Potassium superoxide composite particles, dry process for preparing the same, and preparation system

Abstract

The present application relates to a kind of potassium superoxide composite particles and its dry preparation process, preparation system, belong to superoxide technical field;Composite particles include core and shell, the core is the mixture of potassium superoxide and bentonite, the shell is the calcium hydroxide coating layer of the core, the core and shell form core-shell structure;Process includes dry powder mixing, dry granulation and whole grain, microwave intensification, surface coating;System includes raw material pretreatment device, dry powder mixing device, dry roller granulation device, microwave intensification processing device, surface coating device;Using dry granulation process, fundamentally eliminate the risk of potassium superoxide and water violent reaction, bentonite as inert matrix, played the role of dilution and stable potassium superoxide, reduce its sensitivity to external stimuli, and the comprehensive performance of granular product is excellent.

Description

Technical Field

[0001] This invention relates to a potassium superoxide composite particle and its dry preparation process and system, belonging to the field of superoxide technology. Background Technology

[0002] Potassium superoxide (KO2) is a highly efficient chemical oxygen-generating material. It reacts with carbon dioxide and water to produce oxygen while simultaneously absorbing carbon dioxide, achieving the dual function of oxygen supply and carbon dioxide reduction. Based on this property, potassium superoxide is widely used in gas control scenarios in confined environments such as submarines, spacecraft, and mine rescue. In these special environments, it can maintain a balance of oxygen and carbon dioxide concentrations for a certain period, providing reliable protection for human life activities. The apparent specific gravity of potassium superoxide powder is 0.4-0.6 g / mL, while its actual specific gravity is 2.136 g / mL. However, if used directly as an oxygen-generating agent, the powder is prone to generating a large amount of dust under external vibration, which can adversely affect human respiration and makes its use inconvenient.

[0003] The existing potassium superoxide powder granulation technology mainly suffers from the following problems: (1) uneven drying and heating. The traditional conveyor belt drying method results in unstable particle turning effect, which easily leads to a large temperature difference between the upper and lower surfaces of the particles; (2) simple dry pressing results in generally poor mechanical strength of the particles, which are prone to pulverization and dust generation during transportation, filling and use. This not only clogs the purification system but also poses a serious risk of explosion; (3) controllability of reaction. Once exposed potassium superoxide particles come into contact with air, they react rapidly, release a large amount of heat and quickly fail, resulting in a short service life and the inability to achieve stable and long-lasting oxygen supply and carbon dioxide adsorption; (4) single function problem. In order to achieve carbon dioxide adsorption and oxygen production at the same time, the existing technology mostly adopts the method of physically mixing potassium superoxide particles with other CO2 adsorbents (such as lithium hydroxide and calcium hydroxide) particles. This method has problems such as uneven component distribution, possible adverse solid-state reactions between different particles, and complex system filling, which limits the improvement of overall performance.

[0004] For example, Chinese Patent Publication No. CN107758623A discloses a method for forming potassium superoxide particles, comprising the following steps: uniformly mixing potassium superoxide powder with excipients to obtain a powder mixture, wherein the amount of excipients added is 10-12% of the total mass of potassium superoxide powder, and the excipients include calcium hydroxide and diatomaceous earth in a mass ratio of 7:(3-5); placing the powder mixture into a cylindrical mold with a diameter of 180-300 mm and a height of 30-35 mm, and pressing it under a pressure of 80-90 MPa to form potassium superoxide flakes; the potassium superoxide flakes are then pulverized to obtain potassium superoxide particles. The potassium superoxide particles obtained by this method have the characteristics of high strength and large specific surface area. However, they are flammable, which presents the aforementioned problem. Therefore, there is an urgent need to develop a safe and efficient preparation method that can produce potassium superoxide-based composite particles with high mechanical strength, controllable reaction, and dual-function synergy to overcome the aforementioned defects of the prior art. Summary of the Invention

[0005] The purpose of this invention is to provide potassium superoxide composite particles and their dry preparation process and system, which solves the problems of high risk in wet granulation of potassium superoxide (KO2), low particle strength in dry granulation, poor controllability of excessively fast reaction rate, and difficulty in efficient integration with carbon dioxide adsorbents in the prior art; the preparation process is safe, the particles have high mechanical strength, and the reaction is stable and long-lasting, resulting in core-shell structured bifunctional composite particles.

[0006] The present invention discloses a potassium superoxide composite particle comprising a core and a shell. The core is a mixture of potassium superoxide and bentonite, and the shell is a calcium hydroxide coating layer that encapsulates the core. The core and the shell form a core-shell structure.

[0007] The bentonite core improves the molding performance of potassium superoxide, reducing dust generation from potassium superoxide powder at the source. The calcium hydroxide shell acts as a protective layer, delaying premature contact and reaction between potassium superoxide and water and carbon dioxide in the external environment, preventing premature deactivation of potassium superoxide, and extending its effective service life. At the same time, calcium hydroxide itself can react with carbon dioxide, synergistically enhancing carbon dioxide absorption with the potassium superoxide core. The core-shell structure can regulate the reaction rate of potassium superoxide with water and carbon dioxide, making the oxygen supply and carbon dioxide absorption process more stable, ensuring the stability of gas balance in a closed environment, and solving the problem of potassium superoxide powder dust hazarding human respiration.

