Method for preparing gel-method silicon dioxide delustering agent by using multi-channel reactor

Abstract

The invention relates to the technical field of coating production, in particular to a method for preparing a gel method silicon dioxide delustering agent by using a multi-channel reactor. Various properties of the silicon dioxide delustering agent prepared by the preparation method disclosed by the invention are obtained by virtue of a comprehensive effect of adding the pore-forming agent with a specific type and proportion and the multi-channel reactor with a specific specification and a specific shape in the step 1 and adding the dispersing agent into the reaction kettle in advance, and particularly, the multi-channel reactor with the specific specification and the specific shape is utilized; a sulfuric acid solution and a water glass solution with a specific flow rate are subjected to parallel flow reaction, so that the sulfuric acid solution and the water glass solution react in advance in a multi-channel reactor to form uniform gel which falls into a reaction kettle, the gel can be prevented from blocking the multi-channel reactor, and the problems that gel blocks at dead corners of the reaction kettle cannot be dispersed, the reaction is insufficient and the like are solved. And the reaction uniformity is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of coating production, and in particular to a method for preparing a gel-process silicon dioxide matting agent by utilizing a multi-channel reactor. Background Art

[0002] Silica matting agent is a matting material widely used in the field of coatings. It has a refractive index similar to that of most resins and has good optical properties in coating systems. The current mainstream silica matting agents are mainly precipitated silica represented by the liquid phase method (prepared using water glass and acid), gel silica, and gas phase method (prepared using halosilanes) gas phase silica. Traditional precipitated silica is formed by the co-current reaction of water glass and sulfuric acid under acidic / alkaline conditions to form a sol system to obtain silica particles with a relatively loose structure, and the product is obtained after washing and drying. Gel silica is the opposite of the precipitation method. It forms a gel system during the reaction process, and then washes and dries to obtain the product. The product has high transparency, large pore volume, and relatively concentrated pore size distribution.

[0003] Due to the high production cost and particularity of fumed silica, its application in some coating systems is limited. Samples prepared by the traditional precipitation method have high oil absorption values ​​but small specific surface area and pore volume, and the non-concentrated pore size distribution leads to weak effect on the matting effect of the coating. Samples prepared by the gel method of silica usually need to be introduced into the reactor with water glass and sulfuric acid, and adjusted to a certain pH to reach the gel point to prepare the gel. Due to the limitations of the reactor structure and stirring power, the mixing uniformity of the materials is poor, and the gel particles prepared in this way are uneven. Moreover, due to the dead corners of the reactor structure, large particles of gel exist, which makes the post-processing time long, which easily leads to poor washing effect and affects the transparency and gloss of the silica matting agent in the coating. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to improve the preparation method of silicon dioxide matting agent so that the prepared matting agent particles have the advantages of good uniformity, high oil absorption value and good matting efficiency.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for preparing a gel-process silica matting agent by using a multi-channel reactor, based on a reaction device, the reaction device comprises a reactor and a multi-channel reactor, the multi-channel reactor comprises a horizontally arranged circular tube, the circular tube is filled with a cross-wave-shaped reflux plate, one end of the circular tube is connected to the reactor, the other end of the circular tube is connected to a water glass feed pipe and a sulfuric acid feed pipe, and the water glass feed pipe and the sulfuric acid feed pipe are respectively connected to valves;

[0007] The method for preparing a gel-based silica matting agent comprises the following steps:

[0008] Step 1: dissolving solid water glass in self-prepared water, removing impurities, obtaining a water glass solution, adding 1-5‰ of a pore-forming agent to the water in advance, mixing the water glass solution and the water with the pore-forming agent in a mass ratio of 1:1.5-2.5, and preparing a water glass solution;

[0009] Prepare a sulfuric acid solution with a sulfuric acid concentration of 5-15%;

[0010] Step 2: Add water and dispersant to the reactor, stir evenly and heat to 40-70°C, open the valve of the water glass feed pipe, and adjust the flow rate of the water glass solution to 8-12m 3 / h, then open the valve of the sulfuric acid feed pipe and adjust the sulfuric acid flow rate to 3.5-8.0m 3 / h, so that the water glass solution and the sulfuric acid solution flow in parallel in the multi-channel reactor at the same time, so that the pH value in the multi-channel reactor is controlled within the range of 9-11, so that the water glass solution and the sulfuric acid solution react to form a gel when flowing out of the multi-channel reactor and entering the reactor, and stop the reaction after the parallel flow reaction for 70-100 minutes;

[0011] Step 3: performing aging and aging treatment on the reaction product in the reactor;

[0012] Step 4: filter press, wash, disperse, pulp, dry and crush the product after aging treatment to obtain a gel-based silica matting agent.

