Environmentally friendly cement grinding aid and preparation method thereof

Abstract

The invention discloses an environmentally friendly cement grinding aid and a preparation method thereof. The cement grinding aid is prepared by polymerizing a modified monomer, a reinforcing monomer and acrylic acid. The cement grinding aid can be adsorbed on the surface of a material, shield active points generated by grinding through charge repulsion, prevent fracture surface recombination, and form a lubricating film on the surface, thereby reducing the friction between the materials. The cement grinding aid can penetrate into the gaps of the materials, weaken the healing effect generated by molecular forces, promote crack expansion, and thus make the materials easier to be crushed. The cement grinding aid molecules contain a large number of silicon-oxygen bonds, so that the cement grinding aid has high surface activity and dispersibility, can well reduce the surface free energy of the material, thereby improving the dispersion effect and accelerating crack expansion. The hyperbranched structure can improve the fluidity of cement and improve the early strength and final strength of cement.

Description

Technical Field

[0001] The invention relates to the technical field of cement additive preparation, and in particular to an environmentally friendly cement grinding aid and a preparation method thereof. Background Art

[0002] The grinding process of cement is completed by the continuous impact of grinding media of different specifications in the ball mill on the clinker particles. In the process of continuous refinement of clinker particles, on the one hand, the valence bonds are broken under stress, especially the breaking of Ca-O and Si-O, and static charges are accumulated on the new cross-section of clinker particles. The charges will attract each other, causing the new cracks to close again or agglomerate. On the other hand, the powder will agglomerate under the action of surface energy, and the finer the particles, the more obvious the agglomeration effect. Usually, the fluidity of cement powder is relatively poor, so cement particles that have been ground to a qualified fineness are prone to agglomeration and cannot be discharged from the mill immediately, resulting in over-grinding, resulting in "mud balls" and "mud mills", which weakens the effective impact of the ball mill media on cement particles. These factors will reduce the grinding efficiency of the ball mill. Adding grinding aids to cement grinding is a simple and easy way to improve grinding efficiency. An appropriate amount of grinding aids can also improve the mechanical properties of cement while improving grinding efficiency. However, the existing grinding aids have a general grinding effect. After use, the particle size of cement particles is still large, and the quality of cement is not significantly improved, resulting in poor use of grinding aids. Summary of the invention

[0003] The purpose of the present invention is to provide an environmentally friendly cement grinding aid and a preparation method thereof, which solves the problem that the grinding aid has limited grinding effect and has no significant improvement on cement strength.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing an environmentally friendly cement grinding aid comprises the following steps: Step A1: 1-(2-aminoethyl)-1H-pyrrole-2,5-dione, a modification additive and DMF are mixed, and reacted for 3-5 hours at a rotation speed of 120-150 r / min, a temperature of 40-50° C. and a pH value of 10-11 to obtain a modified monomer; Step A2: acrylic acid, diethanolamine, dicyclohexylcarbodiimide and toluene are mixed, and reacted for 3-5 hours at a speed of 150-200 r / min and a temperature of 40-50° C. to obtain a reinforcing monomer, and the modified monomer, reinforcing monomer, acrylic acid and DMF are evenly mixed, and potassium persulfate is added under stirring at a speed of 80-85° C. to react for 3-4 hours, and the pH value is adjusted to 6.5, and DMF is removed to obtain an environmentally friendly cement grinding aid.

[0005] Furthermore, the molar ratio of 1-(2-aminoethyl)-1H-pyrrole-2,5-dione and the epoxy group on the modified additive described in step A1 is 1:1.

[0006] Furthermore, the molar ratio of acrylic acid, diethanolamine and dicyclohexylcarbodiimide in step A2 is 1:1:1.1, the mass ratio of the modified monomer, the reinforcing monomer and acrylic acid is 1:5:10, and the amount of potassium persulfate used is 1‰ of the mass of the modified monomer.

