A method for synthesizing dust-free silica gel cat litter at its source

Abstract

This invention relates to a method for synthesizing dust-free silica gel cat litter at the source. Its morphology and mesoporous structure can be controlled at the source according to usage requirements, belonging to the field of pet product manufacturing technology. This method uses sodium silicate and an acidic solution as raw materials. By controlling the pH, temperature, and reaction time during the gel synthesis stage, the density of hydroxyl groups and the pore structure of the silica gel surface can be controlled at the source. Further optimization of its mesoporous structure and surface properties is achieved through treatment in an alkali metal salt solution. This method eliminates the need for subsequent resin coating or chemical additives, simultaneously achieving dust-free, high-adsorption, long-lasting odor-locking, and structural antibacterial functions at the synthesis source. The resulting silica gel cat litter has low dust content, high water absorption, and strong adsorption capacity for odors such as ammonia. The production process covers the entire process from synthesis and modification to sorting and packaging, making it suitable for large-scale continuous production. It solves the problems of balancing performance and environmental protection, unstable quality control, and fragmented industrial chains inherent in traditional processes.

Description

Technical Field

[0001] This invention relates to the field of pet product manufacturing technology, specifically to a method for synthesizing dust-free silica gel cat litter from its source. Background Technology

[0002] Silica gel cat litter has become one of the mainstream pet cat litter products due to its excellent absorbency, lightweight nature, flushability (for some products), and low replacement frequency. However, existing silica gel cat litter production technology still faces a series of prominent problems. First, to achieve a "dust-free" effect, the industry generally relies on additional coating treatments of resin, enzymes, or other chemicals on the surface of the finished silica gel granules. This post-addition method not only easily clogs the valuable pore structure inside the silica gel, thus weakening its core adsorption capacity, but also leads to unstable dust control in large-scale production. Furthermore, the added chemical raw materials may pose potential risks to the environment and pet health.

[0003] Secondly, to achieve deodorization and antibacterial functions, existing products mostly rely on adding chemical deodorizers (such as fragrances and citric acid) and chemical antibacterial agents (such as alum). These chemical additives may leave volatile residues, and long-term use may lead to safety risks such as aluminum accumulation in pets, which contradicts consumers' growing demand for green and healthy pet ownership. Furthermore, most traditional manufacturing processes lack precise control over the morphology (such as spherical or blocky shapes) and internal mesoporous structure of silicone, resulting in products with limited performance and an inability to meet the refined needs of different usage scenarios.

[0004] Finally, existing technologies mostly focus on optimizing and improving single steps in the production process, such as drying, crushing, and sorting, lacking a comprehensive, integrated design and autonomous control of the entire process from raw material synthesis and structural modification to finished product packaging. This fragmented production model leads to strong dependence on upstream and downstream industries, difficulty in quality control, inconsistent product performance between batches, and supply cycles that are easily constrained by upstream raw material suppliers, making it difficult to achieve high-quality, highly consistent, continuous, and stable production at the ton level. Therefore, developing a method for preparing silica gel cat litter that can simultaneously achieve morphology and structure control from the source synthesis stage, possesses excellent dust-free, odor-locking, and antibacterial properties, and is suitable for continuous industrial production throughout the entire process has urgent market demand and significant technological innovation value. Summary of the Invention

[0005] The technical objective of this invention is to provide a continuous production method that can simultaneously control the morphology and mesoporous structure from the source synthesis stage without relying on later chemical additives, thereby solving the problems of traditional silica gel cat litter's difficulty in achieving both "dust-free" and "high adsorption" performance, reliance on chemical deodorizing / antibacterial agents, and fragmented production processes.