[0013] Furthermore, in the above method for preparing a gel-based silica matting agent using a multi-channel reactor, the water glass feed tube coincides with the axis of the circular tube, the sulfuric acid feed tube is connected to the upper part of the circular tube, and the axis of the sulfuric acid feed tube is perpendicular to the axis of the circular tube.

[0014] Furthermore, in the above method for preparing a gel-based silica matting agent using a multi-channel reactor, in step 1, the pore-forming agent is selected from one or more of potassium hydroxide, sodium hydroxide or sodium carbonate.

[0015] Furthermore, in the above method for preparing a gel-based silica matting agent using a multi-channel reactor, in step 2, the dispersant is selected from one or more of glycerol, isomeric tridecanol polyoxyethylene ether or OP-10.

[0016] Furthermore, in the above method for preparing a gel-based silica matting agent using a multi-channel reactor, the cross-wavy reflux plate is welded in a criss-cross pattern by a plurality of first plates arranged perpendicular to the X direction and a second plate arranged perpendicular to the Y direction, the X direction is perpendicular to the Y direction, and the angle between the X direction and the axial direction of the circular tube is 45 degrees; the spacing between two adjacent first plates is 4-6 cm, and the spacing between two adjacent second plates is 4-6 cm. Each first plate is composed of a plurality of first strips distributed at equal intervals, the spacing between two adjacent first strips is 1.5-2.5 cm, and the width of the first strip is 2-3 cm; the spacing between two adjacent second strips is 1.5-2.5 cm, and the width of the second strip is 2-3 cm; the first strips and the second strips are distributed in an alternating pattern.

[0017] Furthermore, in the above method for preparing a gel-process silica matting agent using a multi-channel reactor, the inner diameter of the circular tube is 8-12 cm and the length is 25-30 cm.

[0018] Further, in the method for preparing a gel-based silica matting agent using a multi-channel reactor, the step 3 is specifically: heating the reaction product in the reactor to 70-90°C, aging for 30-60 minutes, and after aging, adding 25% sulfuric acid solution at 2-4 m 3 The pH value was adjusted to 4.2±0.2 at a flow rate of / h, and then aged for 30-40min.

[0019] Furthermore, in the above method for preparing a gel-based silica matting agent using a multi-channel reactor, step 4 is specifically: sending the slurry after aging treatment into a plate and frame filter press for filtration, washing until the conductivity is ≤400μS / cm, sending the washed filter cake into a pulping tank via a belt conveyor for high-speed dispersion and pulping, spray drying, crushing and grading to obtain a gel-based silica matting agent.

[0020] The present invention also protects the silica matting agent prepared by the method for preparing the gel-process silica matting agent by using a multi-channel reactor.

[0021] The beneficial effects of the present invention are:

[0022] 1. The liquid phase method is used for reaction, and the production cost is lower than that of the gas phase method.

[0023] 2. Different from the traditional gel method of preparing the gel system in the reactor, the multi-channel reactor is used for reaction. The gel system is formed before entering the bottom liquid of the reactor, avoiding the gel blocks in the dead corners of the reactor from being unable to disperse, making the reaction more complete.

[0024] 3. Use specially treated water glass, add pore-forming agents, etch and expand pores to further improve the matting efficiency of the product in the coating system.

