Low-temperature composite granulation preparation process of cat litter based on natural sodium-based ore

Abstract

The invention provides a cat litter low-temperature composite granulation preparation process based on natural sodium-based ore, and relates to the technical field of pet product manufacturing, and the cat litter low-temperature composite granulation preparation process comprises the following steps: S1, raw material treatment, including sodium-based ore and plant fiber treatment, S2, gradient mixing, including putting sodium-based ore, plant fiber and modified mineral materials in a preset proportion into stirring equipment for dry mixing; s3, carrying out low-temperature composite granulation, and carrying out segmented temperature control on a twin-screw extruder; S4, spraying a nano coating, and putting the particles into a fluidized bed, and adjusting the spraying pressure to 0.20-0.27 MPa; and S5, carrying out dynamic grading screening, and putting the particles sprayed with the nano coating into an intelligent dynamic grading screening machine. The natural sodium-based ore and the plant fibers are adopted as main raw materials, and the uniformity and the performance stability of components of the cat litter are improved through gradient mixing; the surface area of the three-dimensional honeycomb reticular particles formed by the low-temperature composite granulation process is increased, and the adsorption performance and the air permeability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pet supplies manufacturing, and particularly relates to a low-temperature composite granulation preparation process for cat litter based on natural sodium-based ore. Background Art

[0002] With the rapid development of the pet industry, the popularity of cats as domestic pets has been continuously increasing, and the market demand for cat litter is growing day by day; cat litter is a material specially provided for the hygiene and cleaning needs of cats, usually placed in the defecation area of cats, and its main functions are to absorb the urine of cats, cover up odors and facilitate cleaning.

[0003] Traditional cat litters mostly use synthetic materials or non-renewable resources, which have a negative impact on the environment. Although they have a certain adsorption capacity, they have a large amount of dust, which is easy to cause harm to the respiratory tract of cats, and are prone to caking and mildew in a humid environment; secondly, traditional cat litters are not effective enough in adsorbing odors and moisture, and the formability and hardness of the particles are not ideal, and are easy to break during use, resulting in a large amount of debris, increasing the cleaning difficulty; in addition, the preparation process of traditional cat litters is simple and extensive, and the components are not evenly mixed, resulting in unstable performance of cat litter during use, and large differences in the quality of products in different batches, and the performance advantages of raw materials are not fully utilized. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-temperature composite granulation preparation process for cat litter based on natural sodium-based ore, and solve the technical problems existing in the prior art.

[0005] In order to achieve the above-mentioned invention purpose, the technical solution adopted by the present invention is as follows:

[0006] A low-temperature composite granulation preparation process for cat litter based on natural sodium-based ore, comprising the following steps: S1: Raw material treatment, including the treatment of sodium-based ore and plant fiber; taking a preset ratio of sodium-based ore and plant fiber; cleaning the sodium-based ore to remove impurities and microorganisms attached to the surface, and crushing and activating it; soaking the plant fiber in a highly alkaline solution, then cleaning it with water, and then drying and crushing it; S2: Gradient mixing, putting a preset ratio of sodium-based ore, plant fiber and modified mineral materials into a stirring device for dry mixing; adding guar gum to the above dry-mixed materials, stirring at a speed of 400 r / min for 5-15 min, and then adding a deodorant and continuing to stir for 20-30 min to form a mixture; S3: Low-temperature composite granulation, controlling the temperature of the twin-screw extruder in sections, adjusting its speed to 20-45 rpm, and adjusting the die head pressure to 20-35 MPa, extruding through a die with a pore diameter of 2 mm to form particles with a three-dimensional honeycomb network on the surface, and air-cooling the particles; S4: Spraying a nano-coating, putting the above particles into a fluidized bed, adjusting its spraying pressure to 0.20-0.27 MPa, starting the fluidized bed to make the particles in a fluid state under the action of air flow and continuously spraying nano-silicon solution in the fluidized bed; adjusting the hot air temperature of the fluidized bed to 50-60 °C for curing for 5-15 min to form a protective layer with a thickness of 5-10 μm; S5: Dynamic grading and screening, putting the particles after spraying the nano-coating into an intelligent dynamic grading and screening machine, and feedback-adjusting the screen inclination angle and vibration frequency to classify the particle size; packaging the classified particles in layers according to a preset ratio.

