A preparation method of a new cement grinding aid

Abstract

The present invention relates to a preparation method of a novel cement grinding aid, belonging to the field of building materials. This method adopts triethanolamine maleate, 1,6-hexyldithiol, oleylamine, and glycerol allyl ether to generate a thiol addition reaction; a novel cement grinding aid with a fat segment, a negatively charged group, and an alcoholamine group is generated; the novel cement grinding aid prepared by the present invention contains three groups in the molecule: a fat segment, a negatively charged group, and an alcoholamine group, and the three have a certain effect on grinding aid; the negatively charged group is adsorbed on cement particles with positive charge during grinding, eliminating the surface electric field of the mud particles and avoiding their re-healing; the fat segment plays a role in accelerating the flow and wetting the fresh interface and avoiding over-grinding during grinding; and the alcoholamine group has a good softening effect on cement particles. When the distribution ratio of various functional groups on the grinding aid molecule is appropriate, it can not only play an active dispersing role, but also make the powder fully ground to avoid the powder running coarse.

Description

Technical Field

[0001] The invention relates to the field of building materials, in particular to a method for preparing a novel cement grinding aid. Background Art

[0002] At present, my country's cement production has exceeded 50% of the world's total. The production process of cement requires a lot of energy consumption. Adding grinding aids is the best way for cement plants to save energy and reduce consumption and save costs. Domestic and foreign cement grinding aids are mostly made of alcohol amines, such as triethanolamine, triisopropanolamine, etc., with good results. A reasonable dosage can reduce energy consumption by more than 20%, and at the same time have a certain early strength effect on the produced cement.

[0003] Patent application number CN202110088540.X: relates to a method for preparing a cement grinding aid, which uses a cement grinding aid preparation device, which includes a preparation box, a conveying and drying mechanism, a crushing and conveying mechanism and a grinding mechanism. The conveying and drying mechanism used in the present invention can directly dry the refined cement grinding aid blocks and convey them at the same time, so that the drying speed of the cement grinding aid blocks is accelerated, avoiding the problem of a long preparation cycle of the cement grinding aid, and at the same time improving the preparation efficiency of the cement grinding aid. The dried cement grinding aid blocks are crushed by the crushing and conveying mechanism and then conveyed through secondary drying, avoiding the phenomenon of insufficient drying of the cement grinding aid raw materials, and facilitating the grinding of the cement grinding aid blocks into a powdery structure.

[0004] Patent application number CN201410248169.9: discloses a method for preparing a cement grinding aid, wherein the raw materials involved are methyl vinyl polyoxyethylene ether (TPEG), methacrylic acid (MAA), sodium methyl propylene sulfonate (MAS), triethanolamine (TEA), ammonium persulfate (APS), and ferric chloride (FeCl3). The grinding aid prepared by the present invention has significant grinding effect, low price and cost, small effective dosage, stable performance, and can be used to guide industrial production.

[0005] Patent application number CN201210535985.9: It relates to the technical field of cement production, and specifically to a preparation process of a polyglycerol cement grinding aid. It is made by mixing 90-95% polyglycerol and 5-10% inorganic reinforcing agent. The polymerization process of polyglycerol is to add 15-30% recycled glycerol, 1-3% NaOH, and 69-84% kerosene into the reactor, heat to 120-180°C under N2 protection, keep warm for 4-8 hours, calculate the average polymerization degree n by measuring the refractive index of the reactants, and control the average polymerization degree of polyglycerol to be 3-5. The cement grinding aid prepared by the present invention can change the dispersibility of the material in the mill under the condition that the condition of the cement mill does not change, effectively eliminate the electrostatic adsorption and ball-coating paste grinding phenomenon of cement fine particles, and optimize the cement particle grading. Maintaining the original mill output unchanged, increasing cement grinding fineness and specific surface area, the 3-day strength of cement can be increased by 15%, and the 28-day strength can be increased by more than 8%; or maintaining the existing cement grinding fineness and specific surface area, the output of the cement mill can be increased by more than 10%.

