are conventional commercially available reagent products.

Example 1

(3) In a 1000 L reactor, 500 kg of water, 260 kg of aluminum chloride hexahydrate, 17.5 kg of lithium carbonate, 40.5 kg of PVP K30, 100 kg of sodium hydroxide, 62 kg of acrylamide, and 7 kg of N,N-methylenebisacrylamide were added, and a reaction was carried out under stirring under normal pressure at 60? C. for 2 h. The above slurry was transferred to a 2000 L double-cone dryer, and 0.2 kg of potassium persulfate was added, stirring was started for uniform mixing, heating was performed to 60? C., a reaction was carried out for 2 h, then a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a tunnel-type hot air circulating tunnel electric heating apparatus to be dried at 90? C. to a water content of less than 5% (w/w) to obtain a finished product.

Example 2

(4) In a 1000 L reactor, 500 kg of water, 400 kg of aluminum nitrate nonahydrate, and 8.75 kg of lithium carbonate were added, hydrochloric acid was added for neutralizing to pH=6, 15 kg of span 65, and 40 kg of polyvinyl alcohol 0599 were added, and the mixture was stirred at 80? C. for 2 h. The above slurry was transferred to a 2000 L kneader, and 5 kg of borax was added, stirring was started for uniform mixing, heating was performed to 70? C., a reaction was carried out under normal pressure for 2 h, a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a double-cone dryer to be dried at 80? C. to a water content of less than 5% (w/w) to obtain a finished product.

Example 3

(5) In a 1000 L reactor, 500 kg of water, 200 kg of aluminum hydroxide, 25 kg of lithium chloride, 5 kg of Span 60, 0.625 kg of Tween 80, 17 kg of sodium hydroxide, 40 kg of acrylamide 1799, and 7 kg of N,N-methylenebisacrylamide were added and stirred under normal pressure at 60? C. for 2 h. The above slurry was transferred to a 2000 L kneader, and 0.2 kg of ammonium persulfate was added, stirring was started for uniform mixing, heating was performed to 70? C., a reaction was carried out for 2 h, a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a double-cone dryer to be dried at 130? C. to a water content of less than 5% (w/w) to obtain a finished product.

Example 4

(6) In a 1000 L reactor, 500 kg of water, 400 kg of industrial grade acidic alumina sol (having an aluminum content of 11.1%), 25 kg of lithium chloride, 20 kg of PEG 20000, 40 kg of methyl acrylate, and 5 kg of TAIC were added, and stirred at 70? C. under normal pressure for 2 h. The above slurry was transferred to a 2000 L kneader, 0.1 kg of azobisisobutyronitrile was added, stirring was started for uniform mixing, heating was performed to 70? C., heat preservation was performed for 2 h, cooling was performed, a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a tunnel-type hot air circulating tunnel electric heating apparatus to be dried at 90? C. to a water content of less than 5% (w/w) to obtain a finished product.

Example 5

(7) In a 1000 L reactor, 500 kg of water, 260 kg of aluminium chloride hexahydrate, 7.52 kg of lithium hydroxide, 30 kg of PVP K30, 20 kg of aluminium ore ground to be 100-mesh (less than 0.15 mm) (purchased from Yunnan Wenshan Aluminum Industry, and having an Al.sub.2O.sub.3 content of 58.27%), 100 kg of sodium hydroxide, and 40 kg of phenol were added, and stirred at 80? C. under normal pressure for 2 h. The above slurry was transferred to a 2000 L double-cone dryer, and 20 kg of formaldehyde was added, stirring was started for uniform mixing, heating was performed to 80? C., a reaction was carried out for 2 h, a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a tunnel-type hot air circulating tunnel electric heating apparatus to be dried at 150? C. to a water content of less than 5% (w/w) to obtain a finished product.

Example 6

(8) In a 1000 L reactor, 500 kg of water, 260 kg of aluminum chloride hexahydrate, 20 kg of lithium hydroxide, 35 kg of PVP K30, 25 kg of lithium ore ground to be 100-mesh (less than 0.15 mm) (purchased from Nanning Biaohong Trade Co., Ltd, and having a Li.sub.2O content of 0.26%), 31 kg of the finished product in Example 1 which was ground to be 100-mesh (less than 0.15 mm), 100 kg of sodium hydroxide, and 40 kg of dextran 2 w were added, and stirred at 90? C. under normal pressure for 1 h, cooling was performed, 7 kg of epichlorohydrin was added, a material was transferred to a kneader to be mixed, heating was performed to 70? C., a reaction was carried out for 0.5 h to be gelatinous, the gelatinous material was transferred to a screw extrusion granulator to produce a suitable particle size, and the cut intermediate was transferred to a tunnel-type hot air circulating tunnel electric heating apparatus to be dried at 90? C. for 6 h to obtain a finished product.

