Multi-stage pore channel composite mineral cat litter as well as preparation method and recovery method thereof

Abstract

The invention relates to a hierarchical porous composite mineral cat litter as well as a preparation method and a recovery method thereof, relates to the technical field of cat litters, and aims to solve at least one of the problems of insufficient adsorption capacity, poor catalytic decomposition capability on organic sulfides, environmental pollution, high cost, poor cyclic utilization capability and the like of the existing cat litter. By constructing a gradient hole structure and a biological-mineral composite deodorization system, targeted capture and efficient decomposition of multi-element peculiar smell molecules in pet excrement are achieved, and the pet excrement treatment device is suitable for excrement management in scenes such as family pet nursing, stray animal rescue stations and zoos. Specifically, the inner core of the cat litter comprises graded porous diatomite and synergistic modified sodium bentonite, gradient adsorption and enrichment of odor molecules are realized, and synergistic degradation of NH3, H2S and VOCs is promoted by adopting a non-metal catalysis-biological enzyme combined system.

Description

Technical Field

[0001] The invention relates to the technical field of cat litter, in particular to a multi-stage pore composite mineral cat litter and a preparation method and a recovery method thereof. Background Art

[0002] Cats are popular pets, but if they defecate anywhere, they can cause significant pollution. Cat litter can effectively solve this problem by catching their excrement. There are many types of cat litter, such as plant fiber litter, sawdust litter, and bentonite litter. These litters can quickly wrap cat urine, forming a clumping mass that's easier to clean and reduces odor.

[0003] However, traditional bentonite cat litter has insufficient adsorption capacity, and commercially available products also contain quaternary ammonium antibacterial agents, which lead to water ecological toxicity. In addition, particles with a size of less than 100μm account for more than 15%, inducing a 12% annual increase in pet respiratory disease cases; it only focuses on physical adsorption and lacks the ability to catalyze the decomposition of organic sulfides. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a multi-stage pore composite mineral cat litter and its preparation and recovery methods, so as to solve at least one of the problems of existing cat litter, such as insufficient adsorption capacity, poor catalytic decomposition ability of organic sulfides, environmental pollution, high cost, and poor recycling capacity.

[0005] In a first aspect, the present invention provides a multi-level pore composite mineral cat litter, which comprises, from the inside to the outside, a water-absorbing inner core layer, a catalytic deodorizing middle layer, and a dust-suppressing outer shell layer;

[0006] The water-absorbing inner core layer is made of modified sodium bentonite, graded pore diatomaceous earth and a binder; the catalytic deodorizing middle layer is made of MnO2-biochar composite material and laccase microcapsules; and the dust suppression outer shell layer is made of polyethylene glycol 2000 and nano-SiO2.

[0007] Furthermore, the diameter of the water-absorbing inner core layer is 2.0 to 2.5 mm, the thickness of the catalytic deodorizing middle layer is 0.8 to 1.2 mm, and the thickness of the dust suppression outer shell layer is 0.2 to 0.5 mm.

[0008] Furthermore, the hierarchical pore diatomite has three levels of mesopores, namely 1-2 nm micropores, 5-20 nm mesopores and 50-200 nm macropores.

[0009] Furthermore, the mass ratio of the modified sodium bentonite to the graded pore diatomite is 3:1 to 6:1, and the mass of the binder accounts for 5-7% of the total mass of the modified sodium bentonite, the graded pore diatomite and the binder.

[0010] Furthermore, the mass ratio of the MnO2-biochar composite material to the laccase microcapsules is 2.5-3.5, and the laccase microcapsules are prepared by co-immobilizing a laccase aqueous solution, trehalose and a cross-linking agent.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned multi-stage pore composite mineral cat litter, comprising the following steps:

[0012] (1) mixing sodium bentonite with sodium citrate solution, ultrasonically treating, centrifuging, and calcining to obtain modified sodium bentonite;

[0013] (2) diatomaceous earth is crushed and sieved, and clay minerals are separated. HCl solution is added and stirred to form micropores of 1 to 2 nm. A surfactant is added and self-assembled in an ammonia environment to form mesopores of 5 to 20 nm. Ammonium bicarbonate is added and pressed and pre-fired to form a honeycomb skeleton. The temperature is raised and kept to react to form macropores of 50 to 200 nm, thereby obtaining the hierarchical pore diatomaceous earth.

[0014] (3) The biomass material is oxidized and cracked to produce biochar, which is then activated and immersed in a Mn(NO3)2 solution to obtain a MnO2-biochar composite material through a hydrothermal reaction;

[0015] (4) mixing the laccase aqueous solution with trehalose, adding the mixture to a cross-linking agent, and freeze-drying the mixture to obtain the laccase microcapsules;

[0016] (5) mixing the modified sodium bentonite described in step (1) and the graded pore diatomite described in step (2), adding a binder, and granulating to obtain a water-absorbing inner core layer;

[0017] (6) mixing the MnO2-biochar composite material described in step (3) and the laccase microcapsules described in step (4), and uniformly coating and depositing them on the water-absorbing inner core layer to form a catalyst deodorizing intermediate layer;

[0018] (7) After heating and melting polyvinyl alcohol 2000, nano-SiO2 is added and stirred to form a uniform slurry. The slurry is sprayed on the catalyst deodorizing middle layer by an electrostatic spraying process to form a dust suppression outer shell layer. The mixture is dried and sieved to obtain the multi-stage pore composite mineral cat litter.

[0019] Furthermore, in step (2), the concentration of the HCl solution is 5-6 mol / L HCl, the solid-liquid ratio of the solution after adding the HCl solution is 0.2-0.3, and the reaction is stirred at 70-80° C. for 2-2.5 hours.

[0020] Furthermore, in step (2), the temperature is raised to 500-550° C., the heating rate is 5-7° C. / min, and the holding time is 2-2.5 h.

[0021] In a third aspect, the present invention provides a method for recovering the multi-stage pore composite mineral cat litter, comprising the steps of:

[0022] (a) the cat litter is laid with a thickness of ≥5cm for the first time, and new litter is added to the original thickness after cleaning the agglomerates every day;

[0023] (b) when cumulative usage reaches 60% of initial amount, all cat litters are reclaimed;

[0024] (c) the cat litter after the recovery is crushed and incinerated at 400-450° C. to obtain regenerated cat litter;

[0025] (d) regenerated cat litter is mixed with biochar, passed into flue gas, calcined, and ball milled to obtain the cat litter after treatment;

[0026] (e) the cat litter after described processing is joined in unused multi-stage pore composite mineral cat litter, and reuses;

[0027] Alternatively, the treated cat litter is used as a garden slow-release fertilizer.