[0006] To achieve the above-mentioned technical objectives of this invention, the following technical solution is adopted: A method for synthesizing dust-free silica gel cat litter at its source includes the following steps: Step 1: Prepare an aqueous solution of sodium silicate as a precursor for silicon dioxide; Step 2: Under stirring conditions, an acidic solution is added to the sodium silicate precursor solution to adjust the pH of the system to synthesize silica gel. The hydroxyl groups on the gel surface are controlled by adjusting the pH, temperature and reaction time of the reaction system. Step 3: Aging treatment is performed on the silica gel synthesized in Step 2; Step 4: Wash the aged gel with water to remove impurity ions; Step 5: Dry the washed gel to obtain silica gel cat litter granules; Step Six: Sorting and packaging the silica gel cat litter granules.

[0007] Preferably, in step three, the aging treatment is an ultrasonic-assisted impregnation treatment in an alkali metal inorganic salt solution; the alkali metal inorganic salt solution is selected from potassium salt, sodium salt solution or a mixture thereof, and its pH value is adjusted to 10-12.

[0008] Preferably, the alkali metal inorganic salt solution has a potassium ion to sodium ion molar ratio of 1:1 to 1:3; the ultrasonic-assisted frequency is 20-100 kHz, the immersion temperature is 50-80°C, and the immersion time is 1-5 hours; the alkali metal inorganic salt loading is 20-40 wt% of the weight of the porous silica matrix.

[0009] Preferably, in step four, after washing with water, the step further includes adding an adhesive, wherein the adhesive is selected from at least one of starch glue, polyvinyl alcohol, sodium carboxymethyl cellulose, and polyacrylic acid (primary) polymer, and the amount added is 20 wt% of the weight of the gel mixture; after adding the adhesive, the step further includes dispersing and mixing.

[0010] Preferably, in step two, the inorganic acid used is selected from at least one of sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, iodic acid, periodic acid, and perchloric acid, with a concentration ≥50wt%, the acid treatment temperature is controlled below 80℃, and the treatment time is below 30 hours.

[0011] Preferably, in step five, the drying is a gradient drying process with a drying temperature of 100-200℃. The heating program is as follows: first, maintain the temperature at 80℃-100℃ for 1 hour, and then increase the temperature to the target drying temperature at a rate of 5℃ / h. The total drying time is 3-5 hours. After drying, the process also includes a calcination step in an oxygen-containing atmosphere with a calcination temperature of 300-600℃, a heating rate of 2-10℃ / min, and a calcination time of 2-5 hours.

[0012] Preferably, in step one, the porous silica matrix is ​​amorphous or spherical, with a particle size of 0.5-8 mm and a pore volume greater than 0.8 mL / g.

[0013] This invention also provides a method for synthesizing silica cat litter with adjustable morphology and mesoporous structure. The method can achieve the construction of a mesoporous structure with a pore volume greater than 0.8 mL / g, a dust content ≤0.1%, a saturated water absorption rate ≥95%, and an ammonia removal rate ≥95%.

[0014] To achieve the objectives of this invention, another technical solution is a continuous production system for silica gel cat litter, which includes a reactor for performing steps one and two of the above method, an aging tank for performing step three, a washing tank for performing step four, a drying and calcining device for performing step five, and an airflow classification, sorting, and intelligent packaging device for performing step six, thereby realizing a continuous closed-loop production process from raw material synthesis to product packaging.

[0015] Compared with the prior art, the present invention achieves the following technical effects: The optimization of "dust-free" and "high adsorption / breathability" has been achieved: by controlling the density of surface hydroxyl groups during gel synthesis, electrostatic adsorption and dust generation between particles are suppressed from the source. There is no need to rely on the later coating process that will block the pores. This achieves a low dust rate (≤0.1%) while maintaining high porosity and excellent adsorption performance.

[0016] It achieves excellent water absorption, odor retention, and antibacterial functions: through the directional design and synthetic regulation of its mesoporous structure, the cat litter possesses high water absorption (up to 200%-382%), rapid water absorption (<2 seconds), and excellent clumping performance (clump integrity ≥90%). Its physical adsorption mechanism can efficiently remove odorous gases such as ammonia (removal rate ≥95%), and it can inhibit bacterial growth through its structure (24-hour sterilization rate ≥85%), achieving green deodorization and antibacterial effects without relying on chemical additives.

