Premixing, catalysis and hydrophobic modification integrated granulation method for crushed crude pearlite and application thereof

Abstract

The invention provides a perlite powder premixing catalysis hydrophobic modification integrated granulation method and application thereof, and belongs to the technical field of inorganic non-metallic material modification. According to the method, efficient hydrophobic modification of perlite particles is achieved through a four-step integrated process of raw material premixing, paste preparation, extrusion granulation and high-temperature catalytic roasting, and the core innovation of the method is that in the high-temperature roasting stage, hydrophobic groups are released through the pyrolysis effect of a catalyst in the particles, a monomolecular hydrophobic membrane is formed from inside to outside, and the hydrophobic performance of the perlite particles is improved. Directional release and uniform distribution of hydrophobic groups are realized, and the hydrophobic groups are tightly combined with internal structures of perlite particles, so that the cost is reduced, and the operation process is simplified; in addition, uniform composite powder is formed through dry grinding, compared with a traditional distribution modification method, intermediate links are reduced through integrated premixing, the modification efficiency is improved, and the method is suitable for direct engineering application in oil-water separation, hazardous chemical substance leakage adsorption, soil remediation or VOCs tail end treatment.

Description

Technical Field

[0001] This invention relates to the field of oil absorbent preparation technology, specifically to an integrated granulation method for premixed catalytic hydrophobic modification of perlite powder and its application. Background Technology

[0002] Perlite is a natural acidic glassy volcanic lava that, after high-temperature expansion, forms a porous, lightweight, and chemically stable granular material. It possesses characteristics such as high porosity, low density, and non-toxicity, making it widely used in environmental remediation fields such as oil-water separation, hazardous chemical adsorption, and soil remediation. Particularly in scenarios involving oil spills in water bodies and the treatment of oily industrial wastewater, perlite-based adsorbent materials, due to their excellent selective adsorption performance for floating oil, have become an important inorganic environmentally friendly material to replace traditional organic oil-absorbing felts and polypropylene fibers.

[0003] Currently, the commonly used perlite adsorbent preparation processes both domestically and internationally mainly fall into the following two categories: (1) Surface modification technology for post-treatment of expanded perlite The typical process represented by CN108905953A has the following technical route: A porous structure is obtained by selecting perlite ore sand with specific composition and expanding it at high temperature (1100–1400℃); Silicone oil-based hydrophobic agents are formulated into solutions and sprayed onto the surface of expanded perlite particles to form a hydrophobic coating. The finished product is obtained after aging.

[0004] While this type of technology can improve the oleophilic and hydrophobic properties of perlite surfaces, it suffers from the following common problems: Uneven surface modification: The spraying method only acts on the outer surface of the particles, and the interior is not modified, resulting in inconsistent hydrophobic properties; and the particle morphology is uncontrollable: Expanded perlite is a natural particle with an irregular shape, which is not conducive to filling, filtering, recycling and other operations in engineering applications. (2) Post-granulation impregnation / coating modification technology Existing general technologies employ granulation followed by impregnation or coating for hydrophobic modification. While this improves particle morphology, it still fails to address the following issues: The modifier only adheres to the outer layer of the particles, and has poor hydrophobicity inside; The process is complicated, with drying and modification separated, resulting in high energy consumption and low efficiency.

[0005] Therefore, technological improvements are needed. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide an integrated granulation method for premixed catalytic hydrophobic modification of perlite powder and its application.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an integrated granulation method for premixed catalytic hydrophobic modification of perlite powder, characterized in that it includes: S1 raw material mixing: Perlite powder and hydrophobic powder catalyst are mixed at a mass ratio of 40-20:1, and then dry-milled in a ball mill for 20-60 minutes to form a uniform composite powder. S2 paste preparation: Solvent, organic binder and plasticizer are gradually added to a mixer and stirred until completely dissolved to obtain a mixed binder. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed binder to form a paste with viscosity and plasticity, and left to stand for 2 hours. S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and the temperature is controlled at 50℃-80℃ and the pressure is 1-5MPa to extrude into columnar granules of equal length. S4 heats the cut particles in a furnace at a temperature of 200℃-350℃ and roasts them for 1-4 hours. After high-temperature extended sintering and pyrolysis of the internal catalyst of the particles, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out to obtain hydrophobic modified perlite particles.

[0008] As a preferred embodiment of this application, the moisture content of the paste made by S2 is controlled between 10% and 25%.

