Preparation method and application of potassium adsorption material and selective extraction method of potassium in mixed alkali metal salt

Abstract

The invention provides a preparation method and application of a potassium adsorption material and a selective extraction method of potassium in mixed alkali metal salt. The method comprises the following steps: firstly, preparing adsorbent slurry, immersing a porous metal material into the slurry, and carrying out ultrasonic treatment, maintenance, drying and activation to obtain a potassium adsorption material which can selectively extract potassium ions in mixed alkali metal salt; the selective extraction method of potassium in mixed alkali metal salt comprises the following steps: adding a potassium adsorption material into alkali metal salt in a molten state to selectively fix potassium ions to the potassium adsorption material, then adding a first extraction agent, converting insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and filtering to obtain a first filtrate; adding a second extracting agent into the first filtrate, filtering to obtain a second filtrate, and performing evaporative crystallization on the second filtrate to obtain a potassium salt product; the problems that an existing industrial mixed salt separation process is tedious, high in cost, low in resource recovery efficiency, free of selectivity and pertinence and the like are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of extraction and recovery of potassium ions in mixed salts, and particularly relates to a preparation method and application of a potassium adsorption material, and a method for selectively extracting potassium in mixed alkali metal salts. Background Art

[0002] In industrial production such as chemical industry, pharmaceuticals, and pesticides, a large amount of industrial waste salts mixed with various salts are generated. With the rapid development of industrialization and urbanization, the amount of waste salts generated is increasing continuously. Therefore, the reasonable disposal of waste salts has also become an urgent problem to be solved. For the resource utilization of waste salts, after removing the organic matter at high temperature, the key task is to resourcefully dispose of the remaining mixed salts. Common treatment processes include salt separation and quality improvement, evaporation crystallization, etc.

[0003] The prior art discloses a waste salt resource utilization process, which uses concentrated sulfuric acid to remove organic matter, separate and resourcefully utilize chloride ions, then uses alkali precipitation to remove impurity cations, reacts calcium bicarbonate with sodium sulfate to generate calcium sulfate and sodium bicarbonate, and finally uses a freeze crystallization and reverse osmosis membrane circulation system to precipitate sodium bicarbonate, so that sodium ions, chloride ions and sulfate ions in the waste salt are all resourcefully utilized; the prior art discloses a new process for resource recovery of salts in high-salt wastewater, which realizes the near-zero discharge of high-salt wastewater and the effective recovery and utilization of salts.

[0004] However, the salt separation and crystallization process mentioned in the above methods has cumbersome operation steps and high costs, and it is difficult to be generally applied. Moreover, the prior art separates and recovers all the main components in the mixed salts, and does not selectively and specifically extract and recover valuable resources (such as potassium salts) in the mixed salts, which may cause unnecessary energy waste and is a defect that needs to be remedied. If the potassium in the mixed salts can be selectively extracted, it is expected to achieve the efficient resource recovery of potassium-containing waste salts.

[0005] In addition, most potassium salts are derived from the mining of water-insoluble potassium ores. However, this method has limitations such as uneven distribution of potassium ores, low potassium grade, and high mining costs. Therefore, industrial mixed (alkali metal) waste salts can also be used as another source of potassium salt resources.

[0006] In summary, it is necessary to develop a method for selectively extracting potassium in mixed alkali metal salts to solve the above problems and achieve the efficient resource recovery of mixed salts. Summary of the Invention

[0007] In view of this, the present invention provides a preparation method and application of a potassium adsorption material, and a method for selectively extracting potassium in mixed alkali metal salts, so as to solve the problems of cumbersome process steps and high costs of the existing industrial mixed salt separation process, as well as low resource recovery efficiency, lack of selectivity and specificity.

[0008] To achieve the above object, the present invention is implemented by the following technical solutions:

[0009] In a first aspect, the present invention provides a preparation method of a potassium adsorption material, comprising the following steps:

[0010] Mix the potassium adsorbent with the activator solution to obtain an adsorbent slurry;

[0011] Immerse the porous metal material in the adsorbent slurry and perform ultrasonic oscillation. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry;

[0012] Dry the cured porous metal material to obtain a porous adsorbent;

[0013] Heat the porous adsorbent to a certain temperature and keep it warm, and at the same time introduce a purge gas to obtain a potassium adsorption material.

[0014] Preferably, the activator solution includes at least one of a salt solution, an acid solution, and an alkali solution;

[0015] The salt in the salt solution includes at least one of ZnCl2, Na2CO3, and K2CO3;

[0016] The acid solution includes at least one of HNO3, H2SO4, and H3PO4;

[0017] The alkali solution includes at least one of NaOH and KOH;

[0018] And / or, the mass ratio of the activator solution to the potassium adsorbent is (0.4 - 1):1, and the concentration of the activator solution is 1 - 10 mol / L.

[0019] Preferably, the ultrasonic frequency during ultrasonic oscillation is 20 - 80 kHz and the ultrasonic oscillation time ≥ 0.5 h;

[0020] And / or, the curing temperature during curing is 20 - 50 °C and the curing time ≥ 2 h;

[0021] And / or, dry the cured porous metal material, and the drying temperature is 20 - 105 °C;

[0022] And / or, heat the porous adsorbent to 400 - 900 °C and keep it warm for 0.5 - 5 h, and at the same time introduce a purge gas; the purge gas includes at least one of water vapor and carbon dioxide.

[0023] Preferably, the pore diameter of the porous metal material is 2 μm - 3 mm;

[0024] The potassium adsorbent includes at least one of Si / Al composite oxides, salts containing Si / Al acid radicals, molecular sieves, fly ash, and bottom slag from waste incineration.