[0025] 4. Use a dispersant to improve the dispersion of the particles after the gel enters the bottom liquid of the reactor and is broken up. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of a multi-channel reactor connected to a reaction kettle in a specific embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a cross-wave reflux plate in which a multi-channel reactor is connected to a reactor in a specific embodiment of the present invention;

[0028] Figure 3 A radial cross-sectional view of a circular tube of a multi-channel reactor according to a specific embodiment of the present invention;

[0029] Description of labels:

[0030] 1. Reactor;

[0031] 2. Multi-channel reactor; 21. Circular tube; 22. Cross-wave reflux plate; 221. First slat; 222. Second slat; 23. Water glass feed pipe; 24. Sulfuric acid feed pipe. DETAILED DESCRIPTION

[0032] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0033] Please refer to Figures 1 to 3 The specific embodiment of the present invention relates to a method for preparing a gel-based silica matting agent using a multi-channel reactor 2, based on a reaction device, the reaction device includes a reactor 1 and a multi-channel reactor 2, the multi-channel reactor 2 includes a horizontally arranged circular tube 21, the circular tube 21 is filled with a cross-wavy backflow plate 22, one end of the circular tube 21 is connected to the reactor 1, and the other end of the circular tube 21 is connected to a water glass feed pipe 23 and a sulfuric acid feed pipe 24, and the water glass feed pipe 23 and the sulfuric acid feed pipe 24 are respectively connected to valves;

[0034] The method for preparing a gel-based silica matting agent comprises the following steps:

[0035] Step 1: dissolving solid water glass in self-prepared water, removing impurities, obtaining a water glass solution, adding 1-5‰ of a pore-forming agent to the water in advance, mixing the water glass solution and the water with the pore-forming agent in a mass ratio of 1:1.5-2.5, and preparing a water glass solution;

[0036] Prepare a sulfuric acid solution with a sulfuric acid concentration of 5-15%;

[0037] Step 2: Add water and dispersant to the reactor 1, stir evenly and heat to 40-70°C, open the valve of the water glass feed pipe 23, and adjust the flow rate of the water glass solution to 8-12m 3 / h, then open the valve of sulfuric acid feed pipe 24 and adjust the sulfuric acid flow rate to 3.5-8.0m 3 / h, so that the water glass solution and the sulfuric acid solution flow in parallel in the multichannel reactor 2 at the same time, so that the pH value in the multichannel reactor 2 is controlled within the range of 9-11, so that the water glass solution and the sulfuric acid solution react to form a gel when flowing out of the multichannel reactor 2 and entering the reactor 1, and the reaction is stopped after the parallel flow reaction for 70-100 minutes;

[0038] Step 3: performing aging and aging treatment on the reaction product in the reactor 1;

[0039] Step 4: filter press, wash, disperse, pulp, dry and crush the product after aging treatment to obtain a gel-based silica matting agent.

[0040] As a preferred embodiment, the water glass feed pipe 23 coincides with the axis of the circular tube 21 , the sulfuric acid feed pipe 24 is connected to the upper part of the circular tube 21 , and the axis of the sulfuric acid feed pipe 24 is perpendicular to the axis of the circular tube 21 .

[0041] As a preferred embodiment, in step 1, the pore-forming agent is selected from one or more of potassium hydroxide, sodium hydroxide or sodium carbonate.

[0042] As a preferred embodiment, in step 2, the dispersant is selected from one or more of glycerol, isomeric tridecanol polyoxyethylene ether or OP-10.

[0043] As a preferred embodiment, the cross-wavy backflow plate 22 is formed by criss-cross welding of multiple first plates arranged perpendicular to the X direction and second plates arranged perpendicular to the Y direction, the X direction is perpendicular to the Y direction, and the angle between the X direction and the axial direction of the circular tube 21 is 45 degrees; the spacing between two adjacent first plates is 4-6cm, and the spacing between two adjacent second plates is 4-6cm. Each first plate is formed by multiple first strips 221 distributed at equal intervals, the spacing between two adjacent first strips 221 is 1.5-2.5cm, and the width of the first strip 221 is 2-3cm; the spacing between two adjacent second strips 222 is 1.5-2.5cm, and the width of the second strip 222 is 2-3cm; the first strips 221 and the second strips 222 are staggered.

[0044] As a preferred embodiment, the inner diameter of the circular tube 21 is 8-12 cm and the length is 25-30 cm.

[0045] As a preferred embodiment, the step 3 is specifically as follows: the reaction product in the reactor 1 is heated to 70-90°C, aged for 30-60 minutes, and after the aging, a 25% sulfuric acid solution is added, the pH value is adjusted to 4.2±0.2 at a flow rate of 2-4m3 / h, and then aged for 30-40 minutes.

