Preparation method of aluminum adsorbent particles for extracting liquid lithium resources
阅读说明：本技术 一种用于液体锂资源提取的铝系吸附剂颗粒制备方法 (Preparation method of aluminum adsorbent particles for extracting liquid lithium resources ) 是由 董明哲 李军 郭敏 刘忠 李�权 张慧芳 吴志坚 于 2020-11-25 设计创作，主要内容包括：一种针对盐湖原卤、老卤均适用提锂的铝系吸附剂颗粒制备方法。该吸附剂颗粒以吸水性聚合物为载体,高负载量添加铝系吸附剂如锂铝水滑石、镁铝水滑石、氢氧化铝等,并通过二次交联的方式制备获得,其制备工艺简单、适用于工业化生产。制得的铝系吸附剂颗粒具有高弹性、多孔、高吸水性、渗透性好等特点。树脂基体耐强酸强碱,基体表面多羟基结构能够有效吸附吸附剂颗粒,有效减少溶损率,可应用于盐湖原卤、老卤,海水及地下水资源中的锂元素提取,同时高强度的颗粒适用于工业化吸附柱工艺。(A preparation method of aluminum adsorbent particles suitable for extracting lithium from both original bittern and old bittern of salt lake. The adsorbent particles are prepared by taking water-absorbing polymers as carriers, adding aluminum adsorbents such as lithium-aluminum hydrotalcite, magnesium-aluminum hydrotalcite, aluminum hydroxide and the like with high loading capacity and performing secondary crosslinking, and the preparation process is simple and is suitable for industrial production. The prepared aluminum adsorbent particles have the characteristics of high elasticity, porosity, high water absorption, good permeability and the like. The resin matrix resists strong acid and strong alkali, the polyhydroxy structure on the surface of the matrix can effectively adsorb adsorbent particles, the dissolution loss rate is effectively reduced, the resin matrix can be applied to extraction of lithium elements in salt lake original brine, old brine, seawater and underground water resources, and meanwhile, the high-strength particles are suitable for an industrial adsorption column process.)
1. A preparation method of aluminum adsorbent particles for extracting liquid lithium resources is characterized by comprising the following steps:
adding the adsorption powder into the first polymer solution, and uniformly mixing to obtain a first mixture; immersing the first mixture into a first cross-linking agent aqueous solution for primary cross-linking to obtain a second mixture; in the primary crosslinking process, hydroxyl in the first polymer is crosslinked with boric acid in a first crosslinking agent; the carboxyl in the first polymer is crosslinked with the polyvalent metal ions in the first crosslinking agent; granulating and drying the second mixture to obtain dried granules, wherein the distance between polymer molecules is shortened in the drying process, and the free volume is reduced to carry out secondary crosslinking; immersing the dried particles into a second cross-linking agent for secondary cross-linking to obtain the aluminum adsorbent particles; in the secondary crosslinking process, the boric acid in a crosslinking state is hydrolyzed in the second crosslinking agent, the boric acid is dissolved again, and the hydroxyl in the crosslinking state is released; the polyvalent metal ions exist stably in the second cross-linking agent, and the second cross-linking agent and the hydroxyl and/or carboxyl in the first polymer are subjected to secondary cross-linking to form a stable cross-linked structure;
or the like, or, alternatively,
adding the adsorption powder into a mixed polymer solution consisting of a first polymer solution and a second polymer solution, and uniformly mixing to obtain a first mixture; immersing the first mixture into a first cross-linking agent aqueous solution for primary cross-linking to obtain a second mixture; in the primary crosslinking process, hydroxyl in the first polymer is crosslinked with boric acid in a first crosslinking agent; the carboxyl in the first polymer is crosslinked with the polyvalent metal ions in the first crosslinking agent; the carboxyl in the second polymer is crosslinked with the polyvalent metal ion in the first crosslinking agent; granulating and drying the second mixture to obtain dried granules, wherein the distance between polymer molecules is shortened in the drying process, and the free volume is reduced to carry out secondary crosslinking; immersing the dried particles into a second cross-linking agent for secondary cross-linking to obtain the aluminum adsorbent particles; in the secondary crosslinking process, the boric acid in a crosslinking state is hydrolyzed in the second crosslinking agent, the boric acid is dissolved again, and the hydroxyl in the crosslinking state is released; the polyvalent metal ions exist stably in the second cross-linking agent, and the second cross-linking agent and the hydroxyl and/or carboxyl in the mixed polymer are subjected to secondary cross-linking to form a stable cross-linked structure;
or the like, or, alternatively,
adding the adsorption powder into a mixed polymer solution consisting of a first polymer solution, a second polymer solution and a third polymer solution, and uniformly mixing to obtain a first mixture; immersing the first mixture into a first cross-linking agent aqueous solution for primary cross-linking to obtain a second mixture; in the primary crosslinking process, hydroxyl in the first polymer is crosslinked with boric acid in a first crosslinking agent; the carboxyl in the first polymer is crosslinked with the polyvalent metal ions in the first crosslinking agent; the carboxyl in the second polymer is crosslinked with the polyvalent metal ion in the first crosslinking agent; the carboxyl in the third polymer is crosslinked with the multivalent metal ion in the first crosslinking agent; granulating and drying the second mixture to obtain dried particles, and immersing the dried particles into a second cross-linking agent for secondary cross-linking to obtain the aluminum adsorbent particles; in the secondary crosslinking process, the boric acid in a crosslinking state is hydrolyzed in the second crosslinking agent, the boric acid is dissolved again, and the hydroxyl in the crosslinking state is released; the polyvalent metal ions exist stably in the second cross-linking agent, and the second cross-linking agent and the hydroxyl and/or carboxyl in the mixed polymer are subjected to secondary cross-linking to form a stable cross-linked structure;
the adsorbent powder is an aluminum adsorbent.
