Method for production and use of all-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 to a composite A-type molecular sieve raw material powder containing a radio wave absorbing material, an all-zeolite molecular sieve, methods for manufacturing these, and their use.

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, forming a solid electrolyte interface film (SEI) that has an important impact on the characteristics of the lithium-ion battery. However, inevitably, trace amounts of impurities such as water, acids, and alcohols are mixed into the electrolyte 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 produce 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 any 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. Theoretically, 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, whose molecular sizes are 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 manufacturing Li-LSX molecular sieve. This method involves exchanging LSX multiple times with an aqueous potassium ion solution to obtain K+-LSX, further exchanging it multiple times with an aqueous ammonium ion 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. This method increases the utilization rate of Li by adopting an exchange method based on NH4+ transition, but the process flow is relatively complex. Moreover, due to the poor hydrothermal stability of the low-silica aluminomolecular sieve framework itself, the molecular sieve framework is damaged by frequent hydrothermal ion exchange. 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 produced in this application cannot be used for removing impurities from lithium ion non-aqueous electrolytes is that it is related to the production of the raw material powder of the molecular sieve. In actual use, the raw material powder of the molecular sieve often cannot be used normally without being made into small spherical shapes through a spheroidization process. However, in the spheroidization process, it is inevitable to add a binder and other additives. Therefore, even if the previous Li exchange degree is high, after going through the spheroidization process, the lithium ion content will inevitably decrease. In addition, when the lithium ion non-aqueous electrolyte highly adsorbs a small amount of water, it causes secondary contamination of other ions by ion exchange in materials such as the binder. In particular, sodium ion contamination is fatal to the lithium ion non-aqueous electrolyte.

[0005] In addition to the above problems, in the process of removing impurities from a large amount of lithium ion non-aqueous electrolytes, there are also problems such as how to efficiently desorb and regenerate the molecular sieve adsorbed with impurities and how to suppress the manufacturing cost of the adsorbent. In order to solve the above problems existing in the prior art, the present invention is completed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Among many types of molecular sieves, A-type molecular sieves are easy to manufacture, have low costs, and can obtain 3A, 4A, and 5A molecular sieves by exchanging with various ions, thereby realizing the sieving, separation, and adsorption effects of molecules of various sizes. In view of this, the present invention proposes a composite A-type molecular sieve raw material powder containing a radio wave absorbing material, an all-zeolite molecular sieve, their manufacturing methods, and uses, in response to the above-mentioned drawbacks existing in the prior art. The manufactured all-zeolite molecular sieve can highly adsorb specific molecules, can be rapidly regenerated by microwave heating, and can improve the activation regeneration efficiency.

Means for Solving the Problems

[0008] The first aspect of the present invention provides a composite A-type molecular sieve raw material powder containing a radio wave absorbing material, including a micro-nano-sized radio wave absorbing material and an A-type molecular sieve grown in-situ using the micro-nano-sized radio wave absorbing material as a seed crystal, with the A-type molecular sieve covering the radio wave absorbing material.

[0009] In some embodiments, the micro-nano-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 LTA (Linde Type A) type molecular sieves, typically, for example, 3A molecular sieve, 4A molecular sieve, and 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] The second aspect of the present invention is Weigh the micro-nano-sized radio wave absorbing material powder, put it into the A-type molecular sieve precursor reaction solution, and then heat it with microwave to react. When heating with microwave, the radio wave absorbing material is selectively heated, and due to the action of the particle surface effect, it grows in-situ as the seed for the growth of the molecular sieve to synthesize the A-type molecular sieve. The synthesized A-type molecular sieve covers the radio wave absorbing material. After the reaction is completed, dry it to obtain the composite A-type molecular sieve raw material powder containing the radio wave absorbing material, and provide the manufacturing method of the composite A-type molecular sieve raw material powder containing the above radio wave absorbing material.

