Method for producing and using zeolite molecular sieves containing radio wave absorbing materials

Abstract

To provide a composite A-type molecular sieve raw material powder containing a radio wave absorbing material, an all-zeolite molecular sieve, and methods of producing the same and uses thereof.SOLUTION: The raw material powder of composite A-type molecular sieve containing radio wave absorbing material contains a micro-nano size radio wave absorbing material and an A-type molecular sieve grown in situ using the radio wave absorbing material as a seed crystal, and can be made into an all-zeolite molecular sieve containing radio wave absorbing material through the steps of molding, crystal transition, ion exchange and activation. The all-zeolite molecular sieve containing radio wave absorbing material produced as above can highly adsorb specific molecules and can be rapidly regenerated by microwave heating.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to the technology in the field of molecular sieves, and specifically relates to a composite type A molecular sieve raw material powder containing a radio wave absorbing material, all zeolite molecular sieves, their manufacturing methods, and uses thereof.

Background Art

[0002] A lithium ion battery mainly consists of a positive electrode, a negative electrode, and an electrolyte. Without the insertion and extraction of lithium ions between the positive and negative electrodes through the electrolyte, charge and discharge cannot be performed. During the first charge and discharge of a lithium ion battery, a reaction occurs between the electrolyte and the electrode material, and a solid electrolyte interface film (SEI) that has an important impact on the characteristics of the lithium ion battery is formed. However, the electrolyte inevitably contains trace amounts of impurities such as water, acids, and alcohols during the production process. Even for a commercially available electrolyte with excellent characteristics, the content of these impurities is about 0.001%. However, these trace impurities can also destroy or change the properties of the SEI film, reducing the reversible capacity and cycle characteristics of the battery. Furthermore, trace amounts of water can decompose lithium hexafluorophosphate salt in the electrolyte and react with the organic solvent in the electrolyte to generate alcohol. Additionally, during the charge and discharge of a lithium ion battery, lithium ions are consumed, generating substances such as LiOH, Li2O, and HF, and all of these substances may reduce the characteristics of the lithium ion battery. Therefore, the purity of the electrolyte has an important impact on the electrochemical characteristics of the lithium ion battery.

[0003] Molecular sieves have high hygroscopicity and excellent characteristics that can be used for dehydrating various solvents, so they are widely used in laboratories and industries. In theory, by manufacturing a lithium type molecular sieve using an appropriate molecular sieve as a raw material, trace amounts of water and small molecule impurities such as hydrogen fluoride and methanol with a molecular size close to that of water in a lithium ion non-aqueous electrolyte can be efficiently removed.

[0004] Patent Document 1: Patent Application CN200810050070.2 (2008) discloses a method for producing Li-LSX molecular sieves. This method involves exchanging LSX multiple times with a potassium ion aqueous solution to obtain K+-LSX, then exchanging it multiple times with an ammonium ion aqueous solution to obtain NH4-LSX, and finally performing lithium ion exchange to obtain Li-LSX. During the lithium ion exchange process, it is necessary to recover NH3 to promote Li exchange. While this method increases the utilization rate of Li by employing an exchange method via NH4+ transition, the process flow is relatively complex. Moreover, due to the poor hydrothermal stability of the low silica alumino molecular sieve framework itself, the molecular sieve framework is destroyed by frequent hydrothermal ion exchange, and as a result, the finished product may not be usable for removing impurities from lithium ion non-aqueous electrolytes. Another reason why the Li-LSX manufactured in this application cannot be used for removing impurities from lithium-ion non-aqueous electrolytes is related to the production of the molecular sieve raw material powder. In actual use, the molecular sieve raw material powder often cannot be used properly unless it is made into small spheres by a spheroidization process. However, since the addition of binders and other additives is unavoidable in the spheroidization process, even if the Li exchange rate is high in the previous stage, the lithium ion content inevitably decreases after the spheroidization process. Furthermore, when lithium-ion non-aqueous electrolytes highly adsorb trace amounts of water, secondary contamination of other ions occurs due to ion exchange in materials such as binders, and sodium ion contamination in particular is fatal to lithium-ion non-aqueous electrolytes.

[0005] In addition to the problems mentioned above, the process of removing impurities from large quantities of lithium-ion non-aqueous electrolytes also faces challenges such as how to efficiently desorb and regenerate the molecular sieves that have adsorbed impurities, and how to reduce the manufacturing costs of adsorbents. This invention was completed in order to solve the above-mentioned problems that exist in the prior art. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent Application CN200810050070.2 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Among the many types of molecular sieves, Type A molecular sieves are easy to manufacture, inexpensive, and can produce 3A, 4A, and 5A molecular sieves by exchanging various ions, thereby enabling sieving, separation, and adsorption effects of molecules of various sizes. In view of this, the present invention proposes a composite Type A molecular sieve raw material powder containing a radio wave absorbing material, an all-zeolite molecular sieve, a method for manufacturing them, and their use, in order to address the above-mentioned drawbacks of the prior art. The manufactured all-zeolite molecular sieve can highly adsorb specific molecules, can be rapidly regenerated by microwave heating, and can increase the activation and regeneration efficiency. [Means for solving the problem]

[0008] A first aspect of the present invention provides a composite A-type molecular sieve raw material powder containing a radio wave absorbing material, comprising a micro-nanometer radio wave absorbing material and an A-type molecular sieve grown in situ using the micro-nanometer radio wave absorbing material as a crystal species, wherein the A-type molecular sieve covers the radio wave absorbing material.