[0007] Further, the modified additive is prepared by the following steps: Step B1: Tetramethyltetrasiloxane, allyl glycidyl ether, chloroplatinic acid and DMF are mixed uniformly, and reacted for 3-5 hours at a speed of 120-150 r / min and a temperature of 60-70° C. to obtain a functional monomer; the functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane are mixed uniformly, and reacted for 2-3 hours at a speed of 150-200 r / min and a temperature of 105-110° C. to obtain polysiloxane; Step B2: uniformly mix polysiloxane, vinyltrimethoxysilane, chloroplatinic acid and DMF, and react for 5-7 hours at a speed of 200-300 r / min and a temperature of 60-70° C. to obtain pretreated polysiloxane; uniformly mix pretreated polysiloxane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react for 3-5 hours at a speed of 120-150 r / min and a temperature of 55-60° C. to obtain modified polysiloxane; Step B3: Evenly mix vinyltrimethoxysilane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react for 3-5 hours at a speed of 120-150 r / min and a temperature of 55-60°C to obtain a modifier; evenly mix the modified polysiloxane, the modifier, chloroplatinic acid and DMF, and react for 2-3 hours at a speed of 150-200 r / min and a temperature of 70-80°C, then add allyl polyoxyethylene ether and continue to react for 3-5 hours to obtain a modified additive.

[0008] Furthermore, the molar ratio of tetramethyltetrasiloxane and allyl glycidyl ether described in step B1 is 1:4, the amount of chloroplatinic acid used is 2‰ of tetramethyltetrasiloxane, and the molar ratio of functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane is 1:5:6:1.

[0009] Furthermore, the molar ratio of the polysiloxane and vinyltrimethoxysilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of polysiloxane, and the molar ratio of the pretreated polysiloxane, dimethylchlorosilane and ferric chloride is 1:3:0.002.

[0010] Furthermore, the molar ratio of vinyltrimethoxysilane, dimethylchlorosilane and ferric chloride described in step B3 is 1:3:0.002, the molar ratio of modified polysiloxane, modifier and allyl polyoxyethylene ether is 1:6:18, and the amount of chloroplatinic acid is 5‰ of the mass of modified polysiloxane.

[0011] The beneficial effects of the present invention are as follows: an environmentally friendly cement grinding aid disclosed by the present invention is prepared by polymerizing a modified monomer, a reinforcing monomer and acrylic acid, wherein the modified monomer uses 1-(2-aminoethyl)-1H-pyrrole-2,5-dione and a modified additive as raw materials, and under alkaline conditions, the amino group on the 1-(2-aminoethyl)-1H-pyrrole-2,5-dione reacts with the epoxy group on the modified additive to obtain the modified monomer, and the reinforcing monomer uses acrylic acid and diethanolamine as raw materials, and under the action of dicyclohexylcarbodiimide, the secondary amine on the reinforcing monomer and the carboxyl group on the acrylic acid are dehydrated to obtain the reinforcing monomer.

[0012] The modified additive uses tetramethyltetrasiloxane and allyl glycidyl ether as raw materials, and under the action of chloroplatinic acid, the Si-H bond on tetramethyltetrasiloxane and the double bond on allyl glycidyl ether are grafted to obtain a functional monomer, the functional monomer and octamethylcyclotetrasiloxane are ring-opened, and then polymerized with 1,1,3,3-tetramethyldisiloxane to obtain polysiloxane, and the polysiloxane is reacted with vinyltrimethoxysilane to react the Si-H bond on the polysiloxane and the double bond on the vinyltrimethoxysilane to obtain a pretreated polysiloxane. The pretreated polysiloxane is reacted with dimethylchlorosilane so that the siloxane group on the pretreated polysiloxane reacts with the chlorine atom site on the dimethylchlorosilane to form a Si-O-Si bond, thereby obtaining a modified polysiloxane; vinyltrimethoxysilane is reacted with dimethylchlorosilane to form a Si-O-Si bond, thereby obtaining a modifier; the modified polysiloxane is reacted with the modifier so that the Si-H bond on the modified polysiloxane reacts with the double bond on the modifier to form a hyperbranched structure; and allyl polyoxyethylene ether is added for end-capping to obtain a modified additive.