[0012] In some embodiments, the A-type molecular sieve precursor reaction solution is an alkaline silica-aluminum reaction solution, and the molar ratio of the composition of the reaction solution materials is xM2O:ySiO2:Al2O3:zH2O (where M is one or more of 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). The output power of microwave heating is 0.1 to 2 kW, the reaction temperature is 40 to 110 °C, the reaction time is 1 to 48 h, and the drying temperature is 80 to 120 °C. Preferably, the heating temperature is 60 to 100 °C and the reaction time is 1 to 24 h.

[0013] The third aspect of the present invention is After milling a mixture of the composite A-type molecular sieve raw material powder containing the radio wave absorbing material and the binder uniformly mixed at a predetermined ratio, form it with a granulator, and then dry and bake it to obtain the formed particle material, the forming step S1; Bake the formed particle material obtained in step S1, put it into an alkaline solution, heat it to perform a crystallization reaction, convert the binder in the formed particle material into zeolite crystals, and obtain an all-zeolite molecular sieve, the crystal conversion step S2; Moisten the all-zeolite molecular sieve produced in step S2, immerse it in water, send it into the ion exchange column by a peristaltic pump, heat it to the ion exchange temperature, then introduce the target ion solution to perform ion exchange. After the ion exchange reaction is completed, rinse it with deionized water, further dehydrate it, and collect the target ion solution modified all-zeolite molecular sieve, the ion exchange step S3; Perform a preliminary baking process on the target ion solution-modified all-zeolite molecular sieve produced in step S3. After the preliminary baking, send the semi-finished product to an activation furnace for roasting. After the roasting is completed, cool it down to the discharge temperature and then discharge it. Optionally, under the protection of nitrogen or dry air, sieve it to obtain a finished product of all-zeolite molecular sieve containing a radio wave absorbing material, including the activation step S4. Provide a method for manufacturing an all-zeolite molecular sieve containing a radio wave absorbing material.

[0014] Preferably, the weight ratio of the binder in the formed particle material is 5% - 20%, and the binder is one or more of kaolin, halloysite, and allophane.

[0015] In step S1, one or more additives for optimizing various properties of the formed particle material, such as improving strength, reducing wear, and improving porosity, are further added. The additives include one or more of water glass, aluminum sol, silica sol, silicone resin emulsion, pyrophosphate, aluminum hydrogen phosphate, celluloses and their derivatives, tannin extract, etc. The shape of the formed product may be spherical, strand-like, etc., and should be designed according to specific applications.

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

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

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

[0019] The fourth aspect of the present invention provides an all-zeolite molecular sieve containing a radio wave absorbing material, which is produced by the above manufacturing method, has a particle size distribution of 0.1 - 5.0 mm, an ion exchange degree in the process of 95% or more, a static moisture adsorption of 20 wt% or more, a water content of 1.5 wt% or less, and a wear rate of less than 1.5 wt%.

[0020] In some embodiments, the all-zeolite molecular sieve containing a radio wave absorbing material is activated and regenerated by microwave heating after adsorption. That is, after the adsorption by the molecular sieve is completed, the molecular sieve is washed, and then dehydrated and regenerated by activating it with microwave heating to restore the adsorption capacity of the molecular sieve. Thereby, the recycling of the molecular sieve is realized. When the output power of microwave heating is set to 0.5 - 2 kW and the temperature of the all-zeolite molecular sieve containing a radio wave absorbing material is raised to 100 - 250°C and processed for 1 - 40 min, the activation regeneration is completed.

[0021] The 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 the impurity removal of 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 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 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 airflow 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 that of the template agent. 3) By granulating the molecular sieve powder, the permeability of the electrolyte in the adsorption process can be improved, the adsorption treatment efficiency can be improved, and for the conventional powdered molecular sieve, the filtration time can be shortened from the hour level to the minute level. 4) By performing a crystal conversion treatment on the binder added in the forming process to convert the binder with a non-zeolite crystal structure into zeolite crystals, the adsorption characteristics of the molecular sieve can be improved, and the adsorption capacity can be improved by 5% to 20% compared with the non-crystal-converted molecular sieve. In addition, all-zeolite molecular sieves can be manufactured without repeating hydrothermal exchange, and the structural stability is effectively improved. 5) The all-zeolite molecular sieve containing the manufactured radio wave absorption material can fully exert the characteristic of the molecular sieve to highly remove water, simplify the process of removing water, improve the efficiency of removing water, and improve the quality of the electrolyte. In addition, if an all-zeolite lithium-type molecular sieve containing a radio wave absorption material is adopted, the contents of Na+ and K+ are extremely low, and when adsorbing trace amounts of water, hydrogen fluoride, methanol and other molecules in the electrolyte, it will not exchange with Li+ and affect the Li+ purity in the electrolyte, and in particular, no secondary pollution will occur, and the cycle characteristics of the lithium-ion battery can be ensured.