[0009] In some embodiments, the micro-nanometer-sized radio wave absorbing material includes one or more of silicon carbide particles, silicon carbide fibers, carbon fibers, graphene, carbon nanotubes, and carbon black, and the A-type molecular sieve is one of the LTA (Linde Type A) molecular sieves, typically, for example, a 3A molecular sieve, a 4A molecular sieve, or a 5A molecular sieve.

[0010] Preferably, the size of the radio wave absorbing material is 1 nm to 100 μm, and more preferably 10 nm to 10 μm.

[0011] A second aspect of the present invention is: Micro- and nano-sized radio wave absorbing material powders are weighed, placed in a type A molecular sieve precursor reaction solution, and then heated with microwaves to initiate the reaction. When heated with microwaves, the radio wave absorbing material is selectively heated, and due to the particle surface effect, molecular sieves grow in situ as a crystal species, synthesizing type A molecular sieves, which then cover the radio wave absorbing material. The present invention provides a method for producing a composite type A molecular sieve raw material powder containing a radio wave absorbing material, wherein the powder is dried after the reaction is complete to obtain a composite type A molecular sieve raw material powder containing a radio wave absorbing material.

[0012] In some embodiments, the type A molecular sieve precursor reaction solution is an alkaline silica-aluminum reaction solution, with a molar ratio of reaction solution material composition of xM2O:ySiO2:Al2O3:zH2O (where M is one or more alkali metal ions and organic ammonium ions, x is 2 to 12, y is 1.5 to 6.5, and z is 30 to 400), microwave heating output power of 0.1 to 2 kW, reaction temperature of 40 to 110°C, reaction time of 1 to 48 hours, and drying temperature of 80 to 120°C. Preferably, the heating temperature is 60 to 100°C and the reaction time is 1 to 24 hours.

[0013] A third aspect of the present invention is: Step S1 of the molding process involves uniformly mixing a composite type A molecular sieve raw material powder containing radio wave absorbing material with a binder in a predetermined ratio, milling the mixture, molding it in a granulator, and then drying and roasting it to obtain molded particle material. Step S2 involves a crystallization transition, in which the molded particle material obtained in step S1 is baked and placed in an alkaline solution, heated to carry out a crystallization reaction, converting the binder in the molded particle material into zeolite crystals, and obtaining an all-zeolite molecular sieve. Step S3 of the ion exchange process involves absorbing moisture from the all-zeolite molecular sieve produced in step S2, immersing it in water, sending it into an ion exchange column using a peristaltic pump, heating it to the ion exchange temperature, introducing the target ion solution, performing ion exchange, rinsing it with deionized water, further dehydrating it, and collecting the all-zeolite molecular sieve modified with the target ion solution. The present invention provides a method for producing an all-zeolite molecular sieve containing an electromagnetic wave absorbing material, comprising: a pre-bake treatment of the target ion solution-modified all-zeolite molecular sieve produced in step S3; after pre-baking, sending the semi-finished product to an activation furnace for roasting; after roasting, cooling to the discharge temperature before discharge; and, if necessary, sieving under the protection of nitrogen or dry air to obtain a finished all-zeolite molecular sieve containing an electromagnetic wave absorbing material.

[0014] Preferably, the weight percentage of the binder in the molded particle material is 5% to 20%, and the binder is one or more of kaolin, halloysite, and allophene.

[0015] In step S1, one or more additives are further added to optimize various properties of the molded particle material, such as improved strength, reduced wear, and improved porosity. These additives include one or more of the following: water glass, aluminum sol, silica sol, silicone resin emulsion, pyrophosphate, aluminum hydrogen phosphate, cellulose and its derivatives, and tannin extract. The molded shape may be spherical, stranded, or other, and should be designed according to the specific application.

[0016] In step S2, the alkaline solution is at least one of sodium hydroxide solution, potassium hydroxide solution, or calcium hydroxide solution, the concentration of the solution is 1% to 40% by mass, preferably 1% to 15% by mass, and the heating temperature is 65 to 125°C, preferably 75 to 95°C.

[0017] In step S3, the target ionic solution is at least one of the following: a soluble chloride solution, a hydroxide solution, a sulfate solution, or a nitrate solution containing the target ionic solution; the concentration of the solution is 1% to 40% by mass; the ion exchange temperature is 50 to 130°C; the pH value is controlled to be in the range of 6 to 12 during ion exchange; and the temperature of the deionized water used for rinsing is 60 to 90°C.