[0007] Further, the treatment of the sodium-based ore includes the following steps: material cleaning, selecting high-purity sodium-based ore and rinsing it with pure water for multiple times, and drying the rinsed sodium-based ore; crushing, putting the dried sodium-based ore into a crusher for crushing, and screening it through a 55-85 mesh sieve; activation, putting the crushed sodium-based ore into an activation furnace, performing activation treatment at a temperature of 280-420 °C for 2-4 h, continuously adding steam into the activation furnace, and then drying the activated sodium-based ore at room temperature.

[0008] Further, the treatment of the plant fiber includes the following steps: soaking, soaking the plant fiber in a sodium hydroxide solution with a concentration of 4% - 6% for a soaking time controlled at 1.5-2.5 h; cleaning, rinsing the soaked plant fiber with water until it is neutral, and then drying it with a dryer at a temperature of 110-130 °C until the water content is less than 3%; crushing, putting the dried plant fiber into a crusher for crushing, and screening it through a 25-35 mesh sieve.

[0009] Further, the sodium-based ore is composed of one or more of bentonite, albite, rock salt or natural sodium-based montmorillonite; the plant fiber is composed of one or more of bamboo fiber, coconut shell fiber, straw fiber or wood fiber.

[0010] Further, the gradient mixing includes: in the first stage, the sodium-based ore, the plant fiber and the modified mineral material are put into a double helix conical mixer according to a preset ratio, the rotation speed is adjusted to 150 r / min, the mixing time is 8-15 min, and the temperature is controlled at 22-28 °C to form a mixture; in the second stage, a guar gum solution with a concentration of 2% - 3% is sprayed into the mixture, the rotation speed of the double helix conical mixer is adjusted to 350 - 450 r / min, and the mixing time is 8-15 min to continuously mix to form wet particles; in the third stage, the deodorant is slowly added into the double helix conical mixer in multiple times, the rotation speed is adjusted to 400 - 500 r / min, and the mixing time is 20-35 min; the mixed material is left to stand and age for 20-35 min.

[0011] Further, the intelligent dynamic grading and screening machine includes the following modules: a feeding module for transporting the particles after spraying the nano-coating into the intelligent dynamic grading and screening machine; a screening module including a screen mesh, an inclination angle adjusting mechanism and a vibration mechanism; the particles entering through the feeding module fall onto the screen mesh, the inclination angle adjusting mechanism is adjusted according to the required particle size, and then the vibration mechanism drives the screen mesh to vibrate, and the particles fall through the screen meshes with different apertures through vibration to achieve grading and screening; a feedback adjustment module, during the screening process, the sensor monitors the flow and screening situation of the particles in real time, and then the sensor transmits the real-time data to the control unit, and the control unit automatically adjusts the vibration frequency and the screen mesh inclination angle to grade and screen the particles; a grading and collection module for separately collecting and packaging the particles of different sizes after the grading and screening.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The present invention uses natural sodium-based ore and plant fiber as the main raw materials. Through gradient mixing, the interaction between various components can be further promoted, and the stability of the cat litter performance can be improved. After the above-mentioned gradient mixing, the components of the cat litter can be evenly distributed, ensuring the stability of the cat litter performance; through low-temperature compound granulation, particles with a three-dimensional honeycomb network on the surface can be extruded, increasing the surface area of the cat litter, enhancing the adsorption performance and air permeability. The cat litter manufactured by the above process has appropriate hardness and is not easily broken; by spraying a nano-coating, the abrasion resistance, waterproofness and antibacterial property of the cat litter can be improved, effectively reducing the generation of dust during the use of the cat litter, and even in a humid environment, the storage time can be extended; through the multi-module collaborative operation of an intelligent dynamic grading screening machine, the finished cat litter can be layered and packaged according to different user requirements, improving the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] In order to make the content of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The same reference numerals are used for the same components. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0016] Embodiment 1:

[0017] As Figure 1 shown, a low-temperature composite granulation preparation process for cat litter based on natural sodium-based ore is provided in this embodiment, including the following steps:

[0018] S1: Raw material treatment, including the treatment of albite and coconut shell fiber; take a preset ratio of albite and coconut shell fiber, specifically, the purity of the albite > 85%; wash the albite to remove the impurities and microorganisms attached to the surface, and crush and activate it; soak the coconut shell fiber in a highly alkaline solution and then wash it with clean water, and then dry and crush it; the treatment of the albite includes the following steps: material washing, select high-purity albite and rinse it with pure water multiple times to remove the impurities adsorbed deep inside; dry the rinsed albite to reduce the water content of the albite to 2%, and the tapped density of the dried albite ≦ 0.6 g / cm 3; Crushing: Put the dried albite into a jaw crusher for crushing and then sieve it through a 55-mesh sieve; Activation: Put the crushed albite into an activation furnace and carry out activation treatment at a temperature of 280 °C for 2 h. Continuously add steam into the activation furnace, spray for 5 s every 10 min to promote the interlayer ion exchange of minerals; Then dry the activated albite at room temperature to stabilize the surface hydroxyl groups; The coconut shell fiber treatment includes the following steps: Soaking: Soak the coconut shell fiber in a sodium hydroxide solution with a concentration of 4% for 1.5 h; Cleaning: Rinse the soaked coconut shell fiber with clean water until it is neutral, until the pH value of the coconut shell fiber is 6; Then dry it with a dryer at a temperature of 110 °C until the water content is less than 3%; Crushing: Put the dried coconut shell fiber into a crusher for crushing and then sieve it through a 25-mesh sieve;

[0019] S2: Gradient mixing: Put the preset proportion of albite, coconut shell fiber and modified mineral material into a stirring device for dry mixing; Add guar gum to the above dry-mixed material. The guar gum is used as an adhesive, which can significantly enhance the binding force between components such as albite and improve the durability of the cat litter in actual use; Stir at a speed of 400 r / min for 5 min, and then add a deodorant and continue to stir for 20 min to form a mixture; Specifically, the gradient mixing includes: The first stage: Put albite, coconut shell fiber and modified mineral material into a double-screw conical mixer according to the preset proportion, adjust its speed to 150 r / min, the mixing time is 8 min, and the temperature is controlled at 22 °C to form a mixture; The second stage: Spray a 2% guar gum solution on the mixture. The preparation method of the guar gum solution is to dissolve guar gum in pure water at 40 °C, and its viscosity is controlled at 3500 mPa·s. Adjust the speed of the double-screw conical mixer to 350 r / min, the mixing time is 8 min, and the temperature is controlled at 28 °C, and continuously mix to form wet particles; The third stage: Slowly add the deodorant to the double-screw conical mixer in the second stage in multiple times, adjust its speed to 400 r / min, the mixing time is 20 min, and the temperature is controlled at 30 °C; Put the mixed material into an aging bin and let it stand for aging for 20 min. The humidity in the aging bin is controlled at 75%; The gradient mixing step enables the cat litter particles to have the effects of high adsorption, low dust and long-term deodorization through precise mechanical and chemical regulation; It further promotes the interaction between components and improves the stability of the cat litter performance. After the above gradient mixing, the components of the cat litter can be evenly distributed, ensuring the stability of the cat litter performance;

[0020] S3: Low-temperature compound granulation. The temperature of the twin-screw extruder is controlled in sections to avoid high temperatures from damaging the material adsorption activity of the mixture in S2 and to reduce energy consumption at the same time. Specifically, the temperature control in sections includes: the first zone at 45°C, the second zone at 60°C, and the third zone at 70°C. The first zone is used to soften the mixture. The second zone is used for fiber plasticization and shear stress conduction. The third zone is used for interface crosslinking enhancement to form preset pores. Adjust its rotation speed to 20 rpm and the die head pressure to 20 MPa, and extrude through a die with a pore diameter of 2 mm to obtain particles with a three-dimensional honeycomb network on the surface, and then air-cool the particles. The low-temperature compound granulation step retains the surface area retention rate of the particles at 95%, increases the surface area of the cat litter, and improves the adsorption performance and air permeability. The cat litter manufactured by the above process has appropriate hardness and is not easily broken;

[0021] S4: Spraying a nano-coating. Put the above particles into a fluidized bed. The model of the fluidized bed is a Wurster bottom-spray fluidized bed. Its atomization system uses a dual-channel ultrasonic atomizer, the air distribution plate uses a multi-layer sintered metal filter screen with an opening rate of 25%, and the pore size gradient is 8 μm. The hot air circulation system is adjusted by PID. Adjust its spraying pressure to 0.20 MPa, start the fluidized bed, so that the particles are in a fluidized state under the action of the air flow and continuously spray the nano-silicon solution in the fluidized bed. The nano-silicon solution is composed of nano-silica sol, cetyltrimethoxysilane, polyethylene glycol, silver ion antibacterial agent, and deionized water. Adjust the hot air temperature of the fluidized bed to 50°C for curing for 5 min to form a 5-μm thick protective layer. The step of spraying the nano-coating realizes the surface functional modification of the cat litter particles, enabling them to have the technical effects of moisture-proof, mold-proof, zero dust, and antibacterial while maintaining high adsorption performance;