Example 7

(9) In a 1000 L reactor, 500 kg of water, 400 kg of industrial grade acidic alumina sol (having an aluminum content of 11.1%), 25 kg of lithium chloride, 20 kg of PEG20000, and 40 kg of agarose were added, and a reaction was carried out under stirring at 90? C. under normal pressure for 2 h. The above slurry was transferred to a 2000 L kneader, stirring was started for uniform mixing, cooling was performed, and a material was discharged, and transferred to a counter-roll granulator to be cut to a suitable particle size to obtain a finished product.

Comparative Example 1

(10) In a 1000 L reactor, 500 kg of water, 200 kg of aluminum hydroxide, 25 kg of lithium chloride, 17 kg of sodium hydroxide, and 40 kg of polyvinyl alcohol 2399 were added, and stirred at 90? C. under normal pressure for 2 h. The above slurry was transferred to a 2000 L kneader, and 20 kg of adipaldehyde was added, stirring was started for uniform mixing, heating was performed to 70? C., a reaction was carried out for 2 h, a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a double-cone dryer to be dried at 130? C. to a water content of less than 5% (w/w) to obtain a finished product.

Comparative Example 2

(11) In a 1000 L reactor, 500 kg of water, 260 kg of aluminum chloride hexahydrate, 17.5 kg of lithium carbonate, 1 kg of PVP K30, 100 kg of sodium hydroxide, 62 kg of acrylamide, and 7 kg of N,N-methylenebisacrylamide were added, and stirred at 60? C. under normal pressure for 2 h. The above slurry was transferred to a 2000 L double-cone dryer, and 0.2 kg of potassium persulfate was added, stirring was started for uniform mixing, heating was performed to 60? C., a reaction was carried out for 2 h, then a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a tunnel-type hot air circulating tunnel electric heating apparatus to be dried at 90? C. to a water content of less than 5% (w/w) to obtain a finished product.

Comparative Example 3

(12) In a 1000 L reactor, 500 kg of water, 260 kg of aluminum chloride hexahydrate, 17.5 kg of lithium carbonate, 100 kg of PVP K30, 100 kg of sodium hydroxide, 62 kg of acrylamide, and 7 kg of N,N-methylenebisacrylamide were added, and stirred at 60? C. under normal pressure for 2 h. The above slurry was transferred to a 2000 L double-cone dryer, and 0.2 kg of potassium persulfate was added, stirring was started for uniform mixing, heating was performed to 60? C., a reaction was carried out for 2 h, then a material was discharged, and transferred to a counter-roll granulator to be cut to a size ranging from 0.8 mm to 2.0 mm, and the cut intermediate was transferred to a tunnel-type hot air circulating tunnel electric heating device apparatus to be dried at 90? C. to a water content of less than 5% (w/w) to obtain a finished product.

Comparative Example 4

(13) A JW-LAHS adsorbent purchased from Jiangsu Jiuwu Hi-Tech Co., Ltd. was used as Comparative example 4.

(14) Pore size data detected by using a JW-BK300 specific surface area and pore size analyzer are as follows:

(15) TABLE-US-00001 Average Specific pore Pore surface diameter volume area Sample (nm) (ml/g) (m.sup.2/g) Example 2.28 0.68 515 1 Example 5.67 0.71 456 2 Example 6.74 0.68 426 3 Example 9.62 0.75 408 4 Example 1.44 0.79 523 5 Example 10.41 0.81 556 6 Example 4.15 0.70 466 7 Comparative 0.03 0.95 598 example 1 Comparative 0.56 0.66 530 example 2 Comparative 5.23 0.77 498 example 3 Comparative 0.6 0.84 566 example 4

(16) Dissolution Loss Rate Evaluation:

(17) 1000 ml of the finished product in each example was measured by using a measuring cylinder, and loaded into an ion exchange column with an inner diameter of 70 mm and a length of 500 mm, 10 bv (1 bv is 1000 ml) of a Qarhan salt lake brine (containing 972 mg/L of K.sup.+, 2021 mg/L of Na.sup.+, 68 mg/L of Ca.sup.2+, 116285 mg/L of Mg.sup.2+, 309 mg/L of B, 56 mg/L of Li.sup.+, 296732 mg/L of Cl.sup.?, 13911 mg/L of SO.sub.4.sup.2?, and 10 mg/L of Si, and having a pH of 4.95) was allowed to pass through the column, and then 10 bv of deionized water was allowed to pass through the column, which was 1 cycle, 1000 cycles in total, and then the volume of the finished product in each example was measured again by using a measuring cylinder.
Dissolution loss rate (%)=(the volume of the finished product after 1-1000 cycles (ml)/1000)*100