[0006] However, the cement grinding aids prepared in the above patent materials and prior art are mostly alcoholamine grinding aids, which have poor performance stability and are very sensitive to changes in dosage. At the same time, their prices are relatively high, which restricts their further application. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the present invention provides a method for preparing a novel cement grinding aid, which has very excellent effects in improving the grinding fineness and the early and late strength of cement.

[0008] A method for preparing a novel cement grinding aid comprises the following steps:

[0009] S1: Add 10-20 parts of maleic anhydride by weight to a stirred reactor, heat it, and slowly drop 10-20 parts of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool it to room temperature to obtain triethanolamine maleate;

[0010] S2: Add 25-32 parts of thioglycolic acid ethanolamine, 2-5 parts of oleylamine, 0.2-1.5 parts of glycerol allyl ether, 300-400 parts of organic solvent, and 2-5 parts of catalyst by mass, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0011] According to some embodiments of the present invention, the organic solvent is selected from one or more mixtures of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide DMF, N,N-dimethylacetamide DMAc, N-methylpyrrolidone NMP, and dimethyl sulfoxide DMSO.

[0012] Furthermore, the organic solvent is selected from one or more mixtures of N,N-dimethylformamide DMF, N,N-dimethylacetamide DMAc, and N-methylpyrrolidone NMP.

[0013] According to some embodiments of the present invention, the catalyst is a mixture of one or more of triethylamine TEA, N,N-dimethylaniline DMA, N,N-diethylaniline DEA, 1,5,7-triazidobicyclo (4.4.0) dec-5-ene TBD, diazabicyclo DBU, triphenylphosphine, tri-n-butylphosphine, triisopropylphosphine, tribenzylphosphine, and tricyclopentylphosphine.

[0014] Furthermore, the catalyst is one of triphenylphosphine, triisopropylphosphine and a mixture of multiple thereof.

[0015] According to some embodiments of the present invention, the stirring rate is 300-500 rpm.

[0016] Further, the stirring rate is 350-450 rpm.

[0017] According to some embodiments of the present invention, the triethanolamine is added dropwise for 2.5-3 hours.

[0018] According to some embodiments of the present invention, the reaction temperature of S1 is 40-50° C., and the reaction time is 1-2 h.

[0019] According to some embodiments of the present invention, the reaction temperature of S2 is 60-70° C., and the reaction time is 3-6 h.

[0020] Reaction mechanism:

[0021] A thiol addition reaction occurs between triethanolamine maleate, 1,6-hexyldithiol, oleylamine and glycerol allyl ether to generate a new cement grinding aid with a fatty chain segment, a negatively charged group and an alcoholamine group.

[0022] Technical effects:

[0023] The preparation method of a novel cement grinding aid of the present invention has the following remarkable effects compared with the prior art:

[0024] 1. The novel cement grinding aid prepared by the present invention contains three groups in the molecule: aliphatic chain segments, negatively charged groups, and alcoholamine groups, all of which have certain effects on grinding aids; the negatively charged groups are adsorbed on cement particles with positive charges during grinding, eliminating the surface electric field of the cement particles and preventing them from healing again; the aliphatic chain segments play a role in accelerating the flow and wetting the fresh interface and avoiding over-grinding during grinding; and the alcoholamine groups have a good softening effect on cement particles. When the distribution ratio of various functional groups on the grinding aid molecules is appropriate, it can not only play an active dispersing role, but also enable the powder to be fully ground to avoid the powder running coarsely;

[0025] 2. The new cement grinding aid prepared by the present invention has excellent effects on the grinding fineness and the improvement of the early and late strength of cement, and the grinding aid performance is significantly better than that of the small molecule triethanolamine grinding aid when the dosage is greatly reduced. DETAILED DESCRIPTION

[0026] 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 the embodiments. 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.

[0027] The present invention provides a technical solution: The technical solution of this patent is further described in detail below in conjunction with a specific implementation method.

[0028] Example 1

[0029] A preparation method of a novel cement grinding aid, the operating steps are:

[0030] S1: Add 10 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 10 g of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0031] S2: Continue to add 25 g of thioglycolic acid ethanolamine, 2 g of oleylamine, 0.2 g of glycerol allyl ether, 300 g of organic solvent, and 2 g of catalyst, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0032] Furthermore, the organic solvent is selected from N,N-dimethylformamide DMF.