[0028] Furthermore, in step (d), the NH3 adsorption capacity of the treated cat litter is at least 85% of the NH3 removal rate of the unused cat litter. Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0029] (1) The present invention achieves targeted capture and efficient decomposition of multiple odor molecules in pet excrement by constructing a gradient pore structure (graded pore diatomite) and a bio-mineral composite deodorization system. It is suitable for feces management in scenarios such as home pet care, stray animal rescue stations, and zoos. Specifically, the cat litter core of the present invention includes graded pore diatomite and synergistically modified sodium bentonite to achieve gradient adsorption and enrichment of odor molecules. A non-metallic catalysis-bioenzyme combination system is used to promote the synergistic degradation of NH3, H2S, and VOCs.

[0030] (2) The diameter of the water-absorbing inner core layer, the thickness of the middle layer, and the thickness of the outer shell layer within the scope of the present invention can reduce dust during transportation of the cat litter, quickly deodorize it when combined with cat urine and cat feces, and continuously absorb water.

[0031] (3) The preparation method of the cat litter of the present invention adopts a low-temperature molding process for the preparation of laccase microcapsules, which reduces production energy consumption while ensuring mechanical strength.

[0032] (4) The recycling method of the present invention establishes a closed-loop waste treatment solution, realizes the recycling of materials, and achieves the goal of zero waste.

[0033] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0035] Figure 1 This is a SEM image of the hierarchical pore diatomite prepared in Example 1 of the present invention;

[0036] Figure 2 This is the SEM image of the MnO2-biochar composite material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0038] A specific embodiment of the present invention discloses a multi-level pore composite mineral cat litter, which comprises, from the inside to the outside, a water-absorbing inner core layer, a catalytic deodorizing middle layer, and a dust-suppressing outer shell layer;

[0039] The water-absorbing inner core layer is made of modified sodium bentonite, graded pore diatomaceous earth and a binder; the catalytic deodorizing middle layer is made of MnO2-biochar composite material and laccase microcapsules; and the dust suppression outer shell layer is made of polyethylene glycol 2000 and nano-SiO2.

[0040] Compared with existing technologies, the present invention achieves targeted capture and efficient decomposition of multiple odor molecules in pet excrement by constructing a gradient pore structure (graded pore diatomaceous earth) and a bio-mineral composite deodorization system. It is suitable for feces management in scenarios such as home pet care, stray animal rescue centers, and zoos. Specifically, the cat litter core of the present invention includes graded pore diatomaceous earth and synergistically modified sodium bentonite to achieve gradient adsorption and enrichment of odor molecules. It also uses a non-metallic catalysis-bioenzyme combination system to promote the synergistic degradation of NH3, H2S, and VOCs.

[0041] Specifically, the diameter of the water-absorbing inner core layer is 2.0 to 2.5 mm, the thickness of the catalytic deodorizing middle layer is 0.8 to 1.2 mm, and the thickness of the dust suppression outer shell layer is 0.2 to 0.5 mm.

[0042] It should be noted that the diameter of the water-absorbing inner core layer, the thickness of the middle layer and the thickness of the outer shell layer of the present invention are within the above-mentioned ranges, which can reduce dust during transportation of the cat litter, and can quickly deodorize and continuously absorb water when combined with cat urine and cat feces.

[0043] Specifically, the hierarchical pore diatomite has three levels of mesopores, namely, 1-2 nm micropores, 5-20 nm mesopores, and 50-200 nm macropores.

[0044] Specifically, the mass ratio of the modified sodium bentonite to the graded pore diatomite is 3:1 to 6:1, and the mass of the binder accounts for 5-7% of the total mass of the modified sodium bentonite, the graded pore diatomite and the binder.

[0045] Preferably, the binder is prepared by mixing hydroxypropyl starch (HPS), polyvinyl alcohol (PVA1788), and silica sol in a ratio of 6-11:3-5:1-4, and then adding a crosslinking agent and a plasticizer and stirring at 65-70°C.

[0046] Preferably, the mass of the cross-linking agent is 3-5% of the mass of the binder, and the mass of the plasticizer is 0.1-0.3% of the mass of the binder.

[0047] More preferably, the cross-linking agent is trisodium citrate, and the plasticizer is glycerol.

[0048] Specifically, the MnO2-biochar composite material has a loading of 30-35%. This loading range helps the MnO2 form evenly dispersed nanosheets on the biochar surface, preventing MnO2 aggregation and thus better maintaining the material's high specific surface area and porous structure. This structure increases active sites, improving catalytic performance, while also enhancing the material's stability and preventing MnO2 from falling off or deactivating during use.

[0049] The MnO2-biochar composite material is a δ-MnO2 nanosheet grown in situ on the surface of biochar, which increases the specific surface area and the catalytic efficiency of NH3.

[0050] Specifically, the mass ratio of the MnO2-biochar composite material to the laccase microcapsule is 2.5 to 3.5.

[0051] Specifically, the laccase microcapsules are prepared by co-immobilizing a laccase aqueous solution, trehalose and a cross-linking agent.

[0052] Preferably, the mass ratio of the laccase aqueous solution to trehalose is 1:3 to 1:5, and the mass of the cross-linking agent is 0.5-1.0% of the total mass of the laccase aqueous solution, trehalose and the cross-linking agent.

[0053] More preferably, the mass concentration of the laccase aqueous solution is 200-250 U / mg, the cross-linking agent is chitosan acetic acid solution, and the mass fraction of the chitosan in acetic acid is 0.5-2%.

[0054] More preferably, the laccase microcapsules are porous microspheres with a diameter of 50 to 100 μm, and the porosity of the microspheres is ≥75%.

[0055] It should be noted that the laccase microcapsules of the present invention are prepared by enzyme immobilization technology and utilize trehalose and chitosan for dual protection, so that the activity retention rate of laccase after storage at 50° C. for 6 months is greater than 85%.