[0025] In a second aspect, the present invention also provides an application of the potassium adsorption material prepared by the described preparation method in extracting potassium from a mixed alkali metal salt.

[0026] In a third aspect, the present invention also provides a method for selectively extracting potassium from a mixed alkali metal salt, comprising the following steps:

[0027] Heating the alkali metal salt containing potassium ions to a molten state;

[0028] Adding the potassium adsorption material prepared by the described preparation method to the molten alkali metal salt and heating for reaction to selectively fix the potassium ions in the alkali metal salt to the potassium adsorption material.

[0029] Preferably, the cations contained in the alkali metal salt include K + and Li + , Na + and at least one of them;

[0030] The anions contained in the alkali metal salt include Cl - , CO3 2- , SO4 2- , OH - and at least one of them;

[0031] And / or, the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is (2 - 20):1;

[0032] And / or, the heating reaction temperature is 400 - 1000 °C and the time is 1 - 300 min.

[0033] Preferably, it further includes: adding a first extractant to the potassium adsorption material fixed with potassium ions, reacting to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and filtering to obtain a first filtrate;

[0034] Adding a second extractant to the first filtrate to adjust the pH of the first filtrate to 6 - 9, filtering to obtain a second filtrate, and subjecting the second filtrate to evaporation crystallization to obtain a potassium salt product.

[0035] Preferably, in the step of adding a first extractant to the potassium adsorption material fixed with potassium ions and reacting, the mass ratio of the first extractant to the potassium adsorption material fixed with potassium ions is (2 - 5):1;

[0036] The first extractant includes a sub-molten salt, or a mixture of an acid solution and an auxiliary agent;

[0037] The solute in the sub-molten salt includes at least one of NaOH, Na2CO3, KOH, K2CO3, CaO, and Ca(OH)2;

[0038] The mass fraction of the solute in the sub-molten salt is 50-70%;

[0039] The acid solution includes at least one of H2SO4, HNO3, HCl, and H3PO4;

[0040] The auxiliary agent includes at least one of HF, CaF2, and phosphate rock;

[0041] When the first extractant is the sub-molten salt, the heating reaction temperature is 160-280 °C and the time is 2-6 h;

[0042] When the first extractant is a mixture of the acid solution and the auxiliary agent, the heating reaction temperature is 80-160 °C and the time is 2-6 h.

[0043] Preferably, the second extractant is CO2 or calcium hydroxide;

[0044] Add the first extractant to the potassium adsorption material fixed with potassium ions, and react to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, filter to obtain the first filtrate while collecting the potassium adsorption material, wash the potassium adsorption material and strip the adsorption product on the potassium adsorption material, and recycle to obtain the porous metal material;

[0045] According to the described method, use the recycled porous metal material to prepare the potassium adsorption material, and use the potassium adsorption material to selectively extract potassium ions from the mixed alkali metal salt again to realize the recycling of the porous metal material.

[0046] The preparation method and application of the potassium adsorption material of the present invention, and the method for selectively extracting potassium in the mixed alkali metal salt have the following beneficial effects compared with the prior art:

[0047] 1. In the preparation method of the potassium adsorption material of the present invention, the porous metal material is used as the carrier of the potassium adsorbent; mix the potassium adsorbent with the activator solution to form an adsorbent slurry; immerse the porous metal material into the adsorbent slurry; use ultrasonic oscillation during the immersion process for a certain period of time; continue to cure at a certain temperature for a certain period of time to make the adsorbent slurry fully loaded on the porous metal material; dry the adsorbent slurry loaded on the porous metal material into a solid to form a porous adsorbent as a whole; heat the porous adsorbent to a certain temperature and keep it warm for a certain period of time, and purge gas to further activate the material to prepare the potassium adsorption material; the potassium adsorption material prepared by the present invention can selectively extract potassium ions from the mixed alkali metal salt;

[0048] 2. Selective extraction method of potassium in the mixed alkali metal salt of the present invention: Heat the alkali metal salt containing potassium ions to a molten state; add the potassium adsorption material to the molten alkali metal salt and heat and react to selectively fix the potassium ions in the alkali metal salt to the potassium adsorption material; add a first extractant to the potassium adsorption material fixed with potassium ions and react to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and then filter to obtain a first filtrate; add a second extractant to the first filtrate to adjust the pH of the first filtrate to 6-9, filter to obtain a second filtrate, and evaporate and crystallize the second filtrate to obtain a potassium salt product. The selective extraction method of potassium in the mixed alkali metal salt of the present invention can specifically extract potassium ions in the mixed alkali metal salt, and can achieve efficient resource recovery of potassium waste salts; it solves the problems of cumbersome salt separation processes, high costs, low resource recovery efficiency, lack of selectivity and pertinence in the existing industrial mixed salt processes. Detailed Embodiments

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0050] It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". The various embodiments of the present invention may exist in a range form; it should be understood that the description in a range form is only for convenience and brevity, and should not be construed as a hard limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the counted range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0051] The embodiments of the present application provide a preparation method of a potassium adsorption material, including the following steps:

[0052] S1. Mix the potassium adsorbent with the activator solution to obtain an adsorbent slurry;

[0053] S2. Immerse the porous metal material in the adsorbent slurry and perform ultrasonic oscillation. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry;

[0054] S3. Dry the cured porous metal material to obtain a porous adsorbent;

[0055] S4. Heat the porous adsorbent to a certain temperature and keep it warm, while introducing a purging gas to obtain a potassium adsorbent material.