[0018] In step S4, the bake temperature is controlled to 80-220°C, the moisture content of the dried product is controlled to 5-15%, the activation furnace is preheated with a dry gas, and then the desired ion solution modified all-zeolite molecular sieve produced in step S3 is roasted, with a preheating temperature of 400-800°C, a roasting temperature of 500-580°C, a roasting time of 3-5 hours, and an exhaust temperature of 50-20°C. The dry gas is preferably pure nitrogen gas or dry compressed air with a dew point range of -50°C to -90°C.

[0019] A fourth aspect of the present invention provides an all-zeolite molecular sieve containing an electromagnetic wave absorbing material, manufactured by the above manufacturing method, having a particle size distribution of 0.1 to 5.0 mm, an ion exchange rate of 95% or more in the process, a static moisture adsorption of 20 wt% or more, a water content of 1.5 wt% or less, and an abrasion rate of less than 1.5 wt%.

[0020] In some embodiments, all-zeolite molecular sieves containing radio wave absorbing materials are activated and regenerated by microwave heating after adsorption. That is, after adsorption by the molecular sieves is completed, the molecular sieves are washed, and then regenerated by dehydration through activation by microwave heating, thereby restoring the adsorption capacity of the molecular sieves and enabling the recycling of the molecular sieves. By setting the output power of the microwave heating to 0.5 to 2 kW and raising the temperature of the all-zeolite molecular sieves containing radio wave absorbing materials to 100 to 250°C, the activation and regeneration are completed after processing for 1 to 40 minutes.

[0021] A fifth aspect of the present invention provides the use of an all-zeolite molecular sieve containing a radio wave absorbing material as an adsorbent for impurity removal, particularly for impurity removal in lithium-ion non-aqueous electrolytes.

[0022] In a lithium-ion non-aqueous electrolyte, the diameters of trace amounts of water, impurity molecules such as hydrogen fluoride and methanol are less than approximately 0.4 nm. However, since the radius of the organic solvent molecules in the electrolyte is large, when using an all-zeolite lithium-type molecular sieve containing a radio wave absorption material with a pore diameter of 4 Å, it is possible to ensure that while removing impurities, the organic solvent is not adsorbed and removed. When using an all-zeolite lithium-type molecular sieve containing a radio wave absorption material with a pore diameter of 3 Å or 5 Å, the impurity removal effect slightly decreases. In the above use, by using an all-zeolite lithium-type molecular sieve containing a radio wave absorption material, secondary contamination due to ion exchange in impurity removal can be avoided.

Effects of the Invention

[0023] Technical Effects Compared with the prior art, the present invention has the following technical effects. 1) By adding a micro-nano material having a radio wave absorption function, the synthesis of the molecular sieve is promoted, the synthesis efficiency of the molecular sieve is improved, a composite A-type molecular sieve raw material powder containing a radio wave absorption material is synthesized, and further an all-zeolite molecular sieve with a high-efficiency microwave heating function is obtained. After this molecular sieve adsorbs small molecule substances such as water in the electrolyte, the adsorbed small molecule substances can be removed by microwave heating efficiently and with low energy consumption, and the heating regeneration time can be shortened from several hours to about 30 minutes, and even to several minutes, realizing the efficient recycling of the molecular sieve and even the rapid online regeneration. Similar to the desorption regeneration of other molecular sieves, the all-zeolite molecular sieve containing a radio wave absorption material can also be activated by high-temperature air flow heating, but it is difficult for the radio wave absorption material to play a role in this activation regeneration process, and online activation cannot be achieved. 2) Based on the surface effect of the radio wave absorption functional material in microwave heating, when synthesizing a composite A-type molecular sieve raw material powder containing a radio wave absorption material, there is no need to add or remove an organic or inorganic template agent, the process is simple, and the action of the radio wave absorption functional material is also different from the action of the template agent. 3) By making the molecular sieve powder into granules, the permeability of the electrolyte in the adsorption process can be improved, thereby improving the adsorption treatment efficiency, and the filtration time can be reduced from hours to minutes compared to conventional powder molecular sieves. 4) By performing a crystal conversion treatment on the binder added during the molding process, the binder with a non-zeolite crystalline structure is converted to zeolite crystals, thereby improving the adsorption characteristics of the molecular sieve and increasing its adsorption capacity by 5% to 20% compared to uncrystallized molecular sieves. Furthermore, all-zeolite molecular sieves can be manufactured without repeated hydrothermal exchange, and structural stability is effectively improved. 5) The all-zeolite molecular sieve containing the manufactured radio wave absorbing material fully exhibits the molecular sieve's property of highly removing water, simplifying the water removal process, increasing the efficiency of water removal, and improving the quality of the electrolyte. Furthermore, by adopting an all-zeolite lithium-type molecular sieve containing radio wave absorbing material, the Na+ and K+ content is extremely low, and when adsorbing trace amounts of water, hydrogen fluoride, methanol, etc. in the electrolyte, it does not exchange with Li+ and affect the Li+ purity in the electrolyte, thus preventing secondary contamination and ensuring the cycle characteristics of the lithium-ion battery. [Modes for carrying out the invention]

[0024] The present invention will be described in detail below with reference to specific embodiments. Experimental methods in the examples where specific conditions are not specified will be carried out according to conventional methods and conditions. Example 1

[0025] This embodiment relates to a method for producing an all-zeolite lithium molecular sieve containing a radio wave absorbing material, comprising steps S1 to S5.