[0046] As a preferred embodiment, step 4 is specifically as follows: sending the aging slurry into a plate and frame filter press for filtration, washing until the conductivity is ≤400μS / cm, sending the washed filter cake into a pulping tank via a belt conveyor for high-speed dispersion and pulping, spray drying, crushing and grading to obtain a gel-based silica matting agent.

[0047] The present invention also protects the silica matting agent prepared by the method for preparing the gel-based silica matting agent using the multi-channel reactor 2.

[0048] Example 1

[0049] A method for preparing a gel-based silica matting agent using a multichannel reactor 2, based on a reaction device, the reaction device comprises a reactor 1 and a multichannel reactor 2, the multichannel reactor 2 comprises a horizontally arranged circular tube 21, the circular tube 21 is filled with a cross-wavy reflow plate 22, one end of the circular tube 21 is connected to the reactor 1, the other end of the circular tube 21 is connected to a water glass feed pipe 23 and a sulfuric acid feed pipe 24, the water glass feed pipe 23 and the sulfuric acid feed pipe 24 are respectively connected to valves; the axis of the water glass feed pipe 23 coincides with the axis of the circular tube 21, the sulfuric acid feed pipe 24 is connected to the upper part of the circular tube 21, and the axis of the sulfuric acid feed pipe 24 is perpendicular to the axis of the circular tube 21; the cross-wavy reflow plate 22 is formed by welding a plurality of first plates arranged perpendicular to the X direction and a second plate arranged perpendicular to the Y direction in a criss-cross manner, the X direction is perpendicular to the Y direction, and the angle between the X direction and the axial direction of the round tube 21 is 45 degrees; the spacing between two adjacent first plates is 5 cm, the spacing between two adjacent second plates is 5 cm, each first plate is formed by a plurality of first strips 221 distributed at equal intervals, the spacing between two adjacent first strips 221 is 2 cm, and the width of the first strip 221 is 2.5 cm; the spacing between two adjacent second strips 222 is 2 cm, and the width of the second strip 222 is 2.5 cm; the first strips 221 and the second strips 222 are distributed in an alternating manner; the inner diameter of the round tube 21 is 10 cm, and the length is 28 cm;

[0050] The method for preparing a gel-based silica matting agent comprises the following steps:

[0051] Step 1: solid water glass is added to the autoclave in a mass ratio of 1:2 with self-prepared water, and the pressure is maintained at 0.6Mpa steam for 2.5 hours. After impurities are removed by a box-type filter plate frame, a water glass solution is obtained. 15‰ potassium hydroxide of the total amount of the reaction water glass is added to the water in advance, and the water glass solution is mixed with water with a pore-forming agent in a mass ratio of 1:1.5 to prepare a water glass solution. The modulus of the water glass solution is 2.9 and the density is 1.05g / mL;

[0052] Prepare a sulfuric acid solution with a sulfuric acid concentration of 15%;

[0053] Step 2: Add 8m 3 Bottom water, 1kg isomeric tridecanol polyoxyethylene ether, stirred for 5 minutes and then heated to 70°C, opened the valve of the water glass feed pipe 23, and adjusted the flow rate of the water glass solution to 12m 3 / h, then open the valve of sulfuric acid feed pipe 24 and adjust the sulfuric acid flow rate to 3.5m 3 / h, so that the water glass solution and the sulfuric acid solution flow in parallel in the multichannel reactor 2 at the same time, so that the pH value in the multichannel reactor 2 is controlled at 11, and the water glass solution and the sulfuric acid solution flow out of the multichannel reactor 2 into the reactor 1 until the reaction stops after the parallel flow reaction for 100 minutes;

[0054] Step 3: The reaction product in the reactor 1 was heated to 90°C and aged for 30 minutes. After the aging, a 25% sulfuric acid solution was added to adjust the pH value to 4.23 at a flow rate of 3m3 / h, and then aged for another 30 minutes;

[0055] Step 4: The aging slurry is sent to a plate and frame filter press for filtration, washed until the conductivity is ≤176μS / cm, and the washed filter cake is sent to a pulping tank via a belt conveyor for high-speed dispersion pulping, spray dried, and ultrafinely crushed and classified to a particle size (D50) of 4.23μm to obtain a gel-based silica matting agent.