2. A preparation method of aluminum adsorbent particles for extracting liquid lithium resources is characterized by comprising the following steps:
step 1, adding adsorbent powder into a polymer mixed solution, and uniformly mixing to obtain a first mixture; the mass ratio of the adsorbent powder to the polymer mixed solution is 1 (2-20);
the adsorbent powder is an aluminum adsorbent with the particle size of 200-1500 meshes;
the polymer mixed solution comprises the following components in parts by mass: 50-90 parts of a first polymer solution, 0-40 parts of a second polymer solution and 0-10 parts of a third polymer solution;
the first polymer solution is 1-50 wt% aqueous solution of polyhydroxy and polycarboxyl-containing polymer, preferably 1-20 wt%;
the second polymer solution is 1-50 wt% of aqueous solution of long carbon chain-containing polymer, preferably 1-10 wt%, and the aqueous solution of the second polymer has high viscosity and more carboxyl, amino and other groups;
the third polymer solution is an aqueous solution containing 1-50 wt% of natural polysaccharide polymer, preferably 1-10 wt%; natural polysaccharide compounds for extracting autobotanic plants;
step 2, immersing the first mixture obtained in the step 1 into a first cross-linking agent aqueous solution for primary cross-linking, and obtaining a second mixture after cross-linking solidification;
the first cross-linking agent is a mixture of at least one of boric acid or borax and soluble multivalent metal salt; the soluble multivalent metal salt is at least one of soluble ferric salt, soluble aluminum salt, soluble calcium salt, soluble magnesium salt, soluble zinc salt, soluble strontium salt or soluble barium salt;
step 3, granulating the second mixture, and drying to obtain dried particles;
the temperature in the drying process is 30-100 ℃, and the time in the drying process is 12-24 hours;
step 4, immersing the dried particles into a second cross-linking agent for secondary cross-linking, wherein the time of the secondary cross-linking is 12-72 hours, and the temperature of the secondary cross-linking is 25-80 ℃; washing the solid particles obtained after secondary crosslinking to obtain the aluminum adsorbent particles for extracting the liquid lithium resource;
the second cross-linking agent is a mixture of epoxy compounds and an alkali solution, and the pH value is 8-14.
3. The method of claim 2, wherein the first polymer is one or more of polyvinyl alcohol, polyvinyl alcohol graft copolymer, polyacrylic acid, hyperbranched polyol, polyester polyol, and isocyanate.
4. The method of claim 2, wherein the second polymer is one or more of isobutylene-maleic anhydride copolymer, sodium polyacrylate, polyacrylamide-maleic anhydride copolymer, polyvinyl alcohol-maleic anhydride copolymer, polyvinylpyrrolidone, polyethylene glycol, and polyethylene oxide.
5. The method for preparing aluminum-based adsorbent particles according to claim 2, wherein the third polymer is one or more of chitosan, gelatin, pectin, carrageenan, sodium alginate, sodium carboxymethylcellulose, water-soluble cellulose, guar gum, and soluble starch.
6. The method for producing aluminum-based adsorbent particles according to claim 2, wherein in the step 2, the first mixture is uniformly mixed with the first crosslinking agent powder or the first crosslinking agent solution;
the first cross-linking agent powder is powder formed by uniformly mixing at least one of boric acid and borax with soluble multivalent metal salt, wherein the soluble multivalent metal salt is at least one of soluble ferric salt, soluble aluminum salt, soluble calcium salt, soluble magnesium salt, soluble zinc salt, soluble strontium salt or soluble barium salt;
the first cross-linking agent solution is a solution obtained by dissolving a mixture of at least one of boric acid or borax and soluble multivalent metal salt in water, and the soluble multivalent metal salt is at least one of soluble ferric salt, soluble aluminum salt, soluble calcium salt, soluble magnesium salt, soluble zinc salt, soluble strontium salt or soluble barium salt.
7. The method for preparing aluminum adsorbent particles according to claim 2, wherein in the step 3, an extrusion granulation mode is adopted in the granulation process, and the particle size is 2-5 mm.
8. The method for producing aluminum-based adsorbent particles according to claim 2, wherein the epoxy compound in the second crosslinking agent is one or more of propylene oxide, epichlorohydrin, bromohydrin, 1, 2-epoxybutane, epoxybutene, epoxypropanol, glycidyl methacrylate, ethylene oxide-PEG-ethylene oxide; the dosage of the epoxy compound is 1-15 ml per 30 g of the dried particles;
the alkali solution is one or two of calcium hydroxide solution, sodium hydroxide solution and lithium hydroxide solution; the dosage of the alkali solution is 20-100 times of the weight of the dried particles.