Embodiments for Carrying out the Invention

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

[0025] This example relates to a method for manufacturing an all-zeolite lithium-type molecular sieve containing a radio wave absorption material, including steps S1 to S5.

[0026] S1: In-situ synthesis of a composite A-type molecular sieve raw material powder having a radio wave absorption function The molar compounding ratio of the materials is 3Na2O:2SiO2:Al2O3:128H2O. Sodium silicate and sodium aluminate were weighed to prepare solutions respectively. Sodium hydroxide was added to the two solutions respectively, and then the two solutions were uniformly mixed. 1 kg of silicon carbide powder was weighed and added to an alkaline silica-alumina sol reaction solution (added according to the theoretical yield of 9 kg of type A molecular sieve), put into a microwave reactor, and reacted at 100 W for 10 min to obtain a composite 4A molecular sieve raw material powder containing a silicon carbide radio wave absorption material.

[0027] S2: Spheroidization 8 kg (dry basis) of the composite 4A molecular sieve raw material powder containing the manufactured silicon carbide radio wave absorption material and 2 kg of kaolin were weighed, put into a mixer with a diameter of Φ500 mm, and mixed for 30 minutes to obtain a mixture. 5 kg (dry basis weight conversion) of the mixture was weighed, put into an EIRICH automatic molding machine, and injected into a mixed solution for molding. The diameter of the molded particles was made 1.2 - 1.8 mm. The molded particles were put into a vacuum muffle furnace and calcined at 350 - 550 °C for 2 - 3 hours to obtain spherical particle materials. The spherical particle materials were put into a drying dish, cooled to room temperature, sampled, and the static moisture adsorption was measured. As a result, the static moisture adsorption reached 21.7 wt%.

[0028] S3: Crystal transition 3 kg of the spherical particle materials were weighed and put into deionized water to measure the weight. As a result, it was 4.84 kg. At a ratio where the weight ratio of the obtained crystallization reaction solution to the spherical particle materials was 3.5:1, 3 kg of the spherical particle materials were added to an 8 mass% sodium hydroxide solution to obtain a crystallization reaction solution. The temperature was raised to 95 °C, put into a solution tank, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was completed, it was washed with 50 L of cold water, then washed twice with 10 L of 70 °C hot water, and further washed with cold water until the pH = 8 (measured with test paper) to obtain crystallization reaction molecular sieve balls. Sampling and analyzing the pH value, as a result, it reached 10.45. The water absorption of the crystallization reaction molecular sieve balls was tested. Test conditions: Absorb water for 24 hours under the conditions of 25°C and 50% RH. Results: 21.7 wt% before the crystallization reaction and 24.5 wt% after the crystallization reaction.

[0029] S4: Lithium ion exchange After the crystal transition, the crystallized reaction molecular sieve balls (4A molecular sieve) were made to absorb moisture, put into a lithium ion exchange device, immersed in water, and the materials in the device were heated to 85 - 90°C and kept warm. A lithium sulfate solution with a concentration of 1 mass% - 8 mass% was introduced into the device, 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 device. 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 in the device was rinsed with deionized water and rinsed to the desired degree, then the materials were taken out and dehydrated, and the all-zeolite lithium type molecular sieve was collected.