[0008] Preferably, the bentonite is sodium-based bentonite, the mass ratio of sodium-based bentonite to potassium superoxide is (5-15):(85-95), and the mass ratio of the core (01) to calcium hydroxide is (92-98):(8-2).

[0009] Sodium-based bentonite exhibits superior adsorption and molding stability compared to other types of bentonite, allowing for better integration with potassium superoxide and enhancing the molding effect and structural stability of the core particles. The defined mass ratio ensures a high proportion of potassium superoxide in the core, guaranteeing efficient and effective oxygen supply. Simultaneously, the bentonite proportion fully leverages its molding and dust-reducing properties. The reasonable proportion of calcium hydroxide in the shell layer forms a complete protective coating without excessively covering the core, thus ensuring effective oxygen supply and carbon dioxide absorption.

[0010] Bentonite can be sodium-based bentonite, calcium-based bentonite, etc. Sodium-based bentonite has a much better bonding strength, expansion stability and adsorption capacity than calcium-based bentonite, and is more suitable for compounding and granulation with potassium superoxide.

[0011] Preferably, the average compressive strength of the potassium superoxide composite particles is not less than 45N, and the dust rate is not higher than 1.0%.

[0012] The average compressive strength is not less than 45N, indicating that the particles have excellent mechanical strength and are not easily broken during transportation, vibration and use, further reducing dust generation; the dust rate is not higher than 1.0%, which directly solves the problem that potassium superoxide powder easily generates a lot of dust and harms human respiration, improving the safety and convenience of use; at the same time, the high strength can also ensure the stability of the core-shell structure and maintain the stability of the reaction during use.

[0013] The dry preparation process of the above-mentioned potassium superoxide composite particles according to the present invention includes:

[0014] (1) Raw material pretreatment: Sodium-based bentonite is deeply dried under vacuum at 190-210℃;

[0015] (2) Dry powder mixing: Bentonite and potassium superoxide powder are mixed evenly under an inert atmosphere to obtain active dry powder;

[0016] (3) Dry granulation and sizing: The active dry powder obtained in step (2) is pressed into shape by a roller press granulator, and then crushed and sizing to obtain primary particles with a particle size of less than 2 mm.

[0017] (4) Microwave strengthening: The primary particles obtained in step (3) are irradiated under a pulsed microwave field while the material temperature is controlled not to exceed 35°C to obtain core particles. After irradiation, the particles are cooled to room temperature.

[0018] (5) Surface coating: The core particles treated in step (4) are mixed with calcium hydroxide powder in an inert atmosphere to coat the core particles with calcium hydroxide, forming a core-shell structured composite particle; after coating is completed, the particle is cooled to obtain the bifunctional composite particle.

[0019] The entire process employs a dry method, avoiding the reaction between potassium superoxide and water that occurs in wet preparations, which can lead to activity loss and ensure the oxygen-generating activity of potassium superoxide. Key steps utilize an inert atmosphere to prevent premature reaction between potassium superoxide and water or carbon dioxide in the air, preserving the effective content of potassium superoxide. Dry granulation directly forms particles from powder, initially improving particle strength. Microwave strengthening, under controlled temperature conditions, promotes the interfacial bonding between bentonite and potassium superoxide, enhancing the strength and stability of the core particles without damaging the activity of potassium superoxide. The surface coating step uniformly forms a calcium hydroxide shell, ensuring the integrity of the core-shell structure. The process steps are highly controllable and suitable for industrial production.

[0020] Step (1) Remove the moisture contained in the sodium bentonite to avoid the moisture carried by the bentonite reacting with potassium superoxide, causing the loss of potassium superoxide activity and ensuring the effective content of potassium superoxide in the core; at the same time, the sodium bentonite after deep drying has better formability and adsorption, and can be better mixed with potassium superoxide to improve the quality of the core particles.

[0021] A screening process can be added between steps (4) and (5) to screen the cooled particles through a vibrating screen and take the qualified particles as core particles.

[0022] Preferably, in step (2), a gas flow mixer is used to mix the dry powder. The gas flow mixer has an inlet pressure of 0.3-0.5 MPa and a mixing time of 8-12 minutes. The mass ratio of bentonite to potassium superoxide is 8:92.

[0023] The parameters of the airflow mixer are limited to ensure a more uniform mixing of bentonite and potassium superoxide powder, guaranteeing the homogeneity of the core components and thus ensuring consistent oxygen supply and molding performance of each composite particle. The limited 8:92 mass ratio balances the molding assistance of bentonite with the oxygen supply activity of potassium superoxide, ensuring both the mechanical strength of the particles and sufficient oxygen production efficiency. At the same time, the airflow mixing method generates less dust during the mixing process, and the inert atmosphere further protects the activity of potassium superoxide.

[0024] Preferably, in step (3), the linear pressure of the roller press of the granulator is 3-9 MPa and the roller speed is 10-20 rpm.