[0056] The preparation method of the potassium adsorbent material of the present invention uses a porous metal material as the carrier of the potassium adsorbent; mix the potassium adsorbent with an activator solution to form an adsorbent slurry; immerse the porous metal material in the adsorbent slurry; use ultrasonic oscillation during the immersion process for a certain period of time; continue to cure at a certain temperature for a certain period of time to fully load the adsorbent slurry on the porous metal material; dry the adsorbent slurry loaded on the porous metal material into a solid to form a porous adsorbent as a whole; heat the porous adsorbent to a certain temperature and keep it warm for a certain period of time, and purge the gas to further activate the material to prepare a potassium adsorbent material; the potassium adsorbent material prepared by the present invention can selectively extract potassium ions from mixed alkali metal salts.

[0057] In some embodiments, the activator solution includes at least one of a salt solution, an acid solution, and an alkali solution;

[0058] The salt in the salt solution includes at least one of ZnCl2, Na2CO3, and K2CO3;

[0059] The acid solution includes at least one of HNO3, H2SO4, and H3PO4;

[0060] The alkali solution includes at least one of NaOH and KOH.

[0061] In some embodiments, the mass ratio of the activator solution to the potassium adsorbent is (0.4 - 1):1, the solvent used for the activator solution is water, and the concentration of the activator solution is 1 - 10 mol / L.

[0062] In some embodiments, during ultrasonic oscillation, the "cavitation" effect of ultrasonic waves is used to strengthen the pore structure of the adsorbent, increase the porosity, improve the adsorption capacity, and enhance the heat and mass transfer characteristics of the adsorbent, etc.; when ultrasonic oscillation is performed, the ultrasonic frequency is 20 - 80 kHz and the ultrasonic oscillation time ≥ 0.5 h.

[0063] In some embodiments, during curing, the curing temperature is 20 - 50 °C and the curing time ≥ 2 h. The purpose of curing is to make the adsorbent slurry fully adhere to the porous metal material and not fall off easily.

[0064] In some embodiments, the cured porous metal material is dried at a temperature of 20 to 105 °C. Specifically, the drying process can be completed in a forced-air oven below 105 °C. After the moisture in the adsorbent slurry is removed, the overall formed by the porous metal material and the loaded adsorbent solid is a porous adsorbent.

[0065] In some embodiments, the porous adsorbent is heated to 400 to 900 °C and held for 0.5 to 5 h, while purging gas is introduced. The purging gas includes at least one of water vapor and carbon dioxide. Specifically, the porous adsorbent is heated to a certain temperature and held for a certain time, and purging gas is introduced to further activate the material. The purpose of physical activation by heating is to further expand the pore structure and enhance the adsorption performance.

[0066] In some embodiments, the porous metal material needs to withstand high temperatures of 600 to 1000 °C. Its pore structure can be a two-dimensional structure formed by the aggregation of a large number of polygonal pores on a plane, or a three-dimensional structure formed by the aggregation and interconnection of a large number of polyhedral pores in space. The pore diameter of the porous metal material is 2 μm to 3 mm. The porous metal material needs to have a large specific surface area to load as much potassium adsorbent as possible.

[0067] In some embodiments, the porous metal material includes NiCr23Fe alloy, NCF600 alloy, Ni, Pt, etc. NiCr23Fe is a high-temperature alloy composed of elements such as nickel, chromium, and iron, and NCF600 is a nickel-based alloy.

[0068] In some embodiments, the potassium adsorbent refers to a substance that can adsorb free soluble K in high-temperature alkali metal molten salts + and fix it as insoluble K. The potassium adsorbent can be one or more of the following substances: Si / Al composite oxides, salts containing Si / Al acid radicals, molecular sieves with different Si / Al ratios, solid wastes with relatively high Si / Al content (such as fly ash and bottom slag of waste incineration after concentration treatment), etc. The potassium adsorbent can be a natural mineral or an artificial product.

[0069] Specifically, the potassium adsorbent is mullite mineral (Si / Al composite oxide), kaolin mineral (Si / Al composite oxide), fly ash after concentration treatment (solid waste with relatively high Si / Al content), the potassium adsorbent is Na2SiO3-NaAlO complex salt (salt containing Si / Al acid radicals), and it is ZSM-5 molecular sieve (molecular sieve with different Si / Al ratios). The mass ratio of Na2SiO3 to NaAlO2 in the Na2SiO3-NaAlO2 complex salt is 2:8 to 8:2.

[0070] Based on the same inventive concept, the present invention also provides an application of the potassium adsorption material prepared by the above preparation method in selectively extracting potassium from a mixed alkali metal salt.

[0071] Based on the same inventive concept, the present invention also provides a method for selectively extracting potassium from a mixed alkali metal salt, comprising the following steps:

[0072] S1. Heating the alkali metal salt containing potassium ions to a molten state;

[0073] S2. Adding the potassium adsorption material prepared by the above preparation method to the molten alkali metal salt, and heating and reacting to selectively fix the potassium ions in the alkali metal salt to the potassium adsorption material.

[0074] In the method for selectively extracting potassium from the mixed alkali metal salt of the present invention, the cations in the alkali metal salt include K + , and the heating temperature needs to be higher than the melting point of the alkali metal salt. The potassium adsorption material is put into the molten alkali metal salt containing K + and fully reacted to obtain a porous adsorbent product containing insoluble K after selectively fixing K; after the reaction, part of the K + in the molten alkali metal salt is selectively fixed to the potassium adsorption material by chemical adsorption and exists in the porous adsorbent product in the form of insoluble K (such as KAlSiO4, KAlSi2O6, KAlSi3O8, etc.).

[0075] In some embodiments, the cations contained in the alkali metal salt include K + and at least one of Li + , Na + ; the anions contained in the alkali metal salt include at least one of Cl - , CO3 2- , SO4 2- , OH - ; the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is (2 - 20):1; the heating reaction temperature is 400 - 1000 °C and the time is 1 - 300 min.