[0013] The cement grinding aid can be adsorbed on the surface of the material, shield the active points generated by grinding through charge repulsion, prevent the fracture surface from compounding, and form a lubricating film on the surface, reducing the friction between the materials. It can also penetrate into the gaps in the materials, weaken the healing effect generated by molecular forces, promote crack expansion, and make the materials easier to be crushed. The cement grinding aid molecules contain a large number of silicon-oxygen bonds, which makes the cement grinding aid have high surface activity and dispersibility, can well reduce the surface free energy of the material, thereby improving the dispersion effect and accelerating crack expansion. The hyperbranched structure can improve the fluidity of cement and increase the early strength and final strength of cement. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Embodiment 1, a method for preparing an environmentally friendly cement grinding aid, specifically comprising the following steps: Step A1: 1-(2-aminoethyl)-1H-pyrrole-2,5-dione, a modification additive and DMF are mixed, and reacted for 3 hours at a speed of 120 r / min, a temperature of 40° C. and a pH value of 10 to obtain a modified monomer; Step A2: acrylic acid, diethanolamine, dicyclohexylcarbodiimide and toluene are mixed, and the mixture is reacted at a speed of 150 r / min and a temperature of 40° C. for 3 hours to obtain a reinforcing monomer. The modified monomer, reinforcing monomer, acrylic acid and DMF are evenly mixed, and potassium persulfate is added under stirring at a speed of 80° C. to react for 3 hours. The pH value is adjusted to 6.5, and DMF is removed to obtain an environmentally friendly cement grinding aid.

[0016] The molar ratio of 1-(2-aminoethyl)-1H-pyrrole-2,5-dione and the epoxy group on the modifying additive described in step A1 is 1:1.

[0017] The molar ratio of acrylic acid, diethanolamine and dicyclohexylcarbodiimide in step A2 is 1:1:1.1, the mass ratio of the modified monomer, the reinforcing monomer and acrylic acid is 1:5:10, and the amount of potassium persulfate used is 1‰ of the mass of the modified monomer.

[0018] The modified additive is prepared by the following steps: Step B1: Tetramethyltetrasiloxane, allyl glycidyl ether, chloroplatinic acid and DMF are mixed evenly, and reacted at a speed of 120 r / min and a temperature of 60° C. for 3 h to obtain a functional monomer; the functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane are mixed evenly, and reacted at a speed of 150 r / min and a temperature of 105° C. for 2 h to obtain polysiloxane; Step B2: uniformly mix polysiloxane, vinyltrimethoxysilane, chloroplatinic acid and DMF, and react at a speed of 200 r / min and a temperature of 60° C. for 5 h to obtain pretreated polysiloxane; uniformly mix pretreated polysiloxane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react at a speed of 120 r / min and a temperature of 55° C. for 3 h to obtain modified polysiloxane; Step B3: Evenly mix vinyltrimethoxysilane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react at a speed of 120 r / min and a temperature of 55°C for 3 hours to obtain a modifier; evenly mix the modified polysiloxane, the modifier, chloroplatinic acid and DMF, and react at a speed of 150 r / min and a temperature of 70°C for 2 hours, then add allyl polyoxyethylene ether and continue the reaction for 3 hours to obtain a modified additive.

[0019] The molar ratio of tetramethyltetrasiloxane and allyl glycidyl ether described in step B1 is 1:4, the amount of chloroplatinic acid used is 2‰ of tetramethyltetrasiloxane, and the molar ratio of functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane is 1:5:6:1.

[0020] The molar ratio of the polysiloxane and vinyltrimethoxysilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of polysiloxane, and the molar ratio of the pretreated polysiloxane, dimethylchlorosilane and ferric chloride is 1:3:0.002.

[0021] The molar ratio of vinyltrimethoxysilane, dimethylchlorosilane and ferric chloride described in step B3 is 1:3:0.002, the molar ratio of modified polysiloxane, modifier and allyl polyoxyethylene ether is 1:6:18, the amount of chloroplatinic acid is 5‰ of the mass of modified polysiloxane, and the specification of allyl polyoxyethylene ether is n=25.