[0056] Preferably, the particle size of the nano-SiO2 is 20-50 nm.

[0057] Another specific embodiment of the present invention discloses a method for preparing the above-mentioned multi-stage pore composite mineral cat litter, comprising the following steps:

[0058] (1) mixing sodium bentonite with sodium citrate solution, ultrasonically treating, centrifuging, and calcining to obtain modified sodium bentonite;

[0059] (2) diatomaceous earth is crushed and sieved, and clay minerals are separated. HCl solution is added and stirred to form micropores of 1 to 2 nm. A surfactant is added and self-assembled in an ammonia environment to form mesopores of 5 to 20 nm. Ammonium bicarbonate is added and pressed and pre-fired to form a honeycomb skeleton. The temperature is raised and kept to react to form macropores of 50 to 200 nm, thereby obtaining the hierarchical pore diatomaceous earth.

[0060] (3) The biomass material is oxidized and cracked to produce biochar, which is then activated and immersed in a Mn(NO3)2 solution to obtain a MnO2-biochar composite material through a hydrothermal reaction;

[0061] (4) mixing the laccase aqueous solution with trehalose, adding the mixture to a cross-linking agent, and freeze-drying the mixture to obtain the laccase microcapsules;

[0062] (5) mixing the modified sodium bentonite described in step (1) and the graded pore diatomite described in step (2), adding a binder, and granulating to obtain a water-absorbing inner core layer;

[0063] (6) mixing the MnO2-biochar composite material described in step (3) and the laccase microcapsules described in step (4), and uniformly coating and depositing them on the water-absorbing inner core layer to form a catalyst deodorizing intermediate layer;

[0064] (7) After heating and melting polyvinyl alcohol 2000, nano-SiO2 is added and stirred to form a uniform slurry. The slurry is sprayed on the catalyst deodorization middle layer by an electrostatic spraying process to form a dust suppression outer shell layer. The mixture is dried and sieved to obtain the multi-stage pore composite mineral cat litter.

[0065] Specifically, in step (1), the concentration of sodium citrate in the sodium citrate solution is 3 to 5 mol / L. Within this range, the sodium citrate solution has good dispersibility and can effectively disperse the sodium bentonite evenly in the solution to prevent particle agglomeration. The mass ratio of sodium bentonite to sodium citrate solution is 0.25 to 0.35.

[0066] Preferably, the Al2O3 content in the sodium bentonite is ≥28%.

[0067] Specifically, in step (1), the temperature of the ultrasonic treatment is 70-80° C., the ultrasonic time is 50-60 min, and the ultrasonic frequency is 30-40 kHz. Under the above ultrasonic conditions, it is beneficial to stimulate the activity of sodium ions and make the reaction more complete.

[0068] Specifically, in step (1), the calcination atmosphere is nitrogen, the calcination temperature is 400-450° C., and the calcination time is 2-2.5 hours.

[0069] Specifically, in step (2), the diatomaceous earth is crushed to a particle size of less than 100 μm and passed through a 200-mesh sieve.

[0070] It should be noted that the present invention removes large particle impurities through a vibrating screen and uses a hydrocyclone to separate clay minerals, thereby increasing the SiO2 content to more than 70%.

[0071] Specifically, in step (2), the concentration of the HCl solution is 5-6 mol / L HCl, the solid-liquid ratio of the solution after adding the HCl solution is 0.2-0.3, and the reaction is stirred at 70-80° C. for 2-2.5 hours.

[0072] The purpose of the above operation is to remove metal oxides such as Fe2O3, selectively dissolve amorphous silicon, and form 1-2 nm micropores.

[0073] Specifically, in step (2), the surfactant is CTAB, and the mass of the surfactant is 3-4% of the diatomaceous earth.

[0074] Preferably, the pH value of the ammonia water is 10 to 10.5, at which point the ammonia water is closest to cat urine, and the self-assembly reaction takes 23 to 24 hours.

[0075] Specifically, in step (2), the amount of ammonium bicarbonate added is 10-15% of the mass of the diatomaceous earth, the pre-calcination temperature is 300-320° C., and the time is 1-1.5 hours.

[0076] Specifically, in step (2), the temperature is raised to 500-550° C., the heating rate is 5-7° C. / min, and the holding time is 2-2.5 h. Under the above temperature conditions, the molecules inside the diatomaceous earth can be fully activated and active.

[0077] Specifically, in step (3), the temperature of the oxidative cracking is 550-600° C., and the time is 15-20 minutes.

[0078] Preferably, in step (3), HNO3 activation is adopted, the mass fraction of Mn(NO3)2 solution is 30-35%, and the mass ratio of biomass material, HNO3 and Mn(NO3)2 solution is 6-7:1:14-12.

[0079] Preferably, the biomass material comprises walnut shells and / or rice husks.

[0080] Specifically, in step (3), the hydrothermal reaction temperature is 160-180° C. and the reaction time is 11-12 hours. The above temperature can provide thermal energy, making the movement between molecules faster and accelerating the reaction to complete.

[0081] Specifically, in step (4), the freeze-drying temperature is -30 to -40°C, and the drying time is 24 to 36 hours.

[0082] Specifically, in step (5), the granulation is carried out using a twin-screw extruder with a length-to-diameter ratio of 40:1 and a die head temperature of 60-70°C.

[0083] Specifically, in step (6), a fluidized bed bottom spraying process is used for uniform coating.

[0084] Preferably, the fluidized bed process parameters are: fluidizing gas velocity 0.8-1.2 m / s, coating deposition efficiency ≥90%, coating cycle 3-5 times, and drying interval of 5-10 minutes each time.

[0085] Preferably, the inlet air temperature is 70-80° C. and the atomization pressure is 0.2-0.3 MPa.

[0086] Specifically, in step (6), the mass of the catalyst deodorizing intermediate layer is 10 to 20% of the mass of the water-absorbing inner core layer.

[0087] Specifically, in step (7), the mass of the dust suppression outer shell layer is 3-5% of the total mass of the water-absorbing inner core layer and the catalytic deodorizing middle layer.

[0088] Specifically, in step (7), the drying temperature is 50-60° C., and the sieving mesh size is 8-35 meshes.