[0076] Specifically, in the step of adding a potassium adsorption material to a molten alkali metal salt and heating for reaction to selectively fix potassium ions in the alkali metal salt to the potassium adsorption material, the alkali metal salt needs to be in excess. Generally, the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is (2 - 20):1. To promote the rapid and complete reaction of this process, the molten salt can be stirred: the stirring action can be achieved by a stirring rod or a rotating blade made of heat-resistant and corrosion-resistant materials (such as stainless steel, quartz, or corundum). The reaction temperature of this process is set depending on the composition and properties of the alkali metal salt, and the basic requirement is to be higher than the melting point of the molten salt, and the temperature range is generally between 400 and 1000 °C. The reaction time of this process can be set to 1 - 300 min. After the reaction, part of the K in the alkali metal molten salt + is selectively fixed to the porous adsorbent by chemical adsorption and exists in the porous adsorbent product in the form of insoluble K (such as KAlSiO4, KAlSi2O6, KAlSi3O8, etc.).

[0077] In some embodiments, it further includes: adding a first extractant to the potassium adsorption material fixed with potassium ions, reacting to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and filtering to obtain a first filtrate;

[0078] Adding a second extractant to the first filtrate to adjust the pH of the first filtrate to 6 - 9, filtering to obtain a second filtrate, and evaporating and crystallizing the second filtrate to obtain a potassium salt product.

[0079] Specifically, place the potassium adsorption material fixed with potassium ions in a first extraction tank, add a first extractant, decompose the adsorbent product on the potassium adsorption material at a certain temperature, and convert the insoluble K into soluble K and enter the first extractant solution; the role of the first extractant is to decompose the K - Si - Al adsorbent product and convert the composite insoluble product into soluble elemental ions and enter the first extractant solution.

[0080] In some embodiments, the first extractant includes a sub - molten salt, or a mixture of an acid solution and an auxiliary agent; the sub - molten salt is a highly active reaction medium between a conventional electrolyte and a molten salt with a concentration of 50 wt% - 70 wt%, and is suitable for efficiently decomposing refractory minerals; the solute in the sub - molten salt includes at least one of NaOH, Na2CO3, KOH, K2CO3, CaO, Ca(OH)2; the mass fraction of the solute in the sub - molten salt is 50 - 70%; the solvent in the sub - molten salt is water; when the first extractant is a sub - molten salt, the heating reaction temperature is 160 - 280 °C and the time is 2 - 6 h.

[0081] In some embodiments, the first extractant comprises a mixture of an acid solution and an auxiliary agent; the acid solution comprises at least one of H2SO4, HNO3, HCl, and H3PO4; the auxiliary agent comprises at least one of HF, CaF2, and phosphate rock; the heating reaction temperature is 80 - 160 °C and the time is 2 - 6 h.

[0082] In some embodiments, in the step of adding the first extractant to the potassium adsorption material fixed with potassium ions and carrying out the reaction, the mass ratio of the first extractant to the potassium adsorption material fixed with potassium ions is (2 - 5):1.

[0083] In some embodiments, it further comprises: adding the first extractant to the potassium adsorption material fixed with potassium ions, and reacting to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions. Microwave, ultrasound and other means can be used as aids in this process, and the heat required for the reaction in this process can be provided by the waste heat of the molten alkali metal salt.

[0084] In some embodiments, the first filtrate is placed in a second extraction tank, and a second extractant is added to adjust the pH of the first filtrate to 6 - 9, followed by filtration to obtain a second filtrate. The second filtrate is subjected to evaporation crystallization to obtain a potassium salt product. The function of the second extractant is to further remove impurities and refine the first filtrate; the second extractant controls the pH value range of the first filtrate to 6 - 9, causing the Si / Al components in the first filtrate to precipitate; the second extractant is CO2 (for alkaline first filtrate) or calcium hydroxide (for acidic filtrate), etc.

[0085] In some embodiments, the first extractant is added to the potassium adsorption material fixed with potassium ions, and the reaction is carried out to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions. After filtration, a first filtrate is obtained, and at the same time, a first solid residue is collected. The first solid residue is the adsorbed product remaining after decomposition, composed of Si / Al and a small amount of K. The first filtrate contains the extracted soluble K and needs to be further refined.

[0086] In some embodiments, a second extractant is added to the first filtrate to adjust the pH of the first filtrate to 6 - 9, followed by filtration to obtain a second filtrate, and at the same time, a second solid residue is collected; the second solid residue is the precipitated Si / Al component, which can be recycled together with the first solid residue as a raw material for preparing molecular sieves, etc.

[0087] In some embodiments, the first extractant is added to the potassium adsorption material fixed with potassium ions, and the reaction is carried out to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions. After filtration, while obtaining the first filtrate, the potassium adsorption material is collected, washed, and the adsorbed product on the potassium adsorption material is peeled off to recover a porous metal material;

[0088] According to the described method, a potassium adsorption material is prepared by using the recycled porous metal material, and the potassium ions in the mixed alkali metal salt are selectively extracted by using the potassium adsorption material again to realize the recycling of the porous metal material.

[0089] Specifically, the potassium adsorption material is washed with a weak acid / water / weak base solution to strip the residue of the adsorbent product attached thereto, and the porous metal material is recovered; the porous metal material is recycled and returned to the adsorbent slurry for curing and regeneration; the porous metal material is the carrier of the potassium adsorbent and can be recycled and used continuously for the selective extraction and recovery of potassium in the alkali metal waste salt.

[0090] Specifically, the weak acid solution includes carbonic acid, hypochlorous acid, formic acid, acetic acid, ammonium chloride solution, etc., and the pH of the weak acid solution is controlled at 3.0-6.5; the weak base solution includes sodium carbonate, sodium bicarbonate, ammonia water and other solutions, and the pH is controlled at 8-10.