[0025] The mixed dry powder obtained in step (2) is fed into a roller press granulator through a screw feeder, and the pressure of the press rollers is controlled to perform dry pressing and granulation. The resulting flaky material is processed by a secondary crushing and granulation device to obtain primary particles with uniform particle size. The parameter settings of the press roller linear pressure and roller speed can not only press the dry powder into shape, effectively improve the mechanical strength of the particles, but also prevent the structure of potassium superoxide from being damaged due to excessive pressure, thus avoiding loss of activity. The appropriate roller speed can ensure the efficiency of granulation, while ensuring that the particle size is uniform and the forming effect is good, reducing the difficulty of subsequent granulation and further reducing dust generation.

[0026] Preferably, in step (4), the power of microwave treatment is 300-600W, the center frequency is 2450MHz, the irradiation time is 3-5 minutes, and the material temperature does not exceed 30℃.

[0027] Limited power, frequency, and irradiation time can effectively promote the interfacial bonding between bentonite and potassium superoxide, and improve the compressive strength of the core particles; strictly controlling the material temperature to not exceed 30°C can prevent the potassium superoxide from being decomposed or deactivated by heat, and ensure the oxygen production activity of potassium superoxide; at the same time, microwave treatment can make the interfacial bonding effect of each particle more uniform, and improve the uniformity of the product.

[0028] Preferably, in step (5), a double cone mixer is used for mixing, the mixing speed is 10-20 rpm, and the mixing time is 20-40 minutes; the feeding sequence is to first add all the core particles to the mixer, and then add calcium hydroxide powder; the mass ratio of the core particles to calcium hydroxide is 95:5.

[0029] The mixing method, feeding sequence, and speed and time limits of the double cone mixer allow calcium hydroxide powder to be evenly coated on the surface of the core particles, forming a complete and uniform shell layer, avoiding shell agglomeration or insufficient coating; the 95:5 mass ratio ensures that the shell layer can fully protect the core without over-covering the core and affecting the contact between potassium superoxide and water and carbon dioxide, ensuring the effectiveness of oxygen supply and carbon dioxide absorption; the inert atmosphere prevents potassium superoxide from being deactivated by contact with air during the coating process.

[0030] Further, the surface coating process described in step (5) is carried out in a double-cone drum mixer equipped with an inert gas protection system, a cooling jacket, and a micro-feeding device. During operation, all core particles are first added to the mixer. Under the condition of continuously introducing high-purity nitrogen to maintain a slight positive pressure, the mixer is started and rotated at a speed of 5-10 rpm. Subsequently, pre-dried calcium hydroxide powder is slowly and evenly added through the micro-feeder. After the addition is complete, the speed is adjusted to 10-20 rpm, and mixing is carried out for 20-40 minutes. During the mixing process, the particles undergo three-dimensional tumbling motion within the double-cone container, allowing the calcium hydroxide powder to be evenly coated onto the surface of the core particles through physical adsorption, forming a complete core-shell structure. After mixing, the cooling jacket is opened to cool the material to below 35°C, and then it is discharged through a sealed discharge valve to obtain the final composite particle product.

[0031] The dry preparation system for the above-mentioned potassium superoxide composite particles according to the present invention comprises:

[0032] The raw material pretreatment device is used to perform vacuum deep dehydration treatment on the bentonite and to transport the dehydrated bentonite to the dry powder mixing device;

[0033] A dry powder mixing device is used to uniformly mix potassium superoxide powder and pretreated bentonite powder in a fluidized state to obtain active dry powder.

[0034] A dry roller pressing granulation device is used to roller press active dry powder mixed by a dry powder mixing device to form granules and improve the mechanical strength of the granules.

[0035] A microwave strengthening treatment device is used to microwave treat the particles to promote the interfacial bonding between bentonite and potassium superoxide in the core and improve the compressive strength of the particles.

[0036] A surface coating device is used to achieve shell coating. The core particles and calcium hydroxide powder are mixed in an inert atmosphere, so that calcium hydroxide is coated on the surface of the core particles to form core-shell structured composite particles.

[0037] An inert atmosphere protection module is used to provide an inert atmosphere during the operation of the dry roll granulation device and the microwave intensification treatment device to prevent the potassium superoxide from coming into contact with air or moisture.

[0038] This system enables continuous and automated production from raw material pretreatment to finished product, improving production efficiency while ensuring stable parameters at each process step and enhancing product uniformity. Each device is perfectly adapted to each process step: the raw material pretreatment device ensures effective drying of bentonite, the dry powder mixing device ensures uniform mixing, the dry roller pressing granulation device improves particle strength, the microwave strengthening device enhances core bonding, and the surface coating device ensures uniform shell layer. An inert atmosphere protection module provides protection at critical steps, preventing potassium superoxide from deactivating upon contact with air and water, thus maximizing the retention of potassium superoxide's activity. The entire system is adapted to the characteristics of potassium superoxide, reducing activity loss during production, ensuring stable product quality, and making it suitable for industrial mass production.