[0009] As a preferred embodiment of this application, the hydrophobic powder catalyst is selected from one or more of organosilicon hydrophobic agents, hydrocarbon hydrophobic agents, or polymeric hydrophobic agents, with a particle size D50 ≤ 20 µm.

[0010] As a preferred embodiment of this application, the solvent is any one of water, ethanol, a water-ethanol mixture, or a water-low carbon ester mixture. Alternatively, it may be isopropanol (1,2-propanediol) or ethyl acetate.

[0011] As a preferred embodiment of this application, the organic adhesive is one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, starch, and polyvinyl alcohol.

[0012] As a preferred embodiment of this application, the plasticizer is one or more of glycerin, polyethylene glycol, or stearate.

[0013] As a preferred embodiment of this application, the forming die of the twin-screw extruder has a diameter of 2-10 mm, a cutter speed of 20-200 rpm, and the resulting columnar particles have an aspect ratio of 1-3:1.

[0014] As a preferred embodiment of this application, the heating furnace is a drum-type hot air furnace, a mesh belt drying furnace, or a rotary kiln, with a heating rate of 2-10 ℃ / min and an oxygen content ≤15 vol in the furnace.

[0015] Furthermore, the hydrophobically modified perlite particles are prepared by the premixed catalytic hydrophobic modification integrated granulation method of perlite powder as described above.

[0016] Furthermore, hydrophobically modified perlite particles have direct engineering applications in oil-water separation, hazardous chemical spill adsorption, soil remediation, or VOCs end-of-pipe treatment.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: During the high-temperature calcination stage, this invention utilizes the pyrolysis of the catalyst inside the particles to release hydrophobic groups, forming a monomolecular hydrophobic film from the inside out. This achieves the directional release and uniform distribution of hydrophobic groups, which are also tightly integrated with the internal structure of the perlite particles, improving the durability and stability of the hydrophobic effect. It also reduces costs and simplifies the operation process, avoiding the problems of unevenness or easy detachment caused by traditional surface coating. Furthermore, this application forms a uniform composite powder through dry grinding. Compared with traditional distribution modification methods, integrated premixing reduces intermediate steps and improves modification efficiency. Attached Figure Description

[0018] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the main structure of the present invention. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] like Figure 1 As shown, Example 1 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (200 mesh, SiO2 content >75%) of perlite powder, 20g of hydrophobic powder catalyst (the hydrophobic powder catalyst is an organosilicon hydrophobic agent with a particle size D50≤20 µm) and 10g of nano SiO2, and dry grind them in a ball mill for 30 minutes to form a uniform composite powder for later use. Among them, the catalyst with a particle size D50≤20 µm forms a "nano-anchoring" effect on the surface of perlite, which improves the gas phase grafting efficiency.

[0021] Implementation principle: Small-particle-size catalysts are embedded in the micropores on the surface of perlite during ball milling, increasing the contact area with Si-OH groups.

[0022] Experimental results: The catalyst dispersion reached 92% (laser particle size analysis), and the hydrophobic film thickness uniformity was <±1 nm (AFM test).

[0023] To prepare the S2 paste, 400g of a liquid adhesive system (a mixture of solvent, organic adhesive, and plasticizer, wherein the mass ratio of solvent, organic adhesive, and plasticizer is 60%–80%:10%–20%:10%–20%, preferably 70%:15%:15% in this embodiment, wherein water is used as the solvent, carboxymethyl cellulose is used as the organic adhesive, and glycerin is used as the plasticizer) is gradually added to a mixer and stirred until completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then allowed to stand for 2 hours. The water content of the paste prepared by S2 is controlled at 17%. It should be noted that solvent systems such as ethanol-water and isopropanol-water reduce surface tension by 30%–40%, accelerate the dehydration rate, and inhibit catalyst aggregation.

[0024] The principle behind this is that the azeotropic solvent initially removes 60% to 70% of the water in the extrusion section at 50-80℃, and the remainder is completely released in the pyrolysis section at 200-350℃.

[0025] Experimental results: Compared with the pure water system, the dehydration time was shortened by 42% and the catalyst activity retention rate was increased by 18%.

[0026] CMC, PVA and other adhesives are used to form a three-dimensional network in the paste, which increases the strength of wet particles by 2-3 times and reduces transport loss.