[0030] S5: Activation The all-zeolite lithium type molecular sieve was slowly added to a belt oven for pre-baking treatment. The temperature in the oven was controlled to 80 - 220°C, and the moisture of the dried material was controlled to 5% - 15%. The materials were collected in a container. The dried materials were put into 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 with an electric heater. The hot gas was introduced into the vertical activation furnace, and the materials were heated to 500 - 580°C for roasting and kept warm for 3 - 5 hours to obtain a finished product of all-zeolite lithium type molecular sieve containing silicon carbide radio wave absorbing material. After that, the finished product of all-zeolite lithium type molecular sieve containing the radio wave absorbing material in the vertical furnace was cooled to 50°C - 20°C with a cooler, then screened under the protection of nitrogen gas or qualified dry air and packaged in a packaging barrel. As a result of detecting the finished product of all-zeolite lithium type molecular sieve containing the manufactured radio wave absorbing material, the static moisture adsorption was 23.6 wt%, the Li exchange degree 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 sieving particle size (<1.00) was 0.1 wt%, the sieving particle size (>1.70) was 0.1 wt%, the water content was 0.952 wt%, and the properties were excellent. The finished product has good sphericity, uniform particle size, excellent stacking effect, and can handle the removal of impurities in the electrolyte of lithium ion batteries. Example 2

[0031] This example relates to a method for manufacturing an all-zeolite lithium type molecular sieve including 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, put into a Φ500 mm mixer, and mixed for 30 minutes. 5 kg of the mixture was weighed, put into an EIRICH automatic molding machine, and a mixed solution was injected to make it for molding, and the diameter of the molded particles was set to 1.2 to 1.8 mm. The molded particles were put into a vacuum muffle furnace and baked at 350 to 550 °C for 2 to 3 hours to obtain spherical particle materials. The spherical particle materials were put into a drying dish, cooled to room temperature, sampled, and the static moisture adsorption was measured. As a result, the static moisture adsorption amount reached 20.0 wt%.

[0033] S2: Crystal transition 3 kg of the spherical particle materials were added to an 8 mass% sodium hydroxide solution at a ratio such that the weight ratio of the obtained crystallization reaction solution to the spherical particle materials was 3.5:1 to obtain a crystallization reaction solution. The temperature was raised to 95 °C, put into a solution tank, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was completed, first, it was washed with 50 L of cold water, then washed twice with 10 L of hot water at 70 °C, and further washed with cold water until the pH reached 8 (measured with test paper), obtaining the molecular sieve balls of the crystallization reaction. As a result of sampling and analyzing the pH value, it reached 10.45. The water absorption of the molecular sieve balls of the crystallization reaction was tested. Test conditions: Absorb water for 24 hours under the conditions of 25 °C and RH50. Results: It was 20.0 wt% before the crystallization reaction and 22.3 wt% after the crystallization reaction.

[0034] S3: Lithium ion exchange After the crystal transition, the molecular sieve balls of the crystallization reaction (4A molecular sieve) were hygroscopic and put into a lithium ion exchange device and immersed in water. The materials in the device were heated to 85 - 90 °C and kept warm. A lithium sulfate solution with a concentration of 1 mass% - 8 mass% was introduced into the device to control the pH to 6 - 12. After a predetermined time, the ion concentration in the liquid was detected from the sampling outlet of the device. When the ion concentration in the liquid reached the 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 in the device was rinsed with deionized water and rinsed to the desired degree, then the materials were taken out and dehydrated, and the all-zeolite lithium type molecular sieve was collected.

[0035] S4: Activation The all-zeolite lithium type molecular sieve was slowly added to a belt oven for pre-baking treatment. The temperature in the oven was controlled at 80 - 220 °C, and the moisture of the dried materials was controlled at 5% - 15%. The materials were collected in a container. The dried materials were put into 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 with an electric heater. The hot gas was introduced into the vertical activation furnace to heat and roast the materials at 500 - 580 °C and keep warm for 3 - 5 hours, obtaining the finished product of the all-zeolite lithium type molecular sieve. After that, the finished product of the all-zeolite lithium type molecular sieve containing the radio wave absorbing material in the vertical furnace was cooled to 20 °C - 50 °C with a cooler, and then sieved under the protection of nitrogen gas or qualified dry air and packaged in a packaging barrel. As a result of detecting the manufactured finished product, the static moisture adsorption was 22.5 wt%, the Li exchange degree 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 sieving particle size (<1.00) was 0.5 wt%, the sieving particle size (>1.70) was 0.5 wt%, the water content was 0.952 wt%, and it had excellent properties. The finished product had good sphericity, uniform particle size, excellent stacking effect, and could handle the removal of impurities in the electrolyte of lithium-ion batteries. Example 3