9. The method for preparing aluminum-based adsorbent particles according to claim 2, wherein the method for preparing the polymer mixed solution comprises the steps of:
step 1.1, dissolving the first polymer in water to obtain a first polymer solution, wherein the concentration of the first polymer solution is 1-50 wt%;
step 1.2, dissolving the second polymer in water to obtain a second polymer solution, wherein the concentration of the second polymer solution is 1-50 wt%;
step 1.3, dissolving the third polymer in water to obtain a third polymer solution, wherein the concentration of the third polymer solution is 1-50 wt%;
step 1.4, mixing the first polymer solution, the second polymer solution and the third polymer solution to obtain a polymer mixed solution;
the first polymer is one or more of polyvinyl alcohol, polyvinyl alcohol graft copolymer, polyacrylic acid, hyperbranched polyol, polyester polyol and isocyanate;
the second polymer is one or more of isobutylene-maleic anhydride copolymer, sodium polyacrylate, polyacrylamide-maleic anhydride copolymer, polyvinyl alcohol-maleic anhydride copolymer, polyvinylpyrrolidone, polyethylene glycol and polyethylene oxide;
the third polymer is one or more of chitosan, gelatin, pectin, carrageenan, sodium alginate, sodium carboxymethylcellulose, water-soluble cellulose, guar gum and soluble starch.
Preferably, the step 1.4 is carried out by mixing with a high-speed stirrer or a grinder.
10. The method of producing aluminum-based adsorbent particles according to claim 2, wherein the aluminum-based adsorbent is lithium aluminum hydrotalcite, magnesium aluminum hydrotalcite, or aluminum hydroxide.
Technical Field
The invention belongs to the technical field of chemical materials, and particularly relates to a preparation method of aluminum adsorbent particles for extracting liquid lithium resources.
Background
With the rapid development of industries such as lithium batteries, lithium alloys, lubricants and the like, the demand of the market for lithium is increasing day by day. Lithium resources in China are mostly stored in salt lakes, underground water and seawater, and the liquid lithium resources are low in content, coexist with a large amount of magnesium ions, calcium ions and the like, and can be utilized after enrichment and purification. At present, the technologies for extracting lithium from liquid lithium resources such as salt lakes mainly comprise a solvent extraction method, a precipitation method and an adsorption method. The precipitation method is only suitable for systems with high lithium content such as old brine, the precipitated lithium needs to be dissolved and purified for the second time, and the acid and alkali consumption is large. The solvent extraction method is simultaneously suitable for brine systems with various lithium contents, but the method has high requirements on corrosion resistance of equipment, the extraction and back-extraction process flow is complex, the used organic reagent can pollute the environment, the adsorption method is suitable for separating and extracting lithium from a low-grade system, and the method has the advantages of simple and convenient operation, short flow, good effect, high recovery rate and the like.
The inorganic ion adsorbent has high selectivity to lithium, and can adsorb lithium from low-grade original halogen or other resources. The inorganic ion adsorbent with large adsorption capacity comprises a manganese ion sieve type adsorbent, a titanium ion sieve adsorbent, a lithium-aluminum hydrotalcite adsorbent and a magnesium-aluminum hydrotalcite adsorbent. The hydrotalcite adsorbent has good selectivity, and fresh water can be directly used for desorption, so that industrialization is realized. However, the inorganic lithium adsorbent is usually in powder form, and cannot meet the operation of an industrial adsorption column, so that various ways are adopted to bond the adsorbent powder together to prepare granules, and the adsorption and desorption operations are performed after the granules are filled into the column.
Chinese patent CN 106902774 discloses a granulation method of an aluminum salt adsorbent for extracting lithium from salt lake brine, which is the aluminum salt adsorbent taking sodium alginate as a matrix, and the outer surface of the particle is wrapped by a shell made of polyethylene and polypropylene. The adsorbent particles prepared by the method have a porous structure and good water permeability, but the adsorbent particles using natural polysaccharides such as sodium alginate as carriers have low strength and are easy to break, and after multiple adsorption and desorption cycles, the cross-linking agent calcium ions are dissolved out, and the adsorbent particles can swell. Chinese patent CN 105664840 discloses that the adsorbent is prepared by taking silicon dioxide microspheres as a carrier, loading aluminum oxide on the surface of the carrier, and converting the carrier into an aluminum adsorbent in an alkaline leaching manner, and the adsorbent is simple in preparation process and free of environmental pollution; the Chinese patent CN 108607500 converts the magnesium aluminum gel loaded in the micropores of the porous ceramic plate into the aluminum adsorbent, so that the lithium adsorption amount of the aluminum salt is increased, the reaction efficiency is improved, and the activity of the adsorbent is ensured. The two adsorbent loading modes using the inorganic material as the carrier have porous structures, which are beneficial to adsorption and desorption, but the ceramic plate is used as the carrier, so that the loading capacity of the adsorbent is lower.
At present, most lithium salt adsorption plants generally select polymer materials such as polyvinyl chloride, polyvinylidene fluoride and the like as carrier materials, and granulate the materials by a certain method in an extrusion or tabletting mode. Due to poor water permeability of polymer base materials such as polyvinyl chloride and polyvinylidene fluoride, particles are tightly stacked by high pressure in the granulation and tabletting process, so that brine slowly permeates into the adsorbent particles in the adsorption process, and the adsorption capacity is reduced.
Therefore, the method for preparing the adsorbent which simultaneously meets the advantages of large loading capacity, porous structure, high strength, corrosion resistance, low dissolution loss rate and the like has wide application prospect.