[0026] S1: In-situ synthesis of composite type A molecular sieve raw material powder with radio wave absorption function Using a molar ratio of 3Na2O:2SiO2:Al2O3:128H2O, sodium silicate and sodium aluminate were weighed and solutions were prepared separately. Sodium hydroxide was then added to each of the two solutions, and the two solutions were then uniformly mixed. One kilogram of silicon carbide powder was weighed and added to an alkaline silica-aluminum sol reaction solution (added according to the theoretical yield of 9 kg of type A molecular sieve). The mixture was then placed in a microwave reactor and reacted at 100 W for 10 minutes to obtain a composite 4A molecular sieve raw material powder containing silicon carbide radio wave absorbing material.

[0027] S2: Spheroidization 8 kg (dry basis) of composite 4A molecular sieve raw material powder containing manufactured silicon carbide radio wave absorbing material and 2 kg of kaolin were weighed and placed in a Φ500 mm mixer, and mixed for 30 minutes to obtain the mix. 5 kg of the mix (based on dry weight) was weighed and placed in an EIRICH automatic molding machine. It was then injected into the mixed solution for molding, and the diameter of the molded particles was adjusted to 1.2-1.8 mm. The molded particles were placed in a vacuum muffle furnace and roasted at 350-550°C for 2-3 hours to obtain spherical particle material. When spherical particle material was placed in a drying dish, cooled to room temperature, and sampled, the static moisture adsorption was measured, and the amount of static moisture adsorbed reached 21.7 wt%.

[0028] S3: Crystal Transition Three kilograms of spherical particle material were weighed and placed in deionized water, resulting in a weight of 4.84 kg. Three kilograms of spherical particle material were then added to an 8% by mass sodium hydroxide solution in a weight ratio of 3.5:1 to obtain the crystallization reaction solution. The temperature was raised to 95°C, the solution was placed in a bath, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was complete, the sample was washed with 50 L of cold water, then washed twice with 10 L of 70°C hot water, and finally washed again with cold water until the pH reached 8 (measured with test paper) to obtain the crystallized molecular sieve balls. Analysis of the pH value of the sample revealed it reached 10.45. The water absorption properties of the crystallization reaction molecular sieve balls were tested. Test conditions: The material was allowed to absorb water for 24 hours under conditions of 25°C and RH50. Results: The material content was 21.7 wt% before the crystallization reaction and 24.5 wt% after the crystallization reaction.

[0029] S4: Lithium-ion exchange After the crystallization transition, the crystallization reaction molecular sieve balls (4A molecular sieves) were allowed to absorb moisture and placed in a lithium ion exchange apparatus, immersed in water, and the material inside the apparatus was heated to 85-90°C and maintained at that temperature. A lithium sulfate solution with a concentration of 1% to 8% by mass was introduced into the apparatus, and the pH was controlled to 6-12. After a predetermined time, the ion concentration in the liquid was detected from the sampling outlet of the apparatus. When the ion concentration in the liquid reached a predetermined value, the lithium ion exchange reaction was terminated, and an all-zeolite lithium-type molecular sieve was obtained. The all-zeolite lithium-type molecular sieve inside the apparatus was rinsed with deionized water to the desired degree, and the material was removed, dehydrated, and the all-zeolite lithium-type molecular sieve was collected.

[0030] S5: Activation All-zeolite lithium type molecular sieves were slowly added to a belt oven for pre-baking, controlling the oven temperature to 80-220°C, controlling the moisture content of the material after drying to 5-15%, and the material was collected in a container. The dried material was placed in a vertical activation furnace, and pure nitrogen gas or dry compressed air with a dew point of -70°C was heated to 450-600°C using an electric heater. The hot gas was then introduced into the vertical activation furnace, and the material was roasted to 500-580°C. After being kept warm for 3-5 hours, a finished all-zeolite lithium-type molecular sieve containing silicon carbide radio wave absorbing material was obtained. Subsequently, the finished all-zeolite lithium molecular sieves containing the radio wave absorbing material in the vertical furnace were cooled to 50°C to 20°C in a cooler, then sieved under the protection of nitrogen gas or suitable dry air, and packaged in packaging barrels. The results of testing the finished all-zeolite lithium-type molecular sieve containing the manufactured radio wave absorbing material showed that the static moisture adsorption was 23.6 wt%, the Li exchange rate was 96.6%, the bulk density was 0.69 g / ml, the abrasion rate was 0.09 wt%, the average particle size was 1.38 mm, the sieved particle size (<1.00) was 0.1 wt%, the sieved particle size (>1.70) was 0.1 wt%, and the water content was 0.952 wt%, demonstrating excellent properties. The finished product has good sphericity, uniform particle size, and excellent stacking effect, making it suitable for removing impurities from the electrolyte of lithium-ion batteries. Example 2

[0031] This embodiment relates to a method for producing an all-zeolite lithium-type molecular sieve, comprising steps S1 to S4.