[0039] Furthermore, the microwave intensification treatment device integrates a closed-loop temperature control module. This module includes an infrared temperature probe, a temperature feedback controller, and a microwave generator with modulated power. The infrared temperature probe monitors the surface temperature of the material in real time and feeds the signal back to the controller; the controller dynamically adjusts the microwave output power according to a preset upper temperature limit (≤30℃) to ensure that the material remains within a safe temperature range during irradiation. This design achieves low-temperature intensification of particle structure using microwaves while eliminating the risk of decreased potassium superoxide activity due to overheating.

[0040] A potassium superoxide composite particle and its dry preparation process and system have the following beneficial effects:

[0041] 1. Precise and effective pretreatment: Sodium-based bentonite is deeply dehydrated under specific temperature and pressure through vacuum target drying, which ensures the absolute safety of subsequent mixing with potassium superoxide and improves its stability as a carrier.

[0042] 2. Significantly improved safety: The dry granulation process avoids the use of water or liquid binders throughout the process, fundamentally eliminating the risk of a violent reaction between potassium superoxide and water. Bentonite, as an inert matrix, plays a role in diluting and stabilizing potassium superoxide, reducing its sensitivity to external stimuli.

[0043] 3. The granular products have excellent overall performance:

[0044] High mechanical strength: Through the synergistic effect of roller pressing granulation and microwave strengthening, the internal bonding of bentonite particles is made tighter, which significantly improves the compressive and abrasion resistance of the particles and reduces pulverization during transportation and use.

[0045] Enhanced reaction controllability and extended service life:

[0046] Core-shell structure design: The outer layer of calcium hydroxide acts as a "buffer layer" or "preferred reaction layer," which can react with CO2 first, providing protection for the inner layer of potassium superoxide, delaying its direct contact with CO2 and water, and making the release of oxygen more gradual and sustained.

[0047] Synergistic Functions: The core (KO2 / bentonite) is responsible for oxygen production and adsorption of some CO2, while the outer shell (Ca(OH)2) is responsible for CO2 adsorption. This achieves a synergistic effect of dual CO2 adsorption and continuous oxygen supply, thus improving air purification efficiency.

[0048] 4. The preparation process is efficient and controllable:

[0049] The process is rationally designed: vortex mixing ensures uniformity, roller pressing granulation is suitable for dry powder materials, secondary crushing and vibrating screening ensure the uniformity of particle size, and microwave processing is fast and efficient.

[0050] Process controllability: By controlling key process parameters such as pressure roller pressure and microwave parameters (combined with infrared thermometry), precise control over particle strength, density, and reactivity can be achieved, ensuring product quality stability. This process route provides a feasible solution for continuous or batch production and has promising industrial application prospects.

[0051] 5. High raw material utilization efficiency and high functional integration: It maximizes the function within a unit volume, saves space, simplifies the design of air purification systems, and has great application potential in chemical oxygen. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the structure of a potassium superoxide composite particle according to the present invention;

[0053] Figure 2 This is a flowchart of a dry preparation process for potassium superoxide composite particles according to the present invention;

[0054] Figure 3 This is a schematic diagram of the dry preparation system for potassium superoxide composite particles according to the present invention;

[0055] Figure 4 This is a control principle diagram of a closed-loop temperature control module according to the present invention.

[0056] In the diagram: 01, core; 02, shell; 10, raw material pretreatment device; 20, dry powder mixing device; 30, dry roller pressing granulation device; 40, microwave strengthening treatment device; 50, surface coating device; 60, inert atmosphere protection module. Detailed Implementation

[0057] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0058] like Figure 1 As shown, this invention discloses a potassium superoxide composite particle, comprising a core 01 and a shell 02. The core 01 is a mixture of potassium superoxide and sodium-based bentonite, and the shell 02 is a calcium hydroxide coating layer encapsulating the core 01. The core 01 and shell 02 form a core-shell structure. The mass ratio of sodium-based bentonite to potassium superoxide is (5-15):(85-95), and the mass ratio of the core (01) to calcium hydroxide is (92-98):(8-2). This potassium superoxide composite particle is used for carbon dioxide adsorption and chemical oxygen production in a closed environment, with an average compressive strength of not less than 45N and a dust rate of not more than 1.0%.

[0059] like Figure 2 As shown, this invention also discloses a dry preparation process for potassium superoxide composite particles, comprising:

[0060] (1) Raw material pretreatment: Sodium-based bentonite is deeply dried under vacuum conditions. In step (1), the drying conditions of the sodium bentonite are: drying at 190-210℃ for 2.5-3.5h in a vacuum rake dryer, with a vacuum degree of -0.07 to -0.08 MPa.

[0061] (2) Dry powder mixing: Bentonite and potassium superoxide powder are mixed evenly under an inert atmosphere to obtain active dry powder, which is then fed into a roller press granulator via a screw feeder.

[0062] (3) Dry granulation and granulation: The active dry powder obtained in step (2) is pressed into shape by a roller press granulator, and then crushed and granulated to obtain primary particles with a particle size of less than 2 mm; the particle size range of the primary particles is 0.5 mm-2 mm.