The above prior art has the following disadvantages;
1. the adsorbent prepared by adopting sodium alginate for granulation has low strength, is easy to break and is slowly hydrolyzed and deteriorated, and the calcium ion serving as a cross-linking agent can swell after being dissolved out.
2. The loading capacity of the adsorbent is low;
3. the adsorbent particles prepared by granulating materials such as polyvinyl chloride or polyvinylidene fluoride have poor water permeability and slow adsorption process.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a preparation method of aluminum adsorbent particles suitable for extracting lithium from both salt lake raw bittern and old bittern. The adsorbent particles are prepared by taking water-absorbing polymers as carriers, adding aluminum adsorbents such as lithium-aluminum hydrotalcite, magnesium-aluminum hydrotalcite, aluminum hydroxide and the like with high loading capacity and performing secondary crosslinking, and the preparation process is simple and is suitable for industrial production. The prepared aluminum adsorbent particles have the characteristics of high elasticity, porosity, high water absorption, good permeability and the like. The resin matrix resists strong acid and strong alkali, the polyhydroxy structure on the surface of the matrix can effectively adsorb adsorbent particles, the dissolution loss rate is effectively reduced, the resin matrix can be applied to extraction of lithium elements in salt lake original brine, old brine, seawater and underground water resources, and meanwhile, the high-strength particles are suitable for an industrial adsorption column process.
The invention prepares the adsorbent particles with large loading capacity, porous structure, high strength, corrosion resistance and low dissolution loss rate by granulating the lithium-aluminum hydrotalcite, the magnesium-aluminum hydrotalcite and the like. Meanwhile, the water-absorbing polymer has a strong adsorption effect on inorganic adsorbent particles, and the adsorbent loss caused by water flow scouring is effectively reduced.
The invention is realized by the following technical scheme:
a preparation method of aluminum adsorbent particles for extracting liquid lithium resources comprises the following steps:
adding the adsorption powder into the first polymer solution, and uniformly mixing to obtain a first mixture; immersing the first mixture into a first cross-linking agent aqueous solution for primary cross-linking to obtain a second mixture; in the primary crosslinking process, hydroxyl in the first polymer is crosslinked with boric acid in a first crosslinking agent; the carboxyl in the first polymer is crosslinked with the polyvalent metal ions in the first crosslinking agent;
granulating and drying the second mixture to obtain dried granules, wherein the distance between polymer molecules is shortened in the drying process, and the free volume is reduced to carry out secondary crosslinking;
immersing the dried particles into a second cross-linking agent for secondary cross-linking to obtain the aluminum adsorbent particles; in the secondary crosslinking process, the boric acid in a crosslinking state is hydrolyzed in the second crosslinking agent, the boric acid is dissolved again, and the hydroxyl in the crosslinking state is released; the polyvalent metal ions exist stably in the second cross-linking agent, and the second cross-linking agent and the hydroxyl and/or carboxyl in the first polymer are subjected to secondary cross-linking to form a stable cross-linked structure;
or the like, or, alternatively,
adding the adsorption powder into a mixed polymer solution consisting of a first polymer solution and a second polymer solution, and uniformly mixing to obtain a first mixture; immersing the first mixture into a first cross-linking agent aqueous solution for primary cross-linking to obtain a second mixture; in the primary crosslinking process, hydroxyl in the first polymer is crosslinked with boric acid in a first crosslinking agent; the carboxyl in the first polymer is crosslinked with the polyvalent metal ions in the first crosslinking agent; the carboxyl in the second polymer is crosslinked with the polyvalent metal ion in the first crosslinking agent; granulating and drying the second mixture to obtain dried granules, wherein the distance between polymer molecules is shortened in the drying process, and the free volume is reduced to carry out secondary crosslinking; immersing the dried particles into a second cross-linking agent for secondary cross-linking to obtain the aluminum adsorbent particles; in the secondary crosslinking process, the boric acid in a crosslinking state is hydrolyzed in the second crosslinking agent, the boric acid is dissolved again, and the hydroxyl in the crosslinking state is released; the polyvalent metal ions exist stably in the second cross-linking agent, and the second cross-linking agent and the hydroxyl and/or carboxyl in the mixed polymer are subjected to secondary cross-linking to form a stable cross-linked structure;
or the like, or, alternatively,
adding the adsorption powder into a mixed polymer solution consisting of a first polymer solution, a second polymer solution and a third polymer solution, and uniformly mixing to obtain a first mixture; immersing the first mixture into a first cross-linking agent aqueous solution for primary cross-linking to obtain a second mixture; in the primary crosslinking process, hydroxyl in the first polymer is crosslinked with boric acid in a first crosslinking agent; the carboxyl in the first polymer is crosslinked with the polyvalent metal ions in the first crosslinking agent; the carboxyl in the second polymer is crosslinked with the polyvalent metal ion in the first crosslinking agent; the carboxyl in the third polymer is crosslinked with the multivalent metal ion in the first crosslinking agent; granulating and drying the second mixture to obtain dried particles, and immersing the dried particles into a second cross-linking agent for secondary cross-linking to obtain the aluminum adsorbent particles; in the secondary crosslinking process, the boric acid in a crosslinking state is hydrolyzed in the second crosslinking agent, the boric acid is dissolved again, and the hydroxyl in the crosslinking state is released; the polyvalent metal ions exist stably in the second cross-linking agent, and the second cross-linking agent and the hydroxyl and/or carboxyl in the mixed polymer are subjected to secondary cross-linking to form a stable cross-linked structure;
the adsorbent powder is an aluminum adsorbent.