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

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

[0038] S2: Spheroidization Weighed 9 kg (dry basis) of the composite 4A molecular sieve raw material powder containing the manufactured silicon carbide radio wave absorbing material and 1 kg of halloysite, put them into a Φ500 mm mixer, and mixed for 30 minutes. Weighed 5 kg of mix (dry basis weight conversion), put it into an EIRICH automatic molding machine, injected a mixed solution for molding, and made the diameter of the molded particles 1.2 - 1.8 mm. The shaped particle material was placed in a vacuum muffle furnace and calcined at 350 - 550 °C for 2 - 3 hours to obtain spherical particle material. The spherical particle material was placed in a drying dish, cooled to room temperature, sampled, and the static moisture adsorption was measured. As a result, the static moisture adsorption reached 25.2 wt%.

[0039] S3: Crystal transition 3 kg of the spherical particle material was added to an 8 mass% sodium hydroxide solution at a ratio such that the weight ratio of the obtained crystallization reaction solution to the spherical particle material was 3.5:2 to obtain a crystallization reaction solution. The temperature was raised to 95 °C, placed in a solution tank, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was completed, first, it was washed with 50 L of cold water, then washed twice with 10 L of 70 °C hot water, and further washed with cold water until the pH reached 8 (measured with test paper) to obtain crystallization reaction molecular sieve balls. Sampling and analyzing the pH value, the result reached 10.45. The water absorption of the crystallization reaction molecular sieve balls was tested. Test conditions: Absorb water for 24 hours under the conditions of 25 °C and RH50. Results: Before the crystallization reaction, it was 25.2 wt%, and after the crystallization reaction, it was 28.0 wt%.

[0040] S4: Calcium ion exchange After the crystal transition, the crystallization reaction molecular sieve balls (4A molecular sieve) were moisture-absorbed, placed in a lithium ion exchange device, immersed in water, and the materials in the device were heated to 85 - 90 °C and kept warm. A calcium chloride solution with a concentration of 2 mass% - 10 mass% was introduced into the device to control the pH to 6 - 9. After a predetermined time, the ion concentration in the liquid was detected from the sampling outlet of the device. When the ion concentration in the liquid reached a predetermined value, the calcium ion exchange reaction was terminated to obtain all-zeolite calcium type molecular sieve (5A molecular sieve). The all-zeolite calcium type molecular sieve in the device was rinsed with deionized water and rinsed to the desired degree, then the material was taken out and dehydrated to collect the all-zeolite calcium type molecular sieve.

[0041] S5: Activation The all-zeolite calcium type molecular sieve was slowly added to a belt oven for preliminary baking. The temperature in the oven was controlled at 80 - 220°C, and the moisture content of the dried material was controlled at 5% - 15%. The material was collected in a container. The dried material was put into 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 with an electric heater. The hot gas was introduced into the vertical activation furnace to heat and roast the material at 500 - 580°C, and it was kept warm for 3 - 5 hours to obtain the finished product of the all-zeolite calcium type molecular sieve containing the radio wave absorbing material. After that, the all-zeolite calcium type molecular sieve containing the radio wave absorbing material in the vertical furnace was cooled to 50°C - 20°C with a cooler, and then the finished product was sieved under the protection of nitrogen gas or qualified dry air and packaged in a packaging barrel. As a result of detecting the manufactured finished product, the static moisture adsorption was 24.1 wt%, the calcium ion exchange degree 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 sieving particle size (<1.00) was 0.4 wt%, the sieving particle size (>1.70) was 0.3 wt%, and the water content was 0.952 wt%, with excellent properties. The finished product has good sphericity, uniform particle size, an excellent stacking effect, and can be used for removing impurities in the electrolyte of lithium-ion batteries. Example 4

[0042] This example relates to a method for manufacturing an all-zeolite calcium type molecular sieve including steps S1 - S4.