[0022] S5: Dynamic grading screening. Put the particles after spraying the nano - coating into an intelligent dynamic grading screening machine, and feedback - regulate the screen inclination angle and vibration frequency to grade the particles by size; package the graded particles in layers according to a preset ratio. The intelligent dynamic grading screening machine includes the following modules: a feeding module for transporting the particles after spraying the nano - coating into the intelligent dynamic grading screening machine; a screening module including a screen, an inclination - adjusting mechanism, and a vibration mechanism. The particles entering through the feeding module fall onto the screen. Adjust the inclination - adjusting mechanism according to the required particle size, and then the vibration mechanism drives the screen to vibrate. The particles fall through the screens with different apertures through vibration to achieve grading screening. The vibration mechanism is composed of a double - mass - body inertial vibration motor, which is a prior art and will not be elaborated here. A feedback - regulating module. During the screening process, sensors monitor the flow and screening situation of the particles in real - time, and then the sensors transmit the real - time data to the control unit. The control unit automatically adjusts the vibration frequency and screen inclination angle to grade the particles. The feedback - regulating module is composed of a high - frame - rate industrial camera and a laser particle size analyzer, which are prior arts and will not be elaborated here. A grading and collecting module for separately collecting and packaging the particles of different sizes after grading screening. The grading and collecting module is composed of a pneumatic flap distributor and an anti - static aggregate bin, which are prior arts and will not be elaborated here. The calculation formula used by the control unit is:

[0023] Q = k1·sinθ·(1 + l -βf )

[0024] n = k2·f 1.5 ·A 0.8

[0025] In the formula: Q: screening efficiency, η: screen passing rate, θ: screen inclination angle, f: vibration frequency, A: vibration acceleration.

[0026] Example 2:

[0027] As Figure 1 shown, in this embodiment, a low - temperature composite granulation preparation process for cat litter based on natural sodium - based ore is provided, including the following steps:

[0028] S1: Raw material treatment, including the treatment of salt rock and wood fiber; Take a preset ratio of salt rock and wood fiber, specifically, the purity of the salt rock > 85%; Wash the salt rock to remove impurities and microorganisms attached to the surface, and crush and activate it; Soak the wood fiber in a highly alkaline solution and then wash it with clean water, and then dry and crush it; The salt rock treatment includes the following steps: Material cleaning, select high-purity salt rock and rinse it with pure water multiple times to remove impurities adsorbed deep inside; Dry the rinsed salt rock to reduce the water content of the salt rock to 2.5%, and the vibration compacted density of the dried salt rock ≦

[0029] 0.6 g / cm 3 ; Crushing, put the dried salt rock into a jaw crusher for crushing and pass through a 65-mesh sieve; Activation, put the crushed salt rock into an activation furnace and carry out activation treatment at a temperature of 300 °C for 3 h, continuously add steam into the activation furnace, and spray for 5 s every 12 min to promote the interlayer ion exchange of minerals; Then dry the activated salt rock at room temperature to stabilize the surface hydroxyl groups; The wood fiber treatment includes the following steps: Soaking, soak the wood fiber in a sodium hydroxide solution with a concentration of 5% for 2 h; Cleaning, use clean water to rinse the soaked wood fiber until it is neutral until the pH value of the wood fiber is 7; Then dry it with a dryer at a temperature of 120 °C until the water content is less than 3%; Crushing, put the dried wood fiber into a crusher for crushing and pass through a 30-mesh sieve;