A preparation method of aluminum adsorbent particles for extracting liquid lithium resources comprises the following steps:
step 1, adding adsorbent powder into a polymer mixed solution, and uniformly mixing to obtain a first mixture; the mass ratio of the adsorbent powder to the polymer mixed solution is 1 (2-20);
the adsorbent powder is an aluminum adsorbent with the particle size of 200-1500 meshes;
the polymer mixed solution comprises the following components in parts by mass: 50-90 parts of a first polymer solution, 0-40 parts of a second polymer solution and 0-10 parts of a third polymer solution;
the first polymer solution is 1-50 wt% aqueous solution of polyhydroxy and polycarboxyl-containing polymer, preferably 1-20 wt%;
the second polymer solution is 1-50 wt% of aqueous solution of long carbon chain-containing polymer, preferably 1-10 wt%, and the aqueous solution of the second polymer has high viscosity and more carboxyl, amino and other groups;
the third polymer solution is an aqueous solution containing 1-50 wt% of natural polysaccharide polymer, preferably 1-10 wt%; natural polysaccharide compounds for extracting autobotanic plants;
step 2, immersing the first mixture obtained in the step 1 into a first cross-linking agent aqueous solution for primary cross-linking, and obtaining a second mixture after cross-linking solidification;
the first cross-linking agent is a mixture of at least one of boric acid or borax and soluble multivalent metal salt; the soluble multivalent metal salt is at least one of soluble ferric salt, soluble aluminum salt, soluble calcium salt, soluble magnesium salt, soluble zinc salt, soluble strontium salt or soluble barium salt;
step 3, granulating the second mixture, and drying to obtain dried particles;
the temperature in the drying process is 30-100 ℃, and the time in the drying process is 12-24 hours;
step 4, immersing the dried particles into a second cross-linking agent for secondary cross-linking, wherein the time of the secondary cross-linking is 12-72 hours, and the temperature of the secondary cross-linking is 25-80 ℃; washing the solid particles obtained after secondary crosslinking to obtain the aluminum adsorbent particles for extracting the liquid lithium resource;
the second cross-linking agent is a mixture of epoxy compounds and an alkali solution, and the pH value is 8-14.
In the above technical scheme, the first polymer is one or more of polyvinyl alcohol, polyvinyl alcohol graft copolymer, polyacrylic acid, hyperbranched polyol, polyester polyol, and isocyanate.
In the above technical scheme, the second polymer is one or more of isobutylene-maleic anhydride copolymer, sodium polyacrylate, polyacrylamide-maleic anhydride copolymer, polyvinyl alcohol-maleic anhydride copolymer, polyvinylpyrrolidone, polyethylene glycol, and polyethylene oxide.
In the above technical scheme, the third polymer is one or more of chitosan, gelatin, pectin, carrageenan, sodium alginate, sodium carboxymethylcellulose, water-soluble cellulose, guar gum and soluble starch.
In the above technical solution, in the step 2, the first mixture and the first cross-linking agent powder or the first cross-linking agent solution are uniformly mixed;
the first cross-linking agent powder is powder formed by uniformly mixing at least one of boric acid and borax with soluble multivalent metal salt, wherein the soluble multivalent metal salt is at least one of soluble ferric salt, soluble aluminum salt, soluble calcium salt, soluble magnesium salt, soluble zinc salt, soluble strontium salt or soluble barium salt;
the first cross-linking agent solution is a solution obtained by dissolving a mixture of at least one of boric acid or borax and soluble multivalent metal salt in water, and the soluble multivalent metal salt is at least one of soluble ferric salt, soluble aluminum salt, soluble calcium salt, soluble magnesium salt, soluble zinc salt, soluble strontium salt or soluble barium salt.
In the above technical scheme, in the step 3, an extrusion granulation mode is adopted in the granulation process, and the particle size is 2-5 mm.
In the above technical scheme, the epoxy compound in the second crosslinking agent is one or more of propylene oxide, epichlorohydrin, epibromohydrin, 1, 2-epoxybutane, epoxybutene, epoxypropanol, glycidyl methacrylate, and ethylene oxide-PEG-ethylene oxide; the dosage of the epoxy compound is 1-15 ml per 30 g of the dried particles;
the alkali solution is one or two of calcium hydroxide solution, sodium hydroxide solution and lithium hydroxide solution; the dosage of the alkali solution is 20-100 times of the weight of the dried particles.
In the above technical solution, the preparation method of the polymer mixed solution comprises the following steps:
step 1.1, dissolving the first polymer in water to obtain a first polymer solution, wherein the concentration of the first polymer solution is 1-50 wt%;
step 1.2, dissolving the second polymer in water to obtain a second polymer solution, wherein the concentration of the second polymer solution is 1-50 wt%;
step 1.3, dissolving the third polymer in water to obtain a third polymer solution, wherein the concentration of the third polymer solution is 1-50 wt%;
step 1.4, mixing the first polymer solution, the second polymer solution and the third polymer solution to obtain a polymer mixed solution;
the first polymer is one or more of polyvinyl alcohol, polyvinyl alcohol graft copolymer, polyacrylic acid, hyperbranched polyol, polyester polyol and isocyanate;
the second polymer is one or more of isobutylene-maleic anhydride copolymer, sodium polyacrylate, polyacrylamide-maleic anhydride copolymer, polyvinyl alcohol-maleic anhydride copolymer, polyvinylpyrrolidone, polyethylene glycol and polyethylene oxide;
the third polymer is one or more of chitosan, gelatin, pectin, carrageenan, sodium alginate, sodium carboxymethylcellulose, water-soluble cellulose, guar gum and soluble starch.