[0033] Furthermore, the catalyst is triphenylphosphine.

[0034] The stirring rate is 300 rpm.

[0035] The triethanolamine addition time is 2.5h.

[0036] The reaction temperature of S1 is 40°C and the reaction time is 1h.

[0037] The reaction temperature of S2 is 60°C and the reaction time is 3h.

[0038] Example 2

[0039] A preparation method of a novel cement grinding aid, the operating steps are:

[0040] S1: Add 14 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 14 g of triethanolamine after the maleic anhydride melts. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0041] S2: Continue to add 28 g of thioglycolic acid ethanolamine, 3 g of oleylamine, 0.5 g of glycerol allyl ether, 3400 g of organic solvent, and 3 g of catalyst, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0042] Furthermore, the organic solvent is selected from N,N-dimethylacetamide DMAc.

[0043] Furthermore, the catalyst is triphenylphosphine.

[0044] The stirring rate is 350 rpm.

[0045] The triethanolamine addition time is 2.5h.

[0046] The reaction temperature of S1 is 45°C and the reaction time is 1.5h.

[0047] The reaction temperature of S2 is 65°C and the reaction time is 4h.

[0048] Example 3

[0049] A preparation method of a novel cement grinding aid, the operating steps are:

[0050] S1: Add 18 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 18 g of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0051] S2: Continue to add 30g of thioglycolic acid ethanolamine, 4g of oleylamine, 1g of glycerol allyl ether, 380g of organic solvent, and 4g of catalyst, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0052] Furthermore, the organic solvent is selected from N,N-dimethylacetamide DMAc.

[0053] Furthermore, the catalyst is triisopropylphosphine.

[0054] The stirring rate is 450 rpm.

[0055] The triethanolamine addition time is 3 hours.

[0056] The reaction temperature of S1 is 45°C and the reaction time is 1.5h.

[0057] The reaction temperature of S2 is 65°C and the reaction time is 5h.

[0058] Example 4

[0059] A preparation method of a novel cement grinding aid, the operating steps are:

[0060] S1: Add 20 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 20 g of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0061] S2: Continue to add 32 g of ethanolamine thioglycolate, 5 g of oleylamine, 1.5 g of glycerol allyl ether, 400 g of organic solvent, and 5 g of catalyst, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0062] Furthermore, the organic solvent is selected from N-methylpyrrolidone NMP.

[0063] Furthermore, the catalyst is triisopropylphosphine.

[0064] The stirring rate is 500 rpm.

[0065] The triethanolamine addition time is 3 hours.

[0066] The reaction temperature of S1 is 50°C and the reaction time is 2h.

[0067] The reaction temperature of S2 is 70°C and the reaction time is 6h.

[0068] Comparative Example 1

[0069] A preparation method of a novel cement grinding aid, the operating steps are:

[0070] S1: Add 10 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 10 g of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0071] S2: Continue to add 2 g of oleylamine, 0.2 g of glycerol allyl ether, 300 g of organic solvent, and 2 g of catalyst, raise the temperature and stir. After the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0072] Furthermore, the organic solvent is selected from N,N-dimethylformamide DMF.

[0073] Furthermore, the catalyst is triphenylphosphine.

[0074] The stirring rate is 300 rpm.

[0075] The triethanolamine addition time is 2.5h.

[0076] The reaction temperature of S1 is 40°C and the reaction time is 1h.

[0077] The reaction temperature of S2 is 60°C and the reaction time is 3h.

[0078] Comparative Example 2

[0079] A preparation method of a novel cement grinding aid, the operating steps are:

[0080] S1: Add 10 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 10 g of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0081] S2: Continue to add 25 g of thioglycolic acid ethanolamine, 0.2 g of glycerol allyl ether, 300 g of organic solvent, and 2 g of catalyst, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0082] Furthermore, the organic solvent is selected from N,N-dimethylformamide DMF.

[0083] Furthermore, the catalyst is triphenylphosphine.

[0084] The stirring rate is 300 rpm.

[0085] The triethanolamine addition time is 2.5h.