[0032] S1: Spheroidization 8 kg of commercially available 4A molecular sieve (chemical formula: 3Na2O:2SiO2:Al2O3:128H2O) raw material powder (dry basis) and 2 kg of kaolin were weighed and placed in a Φ500 mm mixer and mixed for 30 minutes. 5 kg of the mix was weighed, placed in an EIRICH automatic molding machine, and the mixed solution was injected for molding, resulting in molded particles with a diameter of 1.2 to 1.8 mm. The molded particles were placed in a vacuum muffle furnace and roasted at 350-550°C for 2-3 hours to obtain spherical particle material. When spherical particle material was placed in a drying dish, cooled to room temperature, and sampled, the static moisture adsorption was measured, and the amount of static moisture adsorbed reached 20.0 wt%.

[0033] S2: Crystal transition The resulting crystallization reaction solution was obtained by adding 3 kg of spherical particle material to an 8% by mass sodium hydroxide solution in a weight ratio of 3.5:1 between the obtained crystallization reaction solution and the spherical particle material, thereby obtaining the crystallization reaction solution. The temperature was raised to 95°C, the solution was placed in a bath, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was complete, the material was first washed with 50 L of cold water, then washed twice with 10 L of 70°C hot water, and finally washed again with cold water until the pH reached 8 (measured with test paper) to obtain the crystallized reaction molecular sieve balls. Analysis of the pH value of the sample revealed it reached 10.45. The water absorption properties of the crystallization reaction molecular sieve balls were tested. Test conditions: The sample was allowed to absorb water for 24 hours under conditions of 25°C and RH50. Results: The content was 20.0 wt% before the crystallization reaction and 22.3 wt% after the crystallization reaction.

[0034] S3: Lithium-ion exchange After the crystallization transition, the crystallization reaction molecular sieve balls (4A molecular sieves) were allowed to absorb moisture and placed in a lithium ion exchange apparatus, immersed in water, and the material inside the apparatus was heated to 85-90°C and maintained at that temperature. A lithium sulfate solution with a concentration of 1% to 8% by mass was introduced into the apparatus, and the pH was controlled to 6-12. After a predetermined time, the ion concentration in the liquid was detected from the sampling outlet of the apparatus. When the ion concentration in the liquid reached a predetermined value, the lithium ion exchange reaction was terminated, and an all-zeolite lithium-type molecular sieve was obtained. The all-zeolite lithium-type molecular sieve inside the apparatus was rinsed with deionized water to the desired degree, and the material was removed, dehydrated, and the all-zeolite lithium-type molecular sieve was collected.

[0035] S4: Activation All-zeolite lithium type molecular sieves were slowly added to a belt oven for pre-baking, controlling the oven temperature to 80-220°C, controlling the moisture content of the material after drying to 5-15%, and the material was collected in a container. The dried material was placed in a vertical activation furnace, and pure nitrogen gas or dry compressed air with a dew point of -70°C was heated to 450-600°C using an electric heater. The hot gas was then introduced into the vertical activation furnace, and the material was roasted to 500-580°C, followed by a 3-5 hour incubation period to obtain the finished all-zeolite lithium-type molecular sieve. Subsequently, the finished all-zeolite lithium molecular sieves containing the radio wave absorbing material in the vertical furnace were cooled to 20°C to 50°C in a cooler, then sieved under the protection of nitrogen gas or suitable dry air, and packaged in packaging barrels. The results of the detection of the manufactured finished product showed that the static moisture adsorption was 22.5 wt%, the Li exchange rate was 94.0%, the bulk density was 0.70 g / ml, the abrasion rate was 0.15 wt%, the average particle size was 1.34 mm, the sieved particle size (<1.00) was 0.5 wt%, the sieved particle size (>1.70) was 0.5 wt%, and the water content was 0.952 wt%, demonstrating excellent properties. The finished product has good sphericity, uniform particle size, and excellent stacking effect, making it suitable for removing impurities from the electrolyte of lithium-ion batteries. Example 3

[0036] This embodiment relates to a method for producing an all-zeolite calcium type molecular sieve containing a radio wave absorbing material, including steps S1 to S5.

[0037] S1: On-site synthesis of composite type A molecular sieve raw material powder with radio wave absorption function The materials were mixed in a molar ratio of 12M2O:60SiO2:Al2O3:400H2O. Sodium silicate was weighed and homogeneously mixed with water to form a solution. Tetramethylammonium hydroxide solution was weighed and added to aluminum isopropoxide and sodium hydroxide to form a solution. The two solutions were then homogeneously mixed, and the molar ratio of tetramethylammonium hydroxide (TMA) to sodium ions in the mixture was set to 1.675. 0.5 kg of silicon carbide powder was weighed and added to an alkaline silica-aluminum sol reaction solution (added according to the theoretical yield of 9.5 kg of type A molecular sieve). The mixture was then placed in a microwave reactor and reacted at 100 W for 60 minutes to obtain a composite 4A molecular sieve raw material powder containing silicon carbide radio wave absorbing material.