The three polymers are first dissolved separately into solution and then mixed in certain proportion. Because the three types of polymers are different in dissolution, the direct mixing and dissolution can cause processing difficulty, and the uniformity of the molecular layer can not be achieved after mixing, thereby causing the quality reduction of the finally prepared adsorbent particles.
In the above technical scheme, the step 1.4 adopts a high-speed stirrer or a grinder to mix.
In the technical scheme, the aluminum adsorbent is lithium aluminum hydrotalcite, magnesium aluminum hydrotalcite or aluminum hydroxide.
The lithium aluminum hydrotalcite is:
LiCl.mAl(OH)3.nH2the molecular formula of the O lithium aluminum hydrotalcite is white powder, wherein the ratio of Li to Al is changed according to the ratio of materials during synthesis, and is usually 1: 1-1: 3.
The magnesium-aluminum hydrotalcite is as follows:
the molecular formula is that the cation is magnesium aluminum ion and the anion An-Can be CO3 2-、NO3 -、Cl-、OH-、SO4 2-、PO4 3-、C6H4May be used. The magnesium aluminum hydrotalcite species are most commonly magnesium aluminum carbonate type hydrotalcites.
The invention has the advantages and beneficial effects that:
the invention aims to provide an aluminum adsorbent granulation method for extracting lithium for both salt lake original brine and old brine. The invention prepares the particles with large loading capacity, porous structure, high strength, corrosion resistance and low dissolution loss rate by granulating the lithium-aluminum hydrotalcite, the magnesium-aluminum hydrotalcite and the like.
The first polymer is one or a mixture of more than two of polyvinyl alcohol, polyvinyl alcohol graft copolymer, polyacrylic acid, hyperbranched polyol, polyester polyol and isocyanate; the first polymer is a polymer containing polyhydroxy and polycarboxyl, the functions of the carboxyl and the hydroxyl (1) boric acid in the first cross-linking agent can be cross-linked with the hydroxyl, the carboxyl can be cross-linked with polyvalent metal ions, and viscous polymer liquid forms a solidified form after being cross-linked by the first cross-linking agent and can be granulated. (2) Hydroxyl and carboxyl can improve the adsorbent powder content (3) in the granule through hydrogen bond adsorbent powder and cross-link the shaping the second time, these carboxyl and hydroxyl structure can last to have an adsorption effect to the adsorbent powder, still have an adsorption effect to the adsorbent powder after adsorbing the desorption many times, therefore finished product polymer granule has longer life (4) first polymer has the long chain structure, the polymer long chain has better acid and alkali resistance, the stable performance, it is stable at secondary crosslinking or later stage acid desorption in-process adsorbent granule base member.
The second polymer is one or a mixture of more than two of isobutene-maleic anhydride copolymer, sodium polyacrylate, polyacrylamide-maleic anhydride copolymer, polyvinyl alcohol-maleic anhydride copolymer, polyvinylpyrrolidone, polyethylene glycol and polyethylene oxide; the second polymer is also a long carbon chain polymer, different from the first polymer, the aqueous solution of the second polymer has larger viscosity and more carboxyl, amino and other groups, the polymer functions (1) can assist the adsorption effect of the first polymer on the adsorbent powder, and if only the first polymer is used, powder particles such as Prussian blue and the like can fall off powder in the multiple adsorption and desorption processes. (2) The filling amount of the adsorbent powder can be increased (3), and after the first polymer and the second polymer are uniformly mixed, an inter-transmission network copolymer structure can be formed through first crosslinking and second crosslinking, the structure can increase the strength and toughness of a polymer material, and the strength of finished adsorbent particles is high.
The third polymer is one or a mixture of more than two of chitosan, gelatin, pectin, carrageenan, sodium alginate, sodium carboxymethylcellulose, water-soluble cellulose, guar gum and soluble starch. The third type of polymer is (1) natural polysaccharide polymer extracted from animal and plant species, the polymer can be cross-linked with the first type of polymer and the second type of polymer, and can also form an interpenetrating network structure with the first type of polymer and the second type of polymer, (2) the third type of polymer is generally soft, and the hardness and the water content of the adsorbent particles can be adjusted by adding the third type of polymer in a small amount in the system.
The primary crosslinking has the following characteristics: (1) boric acid is crosslinked with hydroxyl in the first polymer, carboxyl in the second polymer is crosslinked with polyvalent metal ions in the first crosslinking agent, so that viscous polymer solution is changed into a solidification form capable of being processed and granulated flexibly (2) in the first crosslinking process, the polymer matrix can almost completely adsorb the adsorbent powder into a solidification phase without loss, therefore, expensive adsorbent powder cannot be wasted (3) the crosslinking of boric acid in the first crosslinking is reversible, and the other main function is to play a temporary binding role on the polymer matrix, and the granulation can be processed after the first crosslinking.