[0017] An integrated production system with full-process controllability has been constructed: The method of this invention connects the entire chain from raw material synthesis, structural modification, drying, sorting to packaging, realizes closed-loop control of process parameters and ensures quality consistency, is suitable for continuous and stable production at the ton level, and solves the problems of unstable quality, high cost and limited supply cycle caused by the fragmented industrial chain in the traditional production mode. Attached Figure Description

[0018] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0019] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0020] The following are specific embodiments of the present invention, described in conjunction with the accompanying drawings, to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments. Specific details, such as particular configurations, are provided in the following description merely to aid in a comprehensive understanding of the embodiments of the present invention. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0022] Example 1: Preparation of spherical clumped silica gel cat litter Step 1: After preparing a 1.0 mol / L sodium silicate solution, transfer it to the reactor; Step 2: After diluting the acidic solution with water, slowly add it to the sodium silicate precursor solution obtained in Step 1 under continuous stirring. Adjust the pH of the system to induce dehydration condensation reaction and synthesize silica gel. At the same time, by precisely controlling the pH, temperature and reaction time of the reaction system, the hydroxyl groups on the gel surface can be directionally controlled. Step 3: After transferring the porous silica gel obtained in Step 2 into the aging tank, add an alkali metal inorganic salt solution for ultrasonic-assisted impregnation treatment. Step 4: The silica obtained from the aging treatment in Step 3 is transferred to a water washing tank for water washing, and then the binder is added and dispersed in a high-speed disperser to obtain a mixed slurry. Step 5: Gradient drying and oxygen-containing atmosphere calcination treatment to obtain silica gel cat litter. Step 6: Achieve dust-free sorting and intelligent packaging through airflow grading.

[0023] In step one of this embodiment, the porous silica matrix obtained is spherical with a particle size of 3 mm and a specific pore volume of 0.93 mL / g.

[0024] In step two of this embodiment, the inorganic acid used in the process of adjusting the pH of the system is sulfuric acid with a concentration of 50 wt%, which adjusts the pH of the system to about 3.5. The acid treatment temperature is controlled below 100°C and the treatment time is 20 hours.

[0025] In step three of this embodiment, the alkali metal inorganic salt solution is a mixture of aqueous solutions of potassium sulfate and sodium sulfate, the molar ratio of potassium ions to sodium ions in the composite salt solution is 1:3, the pH value of the solution is adjusted to 10-12, the immersion treatment temperature is 50-80℃, the time is 3 hours, and the ultrasonic-assisted frequency is 40-60 kHz.

[0026] In step three of this embodiment, the alkali metal inorganic salt is 30% by weight of the porous silica matrix.

[0027] In step four of this embodiment, the adhesive added is starch glue, the amount added is 20%, and the dispersion and mixing time is 20-30 minutes.

[0028] In step five of this embodiment, the gradient drying temperature is 200℃, and the heating program is as follows: maintain at 80℃ for 30 minutes and then increase to 200℃ at a rate of 5℃ / h, with a drying time of 3 hours.

[0029] In step five of this embodiment, the raw materials are roasted in a pure oxygen atmosphere at a temperature of 600°C for 2 hours.

[0030] In step six of this embodiment, the specification of the intelligent packaging after dust-free sorting is 1.8kg / bag.