(18) TABLE-US-00002 Dissolution loss Sample rate (%) Example 1 0.1 Example 2 0.5 Example 3 0.6 Example 4 0.7 Example 5 0.9 Example 6 0.3 Example 7 1.5 Comparative example 1 0.5 Comparative example 2 0.2 Comparative example 3 10.1

(19) Application Evaluation:

(20) 1000 ml of the finished product in each of the examples and Comparative examples and the sample in each of Example 1, Example 2, and Comparative example 3 after 1000 cycles obtained in the dissolution loss rate evaluation were loaded into an ion exchange column, a Qarhan salt lake brine having a lithium content of 56 ppm (containing 972 mg/L of K.sup.+, 2021 mg/L of Na.sup.+, 68 mg/L of Ca.sup.2+, 116285 mg/L of Mg.sup.2+, 309 mg/L of B, 56 mg/L of Li.sup.+, 296732 mg/L of Cl.sup.?, 13911 mg/L of SO.sub.4.sup.2?, and 10 mg/L of Si, and having a pH of 4.95) was allowed to pass through the column at a rate of 20 bv/h (1 bv is 1000 ml), 40 bv of the brine was adsorbed, and a mixed liquid of adsorption tail liquid was collected every 10 bv to detect the lithium content. After the adsorption was completed, 5 bv of the brine was desorbed with deionized water at a flow rate of 20 bv/h, and a desorption mixed liquid was collected every 1 bv for detection. The detection results and the total adsorption amount and the total desorption amount calculated according to a formula (1) and a formula (2) are as follows:
Total adsorption amount=56*40?10*(Li.sup.+content.sub.0-10 bv+Li.sup.+content.sub.10-20 bv+Li.sup.+content.sub.20-30 bv+Li.sup.+content.sub.30-40 bv)(1)
Total desorption amount=1*(Li.sup.+content.sub.1 bv+Li.sup.+content.sub.2 bv+Li.sup.+content.sub.3 bv+Li.sup.+content.sub.4 bv+Li.sup.+content.sub.5 bv)(2)

(21) The detection results are as follows:

(22) TABLE-US-00003 Content of lithium ions in Total Total adsorption tail liquid mg/L adsorption Content of lithium ions in desorption Sample 0-10b 10-20 20-30 30-40 amount desorption liquid mg/L amount name v bv bv bv mg/L 1bv 2bv 3bv 4bv 5bv mg/L Example 0 8 19 28 1690 214 241 164 164 140 923 1 Example 1 4 18 21 1800 222 236 188 176 155 977 2 Example 0 10 20 32 1620 261 244 233 188 166 1092 3 Example 0 12 22 34 1560 255 264 251 200 177 1147 4 Example 2 10 19 33 1600 211 233 177 166 144 931 5 Example 0 9 22 35 1580 200 255 211 188 155 1009 6 Example 2 11 23 37 1510 212 233 188 177 141 951 7 Comparative 12 26 33 38 1150 95 108 82 82 70 437 example 1 Comparative 10 22 28 35 1290 99 152 102 99 84 536 example 2 Comparative 2 13 24 30 1550 188 212 155 133 98 776 example 3 Comparative 0 9 25 40 1500 150 178 166 123 99 716 example 4 Example 0 10 22 29 1630 210 234 168 160 143 915 1 (after 1000 cycles) Example 1 3 19 22 1790 232 225 178 169 149 953 2 (after 1000 cycles) Comparative 5 22 28 33 1360 166 165 135 112 105 683 example 3 (after 1000 cycles)

(23) Through application experiments, it can be found that the lithium adsorbent of the present disclosure has a larger adsorption amount and a larger desorption amount at a high flow rate compared with Comparative examples, a desorption peak is twice that without the addition of the pore-forming agent, and the desorption is more concentrated, and the tailing phenomenon is reduced. Compared with the commercially available sample in Comparative example 4, the lithium adsorbent of the present disclosure has the advantages that the desorption peak is higher and the desorption amount is also larger, which has a significant advantage. As can be seen from the adsorption and desorption data of Example 1, Example 2 and Comparative example 3 after 1000 cycles of use, the samples prepared according to the solution of the present disclosure have a long service life and an attenuation of less than 5% after 1000 cycles of adsorption and desorption.

(24) Obviously, the above examples are merely instances for clarity of illustration and are not intended to limit the embodiments. Other variations or changes in different forms may be made on the basis of the above description for those of ordinary skill in the art. There is no need and cannot be an exhaustive list of all embodiments here. The obvious variations or changes derived therefrom are still within the scope of protection of the present disclosure.