[0089] Specifically, in step (7), the electrostatic spraying process parameters are: slurry solid content 12-15%, spraying distance 150-200 mm, and deposition electric field strength 4-6 kV / cm.

[0090] In the preparation method of the cat litter of the present invention, a low-temperature molding process is adopted for the preparation of laccase microcapsules, thereby reducing production energy consumption while ensuring mechanical strength.

[0091] Another specific embodiment of the present invention discloses a method for recovering the above-mentioned multi-stage pore composite mineral cat litter, comprising the following steps:

[0092] (a) the cat litter is laid with a thickness of ≥5cm for the first time, and new litter is added to the original thickness after cleaning the agglomerates every day;

[0093] (b) when cumulative usage reaches 60% of initial amount, all cat litters are reclaimed;

[0094] (c) the cat litter after the recovery is crushed and incinerated at 400-450° C. to obtain regenerated cat litter;

[0095] (d) regenerated cat litter is mixed with biochar, passed into flue gas, calcined, and ball milled to obtain the cat litter after treatment;

[0096] (e) the cat litter after described processing is joined in unused multi-stage pore composite mineral cat litter, and reuses;

[0097] Alternatively, the treated cat litter is used as a garden slow-release fertilizer.

[0098] Specifically, in step (d), the mass of the biochar is 5 to 8% of the mass of the multi-level pore composite mineral cat litter after use.

[0099] Specifically, in step (d), the oxygen content of the flue gas is 8-10%, the calcination temperature is 380-420° C., and the calcination time is 30-45 minutes.

[0100] Preferably, in step (d), the NH3 adsorption capacity of the treated cat litter is NH3 of the unused cat litter. 3去除率 More than 85% of.

[0101] Specifically, in step (d), the powder is crushed to 200-250 mesh.

[0102] Specifically, in step (e), the mass of the treated cat litter is 20-30% of the mass of the unused multi-stage pore composite mineral cat litter.

[0103] The recycling method of the present invention establishes a closed-loop waste treatment solution, realizes the recycling of materials, and achieves the goal of zero waste.

[0104] All raw materials in the present invention are commercially available or prepared by existing methods. The technical solutions of the present invention are further explained below with reference to specific examples.

[0105] Example 1

[0106] A method for preparing a multi-stage pore composite mineral cat litter of the present embodiment comprises the following steps:

[0107] (1) Sodium bentonite with Al2O3 ≥ 28% was mixed with 5 mol / L sodium citrate solution in a mass ratio of 1:4, and ultrasonically treated at 80°C and 40 kHz for 60 min. The mixture was centrifuged to obtain exfoliated nanosheets, which were then calcined at 450°C for 2.5 h under a nitrogen atmosphere to obtain modified sodium bentonite.

[0108] (2) diatomite was crushed to less than 100 μm, passed through a 200 mesh sieve, and clay minerals were separated by a hydrocyclone. A 6 mol / L HCl solution was added to make the solid-liquid ratio in the solution 1:5. The solution was stirred and reacted at 80°C for 2.5 hours to form 1-2 nm micropores. A surfactant CTAB was added, and the mass of the surfactant was 3% of the mass of the diatomite. The solution was self-assembled in an ammonia environment with a pH of 10.5 for 24 hours to form 5-20 nm mesopores. Ammonium bicarbonate was added, and the amount of ammonium bicarbonate added was 15% of the mass of the diatomite. After pressing and molding, the solution was pre-calcined at 300°C for 1 hour to form a honeycomb skeleton. The solution was heated to 550°C at a heating rate of 5°C / min under nitrogen protection and kept warm for 2 hours to form 50-200 nm macropores, thereby obtaining the hierarchical pore diatomite.

[0109] (3) Walnut shells were oxidized and cracked at 600°C for 20 min to produce biochar, which was activated with HNO3 and then impregnated into a Mn(NO3)2 solution with a mass fraction of 35% and a mass ratio of walnut shells, HNO3, and Mn(NO3)2 solution of 7:1:12. The biochar was then hydrothermally reacted at 180°C for 12 h to obtain a MnO2-biochar composite material.

[0110] (4) mixing a laccase aqueous solution with trehalose, wherein the mass ratio of the laccase aqueous solution to the trehalose is 1:4 and the mass concentration of the laccase aqueous solution is 225 U / mg, adding the mixture to a cross-linking agent, and freeze-drying the mixture at -40°C for 30 hours to obtain the laccase microcapsules;

[0111] The mass of the cross-linking agent is 0.75% of the total mass of the laccase aqueous solution, trehalose and the cross-linking agent; the cross-linking agent is a chitosan acetic acid solution; the mass fraction of the chitosan in the acetic acid is 2%; the laccase microcapsules are porous microspheres with a diameter of 50 to 100 μm, and the porosity of the microspheres is ≥75%;

[0112] (5) mixing the modified sodium bentonite described in step (1) and the graded pore diatomite described in step (2), adding a binder, wherein the mass ratio of the modified sodium bentonite to the graded pore diatomite is 4.5:1, and the mass of the binder accounts for 6% of the total mass of the modified sodium bentonite, the graded pore diatomite and the binder, and granulating to obtain a water-absorbing inner core layer;

[0113] The binder is prepared by mixing hydroxypropyl starch (HPS), polyvinyl alcohol (PVA1788), and silica sol in a ratio of 6:3:1, and then adding a crosslinker trisodium citrate and a plasticizer glycerol and stirring at 70°C. The mass of the crosslinker is 5% of the mass of the binder, and the mass of the plasticizer is 0.1% of the mass of the binder.

[0114] (6) The MnO2-biochar composite material described in step (3) and the laccase microcapsules described in step (4) are mixed in a mass ratio of 3:1, and uniformly coated and deposited on the water-absorbing inner core layer using a fluidized bed bottom spraying process. The fluidized bed process parameters are: inlet air temperature of 80°C, atomization pressure of 0.3 MPa, fluidization gas velocity of 1.0 m / s, coating deposition efficiency ≥ 90%, coating cycle of 3 to 5 times, each interval drying of 5 to 10 minutes, to form a catalyst deodorization intermediate layer;

[0115] Wherein, the mass of the catalyst deodorizing intermediate layer is 15% of the mass of the water-absorbing inner core layer;

[0116] (7) After heating and melting polyvinyl alcohol 2000, nano-SiO2 is added and stirred to form a uniform slurry with a solid content of 13.5%. The slurry is sprayed on the catalyst deodorization middle layer using an electrostatic spraying process with a spraying distance of 175 mm and a deposition electric field strength of 5 kV / cm to form a dust suppression outer shell layer. The mass of the dust suppression outer shell layer is controlled to be 4% of the total mass of the water-absorbing inner core layer and the catalytic deodorization middle layer. The slurry is dried at a temperature of 55°C to a moisture content of ≤10%, and sieved through a vibrating sieve with a mesh size of 8 to 10 to obtain the multi-stage pore composite mineral cat litter.