[0091] The following further describes the preparation method and application of the potassium adsorption material of the present application and the method for selectively extracting potassium in the mixed alkali metal salt. This part further describes the content of the present invention in combination with specific embodiments, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0092] Example 1

[0093] The embodiment of the present application provides a preparation method of a potassium adsorption material, including the following steps:

[0094] A preparation method of a potassium adsorption material, including the following steps:

[0095] S1. Mix the potassium adsorbent with the activator solution to obtain an adsorbent slurry;

[0096] S2. Immerse the porous metal material in the adsorbent slurry, and perform ultrasonic oscillation at an ultrasonic frequency of 60 kHz and an ultrasonic time of 1 h. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry at a temperature of 35 °C for 2 h;

[0097] S3. Dry the cured porous metal material at 80 °C for 4 h to obtain a porous adsorbent;

[0098] S4. Heat the porous adsorbent to 500 °C and keep it warm for 1 h, and at the same time introduce a purge gas to obtain a potassium adsorption material; the purge gas is water vapor;

[0099] Among them, the potassium adsorbent is mullite (Si / Al composite oxide), the activator solution is H2SO4 solution (concentration 10 mol / L), and the mass ratio of the activator solution to the potassium adsorbent is 0.8:1;

[0100] The porous metal material is a foamed material made of NiCr23Fe alloy, with a pore diameter of 0.2 mm and a porosity of 96%; the foamed material is prepared by the existing electrochemical deposition method.

[0101] This embodiment also provides a method for selectively extracting potassium from mixed alkali metal salts, including the following steps:

[0102] S1. Heat the alkali metal salt containing potassium ions to a molten state; among them, the alkali metal salt containing potassium ions includes NaCl and KCl, the mass fraction of NaCl in the alkali metal salt is 60%, and the mass fraction of KCl is 40%;

[0103] S2. Add the potassium adsorption material prepared in Example 1 to the molten alkali metal salt in S1, and react at a temperature of 700 °C for 100 min to selectively fix the potassium ions in the alkali metal salt to the potassium adsorption material; the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is 10:1;

[0104] S3. Place the potassium adsorption material fixed with potassium ions in S2 into the first extraction tank, add the first extractant, and react at 200 °C for 3 h to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, filter, and obtain the first filtrate; the first extractant is an aqueous NaOH solution, and the mass fraction of the aqueous NaOH solution is 50%; the mass ratio of the first extractant to the potassium adsorption material fixed with potassium ions is 3:1;

[0105] S4. Place the first filtrate into the second extraction tank, add the second extractant to adjust the pH of the first filtrate to 8, filter, obtain the second filtrate, and evaporate and crystallize the second filtrate to obtain a potassium salt product; the second extractant is CO2;

[0106] S5. While obtaining the first filtrate in step S2, collect the potassium adsorption material, wash the potassium adsorption material with an acetic acid solution (pH 4.0) and strip the adsorption product on the potassium adsorption material, and recycle the porous metal material;

[0107] According to the method in Example 1, use the recycled porous metal material to prepare a potassium adsorption material, and use the potassium adsorption material to selectively extract potassium ions from the mixed alkali metal salt again to realize the recycling of the porous metal material.

[0108] According to the method in Example 1, after the potassium adsorption material selectively fixes K in step S2, the mass of insoluble K adsorbed by the potassium adsorption material is 13.385% of the mass of the potassium adsorption material. In step S4, after secondary extraction, the K dissolution rate is 96.69% (the calculation method of the K dissolution rate is as follows: the mass of K element m1 is calculated from the mass of the potassium salt product recovered, and based on the mass of K element m2 in the insoluble K product calculated in S2, m1 / m2 is the K dissolution rate. The calculation method of the K dissolution rate in Examples 2-5 is the same as that in Example 1).

[0109] Example 2

[0110] The embodiment of the present application provides a preparation method of a potassium adsorption material, including the following steps:

[0111] A preparation method of a potassium adsorption material, including the following steps:

[0112] S1. Mix the potassium adsorbent with the activator solution to obtain an adsorbent slurry;

[0113] S2. Immerse the porous metal material in the adsorbent slurry, and perform ultrasonic oscillation at an ultrasonic frequency of 80 kHz and an ultrasonic time of 3 h. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry at a temperature of 25 °C for 4 h;

[0114] S3. Dry the cured porous metal material at 80 °C for 4 h to obtain a porous adsorbent;

[0115] S4. Heat the porous adsorbent to 400 °C and keep it warm for 2.5 h, and at the same time introduce a purge gas to obtain the potassium adsorption material; the purge gas is carbon dioxide;

[0116] Among them, the potassium adsorbent is kaolin (Si / Al composite oxide), the activator solution is Na2CO3 solution (2 mol / L), and the mass ratio of the activator solution to the potassium adsorbent is 1:1;

[0117] The porous metal material is a foamed material made of NCF600 alloy, with a pore diameter of 0.1 mm and a porosity of 95%; this foamed material is prepared by the existing electrochemical deposition method.

[0118] This embodiment also provides a method for selectively extracting potassium from a mixed alkali metal salt, including the following steps:

[0119] S1. Heat the alkali metal salt containing potassium ions to the molten state; among them, the alkali metal salt containing potassium ions includes Li2CO3, Na2CO3, and K2CO3, and the mass fraction of Li2CO3 in the alkali metal salt is 33.3%, the mass fraction of Na2CO3 is 33.3%, and the mass fraction of K2CO3 is 33.4%;

[0120] S2. Add the potassium adsorption material prepared in Example 2 to the molten alkali metal salt in S1, and react at a temperature of 900 °C for 150 min to selectively fix potassium ions in the alkali metal salt to the potassium adsorption material; the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is 15:1.