[0063] (4) Microwave strengthening: The primary particles obtained in step (3) are irradiated under a pulsed microwave field while the material temperature is controlled not to exceed 35°C to obtain core particles;

[0064] (5) Surface coating: The core particles treated in step (4) are mixed with calcium hydroxide powder under an inert atmosphere, so that calcium hydroxide is coated on the surface of the core particles to form core-shell structured composite particles.

[0065] The dry preparation process of this potassium superoxide composite particle is further described in detail below through examples and comparative examples, but the scope of protection of this invention is not limited thereto. Unless otherwise specified, all operations are carried out in a strictly anhydrous and carbon dioxide-free environment.

[0066] Example 1

[0067] (1) Bentonite pretreatment: Weigh 500g of sodium-based bentonite and spread it evenly in the tray of a vacuum target dryer. Close the chamber door, evacuate to -0.07MPa, and then start the heating program to dry at a constant temperature of 200℃ for 3 hours. After drying, allow it to cool naturally to below 60℃ in a vacuum environment, and immediately transfer it to a glove box filled with high-purity nitrogen for later use.

[0068] (2) Dry powder mixing: In the glove box, accurately weigh 80g of bentonite and 920g of potassium superoxide (mass ratio 8:92) treated in step (1) and pour them into the material tank of the airflow mixer. After sealing the material tank, introduce dry nitrogen gas and adjust the inlet pressure to 0.4MPa to fluidize and mix the materials for 10 minutes.

[0069] (3) Dry roller pressing granulation and sizing: The uniformly mixed active dry powder is fed into the gap between the rollers of the roller press granulator at a constant speed through a closed screw feeder. The double roller linear pressure is controlled at 5MPa, the roller speed at 15rpm, and the roller gap is set at 2mm. The pressed dense flaky material is fed into a crusher for preliminary crushing, and then transferred to a sizing mill for sizing through a 2mm aperture screen to collect primary particles with a particle size distribution between 0.5-2.0mm.

[0070] (4) Microwave-enhanced treatment: Approximately 800g of primary particles were evenly spread on the quartz tray of the microwave processor (with a thickness of approximately 5mm). The microwave generator was set to pulse mode, with a center frequency of 2450MHz, an average power of 450W, and a treatment time of 4 minutes. During the treatment, the surface of the material was scanned and monitored using an infrared thermometer to ensure that the maximum temperature was maintained at 30±3℃. After treatment, the particles were cooled to room temperature under a nitrogen atmosphere. The cooled particles were then passed through a vibrating screen, and qualified particles with a particle size between 0.8mm and 1.2mm were selected.

[0071] (5) Surface coating: Accurately weigh 750g of the core particles obtained in step (4) and 40g of calcium hydroxide powder dried at 100℃ for 2 hours (mass ratio 95:5). First, add all the core particles to a double cone mixer, and then slowly add the calcium hydroxide powder. Turn off the mixer and continuously introduce a small amount of nitrogen to maintain positive pressure. Mix at a speed of 15 rpm for 25 minutes. Discharge the product to obtain the composite particle product A of this invention.

[0072] Example 2

[0073] (1) Bentonite pretreatment: Same as in Example 1.

[0074] (2) Change the raw material ratio: In the glove box, accurately weigh 70g of treated bentonite and 930g of potassium superoxide (mass ratio 7:93) and pour them into the air mixer. Adjust the air pressure to 0.3MPa and mix for 12 minutes.

[0075] (3) Dry roller pressing and granulation: The double roller linear pressure is controlled at 7MPa and the roller speed is 20rpm for pressing. The granulation screen aperture is 2mm to obtain primary particles.

[0076] (4) Microwave strengthening treatment: Set the microwave power to 400W, the treatment time to 5 minutes, and control the material temperature at 30±2℃.

[0077] (5) Surface coating: Weigh 960g of core particles and 40g of calcium hydroxide powder (mass ratio 96:4). Mix at 20 rpm for 20 minutes. The remaining conditions are the same as in Example 1 to obtain the final product B.

[0078] Example 3

[0079] (1) Bentonite pretreatment: Same as in Example 1.

[0080] (2) Dry powder mixing: In a glove box, accurately weigh 90g of the treated bentonite and 910g of potassium superoxide (mass ratio 9:91) and pour them into an air mixer. Adjust the air pressure to 0.5MPa and mix for 8 minutes.

[0081] (3) Dry roller pressing and granulation: The double roller linear pressure is controlled at 9MPa and the roller speed is 10rpm for pressing. The granulation screen aperture is 2mm to obtain primary particles.

[0082] (4) Microwave intensification treatment: Set the microwave power to 500W, the treatment time to 3 minutes, and control the material temperature at 35±2℃.

[0083] (5) Surface coating: Weigh 940g of core particles and 60g of calcium hydroxide powder (mass ratio 94:6). Mix at 10 rpm for 30 minutes. The remaining conditions are the same as in Example 1 to obtain the final product C.

[0084] Example 4

[0085] (1) Bentonite pretreatment: Same as in Example 1.

[0086] (2) Dry powder mixing: In a glove box, accurately weigh 150g of treated bentonite and 850g of potassium superoxide (mass ratio 15:85) and pour them into an air mixer. Adjust the air pressure to 0.5MPa and mix for 10 minutes.