[0027] The principle behind this is that the binder molecular chains form hydrogen bonds with the surface of the perlite, while simultaneously encapsulating the catalyst particles to prevent premature reaction.

[0028] Test results: The compressive strength of wet granules reached 0.8 MPa, and the breakage rate during transport was <2%.

[0029] Plasticizers such as glycerin and PEG are used to lower the glass transition temperature of the paste by 15-20℃, thereby improving its fluidity at low temperatures (50-80℃).

[0030] Principle of implementation: Plasticizer molecules insert into the molecular chains of adhesives, reducing the system modulus and reducing extrusion shear force by 35% to 45%.

[0031] Test results: Extrusion energy consumption was reduced by 28%, and die wear rate decreased by 41%.

[0032] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under controlled conditions of 50°C and 3MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at 250°C for 2 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0033] The hot air furnace uses a drum-type hot air furnace to achieve uniform tumbling of particles, with a hydrophobic film uniformity variation coefficient of <5%, thus improving the batch stability of products.

[0034] Implementation principle: Hot air enters in a spiral tangential direction, forming forced convection, and the particles are heated evenly within ±2℃.

[0035] Experimental results: contact angle standard deviation < 3°, adsorption capacity RSD < 4%.

[0036] Working principle: The organosilicon hydrophobic agent is premixed with perlite powder by dry grinding, so that the catalyst is evenly distributed on the surface and in the micropores of the perlite. During calcination at 250℃, the ≡Si-CH3 free radicals generated by the pyrolysis of the catalyst undergo gas-phase grafting with the ≡Si-OH of the perlite to form a covalently bonded monomolecular hydrophobic film, achieving hydrophobic modification from the inside out.

[0037] Experimental data: The oil adsorption capacity is 3.5g / g.

[0038] The contact angle is greater than 120°.

[0039] Porosity is 88.5% The oil absorption rate is 95%.

[0040] Technical effects: Improved adsorption performance: Compared with unmodified perlite, the adsorption capacity is increased by 35%, the contact angle is increased by 40°, and the porosity is optimized by 5%.

[0041] Stable process: The paste with a water content of 17% has good extrusion stability and a particle formation rate of >99%.

[0042] Reduced energy consumption: Compared with traditional processes, energy consumption is reduced by 60% and the cycle time is shortened by 67%.

[0043] Example 2 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (200 mesh, SiO2 content >75%) of perlite powder, 30g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a hydrocarbon hydrophobic agent with a particle size D50≤20 µm) and 10g of nano SiO2, add them to a ball mill and dry grind for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 70%:15%:15% in this embodiment, wherein the solvent is water, the organic adhesive is carboxymethyl cellulose, and the plasticizer is glycerin). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 17%.

[0044] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 50℃-80℃ and pressure at 1-5MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at 250°C for 2 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0045] Compared to Example 1, this embodiment adjusts the weight distribution in the raw material mixing and changes the type of hydrophobic powder catalyst to a hydrocarbon hydrophobic agent.

[0046] Working principle: The hydrocarbon chains (-CnH2n+1) released by the hydrocarbon hydrophobic agent during the calcination stage interact with the perlite surface through van der Waals interactions, forming a physically adsorbed hydrophobic layer, which is suitable for adsorbing moderately polar oils.

[0047] Experimental data: The oil adsorption capacity is 3.5g / g.

[0048] The contact angle is greater than 120°.

[0049] The diesel adsorption capacity is 4.2 g / g.

[0050] Technical effects: Multi-oil adaptability: Enables universal adsorption of diesel and engine oil, with contact angles >120°.

[0051] High temperature stability: The hydrocarbon chain can still maintain a stable adsorption structure at 250℃.

[0052] Cost optimization: The cost of hydrocarbon catalysts is 23% lower than that of organosilicon.

[0053] Example 3 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (200 mesh, SiO2 content >75%) of perlite powder, 10g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a high molecular hydrophobic agent with a particle size D50≤20 µm) and 20g of nano SiO2, add them to a ball mill and dry grind for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 70%:15%:15% in this embodiment, wherein the solvent is water, the organic adhesive is carboxymethyl cellulose, and the plasticizer is glycerin). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 17%.

[0054] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 50℃-80℃ and pressure at 1-5MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at 250°C for 2 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0055] Compared to Example 1, this embodiment adjusts the weight distribution in the raw material mixing and uses a hydrocarbon hydrophobic agent instead of a hydrophobic powder catalyst. Working principle: The pyrolysis of the polymer hydrophobic agent generates a network polymer, which fills the pores of perlite and adsorbs onto the pore walls, forming a physical barrier hydrophobic layer that enhances the adsorption of highly polar organic matter.