[0030] S2: Gradient mixing. Put salt rock, wood fiber and modified mineral materials in a preset ratio into a stirring device for dry mixing. Add guar gum to the above dry-mixed materials. The guar gum is used as an adhesive, which can significantly enhance the bonding force between components such as salt rock, wood fiber and modified mineral materials, and improve the durability of the cat litter in actual use. Stir at a speed of 400 r / min for 10 min, and then add a deodorant and continue to stir for 25 min to form a mixture. Specifically, the gradient mixing includes: In the first stage, put salt rock, wood fiber and modified mineral materials in a preset ratio into a double-screw conical mixer, adjust its speed to 150 r / min, the mixing time is 12 min, and the temperature is controlled at 24 °C to form a mixture. In the second stage, spray a 2.5% guar gum solution on the mixture. The preparation method of the guar gum solution is to dissolve guar gum in pure water at 40 °C, and its viscosity is controlled at 4000 mPa·s. Adjust the speed of the double-screw conical mixer to 400 r / min, the mixing time is 13 min, and the temperature is controlled at 28 - 30 °C, and continuously mix to form wet particles. In the third stage, add the deodorant to the double-screw conical mixer in the second stage in several portions slowly, adjust its speed to 450 r / min, the mixing time is 30 min, and the temperature is controlled at 31 °C. Put the mixed material into an aging bin and let it stand and age for 28 min. The humidity in the aging bin is controlled at 75%. The gradient mixing step, through precise mechanical and chemical regulation, enables the cat litter particles to have the effects of high adsorption, low dust and long-term deodorization. It further promotes the interaction between components and improves the stability of the cat litter performance. After the above gradient mixing, the components of the cat litter can be evenly distributed, ensuring the stability of the cat litter performance;

[0031] S3: Low-temperature composite granulation. Control the temperature of the twin-screw extruder in sections to avoid high temperature damaging the material adsorption activity of the mixture in S2 and reduce energy consumption at the same time. Specifically, the temperature control in sections includes: the first zone at 50 °C, the second zone at 62 °C, and the third zone at 75 °C. The first zone is used to soften the mixture. The second zone is used for fiber plasticization and shear stress conduction. The third zone is used for interface cross-linking strengthening to form preset pores. Adjust its speed to 30 rpm and the die head pressure to 30 MPa, and extrude through a die with a pore diameter of 2 mm to form particles with a three-dimensional honeycomb network on the surface, and air-cool the particles. The low-temperature composite granulation step enables the surface area retention rate of the particles to reach 96%, increases the surface area of the cat litter, improves the adsorption performance and air permeability. The cat litter manufactured by the above process has appropriate hardness and is not easy to break;

[0032] S4: Spraying a nano - coating. Put the above - mentioned particles into a fluidized bed. The model of the fluidized bed is a Wurster bottom - spraying fluidized bed. Its atomization system uses a dual - channel ultrasonic atomizer, the air - flow distribution plate uses a multi - layer sintered metal filter screen with an opening ratio of 25%, and the pore size gradient is 8μm. The hot - air circulation system is adjusted by PID; adjust its spraying pressure to 0.25 MPa, start the fluidized bed, so that the particles are in a fluidized state under the action of air flow and continuously spray a nano - silicon solution in the fluidized bed. The nano - silicon solution is composed of nano - silica sol, cetyltrimethoxysilane, polyethylene glycol, silver - ion antibacterial agent, and deionized water; adjust the hot - air temperature of the fluidized bed to 55°C for curing for 11 min to form an 8 - μm thick protective layer; the step of spraying the nano - coating realizes the surface functional modification of the cat litter particles, enabling them to maintain high adsorption performance while having the technical effects of moisture - proof, mildew - proof, zero - dust, and antibacterial;

[0033] S5: Dynamic classification screening. Put the particles after spraying the nano - coating into an intelligent dynamic classification screening machine, and feedback - adjust the screen inclination angle and vibration frequency to classify the particle size; package the classified particles in layers according to a preset ratio; the intelligent dynamic classification screening machine includes the following modules: a feeding module, which is used to transport the particles after spraying the nano - coating into the intelligent dynamic classification screening machine; a screening module, including a screen, an inclination - adjusting mechanism, and a vibration mechanism; the particles entering through the feeding module fall onto the screen. Adjust the inclination - adjusting mechanism according to the required particle size, and then the vibration mechanism drives the screen to vibrate. The particles fall through the screens with different pore sizes through vibration to achieve classification screening; the vibration mechanism is composed of a double - mass - body inertial vibration motor, which is a prior art and will not be elaborated here; a feedback - adjustment module. During the screening process, sensors monitor the flow and screening situation of the particles in real - time, and then the sensors transmit the real - time data to the control unit. The control unit automatically adjusts the vibration frequency and screen inclination angle to classify the particles; the feedback - adjustment module is composed of a high - frame - rate industrial camera and a laser particle size analyzer, which are prior arts and will not be elaborated here; a classification and collection module, which separately collects and packages the particles of different sizes after classification screening; the classification and collection module is composed of a pneumatic flap diverter and an anti - static aggregate bin, which are prior arts and will not be elaborated here; the calculation formula used by the control unit is:

[0034] Q = k1·sinθ·(1 + l -βf )

[0035] n = k2·f 1.5 ·A 0.8

[0036] Where: Q: screening efficiency, η: sieve penetration rate, θ: sieve inclination angle, f: vibration frequency, A: vibration acceleration.