[0022] Embodiment 2: A method for preparing an environmentally friendly cement grinding aid, comprising the following steps: Step A1: 1-(2-aminoethyl)-1H-pyrrole-2,5-dione, a modification additive and DMF are mixed, and reacted for 4 hours at a speed of 120 r / min, a temperature of 45° C. and a pH value of 11 to obtain a modified monomer; Step A2: acrylic acid, diethanolamine, dicyclohexylcarbodiimide and toluene are mixed, and the mixture is reacted at a speed of 150 r / min and a temperature of 45° C. for 4 hours to obtain a reinforcing monomer. The modified monomer, reinforcing monomer, acrylic acid and DMF are evenly mixed, and potassium persulfate is added under stirring at a speed of 80° C. to react for 4 hours. The pH value is adjusted to 6.5, and DMF is removed to obtain an environmentally friendly cement grinding aid.

[0023] The molar ratio of 1-(2-aminoethyl)-1H-pyrrole-2,5-dione and the epoxy group on the modifying additive described in step A1 is 1:1.

[0024] The molar ratio of acrylic acid, diethanolamine and dicyclohexylcarbodiimide in step A2 is 1:1:1.1, the mass ratio of the modified monomer, the reinforcing monomer and acrylic acid is 1:5:10, and the amount of potassium persulfate used is 1‰ of the mass of the modified monomer.

[0025] The modified additive is prepared by the following steps: Step B1: Tetramethyltetrasiloxane, allyl glycidyl ether, chloroplatinic acid and DMF are mixed evenly, and reacted at a speed of 120 r / min and a temperature of 65° C. for 4 hours to obtain a functional monomer; the functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane are mixed evenly, and reacted at a speed of 150 r / min and a temperature of 110° C. for 2 hours to obtain polysiloxane; Step B2: uniformly mix polysiloxane, vinyltrimethoxysilane, chloroplatinic acid and DMF, and react at a speed of 300 r / min and a temperature of 65° C. for 6 hours to obtain pretreated polysiloxane; uniformly mix pretreated polysiloxane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react at a speed of 120 r / min and a temperature of 60° C. for 4 hours to obtain modified polysiloxane; Step B3: Evenly mix vinyltrimethoxysilane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react at a speed of 120 r / min and a temperature of 60°C for 4 hours to obtain a modifier; evenly mix the modified polysiloxane, the modifier, chloroplatinic acid and DMF, and react at a speed of 150 r / min and a temperature of 75°C for 3 hours, then add allyl polyoxyethylene ether and continue the reaction for 4 hours to obtain a modified additive.

[0026] The molar ratio of tetramethyltetrasiloxane and allyl glycidyl ether described in step B1 is 1:4, the amount of chloroplatinic acid used is 2‰ of tetramethyltetrasiloxane, and the molar ratio of functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane is 1:5:6:1.

[0027] The molar ratio of the polysiloxane and vinyltrimethoxysilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of polysiloxane, and the molar ratio of the pretreated polysiloxane, dimethylchlorosilane and ferric chloride is 1:3:0.002.

[0028] The molar ratio of vinyltrimethoxysilane, dimethylchlorosilane and ferric chloride described in step B3 is 1:3:0.002, the molar ratio of modified polysiloxane, modifier and allyl polyoxyethylene ether is 1:6:18, the amount of chloroplatinic acid is 5‰ of the mass of modified polysiloxane, and the specification of allyl polyoxyethylene ether is n=25.

[0029] Embodiment 3, a method for preparing an environmentally friendly cement grinding aid, specifically comprising the following steps: Step A1: 1-(2-aminoethyl)-1H-pyrrole-2,5-dione, a modification additive and DMF are mixed, and reacted for 5 hours at a speed of 150 r / min, a temperature of 50° C. and a pH value of 11 to obtain a modified monomer; Step A2: acrylic acid, diethanolamine, dicyclohexylcarbodiimide and toluene are mixed, and reacted at a speed of 200 r / min and a temperature of 50° C. for 5 hours to obtain a reinforcing monomer. The modified monomer, reinforcing monomer, acrylic acid and DMF are evenly mixed, stirred and potassium persulfate is added at a speed of 85° C., and the reaction is carried out for 4 hours. The pH value is adjusted to 6.5, and DMF is removed to obtain an environmentally friendly cement grinding aid.