[0121] S3. Place the potassium adsorption material fixed with potassium ions in S2 into the first extraction tank, add the first extractant, and react at 120 °C for 5 h to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and filter to obtain the first filtrate; the first extractant includes H2SO4 solution and HF solution; the mass ratio of the first extractant to the potassium adsorption material fixed with potassium ions is 5:1; the concentration of the H2SO4 solution is 18.4 mol / L (mass fraction 98%), the mass concentration of the HF solution is 40%, and the mass ratio of the H2SO4 solution to the HF solution is 4:1.

[0122] S4. Place the first filtrate into the second extraction tank, add the second extractant to adjust the pH of the first filtrate to 6.5, filter to obtain the second filtrate, and evaporate and crystallize the second filtrate to obtain the potassium salt product; the second extractant is calcium hydroxide.

[0123] S5. While obtaining the first filtrate in step S2, collect the potassium adsorption material, wash the potassium adsorption material with a Na2CO3 solution (concentration 1 mol / L) and strip the adsorption product on the potassium adsorption material, and recycle to obtain the porous metal material.

[0124] According to the method in Example 2, use the recycled porous metal material to prepare the potassium adsorption material, and use the potassium adsorption material to selectively extract potassium ions from the mixed alkali metal salt again to realize the recycling of the porous metal material.

[0125] According to the method in Example 2, after the potassium adsorption material selectively fixes K in step S2, the mass of the insoluble K adsorbed by the potassium adsorption material is 13.235% of the mass of the potassium adsorption material, and the K dissolution rate after secondary extraction in step S4 is 90.45%.

[0126] Example 3

[0127] The embodiment of the present application provides a preparation method of a potassium adsorption material, including the following steps:

[0128] A preparation method of a potassium adsorption material, including the following steps:

[0129] S_{1}. Mix the potassium adsorbent with the activator solution to obtain an adsorbent slurry.

[0130] S2. Immerse the porous metal material in the adsorbent slurry, and perform ultrasonic oscillation at an ultrasonic frequency of 40 kHz for 2 h. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry at a temperature of 50 °C for 3 h;

[0131] S3. Dry the cured porous metal material at 80 °C for 4 h to obtain a porous adsorbent;

[0132] S4. Heat the porous adsorbent to 650 °C and keep it warm for 1.5 h, while introducing a purge gas, to obtain a potassium adsorbent material; the purge gas is water vapor;

[0133] Among them, the potassium adsorbent is fly ash (a solid waste with a high Si / Al content), the activator solution is a NaOH solution (concentration 1.5 mol / L), and the mass ratio of the activator solution to the potassium adsorbent is 0.5:1;

[0134] The porous metal material is a foamed material made of Ni, with a pore diameter of 0.3 mm and a porosity of 98%; this foamed material is prepared by the existing electrochemical deposition method.

[0135] This embodiment also provides a method for selectively extracting potassium from a mixed alkali metal salt, including the following steps:

[0136] S1. Heat the alkali metal salt containing potassium ions to a molten state; among them, the alkali metal salt containing potassium ions includes Na2SO4, KCl, and K2CO3, and the mass fraction of Na2SO4 in the alkali metal salt is 30%, the mass fraction of KCl is 50%, and the mass fraction of K2CO3 is 20%;

[0137] S2. Add the potassium adsorbent material prepared in Example 3 to the molten alkali metal salt in S1, and react at a temperature of 800 °C for 120 min to selectively fix the potassium ions in the alkali metal salt to the potassium adsorbent material; the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorbent material is 5:1;

[0138] S3. Place the potassium adsorbent material fixed with potassium ions in S2 in a first extraction tank, and add a first extractant, and react at 240 °C for 2 h to convert the insoluble potassium fixed in the potassium adsorbent material into soluble potassium ions, and filter to obtain a first filtrate; the first extractant includes an aqueous solution containing NaOH and Na2CO3, the mass ratio of NaOH to Na2CO3 in the first extractant is 7:3, and the sum of the mass concentrations of NaOH and Na2CO3 in the first extractant is 60%; the mass ratio of the first extractant to the potassium adsorbent material fixed with potassium ions is 4:1;

[0139] S4. Place the first filtrate in a second extraction tank, add a second extracting agent to adjust the pH of the first filtrate to 8.5, filter to obtain a second filtrate, and subject the second filtrate to evaporation crystallization to obtain a potassium salt product; the second extracting agent is CO2;

[0140] S5. While obtaining the first filtrate in step S2, collect the potassium adsorption material, wash the potassium adsorption material with an acetic acid solution (pH 4.0) and strip the adsorbed product on the potassium adsorption material to recover a porous metal material;

[0141] According to the method in Example 3, use the recovered porous metal material to prepare a potassium adsorption material, and use the potassium adsorption material to selectively extract potassium ions from the mixed alkali metal salts again to realize the recycling of the porous metal material.

[0142] According to the method in Example 3, after the potassium adsorption material selectively fixes K in step S2, the mass of insoluble K adsorbed by the potassium adsorption material is 17.436% of the mass of the potassium adsorption material, and the K dissolution rate after secondary extraction in step S4 is 94.53%.