[0056] Experimental data: The adsorption capacity for cyclohexane is 4.0 g / g.

[0057] Contact angle > 120°.

[0058] Porosity was optimized to 89%.

[0059] Technical effects: Polarity adaptability: Increases adsorption capacity for low surface energy liquids such as cyclohexane by 28%.

[0060] Pore ​​optimization: Polymer filling makes the pore size distribution more uniform (average pore size 2.3μm→1.8μm).

[0061] Cyclic stability: After 5 adsorption-regeneration cycles, the adsorption capacity retention rate is >92%.

[0062] Example 4 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (300 mesh, SiO2 content >85%) of perlite powder, 30g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a high molecular hydrophobic agent with a particle size D50≤20 µm) and 10g of nano SiO2, and dry grind them in a ball mill for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 70%:15%:15% in this embodiment, wherein the solvent is water, the organic adhesive is carboxymethyl cellulose, and the plasticizer is glycerin). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 17%.

[0063] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 50℃-80℃ and pressure at 3MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 involves heating the cut columnar particles in a furnace at 250°C for 2.5 hours, followed by prolonged high-temperature sintering and pyrolysis of the internal catalyst to release hydrophobic groups. The particles are then dehydrated and dried. Properties of modified perlite particles: Diesel adsorption capacity: 4.2 g / g; Cyclohexane adsorption capacity: 4.0 g / g.

[0064] Compared to Example 1, this embodiment increases the perlite powder particle size to 300 mesh, the SiO2 content to >85%, and the amount of hydrophobic powder catalyst to 30g.

[0065] Working principle: Utilizing 300-mesh high-purity perlite powder and a polymer catalyst, the adhesion of the hydrophobic film is enhanced through the bridging effect of nano-SiO2. The polymer chains released during calcination form a three-dimensional network, improving the adsorption of linear hydrocarbons such as diesel fuel.

[0066] Experimental data: The adsorption capacity for diesel fuel is 4.2 g / g.

[0067] The adsorption capacity for cyclohexane is 4.0 g / g.

[0068] Contact angle > 120°.

[0069] Technical effects: Breakthrough in adsorption capacity: Diesel adsorption reaches 4.2g / g (2.8 times that of unmodified perlite).

[0070] Purity gain: Increased SiO2 content makes the pore walls smoother and improves adsorption selectivity.

[0071] High temperature and short time: 2.5h roasting balances energy consumption and performance.

[0072] Example 5 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (200 mesh, SiO2 content >75%) of perlite powder, 10g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a high molecular hydrophobic agent with a particle size D50≤20 µm) and 20g of nano SiO2, add them to a ball mill and dry grind for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 70%:20%:10% in this embodiment, wherein the solvent is a water-ethanol mixture, the organic adhesive is hydroxypropyl methylcellulose, and the plasticizer is polyethylene glycol). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 25%.

[0073] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 80°C and pressure at 1MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at a temperature of 200°C for 2 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0074] The difference between this embodiment and Embodiment 1 is that the solvent of the adhesive system liquid is changed to a water-ethanol mixture, the organic adhesive is changed to hydroxypropyl methylcellulose, the plasticizer is changed to polyethylene glycol, and the water content of the paste is increased to 25%.

[0075] Working principle: Ethanol co-solvent reduces surface tension, making it easier for the adhesive system to penetrate the micropores of perlite. HPMC and PEG combine to form a thermally reversible gel, enhancing the extrusion stability of the paste.

[0076] Experimental data: The oil adsorption capacity is 3.5g / g.

[0077] Contact angle > 120°.

[0078] The compressive strength of the particles reaches 0.8 MPa.

[0079] Technical effects: Advantages of alcohol solubility: Ethanol makes the pores more uniformly filled, increasing the adsorption rate by 31%.

[0080] Mechanical strength: The particle strength is 47% higher than that of the water system, reducing transport losses.

[0081] Low temperature adaptation: 200℃ calcination is suitable for heat-sensitive polymer catalysts.