[0056] Example 2

[0057] A method for preparing a gel-based silica matting agent using a multichannel reactor 2, based on a reaction device, the reaction device comprises a reactor 1 and a multichannel reactor 2, the multichannel reactor 2 comprises a horizontally arranged circular tube 21, the circular tube 21 is filled with a cross-wavy reflow plate 22, one end of the circular tube 21 is connected to the reactor 1, the other end of the circular tube 21 is connected to a water glass feed pipe 23 and a sulfuric acid feed pipe 24, the water glass feed pipe 23 and the sulfuric acid feed pipe 24 are respectively connected to valves; the axis of the water glass feed pipe 23 coincides with the axis of the circular tube 21, the sulfuric acid feed pipe 24 is connected to the upper part of the circular tube 21, and the axis of the sulfuric acid feed pipe 24 is perpendicular to the axis of the circular tube 21; the cross-wavy reflow plate 22 is formed by welding a plurality of first plates arranged perpendicular to the X direction and a second plate arranged perpendicular to the Y direction in a criss-cross manner, the X direction is perpendicular to the Y direction, and the angle between the X direction and the axial direction of the round tube 21 is 45 degrees; the spacing between two adjacent first plates is 5 cm, the spacing between two adjacent second plates is 5 cm, each first plate is formed by a plurality of first strips 221 distributed at equal intervals, the spacing between two adjacent first strips 221 is 2 cm, and the width of the first strip 221 is 2.5 cm; the spacing between two adjacent second strips 222 is 2 cm, and the width of the second strip 222 is 2.5 cm; the first strips 221 and the second strips 222 are distributed in an alternating manner; the inner diameter of the round tube 21 is 10 cm, and the length is 28 cm;

[0058] The method for preparing a gel-based silica matting agent comprises the following steps:

[0059] Step 1: solid water glass is added to the autoclave in a mass ratio of 1:2 with self-prepared water, and the pressure is maintained at 0.6Mpa steam for 2.5 hours to dissolve, and the impurities are removed by a box-type filter plate frame to obtain a water glass solution, 2‰ sodium hydroxide of the total amount of water glass in the reaction is added to the water in advance, and the water glass solution is mixed with water with a pore-forming agent in a mass ratio of 1:2 to prepare a water glass solution, the modulus of the water glass solution is 3.2, and the density is 1.10g / mL;

[0060] Prepare a sulfuric acid solution with a sulfuric acid concentration of 10%;

[0061] Step 2: Add 9m 3 Bottom water, 10kg isopropylene glycol, stirred for 5 minutes and then heated to 40°C, the valve of the water glass feed pipe 23 was opened, and the flow rate of the water glass solution was adjusted to 10m 3 / h, then open the valve of sulfuric acid feed pipe 24 and adjust the sulfuric acid flow rate to 4.5m 3 / h, so that the water glass solution and the sulfuric acid solution flow in parallel in the multichannel reactor 2 at the same time, so that the pH value in the multichannel reactor 2 is controlled at 10, and the water glass solution and the sulfuric acid solution flow out of the multichannel reactor 2 into the reactor 1 until the reaction stops after the parallel flow reaction for 100 minutes;

[0062] Step 3: The reaction product in the reactor 1 was heated to 70°C and aged for 30 minutes. After the aging, 25% sulfuric acid solution was added at 2m 3 / h flow rate to adjust the pH value to 4.21, and then age for 30 minutes;

[0063] Step 4: The aging slurry is sent to a plate and frame filter press for filtration, washed until the conductivity is ≤156μS / cm, and the washed filter cake is sent to a pulping tank via a belt conveyor for high-speed dispersion pulping, spray dried, and ultrafinely crushed and classified to a particle size (D50) of 4.31μm to obtain a gel-based silica matting agent.