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

[0044] S2: Crystal transition 3 kg of the spherical particle materials were added to an 8 mass% sodium hydroxide solution at a ratio such that the weight ratio of the obtained crystallization reaction solution to the spherical particle materials was 3.5:2 to obtain a crystallization reaction solution. The temperature was raised to 95 °C, placed in a solution tank, and the crystallization reaction was carried out for 3 hours. After the crystallization reaction was completed, first, it was washed with 50 L of cold water, then washed twice with 10 L of 70 °C hot water, and further washed with cold water until the pH reached 8 (measured with test paper) to obtain crystallization reaction molecular sieve balls. Sampling and analyzing the pH value, the result reached 10.45. The water absorption of the crystallization reaction molecular sieve balls was tested. Test conditions: Absorb water for 24 hours under the conditions of 25 °C and RH50. Results: Before the crystallization reaction, it was 22.7 wt%, and after the crystallization reaction, it was 25.2 wt%.

[0045] S3: Calcium ion exchange After the crystal transition, the crystallization reaction molecular sieve balls (4A molecular sieve) were moisture-absorbed, placed in a lithium ion exchange device and immersed in water, and the materials in the device were heated to 85 - 90 °C and kept warm. A 2 - 10 mass% calcium chloride solution was introduced into the device, 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 device. When the ion concentration in the liquid reached a predetermined value, the calcium ion exchange reaction was terminated to obtain all-zeolite calcium type molecular sieves (5A molecular sieves). The all-zeolite calcium type molecular sieves in the device were rinsed with deionized water and rinsed to the desired extent, then the materials were taken out and dehydrated, and the all-zeolite calcium type molecular sieves were collected.

[0046] S4: Activation The all-zeolite calcium type molecular sieve was slowly added to a belt oven for pre-baking treatment. The temperature in the oven was controlled at 80 - 220°C, and the moisture content of the dried material was controlled at 5% - 15%. The material was collected in a container. The dried material was put into 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 with an electric heater. The hot gas was introduced into the vertical activation furnace to heat and roast the material at 500 - 580°C, and it was kept warm for 3 - 5 hours to obtain the finished product of the all-zeolite calcium type molecular sieve. After that, the finished product of the all-zeolite calcium type molecular sieve in the vertical furnace was cooled to 50°C - 20°C with a cooler, and then sieved under the protection of nitrogen gas or qualified dry air and packaged in a packaging barrel. As a result of detecting the manufactured finished product, the static moisture adsorption was 22.1 wt%, the calcium ion exchange degree 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 screening particle size (<1.00) was 0.4 wt%, the screening particle size (>1.70) was 0.3 wt%, the water content was 0.952 wt%, and the properties were excellent. The finished product has good sphericity, uniform particle size, excellent stacking effect, and can be used for removing impurities in the electrolyte of lithium-ion batteries. After the molecular sieve adsorbs water until saturation or the adsorption capacity drops to a predetermined value in the electrolyte, the molecular sieve is washed, and then the molecular sieve adsorbed with water is dehydrated and regenerated by the microwave high-temperature activation process of the present invention, so that the adsorption capacity of the molecular sieve can be restored and the recycling of the molecular sieve can be realized.

[0047] As a result of comparing Examples 1-2 and Examples 3-4, even by performing spheroidization, crystallization, crystal transition, and activation steps on ordinary commercially available Type A molecular sieves, all-zeolite molecular sieves can be produced and used for removing impurities in lithium-ion non-aqueous electrolytes. However, in Examples 1 and 3, since the composite Type A molecular sieve raw material powder was synthesized by microwave heating, the reaction was efficient and the energy consumption was low. As a result, the all-zeolite molecular sieves containing the manufactured radio wave absorption material were further improved in terms of static moisture adsorption characteristics and the like.