[0143] Example 4

[0144] The embodiment of the present application provides a preparation method of a potassium adsorption material, including the following steps:

[0145] A preparation method of a potassium adsorption material, including the following steps:

[0146] S1. Mix a potassium adsorbent with an activator solution to obtain an adsorbent slurry;

[0147] S2. Immerse the porous metal material in the adsorbent slurry, perform ultrasonic oscillation at an ultrasonic frequency of 50 kHz and an ultrasonic time of 0.5 h. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry at a temperature of 20°C for 5 h;

[0148] S3. Dry the cured porous metal material at 80°C for 4 h to obtain a porous adsorbent;

[0149] S4. Heat the porous adsorbent to 600°C and keep it warm for 3 h, while introducing a purge gas to obtain a potassium adsorption material; the purge gas is carbon dioxide;

[0150] Among them, the potassium adsorbent is a Na2SiO3-NaAlO2 composite salt (a salt containing Si / Al acid radicals), and the mass ratio of Na2SiO3 to NaAlO2 in the Na2SiO3-NaAlO2 composite salt is 6:4; the activator solution is an HNO3 solution (mass fraction 65%), and the mass ratio of the activator solution to the potassium adsorbent is 0.7:1;

[0151] The porous metal material is a foamed material made of Pt, with a pore diameter of 0.2 mm and a porosity of 97%; this foamed material is prepared by the existing electrochemical deposition method.

[0152] This embodiment also provides a method for selectively extracting potassium in a mixed alkali metal salt, including the following steps:

[0153] S1. Heat the alkali metal salt containing potassium ions to a molten state; among them, the alkali metal salt containing potassium ions includes NaCl, KCl, and KOH, and the mass fraction of NaCl in the alkali metal salt is 30%, the mass fraction of KCl is 40%, and the mass fraction of KOH is 30%;

[0154] S2. Add the potassium adsorption material prepared in Example 4 to the molten alkali metal salt in S1, and react at a temperature of 500 °C for 200 min to selectively fix the potassium ions in the alkali metal salt to the potassium adsorption material; the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is 20:1;

[0155] S3. Place the potassium adsorption material fixed with potassium ions in S2 in a first extraction tank, add a first extractant, and react at 90 °C for 6 h to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and filter to obtain a first filtrate; the first extractant includes an HCl solution and CaF2, the concentration of the HCl solution used in the first extractant is 6 mol / L, the mass ratio of CaF2 to the potassium adsorption material fixed with potassium ions is 1:1, and the mass ratio of the HCl solution to CaF2 is 4:1;

[0156] S4. Place the first filtrate in a second extraction tank, add a second extractant to adjust the pH of the first filtrate to 7, filter to obtain a second filtrate, and evaporate and crystallize the second filtrate to obtain a potassium salt product; the second extractant is calcium hydroxide;

[0157] S5. While obtaining the first filtrate in step S2, collect the potassium adsorption material, wash the potassium adsorption material with clean water and strip the adsorption products on the potassium adsorption material, and recycle to obtain the porous metal material;

[0158] According to the method in Example 4, use the recycled porous metal material to prepare a potassium adsorption material, and use the potassium adsorption material to selectively extract potassium ions in the mixed alkali metal salt again to realize the recycling of the porous metal material.

[0159] According to the method in Example 4, after the potassium adsorption material selectively fixes K in step S2, the mass of the insoluble K adsorbed by the potassium adsorption material is 14.633% of the mass of the potassium adsorption material, and the K dissolution rate after secondary extraction in step S4 is 93.22%.

[0160] Example 5

[0161] An embodiment of the present application provides a preparation method of a potassium adsorption material, comprising the following steps:

[0162] A preparation method of a potassium adsorption material, comprising the following steps:

[0163] S1. Mix a potassium adsorbent with an activator solution to obtain an adsorbent slurry;

[0164] S2. Immerse a porous metal material in the adsorbent slurry, and perform ultrasonic oscillation at an ultrasonic frequency of 30 kHz and an ultrasonic time of 1 h. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry at a temperature of 40 °C for 3.5 h;

[0165] S3. Dry the cured porous metal material at 80 °C for 4 h to obtain a porous adsorbent;

[0166] S4. Heat the porous adsorbent to 550 °C and keep it warm for 4.5 h, and simultaneously introduce a purge gas to obtain a potassium adsorption material; the purge gas is water vapor;

[0167] Wherein, the potassium adsorbent is ZSM-5 molecular sieve (molecular sieves with different Si / Al ratios), the activator solution is KOH solution, and the mass ratio of the activator solution to the potassium adsorbent is 0.6:1;

[0168] The porous metal material is a foamed material made of NiCr23Fe alloy, with a pore diameter of 0.2 mm and a porosity of 96%; this foamed material is prepared by an existing electrochemical deposition method.

[0169] This embodiment also provides a method for selectively extracting potassium from a mixed alkali metal salt, comprising the following steps:

[0170] S1. Heat an alkali metal salt containing potassium ions to a molten state; wherein, the alkali metal salt containing potassium ions includes NaOH, NaCl, and K2SO4, and the mass fraction of NaOH in the alkali metal salt is 10%, the mass fraction of NaCl is 50%, and the mass fraction of K2SO4 is 40%;

[0171] S2. Add the potassium adsorption material prepared in Example 5 to the molten alkali metal salt in S1, and react at a temperature of 950 °C for 60 min to selectively fix the potassium ions in the alkali metal salt to the potassium adsorption material; the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is 3:1;

[0172] S3. Place the potassium adsorption material with potassium ions fixed in S2 into the first extraction tank, add the first extractant, and react at 180 °C for 4 h to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, then filter to obtain the first filtrate; the first extractant is an aqueous KOH solution with a mass concentration of 70%; the mass ratio of the first extractant to the potassium adsorption material with potassium ions fixed is 5:1.

[0173] S4. Place the first filtrate into the second extraction tank, add the second extractant to adjust the pH of the first filtrate to 9, filter to obtain the second filtrate, and evaporate and crystallize the second filtrate to obtain a potassium salt product; the second extractant is CO2.

[0174] S5. While obtaining the first filtrate in step S2, collect the potassium adsorption material, wash the potassium adsorption material with an acetic acid solution (pH 4.0) and strip the adsorption products on the potassium adsorption material to recover the porous metal material.