[0037] Example 3:

[0038] As Figure 1 shown, in this embodiment, a low-temperature composite granulation preparation process of cat litter based on natural sodium-based ore is provided, including the following steps:

[0039] S1: Raw material treatment, including the treatment of bentonite and bamboo fiber; take a preset proportion of bentonite and bamboo fiber, specifically, the purity of the bentonite > 85%; clean the bentonite to remove the impurities and microorganisms attached to the surface, and crush and activate it; soak the bamboo fiber in a highly alkaline solution and then wash it with clean water, and then dry and crush it; the treatment of the bentonite includes the following steps: material cleaning, select high-purity bentonite and rinse it with pure water multiple times to remove the impurities adsorbed deep inside; dry the rinsed bentonite to reduce the water content of the bentonite to 3%, and the tapped density of the dried bentonite ≦ 0.6 g / cm 3 ; crushing, put the dried bentonite into a jaw crusher for crushing and pass through a 85-mesh sieve; activation, put the crushed bentonite into an activation furnace and carry out activation treatment at a temperature of 420 °C for 4 h, continuously add steam into the activation furnace, spray for 5 s every 15 min to promote the ion exchange between mineral layers; then dry the activated bentonite at room temperature to stabilize the surface hydroxyl groups; the treatment of the bamboo fiber includes the following steps: soaking, soak the bamboo fiber in a sodium hydroxide solution with a concentration of 6% for 2.5 h; cleaning, use clean water to rinse the soaked bamboo fiber until it is neutral until the pH value of the bamboo fiber is 8; then dry it in a dryer at a temperature of 130 °C until the water content is lower than 3%; crushing, put the dried bamboo fiber into a crusher for crushing and pass through a 35-mesh sieve;

[0040] S2: Gradient mixing. Put bentonite, bamboo fiber, and modified diatomaceous earth in a preset ratio into a stirring device for dry mixing. Add guar gum to the above dry-mixed materials. The guar gum is used as an adhesive, which can significantly enhance the bonding force between components such as bentonite, bamboo fiber, and modified diatomaceous earth, and improve the durability of the cat litter in actual use. Stir at a speed of 400 r / min for 15 min, and then add activated carbon and continue to stir for 30 min to form a mixture. Specifically, the gradient mixing includes: In the first stage, put bentonite, bamboo fiber, and modified diatomaceous earth in a preset ratio into a double-screw conical mixer, adjust its speed to 150 r / min, the mixing time is 15 min, and the temperature is controlled at 28 °C to form a mixture. In the second stage, spray a 3% guar gum solution on the mixture. The preparation method of the guar gum solution is to dissolve guar gum in pure water at 40 °C, and its viscosity is controlled at 4500 mPa·s. Adjust the speed of the double-screw conical mixer to 450 r / min, the mixing time is 15 min, and the temperature is controlled at 30 °C, and continuously mix to form wet particles. In the third stage, add activated carbon to the double-screw conical mixer in the second stage in several batches slowly, adjust its speed to 500 r / min, the mixing time is 35 min, and the temperature is controlled at 32 °C. Put the mixed material into an aging bin and let it stand for aging for 35 min. The humidity in the aging bin is controlled at 75%. The gradient mixing step enables the cat litter particles to have the effects of high adsorption, low dust, and long-term deodorization through precise mechanical and chemical regulation; it further promotes the interaction between components and improves the stability of the cat litter performance. After the above gradient mixing, the components of the cat litter are evenly distributed, ensuring the stability of the cat litter performance;