[0048] The all-zeolite molecular sieves produced in Examples 2 and 4 were allowed to absorb water for 24 hours under the conditions of 25°C and 50% RH, and then placed in an oven for desorption and regeneration. They were baked at 150°C for 2 hours, the power of the oven was set to 2 kW, the water content was reduced to 10% or less, and the estimated power consumption was 4 kW·h. When the water content was reduced to 10% by microwave heating, the power of the microwave was 1 kW, the time was 1 hour, and the estimated power consumption was 1 kW·h.

[0049] The all-zeolite molecular sieves containing the radio wave absorption material produced in Examples 1 and 3 were allowed to absorb water for 24 hours under the conditions of 25°C and 50% RH, and then placed in a microwave heater for desorption and regeneration. The microwave was turned on and continued for 30 minutes, the power was 1 kW, the water content could be reduced to 10% or less, and the estimated power consumption was 0.5 kW·h.

[0050] As described above, by activating and regenerating the all-zeolite molecular sieves containing the radio wave absorption material produced in Examples 1 and 3 by microwave heating, efficient recycling of the molecular sieve can be realized, and moreover, the energy consumption and cost can be significantly reduced.

[0051] Note that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical spirit of the present invention are included in the scope of the technical solutions of the present invention.

Claims

1. A method for producing an all-zeolite molecular sieve containing a radio wave absorbing material, comprising the steps of: A molding step S1 in which a composite A-type molecular sieve raw material powder containing an electromagnetic wave absorbing material and a binder are uniformly mixed in a predetermined ratio, milled, molded in a granulator, and then dried and roasted to obtain a molded particle material; The molded particle material obtained in step S1 is baked and put into an alkaline solution, and then heated to carry out a crystallization reaction, so that the binder in the molded particle material is converted into zeolite crystals to obtain an all-zeolite molecular sieve; and a crystal transformation step S2. Step S3 of ion exchange: the all-zeolite molecular sieve produced in step S2 is humidified and immersed in water, then sent into an ion exchange column by a peristaltic pump, heated to an ion exchange temperature, and then introduced with a target ion solution to carry out ion exchange; after the ion exchange reaction is completed, the all-zeolite molecular sieve is rinsed with deionized water, further dehydrated, and the target ion solution modified all-zeolite molecular sieve is collected; and an activation step S4, in which the target ion solution modified all-zeolite molecular sieve produced in step S3 is subjected to a pre-baking treatment, and after the pre-baking, the semi-finished product is sent to an activation furnace for roasting, and after the roasting is completed, the semi-finished product is cooled to a discharge temperature, and then discharged and sieved to obtain a finished all-zeolite molecular sieve containing a radio wave absorbing material. A manufacturing method comprising the steps of:

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

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

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

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

6. In step S4, the baking temperature is controlled at 80-220°C, the moisture content of the product after drying is controlled at 5%-15%, and the activation furnace is preheated with dry gas, and then the target ion solution modified all-zeolite molecular sieve prepared in step S3 is roasted, the preheating temperature is 400-800°C, the roasting temperature is 500-580°C, the roasting time is 3-5 hours, and the discharge temperature is 50-20°C. The method of claim 1 .

7. An all-zeolite molecular sieve containing a radio wave absorbing material, Produced by the production method according to any one of claims 1 to 6, The particle size distribution is 0.1-5.0 mm, the ion exchange degree in the process is 95% or more, the static moisture adsorption is 20 wt% or more, the moisture content is 1.5 wt% or less, and the wear rate is less than 1.5 wt%.

1. An all-zeolite molecular sieve comprising:

8. The all-zeolite molecular sieve containing the radio wave absorbing material is activated and regenerated by microwave heating after adsorption. The output power of microwave heating is set to 0.5-2 kW, the temperature of the all-zeolite molecular sieve containing the radio wave absorbing material is raised to 100-250°C, and the activation and regeneration are completed when the treatment is performed for 1-40 minutes. An all-zeolite molecular sieve comprising the radio wave absorbing material according to claim 7.

9. 9. Use of the all-zeolite molecular sieve containing the radio wave absorbing material according to claim 8 as an adsorbent for removing impurities.