[0064] Example 3

[0065] A method for preparing a gel-based silica matting agent using a multichannel reactor 2, based on a reaction device, the reaction device comprises a reactor 1 and a multichannel reactor 2, the multichannel reactor 2 comprises a horizontally arranged circular tube 21, the circular tube 21 is filled with a cross-wavy reflow plate 22, one end of the circular tube 21 is connected to the reactor 1, the other end of the circular tube 21 is connected to a water glass feed pipe 23 and a sulfuric acid feed pipe 24, the water glass feed pipe 23 and the sulfuric acid feed pipe 24 are respectively connected to valves; the axis of the water glass feed pipe 23 coincides with the axis of the circular tube 21, the sulfuric acid feed pipe 24 is connected to the upper part of the circular tube 21, and the axis of the sulfuric acid feed pipe 24 is perpendicular to the axis of the circular tube 21; the cross-wavy reflow plate 22 is formed by welding a plurality of first plates arranged perpendicular to the X direction and a second plate arranged perpendicular to the Y direction in a criss-cross manner, the X direction is perpendicular to the Y direction, and the angle between the X direction and the axial direction of the round tube 21 is 45 degrees; the spacing between two adjacent first plates is 5 cm, the spacing between two adjacent second plates is 5 cm, each first plate is formed by a plurality of first strips 221 distributed at equal intervals, the spacing between two adjacent first strips 221 is 2 cm, and the width of the first strip 221 is 2.5 cm; the spacing between two adjacent second strips 222 is 2 cm, and the width of the second strip 222 is 2.5 cm; the first strips 221 and the second strips 222 are distributed in an alternating manner; the inner diameter of the round tube 21 is 10 cm, and the length is 28 cm;

[0066] The method for preparing a gel-based silica matting agent comprises the following steps:

[0067] Step 1: solid water glass is added to the autoclave in a mass ratio of 1:2 with self-prepared water, and the pressure is maintained at 0.6Mpa steam for dissolution for 2.5 hours. After impurities are removed by a box-type filter plate frame, a water glass solution is obtained. 1‰ sodium carbonate of the total amount of the reacted water glass is added to the water in advance, and the water glass solution is mixed with water with a pore-forming agent in a mass ratio of 1:2.2 to prepare a water glass solution. The modulus of the water glass solution is 3.4 and the density is 1.15g / mL;

[0068] Prepare a sulfuric acid solution with a sulfuric acid concentration of 5%;

[0069] Step 2: Add 8m 3 Bottom water, 3kg propylene glycol, 2kg OP-10, stir for 5 minutes and then heat to 50℃, open the valve of water glass feed pipe 23, and adjust the flow rate of water glass solution to 8m 3 / h, then open the valve of sulfuric acid feed pipe 24 and adjust the sulfuric acid flow rate to 8m 3 / h, so that the water glass solution and the sulfuric acid solution flow in parallel in the multichannel reactor 2 at the same time, so that the pH value in the multichannel reactor 2 is controlled at 9, and the water glass solution and the sulfuric acid solution flow out of the multichannel reactor 2 into the reactor 1, and the reaction is stopped after the parallel flow reaction for 70 minutes;

[0070] Step 3: The reaction product in the reactor 1 was heated to 70°C and aged for 60 minutes. After the aging, a 25% sulfuric acid solution was added to adjust the pH value to 4.23 at a flow rate of 2m3 / h, and then aged for another 40 minutes;

[0071] Step 4: The aging slurry is sent to a plate and frame filter press for filtration, washed until the conductivity is ≤152μS / cm, and the washed filter cake is sent to a pulping tank via a belt conveyor for high-speed dispersion and pulping, spray dried, and ultrafinely crushed and classified to a particle size (D50) of 4.46μm to obtain a gel-based silica matting agent.

[0072] Comparative Example 1

[0073] The method for preparing a gel-based silica matting agent using a multi-channel reactor 2 described in Example 2 is different in that the addition of the pore-forming agent sodium hydroxide is omitted in step 1, and the other steps remain unchanged.

[0074] Comparative Example 2

[0075] The method for preparing a gel-based silica matting agent using a multi-channel reactor 2 described in Example 2 is different in that in step 2, the multi-channel reactor 2 is omitted, and the other steps remain unchanged. Step 2 is specifically as follows:

[0076] Add 9m 3Bottom water, 10kg isopropylene glycol, stirred for 5 minutes and then heated to 40°C, water glass solution and sulfuric acid were directly introduced into the reactor 1 at the corresponding flow rate, and the flow rate of the water glass solution was 10m 3 / h, sulfuric acid flow rate is 4.5m 3 / h, and stop the reaction after 100min.

[0077] Comparative Example 3

[0078] The method for preparing a gel-based silica matting agent using a multi-channel reactor 2 described in Example 2 is different in that the cross-wave-shaped reflow plate 22 structure in the multi-channel reactor 2 is removed, and the other steps remain unchanged.