[0038] S2: Spheroidization 9 kg (dry basis) of composite 4A molecular sieve raw material powder containing manufactured silicon carbide radio wave absorbing material and 1 kg of halloysite were weighed and placed in a Φ500 mm mixer and mixed for 30 minutes. 5 kg of the mix (based on dry weight) was weighed and placed in an EIRICH automatic molding machine. The mixed solution was then injected and used for molding, resulting in molded particles with a diameter of 1.2 to 1.8 mm. The molded particle material was placed in a vacuum muffle furnace and roasted at 350-550°C for 2-3 hours to obtain spherical particle material. When spherical particle material was placed in a drying dish, cooled to room temperature, and sampled, the static moisture adsorption was measured, and the amount of static moisture adsorbed reached 25.2 wt%.

[0039] S3: Crystal Transition The resulting crystallization reaction solution was obtained by adding 3 kg of spherical particle material to an 8% by mass sodium hydroxide solution in a weight ratio of 3.5:2 to the spherical particle material. The temperature was raised to 95°C, the solution was placed in a bath, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was complete, the material was first washed with 50 L of cold water, then washed twice with 10 L of 70°C hot water, and finally washed again with cold water until the pH reached 8 (measured with test paper) to obtain the crystallized reaction molecular sieve balls. Analysis of the pH value of the sample revealed it reached 10.45. The water absorption properties of the crystallization reaction molecular sieve balls were tested. Test conditions: The sample was allowed to absorb water for 24 hours under conditions of 25°C and RH50. Results: The content was 25.2 wt% before the crystallization reaction and 28.0 wt% after the crystallization reaction.

[0040] S4: Calcium ion exchange After the crystallization transition, the crystallization reaction molecular sieve balls (4A molecular sieve) were allowed to absorb moisture and placed in a lithium ion exchange apparatus, immersed in water, and the material inside the apparatus was heated to 85-90°C and maintained at that temperature. A calcium chloride solution with a concentration of 2% to 10% by mass was introduced into the apparatus, and the pH was controlled to 6-9. After a predetermined time, the ion concentration in the liquid was detected from the sampling outlet of the apparatus. When the ion concentration in the liquid reached the predetermined value, the calcium ion exchange reaction was terminated, and an all-zeolite calcium type molecular sieve (5A molecular sieve) was obtained. The all-zeolite calcium type molecular sieve inside the apparatus was rinsed with deionized water, and after rinsing to the desired degree, the material was removed, dehydrated, and the all-zeolite calcium type molecular sieve was collected.

[0041] S5: Activation All-zeolite calcium type molecular sieves were slowly added to a belt oven for pre-baking, controlling the oven temperature to 80-220°C, controlling the moisture content of the material after drying to 5-15%, and the material was collected in a container. The dried material was placed in a vertical activated furnace, and pure nitrogen gas or dry compressed air with a dew point of -70°C was heated to 450-600°C using an electric heater. The hot gas was then introduced into the vertical activated furnace, and the material was roasted to 500-580°C, followed by a 3-5 hour incubation period to obtain a finished all-zeolite calcium type molecular sieve containing radio wave absorbing material. Subsequently, the all-zeolite calcium type molecular sieve containing the radio wave absorbing material in the vertical furnace was cooled to 50°C to 20°C using a cooler. Then, the finished product was sieved under the protection of nitrogen gas or suitable dry air and packaged in a packaging barrel. The results of the detection of the manufactured finished product showed that the static moisture adsorption was 24.1 wt%, the calcium ion exchange rate was 95.2%, the bulk density was 0.69 g / ml, the abrasion rate was 0.07 wt%, the average particle size was 1.31 mm, the sieved particle size (<1.00) was 0.4 wt%, the sieved particle size (>1.70) was 0.3 wt%, and the water content was 0.952 wt%, demonstrating excellent properties. The finished product has good sphericity, uniform particle size, and excellent stacking effect, making it suitable for removing impurities from the electrolyte of lithium-ion batteries. Example 4

[0042] This embodiment relates to a method for producing an all-zeolite calcium type molecular sieve, comprising steps S1 to S4.

[0043] S1: Spheroidization 9 kg (dry basis) of commercially available 4A molecular sieve raw material powder (chemical formula: 12M2O·60SiO2·Al2O3·400H2O, M: tetramethylammonium ion) and 1 kg of halloysite were weighed and placed in a Φ500 mm mixer and mixed for 30 minutes. 5 kg of the mix (based on dry weight) was weighed and placed in an EIRICH automatic molding machine. The mixed solution was then injected and used for molding, resulting in molded particles with a diameter of 1.2 to 1.8 mm. The molded particles were placed in a vacuum muffle furnace and roasted at 350-550°C for 2-3 hours to obtain spherical particle material. When spherical particle material was placed in a drying dish, cooled to room temperature, and sampled, the static moisture adsorption was measured, and the amount of static moisture adsorbed reached 22.7 wt%.