[0087] (3) Dry roller pressing and granulation: The double roller linear pressure is controlled at 3MPa and the roller speed is 15rpm for pressing. The granulation screen aperture is 2mm to obtain primary particles.

[0088] (4) Microwave enhancement treatment: Set the microwave power to 500W, the treatment time to 5 minutes, and control the material temperature at 32±2℃.

[0089] (5) Surface coating: Weigh 920g of core particles and 80g of calcium hydroxide powder (mass ratio 92:8). Mix at 18 rpm for 40 minutes. The remaining conditions are the same as in Example 1 to obtain the final product D.

[0090] Example 5

[0091] (1) Bentonite pretreatment: Same as in Example 1.

[0092] (2) Dry powder mixing: In a glove box, accurately weigh 150g of treated bentonite and 850g of potassium superoxide (mass ratio 5:95) and pour them into an air mixer. Adjust the air pressure to 0.3MPa and mix for 11 minutes.

[0093] (3) Dry roller pressing and granulation: The double roller linear pressure is controlled at 5MPa and the roller speed is 15rpm for pressing. The granulation screen aperture is 2mm to obtain primary particles.

[0094] (4) Microwave intensification treatment: Set the microwave power to 400W, the treatment time to 5 minutes, and control the material temperature at 33±2℃.

[0095] (5) Surface coating: Weigh 980g of core particles and 20g of calcium hydroxide powder (mass ratio 98:2). Mix at 13 rpm for 20 minutes. The remaining conditions are the same as in Example 1 to obtain the final product E.

[0096] Comparative Example 1

[0097] Primary particles were prepared using steps (1)-(3) of Example 1, but without undergoing the microwave strengthening treatment in step (4), they were directly encapsulated in step (5) to obtain comparative sample F. This was used to verify the key role of microwave strengthening treatment in particle strength.

[0098] Comparative Example 2

[0099] Core particles were prepared using steps (1)-(4) of Example 1, but calcium hydroxide was not added for surface coating in step (5), and the core particles were used directly as the final product G. This was used to verify the effect of the surface calcium hydroxide coating layer on the controllability of the reaction.

[0100] Comparative Example 3

[0101] Traditional wet granulation was employed: The mixed dry powder from step (2) of Example 1 was taken out, and 5% wt of pure water was added to the air as a binder for stirring and granulation. It was found that a violent reaction occurred during the addition of water, generating a large amount of heat and oxygen. The mixture quickly became wet, clumped, and produced white smoke, making subsequent granulation impossible, and the experiment was forced to terminate. This was used to compare and highlight the safety advantages of the dry process of this invention.

[0102] Comparative Example 4

[0103] By replacing bentonite with diatomaceous earth, and otherwise following the same procedure as in Example 1, comparative sample H was obtained.

[0104] Effect verification

[0105] The products prepared in Examples 1-5 of this invention and the products of Comparative Examples 1-2 and 4 were tested (Comparative Example 3 could not be granulated due to safety issues, so its performance was not tested). The test results are shown in Table 1 below:

[0106] Table 1 Test Results

[0107] product A B C D E F G H Particle strength (N) 45 50 48 46 52 30 43 38 Dust rate (%) 0.8 0.6 0.7 0.9 0.5 2.3 0.7 1.2

[0108] Dust content: 50g of granules were placed in a vibrating sieve and shaken for 10 minutes. The mass of fine powder (<0.1mm) produced was then weighed. The results are shown in the table above, indicating that the product of this invention has excellent anti-dustling ability.

[0109] Reaction performance: In a standard test chamber, 1% by volume of CO2 was injected, and the duration for which the oxygen concentration remained between 19-21% and the time required for the CO2 concentration to drop below 0.1% were monitored. Results: Products A, B, and C exhibited stable oxygen release, with a duration approximately 50% longer than Comparative Example 2, and higher CO2 adsorption efficiency. This indicates that the core-shell structure effectively delays the core reaction, achieving functional synergy and long-lasting effects.

[0110] Conclusion: The composite particles prepared in all embodiments (AE) of this invention exhibited particle strengths higher than 45 N and dust rates lower than 1.0%, demonstrating excellent mechanical properties and resistance to pulverization. Comparison of the embodiments and Comparative Example F shows that the microwave strengthening treatment step significantly improves particle strength by approximately 50% (as shown in Example E compared to F) and substantially reduces dust rate, making it one of the core innovative aspects of this process. Comparison of the embodiments and Comparative Example G shows that although the calcium hydroxide coating layer has little impact on particle strength, its "buffer layer" design is crucial for delaying the core reaction and achieving long-term stable oxygen supply (see reaction performance test). Example E (ratio 5:95) showed the best performance in terms of strength and dust rate, indicating that, under the premise of ensuring safety, appropriately increasing the potassium superoxide content is beneficial to improving the overall performance of the particles.