[0031] Example 2: Preparation of clumpy silica gel cat litter Step 1: Prepare a 1.0 mol / L sodium silicate solution; Step 2: After diluting the acidic solution with water, slowly add it to the sodium silicate precursor solution obtained in Step 1 under continuous stirring. Adjust the pH of the system to induce dehydration condensation reaction and synthesize silica gel. At the same time, by precisely controlling the pH, temperature and reaction time of the reaction system, the hydroxyl groups on the gel surface can be directionally controlled. Step 3: After transferring the porous silica gel obtained in Step 2 into the aging tank, add an alkali metal inorganic salt solution for ultrasonic-assisted impregnation treatment. Step 4: The silica obtained from the aging treatment in Step 3 is transferred to a water washing tank for washing, and then the binder is added and dispersed in a high-speed disperser to obtain a mixed slurry. Step 5: Place the mixed slurry obtained in Step 4 into a granulator and extrude it to granulate it into silica gel cat litter granules; Step Six: Gradient drying and oxygen-containing atmosphere calcination treatment are used to obtain silica gel cat litter; Step 7: Achieve dust-free sorting and intelligent packaging through airflow grading.

[0032] In step one of this embodiment, the porous silica matrix obtained is amorphous, with a particle size of 1 mm and a specific pore volume of 0.88 mL / g.

[0033] In step two of this embodiment, the inorganic acid used in the process of adjusting the pH of the system is sulfuric acid with a concentration of 80 wt%, which adjusts the pH of the system to about 4. The acid treatment temperature is controlled below 100°C and the treatment time is 10 hours.

[0034] In step three of this embodiment, the alkali metal inorganic salt solution is a mixture of aqueous solutions of potassium sulfate and sodium sulfate, the molar ratio of potassium ions to sodium ions in the composite salt solution is 1:3, the pH value of the solution is adjusted to 10-12, the immersion treatment temperature is 50-80℃, the time is 3 hours, and the ultrasonic-assisted frequency is 40-60 kHz.

[0035] In step three of this embodiment, the alkali metal inorganic salt is 30% by weight of the porous silica matrix.

[0036] In step four of this embodiment, the adhesive added is a mixture of sodium carboxymethyl cellulose and starch glue, with an adhesive addition amount of 20% and a dispersion and mixing time of 20-30 minutes.

[0037] In step five of this embodiment, an extrusion granulator is used for granulation at a temperature of 120°C and an extrusion pressure of 12 MPa.

[0038] In step six of this embodiment, the gradient drying temperature is 200℃, and the heating program is as follows: maintain at 80℃ for 30 minutes and then increase to 200℃ at a rate of 5℃ / h, with a drying time of 3 hours.

[0039] In step six of this embodiment, the raw materials are roasted in a pure oxygen atmosphere at a temperature of 600°C for 2 hours.

[0040] In step seven of this embodiment, the specification of the intelligent packaging after dust-free sorting is 1.8kg / bag.

[0041] Example 3: Preparation of blocky, non-clumping silica gel cat litter Step 1: Prepare a 2.0 mol / L sodium silicate solution; Step 2: After diluting the acidic solution with water, slowly add it to the sodium silicate precursor solution obtained in Step 1 under continuous stirring. Adjust the pH of the system to induce dehydration condensation reaction and synthesize silica gel. At the same time, by precisely controlling the pH, temperature and reaction time of the reaction system, the hydroxyl groups on the gel surface can be directionally controlled. Step 3: After transferring the porous silica gel obtained in Step 2 into the aging tank, add an alkali metal inorganic salt solution for ultrasonic-assisted impregnation treatment. Step 4: The silica obtained from the aging treatment in Step 3 is transferred to a water washing tank for washing. Step 5: Place the mixed slurry obtained in Step 4 into a granulator and extrude it to granulate it into silica gel cat litter granules; Step Six: Gradient drying and oxygen-containing atmosphere calcination treatment to obtain silica gel cat litter. Step 7: Achieve dust-free sorting and intelligent packaging through airflow grading.

[0042] In step one of this embodiment, the porous silica matrix obtained is amorphous, with a particle size of 8 mm and a specific pore volume of 1.0 mL / g.

[0043] In step two of this embodiment, the inorganic acid used in the process of adjusting the pH of the system is sulfuric acid with a concentration of 65 wt%, which adjusts the pH of the system to about 4. The acid treatment temperature is controlled below 100°C and the treatment time is 10 hours.