[0030] The molar ratio of 1-(2-aminoethyl)-1H-pyrrole-2,5-dione and the epoxy group on the modifying additive described in step A1 is 1:1.

[0031] The molar ratio of acrylic acid, diethanolamine and dicyclohexylcarbodiimide in step A2 is 1:1:1.1, the mass ratio of the modified monomer, the reinforcing monomer and acrylic acid is 1:5:10, and the amount of potassium persulfate used is 1‰ of the mass of the modified monomer.

[0032] The modified additive is prepared by the following steps: Step B1: Tetramethyltetrasiloxane, allyl glycidyl ether, chloroplatinic acid and DMF are mixed evenly, and reacted at a speed of 150 r / min and a temperature of 70° C. for 5 hours to obtain a functional monomer; the functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane are mixed evenly, and reacted at a speed of 200 r / min and a temperature of 110° C. for 3 hours to obtain polysiloxane; Step B2: uniformly mix polysiloxane, vinyltrimethoxysilane, chloroplatinic acid and DMF, and react at a speed of 300 r / min and a temperature of 70° C. for 7 hours to obtain pretreated polysiloxane; uniformly mix pretreated polysiloxane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react at a speed of 150 r / min and a temperature of 60° C. for 5 hours to obtain modified polysiloxane; Step B3: Evenly mix vinyltrimethoxysilane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react at a speed of 150 r / min and a temperature of 60°C for 5 hours to obtain a modifier; evenly mix the modified polysiloxane, the modifier, chloroplatinic acid and DMF, and react at a speed of 200 r / min and a temperature of 80°C for 3 hours, then add allyl polyoxyethylene ether and continue the reaction for 5 hours to obtain a modified additive.

[0033] The molar ratio of tetramethyltetrasiloxane and allyl glycidyl ether described in step B1 is 1:4, the amount of chloroplatinic acid used is 2‰ of tetramethyltetrasiloxane, and the molar ratio of functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane is 1:5:6:1.

[0034] The molar ratio of the polysiloxane and vinyltrimethoxysilane described in step B2 is 1:2, the amount of chloroplatinic acid used is 1‰ of the mass of polysiloxane, and the molar ratio of the pretreated polysiloxane, dimethylchlorosilane and ferric chloride is 1:3:0.002.

[0035] The molar ratio of vinyltrimethoxysilane, dimethylchlorosilane and ferric chloride described in step B3 is 1:3:0.002, the molar ratio of modified polysiloxane, modifier and allyl polyoxyethylene ether is 1:6:18, the amount of chloroplatinic acid is 5‰ of the mass of modified polysiloxane, and the specification of allyl polyoxyethylene ether is n=25.

[0036] Comparative Example 1: Compared with Example 1, no modifier was added to this comparative example, and the remaining steps were the same.

[0037] Comparative Example 2: Compared with Example 1, this comparative example uses allyl polyoxyethylene ether instead of the modified monomer, and the other steps are the same.

[0038] 95% cement clinker + 5% gypsum (calcium sulfate dihydrate content is about 95%), 0.1% by mass of Example 1-3 and Comparative Example 1-2 were respectively added to the grinding material to prepare cement grinding aids, placed in a 500mmx500mm cement ball machine and ground for 30 minutes. After the mill, the specific surface area of ​​the cement particles was detected in accordance with GB / T8074-2008 standard, and the cement particle size distribution was determined using a JL-1166 laser particle size analyzer. In accordance with GB / T17671-2021 standard, cement, standard sand and water were made into 40mm×40mm×160mm samples in a mass ratio of 1:3:0.5, and the compressive strength after curing for 3 days and 28 days was tested. The test results are shown in Table 1 below.

[0039] Table 1

[0040] It can be seen from Table 1 above that the present invention has a very good grinding aid effect.