[0041] S3: Low-temperature compound granulation. Control the temperature of the twin-screw extruder in sections to avoid high temperature from damaging the material adsorption activity of the mixture in S2 and reduce energy consumption at the same time. Specifically, the temperature control in sections includes: the first zone at 55 °C, the second zone at 65 °C, and the third zone at 80 °C. The first zone is used to soften the mixture. The second zone is used for fiber plasticization and shear stress conduction. The third zone is used for interface cross-linking strengthening to form preset pores. Adjust its speed to 45 rpm and the die head pressure to 35 MPa, and extrude through a die with a pore diameter of 2 mm to form particles with a three-dimensional honeycomb network on the surface. Air-cool the particles. The low-temperature compound granulation step enables the surface area retention rate of the particles to reach 98%, increases the surface area of the cat litter, and improves the adsorption performance and air permeability. The cat litter manufactured by the above process has appropriate hardness and is not easy to break;

[0042] S4: Spray a nano - coating. Put the above - mentioned particles into a fluidized bed. The model of the fluidized bed is a Wurster bottom - spray fluidized bed. Its atomization system uses a dual - channel ultrasonic atomizer, the air - flow distribution plate uses a multi - layer sintered metal filter screen with an opening ratio of 25%, the pore size gradient is 8μm, and a PID is used to adjust the hot - air circulation system. Adjust its spraying pressure to 0.27 MPa, start the fluidized bed, so that the particles are in a fluid state under the action of air flow and continuously spray nano - silicon solution in the fluidized bed. The nano - silicon solution is composed of nano - silica sol, cetyltrimethoxysilane, polyethylene glycol, silver - ion antibacterial agent and deionized water. Adjust the hot - air temperature of the fluidized bed to 60 °C for curing for 15 min to form a 10 - μm - thick protective layer. The step of spraying the nano - coating realizes the surface functional modification of the cat litter particles, enabling them to have the technical effects of moisture - proof, mildew - proof, zero - dust and antibacterial while maintaining high adsorption performance;

[0043] S5: Dynamic classification screening. Put the particles after spraying the nano - coating into an intelligent dynamic classification screening machine, and feedback - adjust the screen inclination angle and vibration frequency to classify the particle size. Package the classified particles in layers according to a preset ratio. The intelligent dynamic classification screening machine includes the following modules: a feeding module, which is used to transport the particles after spraying the nano - coating into the intelligent dynamic classification screening machine; a screening module, including a screen, an inclination - adjusting mechanism and a vibration mechanism. The particles entering through the feeding module fall onto the screen. Adjust the inclination - adjusting mechanism according to the required particle size, and then the vibration mechanism drives the screen to vibrate. The particles fall through the screens with different pore sizes through vibration to achieve classification screening. The vibration mechanism is composed of a double - mass - body inertial vibration motor, which is a prior art and will not be elaborated here; a feedback - adjustment module. During the screening process, sensors monitor the flow and screening situation of the particles in real time, and then the sensors transmit the real - time data to the control unit. The control unit automatically adjusts the vibration frequency and screen inclination angle to classify the particles. The feedback - adjustment module is composed of a high - frame - rate industrial camera and a laser particle size analyzer, which are prior arts and will not be elaborated here; a classification and collection module, which separately collects and packages the particles of different sizes after classification screening. The classification and collection module is composed of a pneumatic flap diverter and an anti - static aggregate bin, which are prior arts and will not be elaborated here. The calculation formula used by the control unit is:

[0044] Q = k1·sinθ·(1 + l -βf )

[0045] n = k2·f 1.5 ·A 0.8

[0046] Where: Q: screening efficiency, η: screen passing rate, θ: screen inclination angle, f: vibration frequency, A: vibration acceleration.

[0047] The above are only the preferred embodiments of the present invention patent, and are not intended to limit the present invention patent. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention patent shall be included within the protection scope of the present invention patent.