[0111] Under the same process conditions, the strength, anti-pulverization ability, and reaction persistence of diatomaceous earth carrier particles are significantly lower than those of bentonite carrier particles. This proves that bentonite is not only an inert filler, but its unique layered structure, ion exchange capacity, and microwave response characteristics play a key role in structural reinforcement and reaction buffering in the dry granulation and microwave strengthening system of this invention, and are an indispensable component for achieving high particle strength and long lifespan.

[0112] The preparation method provided by this invention can safely and efficiently produce high-strength, long-life, and dual-functional synergistic air purification particles, with overall performance significantly superior to traditional methods. This invention provides a complete, controllable, and safe solution from raw material processing, mixing, granulation, fortification to functionalization encapsulation, successfully transforming a highly active chemical substance into a stable, reliable, and practically applicable engineered product, demonstrating significant technological advancement and commercial application value.

[0113] like Figure 3 As shown, this invention also discloses a dry preparation system for potassium superoxide composite particles, comprising:

[0114] The raw material pretreatment device 10 is used to perform vacuum deep dehydration treatment on the bentonite and to transport the dehydrated bentonite to the dry powder mixing device 20.

[0115] The dry powder mixing device 20 is used to uniformly mix potassium superoxide powder and pretreated bentonite powder in a fluidized state to obtain active dry powder.

[0116] The dry roller pressing granulation device 30 is used to roller press the active dry powder mixed by the dry powder mixing device (20) to form granules and improve the mechanical strength of the granules.

[0117] The microwave strengthening treatment device 40 is used to microwave treat the particles to promote the interfacial bonding between bentonite and potassium superoxide in the core 01 and improve the compressive strength of the particles.

[0118] The surface coating device 50 is used to achieve shell 02 coating. The core particles and calcium hydroxide powder are mixed in an inert atmosphere so that calcium hydroxide is coated on the surface of the core particles to form core-shell structured composite particles.

[0119] An inert atmosphere protection module 60 is used to provide an inert atmosphere during the operation of the dry roll granulation device 30 and the microwave intensification treatment device 40 to prevent the potassium superoxide from coming into contact with air or moisture.

[0120] Specifically, the raw material pretreatment device 10 uses a dryer or a vacuum rake dryer, configured to deeply dry the sodium-based bentonite at a temperature of 190-210℃ and a vacuum of -0.07 to -0.08 MPa.

[0121] The dry powder mixing device 20 uses an airflow mixer, configured to mix potassium superoxide powder and pretreated sodium-based bentonite powder for 8-12 minutes under a dry inert atmosphere with an inlet pressure of 0.3-0.5 MPa to form active dry powder.

[0122] The dry roller press granulation device 30 includes a roller press granulator and a crushing and sizing device. The roller press granulator is configured to press and form materials under a pressure of 3-9 MPa. The crushing and sizing device is connected to the discharge port of the roller press granulator and is configured to crush and size the sheet-like material pressed by the roller press granulator to obtain primary particles with a particle size range of 0.5-2 mm.

[0123] like Figure 4 As shown, the microwave enhancement processing apparatus 40 includes:

[0124] Microwave generator: operating frequency 2450MHz, output power adjustable range 300–600W, pulse mode is preferred;

[0125] Microwave resonant cavity: The inner wall is made of stainless steel, and the cavity is equipped with a quartz tray that can hold materials.

[0126] Infrared temperature measurement module: includes a non-contact infrared temperature measurement probe and a temperature feedback controller;

[0127] Inert gas protection unit: It is equipped with an inlet and an outlet for introducing high-purity nitrogen or argon to maintain an anhydrous and oxygen-free environment in the cavity;

[0128] Microwave intensification processing control module: integrates a PLC or microprocessor to coordinate microwave power, irradiation time and temperature feedback signals.

[0129] An infrared temperature probe is fixedly installed on the top or side wall of the microwave resonant cavity. The probe's optical path is vertically or obliquely aligned with the material surface on the quartz tray, ensuring that the monitoring area covers the entire material layer. The signal output of the infrared temperature probe is connected to a temperature feedback controller. The output signal of the temperature feedback controller is connected to the power modulation module of the microwave generator. The start / stop and power output of the microwave generator are controlled by a microwave enhancement processing control module, which can dynamically adjust the microwave output according to a preset program or real-time temperature signal. The workflow (closed-loop control) is as follows:

[0130] 1. Begin microwave processing, set the target upper temperature limit: T_max≤30℃ (adjustable), and set the initial microwave power: P_initial (e.g., 450W).

[0131] 2. Start the microwave irradiation. The infrared temperature probe scans the surface temperature T_current of the material in real time, and the temperature signal is transmitted to the feedback controller. If T_current < T_max - ΔT (e.g., ΔT = 2°C), maintain or increase the microwave power (within the set range). If T_current ≥ T_max - ΔT, the feedback controller sends a signal to the microwave generator, and the microwave power gradually decreases or switches to the pulse mode. If T_current ≥ T_max, the microwave power is temporarily closed or reduced to the minimum, and it resumes after the temperature drops back to the safe range.

[0132] 3. When the set irradiation time (e.g., 3 - 5 minutes) is reached, the microwave stops, and the system prompts that the processing is completed.