[0044] In step three of this embodiment, the alkali metal inorganic salt solution is a mixture of aqueous solutions of potassium sulfate and sodium sulfate, the molar ratio of potassium ions to sodium ions in the composite salt solution is 1:1, the pH value of the solution is adjusted to 11-12, the immersion treatment temperature is 50-80℃, the time is 3 hours, and the ultrasonic-assisted frequency is 40-60 kHz.

[0045] In step three of this embodiment, the alkali metal inorganic salt is 20% by weight of the porous silica matrix.

[0046] In step five of this embodiment, an extrusion granulator is used for granulation at a temperature of 50°C and an extrusion pressure of 1.0 MPa.

[0047] In step six of this embodiment, the gradient drying temperature is 200℃, and the heating program is as follows: maintain at 100℃ for 30 minutes and then increase to 200℃ at a rate of 5℃ / h, with a drying time of 3 hours.

[0048] In step six of this embodiment, the raw materials are roasted in a pure oxygen atmosphere at a temperature of 600°C for 2 hours.

[0049] In step seven of this embodiment, the specification of the intelligent packaging after dust-free sorting is 20kg / bag.

[0050] Example 4: Preparation of clumpy silica gel cat litter Step 1: Prepare a 2.0 mol / L sodium silicate solution; Step 2: After diluting the acidic solution with water, slowly add it to the sodium silicate precursor solution obtained in Step 1 under continuous stirring. Adjust the pH of the system to induce dehydration condensation reaction and synthesize silica gel. At the same time, by precisely controlling the pH, temperature and reaction time of the reaction system, the hydroxyl groups on the gel surface can be directionally controlled. Step 3: After transferring the porous silica gel obtained in Step 2 into the aging tank, add an alkali metal inorganic salt solution for ultrasonic-assisted impregnation treatment. Step 4: The silica obtained from the aging treatment in Step 3 is transferred to a water washing tank for washing, and then the binder is added and dispersed in a high-speed disperser to obtain a mixed slurry. Step 5: Place the mixed slurry obtained in Step 4 into a granulator and extrude it to granulate it into silica gel cat litter granules; Step Six: Gradient drying and oxygen-containing atmosphere calcination treatment are used to obtain silica gel cat litter; Step 7: Achieve dust-free sorting and intelligent packaging through airflow grading.

[0051] In step one of this embodiment, the porous silica matrix obtained is amorphous with a particle size of 0.5 mm and a specific pore volume of 0.85 mL / g.

[0052] In step two of this embodiment, the inorganic acid used in the process of adjusting the pH of the system is sulfuric acid with a concentration of 10w%, which adjusts the pH of the system to about 4. The acid treatment temperature is controlled below 100°C and the treatment time is 10h.

[0053] In step three of this embodiment, the alkali metal inorganic salt solution is a mixture of aqueous solutions of potassium sulfate and sodium sulfate, the molar ratio of potassium ions to sodium ions in the composite salt solution is 1:1, and the pH value of the solution is adjusted to 11-12; the immersion treatment temperature is 50-80℃ and the time is 1.5 hours; the ultrasonic-assisted frequency is 40-60 kHz.

[0054] In step three of this embodiment, the alkali metal inorganic salt is 20% by weight of the porous silica matrix.

[0055] In step four of this embodiment, the adhesive added is polyvinyl alcohol, the amount of adhesive added is 20%, and the dispersion and mixing time is 20-30 minutes.

[0056] In step five of this embodiment, an extrusion granulator is used for granulation at a temperature of 80°C and an extrusion pressure of 0.8 MPa.

[0057] In step six of this embodiment, the gradient drying temperature is 200℃, and the heating program is as follows: maintain at 80℃ for 30 minutes and then increase to 200℃ at a rate of 5℃ / h, with a drying time of 3 hours.

[0058] In step six of this embodiment, the raw materials are roasted in a pure oxygen atmosphere at a temperature of 600°C for 2 hours.