[0079] Comparative Example 4

[0080] The method for preparing a gel-based silica matting agent using a multi-channel reactor 2 described in Example 2 is different in that the length of the circular tube 21 of the multi-channel reactor 2 is 5 cm, and the other steps remain unchanged.

[0081] Comparative Example 5

[0082] The method for preparing a gel-based silica matting agent using a multi-channel reactor 2 described in Example 2 is different in that the length of the circular tube 21 of the multi-channel reactor 2 is 58 cm; the other steps remain unchanged.

[0083] The gel-process silica matting agents prepared in Examples 1-3 and Comparative Examples 1-5 were tested for various indicators, and the results are shown in Table 1:

[0084] Table 1

[0085]

[0086] From the results in Table 1, it can be seen that Example 2 is the best example. Comparative Example 1 is based on Example 2, but omits the addition of the pore-forming agent in step 1, resulting in a decrease in the BET specific surface area, pore volume, and average pore size of the matting agent product, an increase in the particle size distribution span, and a decrease in the DBP oil absorption value;

[0087] Comparative Example 2 omits the use of a multi-channel reactor in step 2 based on Example 2, resulting in a significant increase in the particle size distribution span. This is because the reactor is large in volume, and the sulfuric acid solution and the water glass solution react directly in the reactor, making it impossible to disperse the gel blocks in the dead corners of the reactor, resulting in an insufficient reaction, which leads to a decrease in the uniformity of the reaction, thereby significantly increasing the particle size distribution span of the product, and causing a decrease in the DBP oil absorption value, and a decrease in the BET specific surface area, pore volume, and average pore size.

[0088] Comparative Example 3: Based on Example 2, the cross-wavy reflow plate structure in the multi-channel reactor was removed, so that the sulfuric acid solution and the water glass solution were directly subjected to gel reaction in the reactor. Since the sulfuric acid solution and the water glass solution were not fully dispersed by the cross-wavy reflow plate, the gel aggregated and agglomerated. After 12 minutes of co-current reaction in step 2, the round tube of the reactor was blocked, so that the reaction could not continue, and therefore the corresponding test results could not be obtained;

[0089] Comparative Example 4, based on Example 2, shortens the length of the circular tube of the multi-channel reactor, resulting in the sulfuric acid solution and the water glass solution directly staying in the reactor for too long, and being unable to be fully dispersed and reacted in the reactor, resulting in most of the gel reaction being carried out in the reactor, making it impossible to disperse the gel blocks in the dead corners of the reactor, resulting in insufficient reaction, resulting in decreased uniformity of the reaction, and thus resulting in a significant increase in the particle size distribution span of the product, while causing a decrease in the DBP oil absorption value, and a decrease in the BET specific surface area, pore volume, and average pore size;

[0090] In Comparative Example 5, based on Example 2, the length of the circular tube of the multi-channel reactor was lengthened, resulting in the sulfuric acid solution and the water glass solution directly undergoing gel reaction in the reactor for too long, causing the gel to aggregate and agglomerate. After 24 minutes of parallel flow reaction in Step 2, the circular tube of the reactor was blocked, making it impossible for the reaction to continue, and therefore no corresponding test results could be obtained.

[0091] In summary, the various properties of the silica matting agent prepared by the present invention are obtained by the combined effect of adding a pore-forming agent of a specific type and proportion and a multi-channel reactor of a specific specification and shape in step 1, and pre-adding a dispersant into the reactor. In particular, a multi-channel reactor of a specific specification and shape is utilized, combined with a sulfuric acid solution and a water glass solution of a specific flow rate for co-flow reaction, so that the sulfuric acid solution and the water glass solution react in advance in the multi-channel reactor to form a uniform gel, and then fall into the reactor, which can avoid the gel clogging the multi-channel reactor and the gel blocks in the dead corners of the reactor from being unable to be dispersed, the reaction is insufficient, and the problem of decreased reaction uniformity can be avoided.