[0133] Through infrared non-contact temperature measurement + real-time power feedback, it is ensured that the temperature of KO2 composite particles is always ≤ 30°C during the microwave treatment process. This not only plays the role of strengthening the structure of bentonite by microwave but also completely avoids the risk of decomposition or reaction of KO2 due to local overheating. In the traditional concept, microwave heating is likely to cause a sudden increase in temperature and is not suitable for heat-sensitive materials. Through the closed-loop temperature control module, microwave irradiation of the particles is realized under low-temperature conditions, promoting the recombination of bound water between bentonite particles and the release of lattice stress, completing low-temperature microwave activation, thereby enhancing the mechanical strength and overcoming the technical prejudice. This device can be connected to the front and back processes (roll granulation, cooling and screening) through a closed conveying system to achieve continuous or batch processing under an inert gas atmosphere, improving the overall safety and automation level of the process.

[0134] The surface coating device 50 uses a double-cone mixer, configured to operate at a rotational speed of 10 - 20 rpm, and the addition order of the core particles and calcium hydroxide is to first add all the core particles to the double-cone mixer, and then add calcium hydroxide powder; the double-cone mixer is more specifically a double-cone drum mixer.

[0135] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A potassium hyperoxide composite particle, characterized by, It includes a core (01) and a shell (02), wherein the core (01) is a mixture of potassium superoxide and bentonite, and the shell (02) is a calcium hydroxide coating layer that encapsulates the core (01), and the core (01) and the shell (02) form a core-shell structure.

2. The potassium hyperoxide composite particle of claim 1, wherein, The bentonite is sodium-based bentonite, and the mass ratio of sodium-based bentonite to potassium superoxide is (5-15):(85-95), and the mass ratio of the core (01) to calcium hydroxide is (92-98):(8-2).

3. The potassium hyperoxide composite particle of claim 2, wherein, The average compressive strength of the potassium superoxide composite particles is not less than 45N, and the dust rate is not higher than 1.0%.

4. A dry process for the preparation of the potassium hyperoxide composite particles according to any one of claims 1 to 3, characterized in that, include: (2) Dry powder mixing: Bentonite and potassium superoxide powder are mixed evenly under an inert atmosphere to obtain active dry powder; (3) Dry granulation and sizing: The active dry powder obtained in step (2) is pressed into shape by a roller press granulator, and then crushed and sizing to obtain primary particles with a particle size of less than 2 mm. (4) Microwave strengthening: The primary particles obtained in step (3) are irradiated under a pulsed microwave field while the material temperature is controlled not to exceed 35°C to obtain core particles; (5) Surface coating: The core particles treated in step (4) are mixed with calcium hydroxide powder under an inert atmosphere, so that calcium hydroxide is coated on the surface of the core particles to form core-shell structured composite particles.

5. The dry process according to claim 4, characterized in that, Also includes: (1) Raw material pretreatment: Sodium-based bentonite is deeply dried at 190-210℃ under vacuum conditions.

6. The dry process of claim 4, wherein, In step (2), a gas flow mixer is used to mix the dry powder. The inlet pressure of the gas flow mixer is 0.3-0.5 MPa, and the mixing time is 8-12 minutes. The mass ratio of bentonite to potassium superoxide is 8:

92.

7. The dry process of claim 4, wherein, In step (3), the roller pressure of the roller granulator is 3-9 MPa and the roller speed is 10-20 rpm.

8. The dry process of claim 4, wherein, In step (4), the microwave treatment power is 400-500W, the center frequency is 2450MHz, the irradiation time is 3-5 minutes, and the material temperature does not exceed 30℃.

9. The dry process of claim 4, wherein, In step (5), a double cone mixer is used for mixing. The mixing speed is 10-20 rpm and the mixing time is 20-40 minutes. The feeding sequence is to first add all the core particles to the mixer, and then add the calcium hydroxide powder. The mass ratio of the core particles to calcium hydroxide is 95:

5.

10. A dry process system for producing the potassium hyperoxide composite particles according to any one of claims 1 to 3, characterized by, include: The raw material pretreatment device (10) is used to perform vacuum deep dehydration treatment on the bentonite and to transport the dehydrated bentonite to the dry powder mixing device (20); Dry powder mixing device (20) is used to uniformly mix potassium superoxide powder and pretreated bentonite powder in a fluidized state to obtain active dry powder; Dry roller pressing granulation device (30) is used to roller press the active dry powder mixed by dry powder mixing device (20) to form granules and improve the mechanical strength of the granules; A microwave strengthening treatment device (40) is used to microwave treat the particles to promote the interfacial bonding between bentonite and potassium superoxide in the core (01) and improve the compressive strength of the particles. The surface coating device (50) is used to achieve the coating of the shell (02). The core particles and calcium hydroxide powder are mixed in an inert atmosphere so that the calcium hydroxide is coated on the surface of the core particles to form a core-shell structure composite particle. An inert atmosphere protection module (60) is used to provide an inert atmosphere during the operation of the dry roll granulation device (30) and the microwave intensification treatment device (40) to prevent the potassium superoxide from coming into contact with air or moisture.

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