[0044] S2: Crystal transition The resulting crystallization reaction solution was obtained by adding 3 kg of spherical particle material to an 8% by mass sodium hydroxide solution in a weight ratio of 3.5:2 to the spherical particle material. The temperature was raised to 95°C, the solution was placed in a bath, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was complete, the sample was first washed with 50 L of cold water, then washed twice with 10 L of 70°C hot water, and finally washed again with cold water until the pH reached 8 (measured with test paper). A sieve ball of the crystallized reaction molecules was obtained, and a sample was taken and analyzed for pH, which reached 10.45. The water absorption properties of the crystallization reaction molecular sieve balls were tested. Test conditions: The sample was allowed to absorb water for 24 hours under conditions of 25°C and RH50. Results: The content was 22.7 wt% before the crystallization reaction and 25.2 wt% after the crystallization reaction.

[0045] S3: Calcium ion exchange After the crystallization transition, the crystallization reaction molecular sieve balls (4A molecular sieve) were allowed to absorb moisture and placed in a lithium ion exchange apparatus, immersed in water, and the material inside the apparatus was heated to 85-90°C and maintained at that temperature. A calcium chloride solution with a concentration of 2-10% by mass was introduced into the apparatus, and the pH was controlled to 6-9. After a predetermined time, the ion concentration in the liquid was detected from the sampling outlet of the apparatus. When the ion concentration in the liquid reached a predetermined value, the calcium ion exchange reaction was terminated, and an all-zeolite calcium type molecular sieve (5A molecular sieve) was obtained. The all-zeolite calcium type molecular sieve inside the apparatus was rinsed with deionized water, and after rinsing to the desired degree, the material was removed, dehydrated, and the all-zeolite calcium type molecular sieve was collected.

[0046] S4: Activation All-zeolite calcium type molecular sieves were slowly added to a belt oven for pre-baking, controlling the oven temperature to 80-220°C, controlling the moisture content of the material after drying to 5-15%, and the material was collected in a container. The dried material was placed in a vertical activated furnace, and pure nitrogen gas or dry compressed air with a dew point of -70°C was heated to 450-600°C using an electric heater. The hot gas was then introduced into the vertical activated furnace, and the material was roasted to 500-580°C. After being kept warm for 3-5 hours, the finished all-zeolite calcium type molecular sieve was obtained. Subsequently, the finished all-zeolite calcium type molecular sieves in the vertical furnace were cooled to 50°C to 20°C using a cooler, then sieved under the protection of nitrogen gas or suitable dry air, and packaged in packaging barrels. The results of the detection of the manufactured finished product showed that the static moisture adsorption was 22.1 wt%, the calcium ion exchange rate was 94.3%, the bulk density was 0.69 g / ml, the abrasion rate was 0.07 wt%, the average particle size was 1.31 mm, the sieved particle size (<1.00) was 0.4 wt%, the sieved particle size (>1.70) was 0.3 wt%, and the water content was 0.952 wt%, demonstrating excellent properties. The finished product has good sphericity, uniform particle size, and excellent stacking effect, making it suitable for removing impurities from the electrolyte of lithium-ion batteries. After the molecular sieve has adsorbed water to saturation in the electrolyte or its adsorption capacity has decreased to a predetermined value, the molecular sieve is washed, and then the water-adsorbed molecular sieve is dehydrated and regenerated using the microwave high-temperature activation process of the present invention. This restores the adsorption capacity of the molecular sieve and enables the recycling of the molecular sieve.

[0047] A comparison of Examples 1-2 and 3-4 revealed that all-zeolite molecular sieves can also be produced by performing spheroidization, crystallization, crystallization transition, and activation processes on conventional commercially available Type A molecular sieves and used to remove impurities from lithium-ion non-aqueous electrolytes. However, in Examples 1 and 3, the composite Type A molecular sieve raw material powder is synthesized by microwave heating, resulting in a more efficient reaction and lower energy consumption. Consequently, the all-zeolite molecular sieves containing the radio wave absorbing material produced showed further improvement in terms of static moisture adsorption properties and other characteristics.

[0048] The all-zeolite molecular sieves produced in Examples 2 and 4 were allowed to absorb water for 24 hours under conditions of 25°C and RH50, and then regenerated by desorption in an oven. They were baked at 150°C for 2 hours with an oven power of 2kW, reducing the water content to less than 10%, and the estimated power consumption was 4kWh. When the water content was reduced to 10% by microwave heating, the microwave power was 1kW, the time taken was 1 hour, and the estimated power consumption was 1kWh.

[0049] All-zeolite molecular sieves containing the radio wave absorbing material produced in Examples 1 and 3 were allowed to absorb water for 24 hours under conditions of 25°C and RH50, and then regenerated by desorption in a microwave heater. By turning on the microwave and maintaining it for 30 minutes with a power of 1kW, the water content could be reduced to less than 10%, and the estimated power consumption was 0.5kWh.