[0059] In step seven of this embodiment, the specification of the intelligent packaging after dust-free sorting is 1.8kg / bag.

[0060] Those skilled in the art to which this application pertains may modify or supplement the specific embodiments described or use similar methods to replace them, but without departing from the inventive concept of this application or exceeding the scope defined by the appended claims.

Claims

1. A method for synthesizing dust-free silica gel cat litter at its source, characterized in that, Includes the following steps: Step 1: Prepare an aqueous solution of sodium silicate as a precursor for silicon dioxide; Step 2: Under stirring conditions, an acidic solution is added to the sodium silicate precursor solution to adjust the pH of the system to synthesize silica gel. The hydroxyl groups on the gel surface are controlled by adjusting the pH, temperature and reaction time of the reaction system. Step 3: Aging treatment is performed on the silica gel synthesized in Step 2; Step 4: Wash the aged gel with water to remove impurity ions; Step 5: Dry the washed gel to obtain silica gel cat litter granules; Step Six: Sorting and packaging the silica gel cat litter granules.

2. The method for synthesizing dust-free silica gel cat litter according to claim 1, characterized in that, In step three, the aging treatment is an ultrasonic-assisted impregnation treatment in an alkali metal inorganic salt solution; the alkali metal inorganic salt solution is selected from potassium salt, sodium salt solution or a mixture thereof, and its pH value is adjusted to 10-12.

3. The method for synthesizing dust-free silica gel cat litter according to claim 2, characterized in that, The molar ratio of potassium ions to sodium ions in the alkali metal inorganic salt solution is 1:1 to 1:3; the ultrasonic-assisted frequency is 40-60kHz, the immersion temperature is 50-80℃, and the immersion time is 1-5 hours; the loading of the alkali metal inorganic salt is 15-30wt% of the weight of the porous silica matrix.

4. The method for synthesizing dust-free silica gel cat litter according to claim 1, characterized in that, In step four, after washing with water, the step of adding an adhesive is also included. The adhesive is selected from at least one of starch glue, polyvinyl alcohol, and sodium carboxymethyl cellulose, and the amount added is 20 wt% of the weight of the gel mixture. After adding the adhesive, the step of dispersing and mixing is also included.

5. The method for synthesizing dust-free silica gel cat litter according to claim 1, characterized in that, In step two, the inorganic acid used is selected from at least one of sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, iodic acid, periodic acid, and perchloric acid, with a concentration ≥50wt%. The acid treatment temperature is controlled below 80℃ and the treatment time is below 30 hours.

6. The method for synthesizing dust-free silica gel cat litter according to claim 1, characterized in that, In step five, the drying is a gradient drying process with a drying temperature of 100-200℃. The heating program is as follows: first, maintain the temperature at 80℃-100℃ for 1 hour, and then increase it to the target drying temperature at a rate of 5℃ / h. The total drying time is 3-5 hours. After drying, the process also includes a calcination step in an oxygen-containing atmosphere with a calcination temperature of 300-600℃, a heating rate of 2-10℃ / min, and a calcination time of 5-30 hours.

7. The method for synthesizing dust-free silica gel cat litter according to claim 1, characterized in that, In step one, the porous silica matrix obtained is amorphous or spherical, with a particle size of 0.5-8 mm and a pore volume greater than 0.8 mL / g.

8. Silica gel cat litter prepared by the method according to any one of claims 1-7.

9. The silica gel cat litter according to claim 8, characterized in that, It can achieve the construction of mesoporous structures with a pore volume greater than 0.8 mL / g, a dust rate ≤0.1%, a saturated water absorption rate ≥95%, and an ammonia removal rate ≥95%.

10. A continuous production system for silica gel cat litter, characterized in that, It includes a reactor for performing steps one and two as described in claim 1, an aging tank for performing step three, a washing tank for performing step four, a drying and roasting device for performing step five, and an airflow classification, sorting and intelligent packaging device for performing step six, connected in sequence.

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