[0117] The diameter of the water-absorbing inner core layer of the cat litter obtained in this example is 2.25 mm, the thickness of the catalytic deodorizing middle layer is 1.0 mm, and the thickness of the dust-suppressing outer shell layer is 0.35 mm.

[0118] The SEM of the hierarchical pore diatomite prepared in this example is as follows: Figure 1 As shown in the SEM of MnO2-biochar composites, Figure 2 As shown, it can be seen that δ-MnO2 nanosheets are loaded on the surface of biochar.

[0119] Example 2

[0120] A method for preparing a multi-stage pore composite mineral cat litter of the present embodiment comprises the following steps:

[0121] (1) Sodium bentonite with Al2O3 ≥ 28% was mixed with 4 mol / L sodium citrate solution in a mass ratio of 2:7, and ultrasonically treated at 75°C and 35 kHz for 55 min. The exfoliated nanosheets were obtained by centrifugation, and calcined at 425°C for 2.25 h under a nitrogen atmosphere to obtain modified sodium bentonite;

[0122] (2) The diatomite was crushed to less than 100 μm, passed through a 200 mesh sieve, and the clay minerals were separated by a hydrocyclone. A 5.5 mol / L HCl solution was added to make the solid-liquid ratio in the solution 1:4. The solution was stirred and reacted at 75°C for 2.25 hours to form 1-2 nm micropores. A surfactant CTAB was added, and the mass of the surfactant was 3.5% of the mass of the diatomite. The solution was self-assembled in an ammonia environment with a pH of 10 for 23.5 hours to form 5-20 nm mesopores. Ammonium bicarbonate was added, and the amount of ammonium bicarbonate added was 15% of the mass of the diatomite. After pressing and molding, the solution was pre-calcined at 310°C for 1.25 hours to form a honeycomb skeleton. The solution was heated to 550°C at a heating rate of 6°C / min under nitrogen protection and kept warm for 2.25 hours to form 50-200 nm macropores, thereby obtaining the hierarchical pore diatomite.

[0123] (3) Walnut shells were oxidatively cracked at 550°C for 17.5 min to produce biochar, which was activated with HNO3 and then impregnated into a Mn(NO3)2 solution with a mass fraction of 30.25% and a mass ratio of walnut shells, HNO3, and Mn(NO3)2 solution of 13:2:25. The biochar was then hydrothermally reacted at 170°C for 11.5 h to obtain a MnO2-biochar composite material.

[0124] (4) mixing a laccase aqueous solution with trehalose, wherein the mass ratio of the laccase aqueous solution to the trehalose is 1:3 and the mass concentration of the laccase aqueous solution is 200 U / mg, adding the mixture to a cross-linking agent, and freeze-drying the mixture at -35°C for 24 hours to obtain the laccase microcapsules;

[0125] The mass of the cross-linking agent is 0.5% of the total mass of the laccase aqueous solution, trehalose and the cross-linking agent; the cross-linking agent is a chitosan acetic acid solution; the mass fraction of the chitosan in the acetic acid is 1.25%; the laccase microcapsules are porous microspheres with a diameter of 50 to 100 μm, and the porosity of the microspheres is ≥75%;

[0126] (5) mixing the modified sodium bentonite described in step (1) and the graded pore diatomite described in step (2), adding a binder, wherein the mass ratio of the modified sodium bentonite to the graded pore diatomite is 3:1, and the mass of the binder accounts for 5% of the total mass of the modified sodium bentonite, the graded pore diatomite and the binder, and granulating to obtain a water-absorbing inner core layer;

[0127] The binder is prepared by mixing hydroxypropyl starch (HPS), polyvinyl alcohol (PVA1788), and silica sol in a ratio of 9:4:4, and then adding a crosslinker trisodium citrate and a plasticizer glycerol and stirring at 67.5°C. The mass of the crosslinker is 4% of the mass of the binder, and the mass of the plasticizer is 0.2% of the mass of the binder.

[0128] (6) The MnO2-biochar composite material described in step (3) and the laccase microcapsules described in step (4) are mixed in a mass ratio of 2.5:1, and uniformly coated and deposited on the water-absorbing inner core layer using a fluidized bed bottom spraying process. The fluidized bed process parameters are: inlet air temperature of 75°C, atomization pressure of 0.25 MPa, fluidization gas velocity of 0.8 m / s, coating deposition efficiency ≥ 90%, coating cycle of 3 to 5 times, each interval drying of 5 to 10 minutes, to form a catalyst deodorization intermediate layer;

[0129] Wherein, the mass of the catalyst deodorizing intermediate layer is 10% of the mass of the water-absorbing inner core layer;

[0130] (7) After heating and melting polyvinyl alcohol 2000, nano-SiO2 is added and stirred to form a uniform slurry with a solid content of 12%. The slurry is sprayed on the catalyst deodorization middle layer using an electrostatic spraying process with a spraying distance of 150 mm and a deposition electric field strength of 4 kV / cm to form a dust suppression outer shell layer. The mass of the dust suppression outer shell layer is controlled to be 3% of the total mass of the water-absorbing inner core layer and the catalytic deodorization middle layer. The slurry is dried at a temperature of 50°C to a moisture content of ≤10%, and sieved through a vibrating sieve with a mesh size of 8 to 10 to obtain the multi-stage pore composite mineral cat litter.

[0131] The diameter of the water-absorbing inner core layer of the cat litter obtained in this example is 2.0 mm, the thickness of the catalytic deodorizing middle layer is 0.8 mm, and the thickness of the dust-suppressing outer shell layer is 0.2 mm.