Claims

1. A low-temperature composite granulation preparation process for cat litter based on natural sodium-based ore, characterized in that: It includes the following steps: S1: Raw material treatment, including the treatment of sodium-based ore and plant fiber; taking a preset ratio of sodium-based ore and plant fiber; cleaning the sodium-based ore to remove impurities and microorganisms attached to the surface, crushing and activating it; soaking the plant fiber in a highly alkaline solution, then cleaning it with clear water, and then drying and crushing it; S2: Gradient mixing, putting a preset ratio of sodium-based ore, plant fiber and modified mineral materials into a stirring device for dry mixing; adding guar gum to the above dry-mixed materials, stirring at a rotation speed of 400 r / min for 5 - 15 min, and then adding a deodorant and continuing to stir for 20 - 30 min to form a mixture; S3: Low-temperature compound granulation, controlling the temperature of the twin-screw extruder in sections, adjusting its rotation speed to 20 - 45 rpm, and adjusting the die head pressure to 20 - 35 MPa, extruding particles with a three-dimensional honeycomb network on the surface through a die with a pore diameter of 2 mm, and air-cooling the particles; S4: Spraying a nano-coating, putting the above particles into a fluidized bed, adjusting the spraying pressure to 0.20 - 0.27 MPa, starting the fluidized bed to make the particles in a fluid state under the action of air flow and continuously spraying nano-silicon solution in the fluidized bed; adjusting the hot air temperature of the fluidized bed to 50 - 60 °C for curing for 5 - 15 min to form a 5 - 10 μm thick protective layer; S5: Dynamic grading and screening, putting the particles after spraying the nano-coating into an intelligent dynamic grading and screening machine, and feedback-adjusting the screen inclination angle and vibration frequency to grade the particle size; packing the graded particles in layers according to a preset ratio.

2. The low-temperature composite granulation preparation process of the cat litter based on natural sodium-based ore according to claim 1, characterized in that: The treatment of the sodium-based ore includes the following steps: Material cleaning, selecting high-purity sodium-based ore and rinsing it with pure water multiple times, and drying the rinsed sodium-based ore; Crushing, putting the dried sodium-based ore into a crusher for crushing, and screening it through a 55 - 85 mesh sieve; Activation, putting the crushed sodium-based ore into an activation furnace, carrying out activation treatment at a temperature of 280 - 420 °C for 2 - 4 h, continuously adding steam into the activation furnace, and then drying the activated sodium-based ore at room temperature.

3. The low-temperature composite granulation preparation process of the cat litter based on natural sodium-based ore according to claim 2, characterized in that: The treatment of the plant fiber includes the following steps: Soaking, soaking the plant fiber in a sodium hydroxide solution with a concentration of 4% - 6%, and controlling the soaking time at 1.5 - 2.5 h; Cleaning, rinsing the soaked plant fiber with clear water until it is neutral, and then drying it with a dryer at a temperature of 110 - 130 °C until the water content is less than 3%; Crushing, putting the dried plant fiber into a crusher for crushing, and screening it through a 25 - 35 mesh sieve.

4. The low-temperature composite granulation preparation process of the cat litter based on natural sodium-based ore according to claim 3, characterized in that: The sodium-based ore is composed of one or more of bentonite, albite, salt rock or natural sodium-based montmorillonite; the plant fiber is composed of one or more of bamboo fiber, coconut shell fiber, rice straw fiber or wood fiber.

5. The low-temperature composite granulation preparation process of the cat litter based on natural sodium-based ore according to claim 1, characterized in that: The gradient mixing includes: The first stage, putting sodium-based ore, plant fiber and modified mineral materials into a double-screw conical mixer according to a preset ratio, adjusting its rotation speed to 150 r / min, mixing for 8 - 15 min, and controlling the temperature at 22 - 28 °C to form a mixture; In the second stage, a guar gum solution with a concentration of 2% - 3% is sprayed into the mixture, the rotation speed of the double - helix conical mixer is adjusted to 350 - 450 r / min, and the mixing time is 8 - 15 min to continuously mix and form wet - like particles; In the third stage, the deodorant is slowly added to the double - helix conical mixer in the second stage in multiple times, its rotation speed is adjusted to 400 - 500 r / min, and the mixing time is 20 - 35 min; the mixed material is left to stand and age for 20 - 35 min.

6. The low-temperature composite granulation preparation process of the cat litter based on natural sodium-based ore according to claim 1, characterized in that: The intelligent dynamic classification screening machine includes the following modules: The feeding module is used to transport the particles after spraying the nano - coating into the intelligent dynamic classification screening machine; The screening module includes a screen, an inclination angle adjustment mechanism and a vibration mechanism; the particles entering through the feeding module fall onto the screen, the inclination angle adjustment mechanism is adjusted according to the required particle size, and then the vibration mechanism drives the screen to vibrate, and the particles fall through the screens with different apertures through vibration to achieve classification screening; The feedback adjustment module, during the screening process, the sensor monitors the flow and screening situation of the particles in real - time, and then the sensor transmits the real - time data to the control unit, and the control unit automatically adjusts the vibration frequency and the screen inclination angle to classify and screen the particles; The classification collection module separately collects and packages the particles with different sizes after the classification screening.

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