[0086] The reaction temperature of S1 is 40°C and the reaction time is 1h.

[0087] The reaction temperature of S2 is 60°C and the reaction time is 3h.

[0088] Comparative Example 3

[0089] A preparation method of a novel cement grinding aid, the operating steps are:

[0090] S1: Add 10 g of maleic anhydride to a stirred reactor, raise the temperature, and slowly drop 10 g of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool to room temperature to obtain triethanolamine maleate;

[0091] S2: Continue to add 25 g of thioglycolic acid ethanolamine, 2 g of oleylamine, 300 g of organic solvent, and 2 g of catalyst, heat up and stir, and after the reaction is completed, evaporate the solvent under reduced pressure to obtain a new cement grinding aid.

[0092] Furthermore, the organic solvent is selected from N,N-dimethylformamide DMF.

[0093] Furthermore, the catalyst is triphenylphosphine.

[0094] The stirring rate is 300 rpm.

[0095] The triethanolamine addition time is 2.5h.

[0096] The reaction temperature of S1 is 40°C and the reaction time is 1h.

[0097] The reaction temperature of S2 is 60°C and the reaction time is 3h.

[0098] The cement grinding aids prepared in the above examples and comparative examples were added to cement clinker at a ratio of 250 g / ton of cement clinker. The test results of cement grinding aids according to GB / T 26748-2011 are shown in the following table:

[0099] 28d flexural strength / MPa 28d compressive strength / MPa Example 1 7.1 39.3 Example 2 7.2 39.8 Example 3 7.3 40.6 Example 4 7.2 40.2 Comparative Example 1 4.9 35.8 Comparative Example 2 5.5 37.5 Comparative Example 3 6.1 38.1

[0100] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for preparing a cement grinding aid, comprising the following steps: S1: Add 10-20 parts of maleic anhydride by weight to a stirred reactor, heat it, and slowly drop 10-20 parts of triethanolamine after the maleic anhydride is melted. After the dropwise addition is completed and the reaction is completed, cool it to room temperature to obtain triethanolamine maleate; S2: Add 25-32 parts of thioglycolic acid ethanolamine, 2-5 parts of oleylamine, 0.2-1.5 parts of glycerol allyl ether, 300-400 parts of organic solvent, and 2-5 parts of catalyst by mass, heat up and stir, and after the reaction is completed, evaporate the organic solvent under reduced pressure to obtain a cement grinding aid.

2. The method for preparing a cement grinding aid according to claim 1, wherein: The organic solvent is selected from one or more mixtures of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide DMF, and N,N-dimethylacetamide DMAC.

3. The method for preparing a cement grinding aid according to claim 2, wherein: Furthermore, the organic solvent is selected from one or more mixtures of N,N-dimethylformamide DMF, N,N-dimethylacetamide DMAC, and N-methylpyrrolidone NMP.

4. The method for preparing a cement grinding aid according to claim 1, wherein: The catalyst is a mixture of one or more of triethylamine TEA, N,N-dimethylaniline DMA, N,N-diethylaniline DEA, 1,5,7-triazidobicyclo (4.4.0) dec-5-ene TBD, diazabicyclo DBU, triphenylphosphine, tri-n-butylphosphine, triisopropylphosphine, tribenzylphosphine, and tricyclopentylphosphine.

5. The method for preparing a cement grinding aid according to claim 4, wherein: Furthermore, the catalyst is triphenylphosphine, triisopropylphosphine or a mixture of the two.

6. The method for preparing a cement grinding aid according to claim 1, wherein: The stirring rate is 300-500 rpm.

7. The method for preparing a cement grinding aid according to claim 6, wherein: Further, the stirring rate is 350-450 rpm.

8. The method for preparing a cement grinding aid according to claim 1, wherein: The triethanolamine is added dropwise for 2.5-3 hours.

9. The method for preparing a cement grinding aid according to claim 1, wherein: The reaction temperature of S1 is 40-50°C, and the reaction time is 1-2h.

10. The method for preparing a cement grinding aid according to claim 1, characterized in that: The reaction temperature of S2 is 60-70°C, and the reaction time is 3-6h.