[0092] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a gel-based silica matting agent using a multi-channel reactor, characterized in that: Based on a reaction device, the reaction device includes a reactor and a multi-channel reactor, the multi-channel reactor includes a horizontally arranged round tube, the round tube is filled with a cross-wave reflux plate, one end of the round tube is connected to the reactor, and the other end of the round tube is connected to a water glass feed pipe and a sulfuric acid feed pipe, and the water glass feed pipe and the sulfuric acid feed pipe are respectively connected to valves; The method for preparing a gel-based silica matting agent comprises the following steps: Step 1: dissolving solid water glass in self-prepared water, removing impurities, obtaining a water glass solution, adding 1-5‰ of a pore-forming agent to the water in advance, mixing the water glass solution and the water with the pore-forming agent in a mass ratio of 1:1.5-2.5, and preparing a water glass solution; Prepare a sulfuric acid solution with a sulfuric acid concentration of 5-15%; Step 2: Add water and dispersant to the reactor, stir evenly and heat to 40-70°C, open the valve of the water glass feed pipe, and adjust the flow rate of the water glass solution to 8-12m 3 / h, then open the valve of the sulfuric acid feed pipe and adjust the sulfuric acid flow rate to 3.5-8.0m 3 / h, so that the water glass solution and the sulfuric acid solution flow in parallel in the multi-channel reactor at the same time, so that the pH value in the multi-channel reactor is controlled within the range of 9-11, so that the water glass solution and the sulfuric acid solution react to form a gel when flowing out of the multi-channel reactor and entering the reactor, and stop the reaction after the parallel flow reaction for 70-100 minutes; Step 3: performing aging and aging treatment on the reaction product in the reactor; Step 4: filter press, wash, disperse, pulp, dry and crush the product after aging treatment to obtain a gel-based silica matting agent.

2. The method for preparing a gel-based silica matting agent using a multi-channel reactor according to claim 1, characterized in that: The axis of the water glass feed pipe coincides with the axis of the circular tube, the sulfuric acid feed pipe is connected to the upper part of the circular tube, and the axis of the sulfuric acid feed pipe is perpendicular to the axis of the circular tube.

3. The method for preparing a gel-based silica matting agent using a multi-channel reactor according to claim 1, characterized in that: In step 1, the pore-forming agent is selected from one or more of potassium hydroxide, sodium hydroxide or sodium carbonate.

4. The method for preparing a gel-based silica matting agent using a multi-channel reactor according to claim 1, characterized in that: In the step 2, the dispersant is selected from one or more of glycerol, isomeric tridecanol polyoxyethylene ether or OP-10.

5. The method for preparing a gel-based silica matting agent using a multi-channel reactor according to claim 1, characterized in that: The cross-wave reflux plate is formed by criss-cross welding of a plurality of first plates arranged perpendicular to the X direction and a second plate arranged perpendicular to the Y direction, the X direction is perpendicular to the Y direction, and the angle between the X direction and the axial direction of the circular tube is 45 degrees; the spacing between two adjacent first plates is 4-6 cm, the spacing between two adjacent second plates is 4-6 cm, each first plate is formed by a plurality of first strips distributed at equal intervals, the spacing between two adjacent first strips is 1.5-2.5 cm, and the width of the first strip is 2-3 cm; the spacing between two adjacent second strips is 1.5-2.5 cm, and the width of the second strip is 2-3 cm; the first strips and the second strips are distributed in an alternating manner.

6. The method for preparing a gel-based silica matting agent using a multichannel reactor according to claim 1, wherein the inner diameter of the circular tube is 8-12 cm and the length is 25-30 cm.

7. The method for preparing a gel-based silica matting agent using a multi-channel reactor according to claim 1, characterized in that: The step 3 is specifically as follows: the reaction product in the reactor is heated to 70-90°C and aged for 30-60 minutes. After the aging is completed, a 25% sulfuric acid solution is added at 2-4 m 3 The pH value was adjusted to 4.2±0.2 at a flow rate of / h, and then aged for 30-40min.

8. The method for preparing a gel-based silica matting agent using a multi-channel reactor according to claim 1, characterized in that: The step 4 is specifically as follows: sending the aging slurry into a plate and frame filter press for filtration, washing until the conductivity is ≤400 μS / cm, sending the washed filter cake into a pulping tank via a belt conveyor for high-speed dispersion and pulping, spray drying, crushing and grading to obtain a gel-based silica matting agent.

9. The silica matting agent prepared by the method for preparing a gel-based silica matting agent using a multi-channel reactor as claimed in any one of claims 1 to 8.

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