[0175] According to the method in Example 5, use the recovered porous metal material to prepare a potassium adsorption material, and selectively extract potassium ions from the mixed alkali metal salt by using the potassium adsorption material again to realize the recycling of the porous metal material.

[0176] According to the method in Example 5, after the potassium adsorption material selectively fixes K in step S2, the mass of the insoluble K adsorbed by the potassium adsorption material is 12.258% of the mass of the potassium adsorption material, and the K dissolution rate after secondary extraction in step S4 is 95.08%.

[0177] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a potassium adsorption material, characterized in that, It includes the following steps: Mix the potassium adsorbent with the activator solution to obtain an adsorbent slurry; Soak the porous metal material in the adsorbent slurry and perform ultrasonic oscillation. After ultrasonic oscillation, the porous metal material continues to be cured in the adsorbent slurry; Dry the cured porous metal material to obtain a porous adsorbent; Heat the porous adsorbent to a certain temperature and keep it warm, and at the same time introduce a purge gas to obtain a potassium adsorption material.

2. The preparation method of the potassium adsorption material according to claim 1, characterized in that, The activator solution includes at least one of a salt solution, an acid solution, and an alkali solution; The salt in the salt solution includes at least one of ZnCl2, Na2CO3, and K2CO3; The acid solution includes at least one of HNO3, H2SO4, and H3PO4; The alkali solution includes at least one of NaOH and KOH; And / or, the mass ratio of the activator solution to the potassium adsorbent is (0.4 - 1):1, and the concentration of the activator solution is 1 - 10 mol / L.

3. The preparation method of the potassium adsorption material according to claim 1, characterized in that, When performing ultrasonic oscillation, the ultrasonic frequency is 20 - 80 kHz, and the ultrasonic oscillation time ≥ 0.5 h; And / or, during curing, the curing temperature is 20 - 50 °C, and the curing time ≥ 2 h; And / or, dry the cured porous metal material, and the drying temperature is 20 - 105 °C; And / or, heat the porous adsorbent to 400 - 900 °C and keep it warm for 0.5 - 5 h, and at the same time introduce a purge gas; the purge gas includes at least one of water vapor and carbon dioxide.

4. The preparation method of the potassium adsorption material according to claim 1, characterized in that, The pore diameter of the porous metal material is 2 μm - 3 mm; The potassium adsorbent includes at least one of Si / Al composite oxides, salts containing Si / Al acid radicals, molecular sieves, fly ash, and bottom slag from waste incineration.

5. Application of the potassium adsorption material prepared by the preparation method according to any one of claims 1 - 4 in extracting potassium from mixed alkali metal salts.

6. A method for selectively extracting potassium in a mixed alkali metal salt, characterized in that, [[ID=XX]]It includes the following steps: Heat the alkali metal salt containing potassium ions to a molten state; Add the potassium adsorption material prepared by the preparation method according to any one of claims 1 - 4 to the molten alkali metal salt and heat it for reaction so that the potassium ions in the alkali metal salt are selectively fixed to the potassium adsorption material.

7. The method for selective extraction of potassium in the mixed alkali metal salts as claimed in claim 6, wherein The cations contained in the alkali metal salt include K + and Li + , Na + and at least one of them; The anions contained in the alkali metal salt include Cl - , CO3 2- , SO4 2- , OH - and at least one of them; And / or, the mass ratio of the alkali metal salt containing potassium ions to the potassium adsorption material is (2 - 20):1; And / or, the heating reaction temperature is 400 - 1000 °C, and the time is 1 - 300 min.

8. The method for selective extraction of potassium in the mixed alkali metal salt according to claim 6, characterized in that, It further includes: Add a first extractant to the potassium adsorption material fixed with potassium ions, and perform a reaction to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, and filter to obtain a first filtrate; Add a second extractant to the first filtrate to adjust the pH of the first filtrate to 6 - 9, filter to obtain a second filtrate, and evaporate and crystallize the second filtrate to obtain a potassium salt product.

9. The method for selectively extracting potassium in the mixed alkali metal salt according to claim 8, wherein In the step of adding a first extractant to the potassium adsorption material fixed with potassium ions and performing a reaction, the mass ratio of the first extractant to the potassium adsorption material fixed with potassium ions is (2 - 5):1; The first extractant includes a sub-molten salt or a mixture of an acid solution and an auxiliary agent; The solute in the sub-molten salt includes at least one of NaOH, Na2CO3, KOH, K2CO3, CaO, and Ca(OH)2; The mass fraction of the solute in the sub-molten salt is 50-70%; The acid solution includes at least one of H2SO4, HNO3, HCl, and H3PO4; The auxiliary agent includes at least one of HF, CaF2, and phosphate rock; When the first extractant is the sub-molten salt, the heating reaction temperature is 160-280 °C and the time is 2-6 h; When the first extractant is a mixture of the acid solution and the auxiliary agent, the heating reaction temperature is 80-160 °C and the time is 2-6 h.

10. The method for selectively extracting potassium in the mixed alkali metal salt according to claim 8, characterized in that, The second extractant is CO2 or calcium hydroxide; Adding the first extractant to the potassium adsorption material fixed with potassium ions, reacting to convert the insoluble potassium fixed by the potassium adsorption material into soluble potassium ions, filtering, collecting the potassium adsorption material while obtaining the first filtrate, cleaning the potassium adsorption material and stripping the adsorption product on the potassium adsorption material, and recovering the porous metal material; According to the method described in claim 1, using the recovered porous metal material to prepare a potassium adsorption material, and selectively extracting potassium ions from the mixed alkali metal salt by the potassium adsorption material again to realize the recycling of the porous metal material.