[0132] Example 3

[0133] A method for preparing a multi-stage pore composite mineral cat litter of the present embodiment comprises the following steps:

[0134] (1) Sodium bentonite with Al2O3 ≥ 28% was mixed with 3 mol / L sodium citrate solution in a mass ratio of 1:3, and ultrasonically treated at 70°C and 30 kHz for 50 min. The mixture was centrifuged to obtain exfoliated nanosheets, which were then calcined at 400°C for 2 h under a nitrogen atmosphere to obtain modified sodium bentonite.

[0135] (2) diatomite was crushed to less than 100 μm, passed through a 200 mesh sieve, and clay minerals were separated by a hydrocyclone. A 5 mol / L HCl solution was added to make the solid-liquid ratio in the solution 1:4. The solution was stirred and reacted at 70°C for 2 h to form 1-2 nm micropores. A surfactant CTAB with a mass fraction of 2% was added, and self-assembled in an ammonia environment with a pH of 9.5 for 23 h to form 5-20 nm mesopores. Ammonium bicarbonate was added, and the amount of ammonium bicarbonate added was 10% of the mass of the diatomite. After pressing and molding, the solution was pre-calcined at 320°C for 1.5 h to form a honeycomb skeleton. The solution was heated to 550°C at a heating rate of 7°C / min under nitrogen protection and kept warm for 2 h to form 50-200 nm macropores, thereby obtaining the hierarchical pore diatomite.

[0136] (3) Walnut shells were oxidized and cracked at 600°C for 15 min to produce biochar, which was activated with HNO3 and then impregnated into a Mn(NO3)2 solution with a mass fraction of 30% and a mass ratio of walnut shells, HNO3, and Mn(NO3)2 solution of 6:1:14. The biochar was then hydrothermally reacted at 160°C for 11 h to obtain a MnO2-biochar composite material.

[0137] (4) mixing a laccase aqueous solution with trehalose, wherein the mass ratio of the laccase aqueous solution to the trehalose is 1:3 and the mass concentration of the laccase aqueous solution is 250 U / mg, adding the mixture to a cross-linking agent, and freeze-drying the mixture at -30°C for 36 hours to obtain the laccase microcapsules;

[0138] The mass of the cross-linking agent is 1.0% of the total mass of the laccase aqueous solution, trehalose and the cross-linking agent; the cross-linking agent is a chitosan acetic acid solution; the mass fraction of the chitosan in the acetic acid is 0.5%; the laccase microcapsules are porous microspheres with a diameter of 50 to 100 μm, and the porosity of the microspheres is ≥75%;

[0139] (5) mixing the modified sodium bentonite described in step (1) and the graded pore diatomite described in step (2), adding a binder, wherein the mass ratio of the modified sodium bentonite to the graded pore diatomite is 6:1, and the mass of the binder accounts for 7% of the total mass of the modified sodium bentonite, the graded pore diatomite and the binder, and granulating to obtain a water-absorbing inner core layer;

[0140] The binder is prepared by mixing hydroxypropyl starch (HPS), polyvinyl alcohol (PVA1788), and silica sol in a ratio of 11:5:4, and then adding a crosslinker trisodium citrate and a plasticizer glycerol and stirring at 65°C. The mass of the crosslinker is 3% of the mass of the binder, and the mass of the plasticizer is 0.3% of the mass of the binder.

[0141] (6) The MnO2-biochar composite material described in step (3) and the laccase microcapsules described in step (4) are mixed in a mass ratio of 3.5:1, and uniformly coated and deposited on the water-absorbing inner core layer using a fluidized bed bottom spraying process. The fluidized bed process parameters are: inlet air temperature of 70°C, atomization pressure of 0.2 MPa, fluidization gas velocity of 1.2 m / s, coating deposition efficiency ≥ 90%, coating cycles of 3 to 5 times, and drying intervals of 5 to 10 minutes each time to form a catalyst deodorization intermediate layer;

[0142] Wherein, the mass of the catalyst deodorizing intermediate layer is 20% of the mass of the water-absorbing inner core layer;

[0143] (7) After heating and melting polyvinyl alcohol 2000, nano-SiO2 is added and stirred to form a uniform slurry with a solid content of 15%. The slurry is sprayed on the catalyst deodorization middle layer using an electrostatic spraying process with a spraying distance of 200 mm and a deposition electric field strength of 6 kV / cm to form a dust suppression outer shell layer. The mass of the dust suppression outer shell layer is controlled to be 5% of the total mass of the water-absorbing inner core layer and the catalytic deodorization middle layer. The slurry is dried at a temperature of 60°C to a moisture content of ≤10%, and sieved through a vibrating sieve with a mesh size of 8 to 10 to obtain the multi-stage pore composite mineral cat litter.

[0144] The diameter of the water-absorbing inner core layer of the cat litter obtained in this example is 2.5 mm, the thickness of the catalytic deodorizing middle layer is 1.2 mm, and the thickness of the dust-suppressing outer shell layer is 0.5 mm.

[0145] Example 4

[0146] A method for recovering the cat litter prepared in Example 1 comprises the following steps:

[0147] (a) the cat litter prepared in Example 1 was laid to a thickness of ≥5 cm for the first time, and new litter was added to the original thickness after cleaning the agglomerates every day;

[0148] (b) when cumulative usage reaches 60% of initial amount, all cat litters are reclaimed;

[0149] (c) the cat litter after the recovery is crushed and incinerated at 400° C. to obtain regenerated cat litter;

[0150] (d) regenerated cat litter is mixed with walnut shell, feeding the flue gas with an oxygen content of 8%, is calcined at 380 ℃ for 45 min in temperature, and ball milling is crushed to 200 mesh to obtain the cat litter after processing;

[0151] (e) the cat litter after the described processing is joined in the multistage pore composite mineral cat litter prepared by unused embodiment 1, the quality of the cat litter after the described processing is 25% of the quality of unused multistage pore composite mineral cat litter, and is reused.