The drying process after the first crosslinking is a key step, free water and most of bound water in the system can be removed in the process, the distance between polymer molecules is shortened, and the free volume is reduced, so that the second crosslinking is facilitated. If not dried, the second crosslinked particles are not strong enough to break or fail to crosslink.
The secondary crosslinking process has the following characteristics: (1) the boric acid crosslinking in the primary crosslinking is reversible, and under the action of an aqueous solution, boric acid crosslinking points in the primary crosslinking are slowly released again in the second crosslinking agent, and the second crosslinking agent is crosslinked with hydroxyl or carboxyl to form a stable crosslinking structure. (2) After the second crosslinking, the crosslinking structure of the boric acid crosslinking points in the adsorbent particles disappears, and the polyvalent metal ion crosslinking points still exist, so that the adsorbent particles form a double crosslinking structure of polyvalent metal ions and chemical crosslinking after the second crosslinking. In fact, there are a very large number of hydroxyl or carboxyl groups in the polymer, and boric acid does not react with all of the hydroxyl groups for the first crosslinking, and there are many hydroxyl groups. The polyvalent metal ion does not react with all of the carboxyl groups, and there are carboxyl groups remaining. Therefore, in the second crosslinking, the crosslinking agent is crosslinked with the hydroxyl group resolved by boric acid and also with other hydroxyl groups.
Meanwhile, the water-absorbing polymer (the first polymer, the second polymer and the third polymer are water-absorbing polymers) has a strong adsorption effect on the inorganic adsorbent particles, and the adsorbent loss and the dissolution loss caused by water flow scouring are effectively reduced. The method for preparing the efficient layered aluminum salt adsorbent specifically comprises the following steps: dissolving one or more water-absorbing polymers to obtain a mixed polymer solution, adding aluminum adsorbent powder into the mixed polymer solution, uniformly mixing at 20-80 ℃, adding a certain amount of first cross-linking agent into the slurry to prepare a granulation precursor, solidifying the mixed polymer solution by viscous liquid after contacting the first cross-linking agent solution, and performing granulation processing, wherein the other function of the first cross-linking is to control the structure and time of the second cross-linking. Then, after granulation by an extruder or a screw granulator, the granules are dried. And finally crosslinking and molding the dried particles in a second crosslinking agent to obtain finished particles. And (3) carrying out secondary crosslinking after drying the particles, and forming a stable curing structure after secondary crosslinking. Two-time crosslinking is a key step in being able to process shape and form high strength particles. The method disclosed by the invention has the advantages of simple preparation process, easiness in operation, low cost, easiness in industrialization and the like.
Drawings
Fig. 1 shows lithium aluminum hydrotalcite adsorbent particles prepared in example 1.
Fig. 2 is a cross-sectional SEM image of lithium aluminum hydrotalcite adsorbent particles prepared in example 1.
For a person skilled in the art, other relevant figures can be obtained from the above figures without inventive effort.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the present invention is further described below with reference to specific examples.
Example one
An aluminum-based adsorbent particle for liquid lithium resource extraction is carried out as follows:
step 1, drying the lithium aluminum hydrotalcite adsorbent at 80 ℃, and crushing the dried lithium aluminum hydrotalcite adsorbent to be 800-1000 meshes by a high-speed crusher to obtain aluminum adsorbent powder.
And step 2, dissolving polyvinyl alcohol with alcoholysis degree of 85% in water to prepare a 10 wt% polyvinyl alcohol aqueous solution.
And 3, taking the polyvinyl alcohol aqueous solution and the aluminum adsorbent powder according to the mass ratio of 5: 1 proportion, and uniformly mixing by using a three-roll grinder.
And 4, adding a certain amount of first cross-linking agent aqueous solution into the mixture obtained in the step 3, wherein the mass ratio of the mixture to the first cross-linking agent aqueous solution is 1: and 2, the first cross-linking agent aqueous solution is composed of 3 wt% of boric acid, 1 wt% of borax, 1 wt% of aluminum chloride and 1 wt% of calcium chloride, and is mechanically and fully stirred and kneaded to form a solidified cross-linked product.
And 5, extruding and granulating the solidified and crosslinked product obtained in the step 4 to obtain particles with the particle size of 3mm, and drying at the drying temperature of 50 ℃ for 8 hours to obtain dried particles.
And (3) immersing the dried particles obtained in the 6 th step and the 5 th step into a second cross-linking agent aqueous solution, and cross-linking for 24 hours at the cross-linking temperature of 45 ℃, wherein the second cross-linking agent aqueous solution comprises 0.1 wt% of LiOH, 0.15 wt% of NaOH and 1 wt% of epichlorohydrin.
And 7, washing the particles subjected to crosslinking in the step 6 with clear water to obtain the finished product of the aluminum adsorbent particles for extracting the liquid lithium resource. The finished product granule adsorbent has a content of 67% (calculated after deducting water), a water content of 45% and a Shore A hardness of 39.
FIG. 1 shows lithium aluminum hydrotalcite adsorbent particles prepared in example 1, which have high adsorbent content, high hardness, and good water permeability, and are suitable for industrial column packing operations.
FIG. 2 is a SEM image of the cross section of the lithium aluminum hydrotalcite adsorbent particles prepared in example 1, wherein (1) the morphology of the lithium aluminum hydrotalcite can be seen; (2) the figure shows that the lithium aluminum hydrotalcite is basically flaky, and the filamentous polymer has less polymer, which shows that the polymer has stronger binding power and large loading of the particle adsorbent; (3) a large number of hollow and porous structures can be seen in the figure, which also indicates that the prepared adsorption particles have good water permeability.