[0082] Example 6 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (300 mesh, SiO2 content >85%) of perlite powder, 30g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a high molecular hydrophobic agent with a particle size D50≤20 µm) and 10g of nano SiO2, and dry grind them in a ball mill for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 80%:1%:10% in this embodiment, wherein the solvent is water, the organic adhesive is carboxymethyl cellulose, and the plasticizer is glycerin). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 25%.

[0083] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 80℃ and pressure at 5MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at 350°C for 2.5 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0084] The difference between this embodiment and Embodiment 1 is that the mass ratio of solvent, organic adhesive and plasticizer in the adhesive system liquid is changed to 80%:1%:10%, the water content of the paste is increased to 25%, the extrusion granulation temperature is increased to 80°C, the pressure is increased to 5MPa, and the furnace temperature is increased to 350°C.

[0085] Working principle: When the high water content (25%) paste is extruded, it forms a microporous foam structure, which is then sintered at 350℃ to transform into hierarchical pores, increasing the specific surface area and enhancing the adsorption of small molecule organic substances such as cyclohexane.

[0086] Experimental data: The adsorption capacity for cyclohexane is 4.0 g / g.

[0087] Its specific surface area reaches 526 m² / g.

[0088] Porosity 91%.

[0089] Technical effects: A pore revolution: forming micron-nano hierarchical structures, improving the adsorption efficiency of small molecules.

[0090] High-temperature activation: calcination at 350℃ increases the crosslinking density of hydrophobic groups by 29%.

[0091] Ultimate performance: Contact angle up to 128°, adsorption rate constant 0.11 min⁻¹.

[0092] Comparative Example 1 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (200 mesh, SiO2 content >75%) of perlite powder, 10g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a high molecular hydrophobic agent with a particle size D50≤20 µm) and 20g of nano SiO2, add them to a ball mill and dry grind for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 70%:15%:15% in this embodiment, wherein the solvent is water, the organic adhesive is carboxymethyl cellulose, and the plasticizer is glycerin). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 17%.

[0093] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 45℃ and pressure at 1-5MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at a temperature of 160°C for 2 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0094] Working principle: 160℃ is insufficient to activate the pyrolysis of the polymer catalyst, and the hydrophobic groups are not fully released, only forming a surface physical adsorption layer, which does not penetrate into the pores.

[0095] Experimental data: The oil adsorption capacity is 2.1g / g.

[0096] Contact angle 95°.

[0097] Porosity 72%.

[0098] Technical effects: Performance deficiencies: The adsorption capacity was only 60% of that in Example 1, and the contact angle did not meet the standard.

[0099] Surface modification: A hydrophobic layer is formed only on the surface to a depth of 2-3 μm, while the interior is hydrophilic.

[0100] Energy consumption fallacy: Low temperature leads to ineffective extension of roasting time, increasing energy consumption by 42%.

[0101] Comparative Example 2 An integrated granulation method for premixed catalytic hydrophobic modification of perlite powder includes: S1 raw materials are mixed. Take 1000g (200 mesh, SiO2 content >75%) of perlite powder, 10g of hydrophobic powder catalyst (the hydrophobic powder catalyst is a high molecular hydrophobic agent with a particle size D50≤20 µm) and 20g of nano SiO2, add them to a ball mill and dry grind for 30 minutes to form a uniform composite powder for later use. S2 paste preparation: 400g of adhesive system liquid (i.e., a mixture of solvent, organic adhesive and plasticizer, wherein the mass ratio of solvent, organic adhesive and plasticizer is 60%~80%:10%~20%:10%~20%, preferably 70%:15%:15% in this embodiment, wherein the solvent is water, the organic adhesive is carboxymethyl cellulose, and the plasticizer is glycerin). The mixture is gradually added to a mixer and stirred until it is completely dissolved to obtain a mixed adhesive. Then, the uniform composite powder prepared in the above steps is poured into the mixer and thoroughly stirred and mixed with the mixed adhesive to form a paste with viscosity and plasticity, which is then left to stand for 2 hours. The moisture content of the paste made by S2 is controlled at 17%.

[0102] S3 extruder granulation: The prepared paste is fed into a twin-screw extruder granulator, and under the conditions of temperature control at 80℃ and pressure at 1-5MPa, columnar granules with a length of 8mm and a width of 4mm are extruded. S4 heats the cut columnar particles in a furnace at 300°C for 2 hours. After high-temperature sintering and pyrolysis of the internal catalyst, hydrophobic groups are released. While dehydrating and drying, a monomolecular hydrophobic film is constructed from the inside out. The particles are then removed and cooled to obtain hydrophobic modified perlite particles.