[0152] Example 5

[0153] A method for recovering the cat litter prepared in Example 2 comprises the following steps:

[0154] (a) the cat litter prepared in Example 2 was laid to a thickness of ≥5 cm for the first time, and new litter was added to the original thickness after cleaning the agglomerates every day;

[0155] (b) when cumulative usage reaches 60% of initial amount, all cat litters are reclaimed;

[0156] (c) the cat litter after the recovery is crushed and incinerated at 425°C to obtain regenerated cat litter;

[0157] (d) regenerated cat litter is mixed with walnut shell, feeding the flue gas that oxygen level is 9%, is calcined 37min at 400 ℃ in temperature, and ball milling is crushed to 200 mesh, obtains the cat litter after processing;

[0158] (e) the cat litter after the described processing is joined in the multi-stage pore composite mineral cat litter prepared by unused embodiment 2, the quality of the cat litter after the described processing is 20% of the quality of unused multi-stage pore composite mineral cat litter, and is reused.

[0159] Example 6

[0160] A method for recovering the cat litter prepared in Example 3 comprises the following steps:

[0161] (a) the cat litter prepared in Example 3 was laid to a thickness of ≥5 cm for the first time, and new litter was added to the original thickness after cleaning the agglomerates every day;

[0162] (b) when cumulative usage reaches 60% of initial amount, all cat litters are reclaimed;

[0163] (c) the cat litter after the recovery is crushed and incinerated at 420° C. to obtain regenerated cat litter;

[0164] (d) regenerated cat litter is mixed with walnut shell, feeding the flue gas that oxygen level is 8%, is calcined 30min at 420 ℃ in temperature, ball milling is crushed to 200 mesh, obtains the cat litter after processing;

[0165] (e) the cat litter after the described processing is joined in the multistage pore composite mineral cat litter prepared by unused embodiment 3, the quality of the cat litter after the described processing is 30% of the quality of unused multistage pore composite mineral cat litter, and is reused.

[0166] Example 7

[0167] A cat litter recovery method is similar to that of Example 4, except that, in step (e), the treated cat litter is used as a garden slow-release fertilizer.

[0168] Comparative Example 1

[0169] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that, in step (1), the sodium bentonite is not modified.

[0170] Comparative Example 2

[0171] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that, in step (2), the diatomaceous earth is not treated, that is, the diatomaceous earth is directly used as the raw material of the cat litter.

[0172] Comparative Example 3

[0173] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that step (3) is omitted, that is, no MnO2-biochar composite material is added to the catalyst deodorization layer, and only laccase microcapsules are added.

[0174] Comparative Example 4

[0175] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that no binder is added in step (5).

[0176] Comparative Example 5

[0177] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that in step (5), the binder is hydroxypropyl starch.

[0178] Comparative Example 6

[0179] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that, in step (7), nano-SiO2 is not added.

[0180] Comparative Example 7

[0181] The preparation method of the cat litter in this comparative example is similar to that in Example 1, except that in step (5), the mass ratio of the modified sodium bentonite to the graded pore diatomaceous earth is 7:1, the coating cycle in step (6) is 1 to 2 times, and the diameter of the water-absorbing inner core layer of the finally prepared cat litter is 1.5 mm, the thickness of the catalytic deodorizing middle layer is 0.6 mm, and the thickness of the dust suppression outer shell layer is 0.5 mm.

[0182] Test Example 1

[0183] (1) Evaluation of deodorization effect

[0184] The deodorizing effects of the cat litters prepared in Examples 1-3 and Comparative Examples 1-7 were tested. The test method was as follows: Standard odor gases (50 ppm of NH3, 20 ppm of H2S, and 30 ppm of butyl acetate) were injected into a 30 L sealed chamber in accordance with ISO 17226-3:2023, and concentration changes were monitored using gas chromatography-mass spectrometry (GC-MS). The test results are shown in Table 1.

[0185] Table 1

[0186]

[0187]

[0188] The cat litter has an NH3 removal rate (24 hours) of 89.2-96.5%, an H2S removal rate (24 hours) of 90.8-98.1%, a VOC removal rate (24 hours) of 78.6-85.4%, and a long-term effect (7-day rebound rate) of 8.3-15.7%.

[0189] Comparing Comparative Examples 1 and 2 with Example 1, the NH3 and H2S removal rates of the unmodified sodium bentonite and diatomaceous earth are relatively low, indicating that the production process needs to be modified.

[0190] Compared with Example 1, Comparative Examples 3 to 6, respectively, have lower NH3 and H2S removal rates without adding MnO2-biochar composite material, binder, binder of the present invention, and nano-SiO2, indicating that the above substances are indispensable in the production process, and that the binder obtained by mixing and proportioning has better effect.

[0191] Comparative Example 7 is compared with Example 1, which shows that if the thickness of the inner, middle and outer layers is too large or too small, it is not conducive to the removal of the odor of the cat litter.

[0192] (2) Physical properties test

[0193] The physical properties of the cat litters prepared by test examples 1-3 and comparative examples 1-7 were tested respectively, and the test standards were as follows:

[0194] Agglomeration strength: ASTM D642, measured after immersion in simulated urine (1% urea + 0.5% NaCl);

[0195] Dust emission: GB / T 16913-2022, using APS 3321 particle size spectrometer to detect PM2.5 generation;

[0196] Water absorption rate: GB / T 8810-2023, record the time required for 10g sample to completely absorb water;

[0197] Bulk density: HG / T2825-2009, tested using a bulk density tester. Test results are shown in Table 2.

[0198] Table 2

[0199]

[0200] The cat litter of the present invention has a clumping strength of 12.6-15.2N and a PM2.5 emission of 1.8-3.2 (mg / m 3 ), water absorption time is 23-30s, and bulk density is 0.68-0.72g / cm 3 .

[0201] Comparative Examples 1 to 2 are compared with Example 1. The agglomeration strength of the unmodified sodium bentonite and diatomite decreases, and the PM2.5 emission increases in water absorption and time, indicating that the modification of sodium bentonite and diatomite helps to optimize the performance of cat litter.

[0202] Compared with Example 1, Comparative Examples 3 to 6 respectively do not add MnO2-biochar composite material, binder, do not use the binder of the present invention, nano-SiO2, etc. The agglomeration strength of algae soil decreases, PM2.5 emission increases water absorption, and time increases, indicating that the above substances are indispensable in the production process, and also that the binder obtained by mixing and matching has better effect.

[0203] Comparative Example 7 is compared with Example 1, which shows that the cat litter with the thickness of the water-absorbing inner core layer and the catalytic deodorizing middle layer not within the range of the present invention has poor performance.