Example two
An aluminum-based adsorbent particle for liquid lithium resource extraction is carried out as follows:
step 1, drying a lithium aluminum hydrotalcite adsorbent at 80 ℃, and crushing the dried lithium aluminum hydrotalcite adsorbent to be 800-1000 meshes in particle size by a high-speed crusher to obtain aluminum adsorbent powder;
step 2, dissolving polyvinyl alcohol with alcoholysis degree of 85% in water to prepare 10 wt% solution
Step 3, polyacrylic acid with an average molecular weight of 125 ten thousand is dissolved in water to prepare a solution with a concentration of 2 wt%.
Step 4, mixing the polymer aqueous solutions prepared in the steps 2 and 3 according to the mass ratio of 10: 1 proportion, and uniformly mixing by using a high-viscosity stirring paddle to obtain a high-viscosity polymer mixed solution. The first type of polymer may be added in two, and the second type of polymer may be added in the absence of the third type of polymer.
And 5, adding the aluminum adsorbent powder obtained in the step 1 into the high-viscosity polymer mixed solution obtained in the step 4 according to the mass ratio of 1: 4, stirring or grinding until the mixture is uniformly mixed.
And 6, adding a certain amount of first cross-linking agent aqueous solution into the mixture obtained in the 5 step, wherein the mass ratio of the mixture to the first cross-linking agent aqueous solution is 1: and 3, the first cross-linking agent aqueous solution comprises 3 wt% of boric acid, 1 wt% of borax, 1 wt% of ferric chloride and 1 wt% of calcium chloride, and is mechanically and fully stirred and kneaded to form a solidified cross-linked product.
And 7, extruding and granulating the solidified and crosslinked product obtained in the step 6, wherein the particle size is 2mm, and drying at the drying temperature of 45 ℃ for 24 hours to obtain dried particles.
And (3) crosslinking the dried particles obtained in the 8 th step and the 7 th step in a second crosslinking agent aqueous solution for 24 hours at the crosslinking temperature of 42 ℃, wherein the second crosslinking agent aqueous solution is composed of 0.1 wt% of LiOH, 0.15 wt% of NaOH and 1 wt% of epichlorohydrin.
And 9, washing the particles subjected to crosslinking in the step 8 with clear water to obtain the finished product of the aluminum adsorbent particles for extracting the liquid lithium resource. The finished product granule adsorbent content is 77.8% (calculated after deducting water), the water content is 35%, and the Shore A hardness is 50.
EXAMPLE III
An aluminum-based adsorbent particle for liquid lithium resource extraction is carried out as follows:
step 1, drying a lithium aluminum hydrotalcite adsorbent at 80 ℃, and crushing the dried lithium aluminum hydrotalcite adsorbent to be 800-1000 meshes in particle size by a high-speed crusher to obtain aluminum adsorbent powder;
step 2, dissolving polyvinyl alcohol with alcoholysis degree of 85% in water to prepare 8 wt% solution
Step 3, sodium polyacrylate with average molecular weight of 125 ten thousand is dissolved in water to prepare solution with concentration of 2 wt%.
Step 4, dissolving sodium alginate in water to prepare 3 wt% solution
Step 5, mixing the polymer aqueous solutions prepared in the steps 2, 3 and 4 according to the mass ratio of 10: 1:1 proportion, and uniformly mixing by using a high-viscosity stirring paddle to obtain a high-viscosity polymer mixed solution.
And 6, adding the adsorbent powder obtained in the step 1 into the high-viscosity polymer mixed solution obtained in the step 5 according to the mass ratio of 1:3, stirring or grinding until the mixture is uniformly mixed.
And 7, adding a certain amount of first cross-linking agent aqueous solution into the mixture obtained in the step 6, wherein the mass ratio of the mixture to the first cross-linking agent aqueous solution is 1: and 2, the first cross-linking agent aqueous solution comprises 3% of boric acid, 0.5% of borax, 1% of aluminum chloride and 1% of zinc chloride, and is mechanically and fully stirred and kneaded to form a solidified cross-linking product.
And 8, extruding and granulating the crosslinked product obtained in the step 7, wherein the particle size is 2mm, and drying at the drying temperature of 45 ℃ for 24 hours to obtain dried particles.
And (3) soaking the dried particles obtained in the 9 th step and the 8 th step in a second cross-linking agent aqueous solution, and cross-linking for 24 hours at the cross-linking temperature of 42 ℃, wherein the second cross-linking agent aqueous solution comprises 0.2 wt% of LiOH, 0.05 wt% of NaOH and 1 wt% of epichlorohydrin.
And step 10, washing the particles subjected to crosslinking in the step 9 by using clear water to obtain finished water-absorbing high-strength particles, namely aluminum adsorbent particles for extracting liquid lithium resources, wherein the water content of the particles is 40%, the loading capacity is 77%, and the Shore A hardness is 40 (the water content is high, namely the particles are porous structures and can absorb water, the water permeability is high, and if the water absorption capacity of the adsorbent obtained by a polyvinyl chloride material granulation method is low).
Relational terms such as "first" and "second," and the like, may be used solely to distinguish one element from another element having the same name, without necessarily requiring or implying any actual such relationship or order between such elements.
The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.