[0041] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an environmentally friendly cement grinding aid, characterized in that: The specific steps include: Step A1: 1-(2-aminoethyl)-1H-pyrrole-2,5-dione, a modification additive and DMF are mixed, and reacted for 3-5 hours at a rotation speed of 120-150 r / min, a temperature of 40-50° C. and a pH value of 10-11 to obtain a modified monomer; Step A2: acrylic acid, diethanolamine, dicyclohexylcarbodiimide and toluene are mixed, and reacted for 3-5 hours at a speed of 150-200 r / min and a temperature of 40-50° C. to obtain a reinforcing monomer, and the modified monomer, reinforcing monomer, acrylic acid and DMF are evenly mixed, and potassium persulfate is added under stirring at a speed of 80-85° C. to react for 3-4 hours, and the pH value is adjusted to 6.5, and DMF is removed to obtain an environmentally friendly cement grinding aid.

2. The method for preparing an environmentally friendly cement grinding aid according to claim 1, characterized in that: The molar ratio of 1-(2-aminoethyl)-1H-pyrrole-2,5-dione and the epoxy group on the modifying additive described in step A1 is 1:

1.

3. The method for preparing an environmentally friendly cement grinding aid according to claim 1, characterized in that: The molar ratio of acrylic acid, diethanolamine and dicyclohexylcarbodiimide in step A2 is 1:1:1.1, and the mass ratio of the modified monomer, the reinforcing monomer and acrylic acid is 1:5:

10.

4. The method for preparing an environmentally friendly cement grinding aid according to claim 1, characterized in that: The modified additive is prepared by the following steps: Step B1: Tetramethyltetrasiloxane, allyl glycidyl ether, chloroplatinic acid and DMF are mixed uniformly, and reacted for 3-5 hours at a speed of 120-150 r / min and a temperature of 60-70° C. to obtain a functional monomer; the functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane are mixed uniformly, and reacted for 2-3 hours at a speed of 150-200 r / min and a temperature of 105-110° C. to obtain polysiloxane; Step B2: uniformly mix polysiloxane, vinyltrimethoxysilane, chloroplatinic acid and DMF, and react for 5-7 hours at a speed of 200-300 r / min and a temperature of 60-70° C. to obtain pretreated polysiloxane; uniformly mix pretreated polysiloxane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react for 3-5 hours at a speed of 120-150 r / min and a temperature of 55-60° C. to obtain modified polysiloxane; Step B3: Evenly mix vinyltrimethoxysilane, dimethylchlorosilane, ferric chloride and tetrahydrofuran, and react for 3-5 hours at a speed of 120-150 r / min and a temperature of 55-60°C to obtain a modifier; evenly mix the modified polysiloxane, the modifier, chloroplatinic acid and DMF, and react for 2-3 hours at a speed of 150-200 r / min and a temperature of 70-80°C, then add allyl polyoxyethylene ether and continue to react for 3-5 hours to obtain a modified additive.

5. The method for preparing an environmentally friendly cement grinding aid according to claim 4, characterized in that: The molar ratio of tetramethyltetrasiloxane and allyl glycidyl ether in step B1 is 1:4, and the molar ratio of the functional monomer, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and 1,1,3,3-tetramethyldisiloxane is 1:5:6:

1.

6. The method for preparing an environmentally friendly cement grinding aid according to claim 4, characterized in that: The molar ratio of the polysiloxane to vinyltrimethoxysilane in step B2 is 1:2, and the molar ratio of the pretreated polysiloxane, dimethylchlorosilane and ferric chloride is 1:3:0.

002.

7. The method for preparing an environmentally friendly cement grinding aid according to claim 4, characterized in that: The molar ratio of vinyltrimethoxysilane, dimethylchlorosilane and ferric chloride described in step B3 is 1:3:0.002, and the molar ratio of modified polysiloxane, modifier and allyl polyoxyethylene ether is 1:6:

18.

8. A method for preparing an environmentally friendly cement grinding aid, characterized in that: Prepared according to any one of claims 1 to 7.

Images