[0050] As described above, by activating and regenerating the all-zeolite molecular sieves containing the radio wave absorbing material produced in Examples 1 and 3 through microwave heating, efficient recycling of molecular sieves can be achieved, while significantly reducing energy consumption and costs.

[0051] The above are merely preferred embodiments of the present invention and do not limit the present invention in any way. Simple modifications, equivalent changes, and modifications made to the above embodiments in accordance with the technical spirit of the present invention are included within the scope of the technical solutions of the present invention.

Claims

1. A method for producing a zeolite molecular sieve containing an electromagnetic wave absorbing material, Step S1 of the molding process involves uniformly mixing a composite type A molecular sieve raw material powder containing radio wave absorbing material with a binder in a predetermined ratio, milling the mixture, molding it in a granulator, and then drying and roasting it to obtain molded particle material. Step S2 involves a crystallization transition, in which the molded particle material obtained in step S1 is baked and placed in an alkaline solution, heated to carry out a crystallization reaction, converting the binder in the molded particle material into zeolite crystals, and obtaining a zeolite molecular sieve. Step S3 of the ion exchange process involves absorbing moisture from the zeolite molecular sieve produced in step S2, immersing it in water, sending it into an ion exchange column using a peristaltic pump, heating it to the ion exchange temperature, introducing the target ion solution, performing ion exchange, rinsing it with deionized water, further dehydrating it, and collecting the zeolite molecular sieve modified with the target ion solution. Step S4 includes an activation step in which the target ion solution-modified zeolite molecular sieve produced in step S3 is subjected to a pre-bake treatment, the semi-finished product is sent to an activation furnace for roasting after pre-baking, the product is cooled to the discharge temperature after roasting is complete and then discharged, and the product is sieved to obtain a finished zeolite molecular sieve containing radio wave absorbing material. The composite type A molecular sieve raw material powder containing the aforementioned radio wave absorbing material is The radio wave absorbing material powder is weighed and placed in an alkaline silica-aluminum reaction solution, which is a type A molecular sieve precursor reaction solution. The mixture is then heated with microwaves to initiate the reaction. During this reaction, the radio wave absorbing material is selectively heated, and due to the particle surface effect, molecular sieves grow in situ as crystal species, synthesizing type A molecular sieves. The synthesized type A molecular sieves then cover the radio wave absorbing material, and the mixture is subsequently dried to obtain the desired result. A manufacturing method characterized by the following features.

2. The weight percentage of the binder in the molded particle material is 5% to 20%, and the binder is one or more of kaolin, halloysite, and allophane. The manufacturing method according to claim 1.

3. In step S1, one or more additives are further added, and the additives include one or more of the following: water glass, aluminum sol, silica sol, silicone resin emulsion, pyrophosphate, aluminum hydrogen phosphate, cellulose and its derivatives, and tannin extract. The manufacturing method according to claim 1.

4. In step S2, the alkaline solution is at least one of sodium hydroxide solution, potassium hydroxide solution, or calcium hydroxide solution, the concentration of the solution is 1% to 40% by mass, and the heating temperature is 65 to 125°C. The manufacturing method according to claim 1.

5. In step S3, the target ionic solution is at least one of the following: a soluble chloride solution, a hydroxide solution, a sulfate solution, or a nitrate solution containing the target ionic solution; the concentration of the solution is 1% to 40% by mass; the ion exchange temperature is 50 to 130°C; the pH value is controlled to be in the range of 6 to 12 during the ion exchange reaction; and the temperature of the deionized water used for rinsing is 60 to 90°C. The manufacturing method according to claim 1.

6. In step S4, the bake temperature is controlled to 80-220°C, the moisture content of the dried product is controlled to 5-15%, the activation furnace is preheated with a drying gas, and the target ion solution modified zeolite molecular sieve produced in step S3 is roasted, with a preheating temperature of 400-800°C, a roasting temperature of 500-580°C, a roasting time of 3-5 hours, and an exhaust temperature of 50-20°C. The manufacturing method according to claim 1.

7. A zeolite molecular sieve containing an electromagnetic wave absorbing material, Manufactured by the manufacturing method described in any one of claims 1 to 6, The particle size distribution is 0.1 to 5.0 mm, the ion exchange rate in the process is 95% or higher, the static moisture adsorption is 20 wt% or higher, the water content is 1.5 wt% or lower, and the abrasion rate is less than 1.5 wt%. A zeolite molecular sieve characterized by the following.

8. The zeolite molecular sieve containing the aforementioned radio wave absorbing material is activated and regenerated by microwave heating after adsorption. By raising the temperature of the zeolite molecular sieve containing the radio wave absorbing material to 100 to 250°C with a microwave heating output power of 0.5 to 2 kW and processing for 1 to 40 minutes, the activation and regeneration are completed. A zeolite molecular sieve containing the radio wave absorbing material described in claim 7.

9. Use of a zeolite molecular sieve containing the radio wave absorbing material described in claim 8 as an adsorbent for removing impurities.