[0103] Working principle: The catalyst is decomposed at 300℃, and the hydrophobic groups undergo secondary polymerization to form a surface aggregate layer that blocks the pores.

[0104] Experimental data: The oil adsorption capacity is 3.0 g / g.

[0105] Contact angle 118°.

[0106] Porosity: 82%.

[0107] Technical effects: Pore ​​damage: Porosity decreased by 6%, and adsorption capacity decreased by 14% compared to Example 1.

[0108] Hydrophobic degradation: Contact angle decreases by 12°, and surface hydrophobicity becomes uneven.

[0109] Energy waste: High temperatures cause the binder to carbonize, reducing particle strength by 63%.

[0110] The present invention provides hydrophobically modified perlite particles prepared by using any one of the premixed catalytic hydrophobic modification integrated granulation methods of perlite powder in Examples 1-6 above.

[0111] Furthermore, these hydrophobically modified perlite particles can be directly applied in engineering applications such as oil-water separation, hazardous chemical spill adsorption, soil remediation, or VOCs end-of-pipe treatment.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for pre-mixing perlite powder, catalyzing, hydrophobic modifying, and integrating granulation, characterized in that, The method comprises the following steps: S1: raw material mixing, mixing perlite powder and hydrophobic powder catalyst at a mass ratio of 40-20:1, adding into a ball mill for dry grinding for 20-60 minutes to form a uniform composite powder; S2: paste preparation, gradually adding solvent, organic binder and plasticizer into a mixer for stirring until completely dissolved to obtain a mixed binder, then pouring the uniform composite powder prepared in the above step into the mixer and fully stirring with the mixed binder to form a paste with viscosity and plasticity, and standing for 2 hours; S3: extruding granulation, putting the prepared paste into a double-screw extruding granulator, controlling the temperature at 50-80℃ and the pressure at 1-5 MPa to extrude into columnar particles with equal length; S4: heating the cut particles in a heating furnace, controlling the heating temperature at 200-350℃, controlling the high-temperature calcination time at 1-4 hours, and using the internal catalyst pyrolysis to release hydrophobic groups, completing the construction of the monomolecular hydrophobic film from inside to outside while dehydrating and drying, to obtain hydrophobic modified perlite particles.

2. The perlite powder premix catalytic hydrophobic modification integrated granulation method according to claim 1, characterized in that, The water content of the paste prepared in S2 is controlled at 10-25%.

3. The perlite powder pre-mixed catalytic hydrophobic modification integrated granulation method according to claim 2, characterized in that, The hydrophobic powder catalyst is selected from one or more than two of organic silicon hydrophobic agent, carbon hydrophobic agent or polymer hydrophobic agent, and the particle size D50 is ≤20 µm.

4. The perlite powder pre-mixed catalytic hydrophobic modification integrated granulation method according to claim 1, characterized in that, The solvent is any one of water, ethanol, water-ethanol mixture, and water-low carbon ester mixture.

5. The perlite powder pre-mixed catalytic hydrophobic modification integrated granulation method according to claim 4, characterized in that, The organic binder is one or more than two of carboxymethyl cellulose, hydroxypropyl methyl cellulose, starch, and polyvinyl alcohol.

6. The perlite powder pre-mixed catalytic hydrophobic modification integrated granulation method according to claim 4, characterized in that, The plasticizer is one or more than two of glycerol, polyethylene glycol or stearate.

7. The perlite powder pre-mixed catalytic hydrophobic modification integrated granulation method according to claim 1, characterized in that, The forming die hole diameter of the double-screw extruding granulator is 2-10 mm, the cutter rotating speed is 20-200 rpm, and the length-diameter ratio of the obtained columnar particles is 1-3:

1.

8. The perlite powder pre-mixed catalytic hydrophobic modification integrated granulation method according to claim 1, characterized in that, The heating furnace is a drum-type hot air furnace, a mesh belt type drying furnace or a rotary kiln, the temperature rising rate is 2-10 ℃ / min, and the oxygen content in the furnace is ≤15 vol%.

9. Hydrophobic modified perlite particles prepared by the method of claim 1-8.

10. Direct engineering application of the hydrophobic modified perlite particles in claim 9 in oil-water separation, hazardous chemical leakage adsorption, soil remediation or VOCs end treatment.

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