[0204] (3) Environmental safety assessment

[0205] The safety performance of the cat litters prepared in Examples 1-3 was tested respectively.

[0206] First, the acute oral toxicity of the cat litters prepared in Examples 1 to 3 was tested respectively according to the standard GB 15193.3-2014, and the LD50 values ​​were all greater than 5000 mg / kg, indicating that the cat litters were practically non-toxic.

[0207] Second, according to the standard EPA6010D, the cat litters prepared in Examples 1-3 were tested for heavy metal migration, 2. Pb < 2ppm, Cd < 0.5ppm, which complies with the EN71-3 standard;

[0208] Third, according to the standard OECD 301B, the biodegradability of the cat litters prepared in Examples 1-3 was tested respectively. The degradation rates after 28 days were all ≥88%, which was significantly better than that of ordinary mineral cat litters (<5%).

[0209] Test Example 2

[0210] According to the standard GB / T 18883-2022, the NH3 adsorption capacity of the cat litters treated in Examples 4-6 and the NH3 adsorption capacity of the cat litters prepared in Examples 1-3 were tested according to the method of Test Example 1. The results are shown in Table 3.

[0211] Table 3

[0212]

[0213] By comparing Example 4 with Example 1, Example 5 with Example 2, and Example 6 with Example 3, it can be seen that the NH3 removal rate (24h) of the cat litter recycled and treated by the method of the present invention is 90.2-93.8% of that of the unused cat litter.

[0214] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A multi-stage pore composite mineral cat litter, characterized in that: The cat litter comprises, from the inside to the outside, a water-absorbing inner core layer, a catalytic deodorizing middle layer and a dust-suppressing outer shell layer; The water-absorbing inner core layer is made of modified sodium bentonite, graded pore diatomaceous earth and a binder; the catalytic deodorizing middle layer is made of MnO2-biochar composite material and laccase microcapsules; and the dust suppression outer shell layer is made of polyethylene glycol 2000 and nano-SiO2.

2. A multi-stage pore composite mineral cat litter according to claim 1, characterized in that, The diameter of the water-absorbing inner core layer is 2.0-2.5 mm, the thickness of the catalytic deodorizing middle layer is 0.8-1.2 mm, and the thickness of the dust suppression outer shell layer is 0.2-0.5 mm.

3. A multi-stage pore composite mineral cat litter according to claim 1, characterized in that, The hierarchical pore diatomite has three levels of mesopores, namely, 1-2 nm micropores, 5-20 nm mesopores and 50-200 nm macropores.

4. A multi-stage pore composite mineral cat litter according to any one of claims 1 to 3, characterized in that: The mass ratio of the modified sodium bentonite to the graded pore diatomite is 3:1-6:1, and the mass of the binder accounts for 5-7% of the total mass of the modified sodium bentonite, the graded pore diatomite and the binder.

5. A multi-stage pore composite mineral cat litter according to any one of claims 1 to 3, characterized in that: The mass ratio of the MnO2-biochar composite material to the laccase microcapsule is 2.5-3.5, and the laccase microcapsule is prepared by co-immobilizing a laccase aqueous solution, trehalose and a cross-linking agent.

6. A method for preparing the multi-stage pore composite mineral cat litter according to any one of claims 1 to 5, characterized in that: The steps include: (1) mixing sodium bentonite with sodium citrate solution, ultrasonically treating, centrifuging, and calcining to obtain modified sodium bentonite; (2) diatomaceous earth is crushed and sieved, and clay minerals are separated. HCl solution is added and stirred to form micropores of 1 to 2 nm. A surfactant is added and self-assembled in an ammonia environment to form mesopores of 5 to 20 nm. Ammonium bicarbonate is added and pressed and pre-fired to form a honeycomb skeleton. The temperature is raised and kept to react to form macropores of 50 to 200 nm, thereby obtaining the hierarchical pore diatomaceous earth. (3) The biomass material is oxidized and cracked to produce biochar, which is then activated and immersed in a Mn(NO3)2 solution to obtain a MnO2-biochar composite material through a hydrothermal reaction; (4) mixing the laccase aqueous solution with trehalose, adding the mixture to a cross-linking agent, and freeze-drying the mixture to obtain the laccase microcapsules; (5) mixing the modified sodium bentonite described in step (1) and the graded pore diatomite described in step (2), adding a binder, and granulating to obtain a water-absorbing inner core layer; (6) mixing the MnO2-biochar composite material described in step (3) and the laccase microcapsules described in step (4), and uniformly coating and depositing them on the water-absorbing inner core layer to form a catalyst deodorizing intermediate layer; (7) After heating and melting polyvinyl alcohol 2000, nano-SiO2 is added and stirred to form a uniform slurry. The slurry is sprayed on the catalyst deodorizing middle layer by an electrostatic spraying process to form a dust suppression outer shell layer. The mixture is dried and sieved to obtain the multi-stage pore composite mineral cat litter.

7. The preparation method according to claim 6, characterized in that In step (2), the concentration of the HCl solution is 5-6 mol / L HCl, the solid-liquid ratio of the solution after adding the HCl solution is 0.2-0.3, and the reaction is stirred at 70-80° C. for 2-2.5 hours.

8. The preparation method according to claim 6, characterized in that In step (2), the temperature is raised to 500-550° C. at a heating rate of 5-7° C. / min and the holding time is 2-2.5 h.

9. A method for recovering multi-stage pore composite mineral cat litter according to any one of claims 1 to 5, characterized in that: The steps include: (a) the cat litter is laid with a thickness of ≥5cm for the first time, and new litter is added to the original thickness after cleaning the agglomerates every day; (b) when cumulative usage reaches 60% of initial amount, all cat litters are reclaimed; (c) the cat litter after the recovery is crushed and incinerated at 400-450° C. to obtain regenerated cat litter; (d) regenerated cat litter is mixed with biochar, passed into flue gas, calcined, and ball milled to obtain the cat litter after treatment; (e) the cat litter after described processing is joined in unused multi-stage pore composite mineral cat litter, and reuses; Alternatively, the treated cat litter is used as a garden slow-release fertilizer.

10. The recycling method according to claim 9, characterized in that: In step (d), the NH3 adsorption capacity of the treated cat litter is more than 85% of the NH3 removal rate of the unused cat litter.

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