A cement grinding enhancer and its preparation method and application

Abstract

The invention discloses a cement grinding aid and enhancer and its preparation method and application. Under an inert atmosphere, an alcohol amine is dissolved in dimethyl sulfoxide to obtain a mixed solution I, and a polycarboxylic acid is dissolved in dimethyl sulfoxide to obtain a mixed solution II; a catalyst is added to the mixed solution I to obtain a mixed solution III, and the mixed solution II is continuously added dropwise to the mixed solution III to react at 100-150°C for 1-12h, and continuously stirred during the reaction, and a mixed solution IV is obtained after being cooled to room temperature; an aminolysis agent is subsequently added to the mixed solution IV to stir and mix uniformly to obtain a mixed solution V, and then the mixed solution V is continuously stirred and reacted at 60-100°C for 1-6h, and the solvent is removed by vacuum distillation, and the mixed solution VI is cooled to room temperature to obtain a mixed solution VI; finally, the mixed solution VI is uniformly mixed with a hydrophilic agent to obtain. The cement grinding aid and enhancer prepared by the present invention has large steric hindrance and strong polarity, can effectively improve the grinding efficiency of cement, and can significantly improve the compressive strength of cement mortar.

Description

Technical Field

[0001] The invention belongs to the field of cement admixtures, and in particular relates to a cement grinding enhancer and a preparation method and application thereof. Background Art

[0002] In recent years, carbon emission reduction has become the current trend of global ecological protection. As one of the "giants" of carbon emissions, the cement industry has received extensive attention for its carbon emission reduction work. To achieve carbon emission reduction in the cement industry, reducing the energy consumption of cement clinker grinding and improving cement performance are two effective ways. Portland cement mainly contains four main phases, mainly alunite, dolomite, aluminate and ferrite, which are impure C3S, C2S, C3A and C4AF solid solutions respectively. Aluminate and bainite hydration provide strength for cement in the early and late stages, respectively, which is attributed to the CSH produced by their hydration. Aluminate hydration speed is fast, the heat is high, and the early hardening is fast. Due to the uneven hardening of cement, it may have a negative impact on the overall strength. Ferrite can provide strength throughout the hydration process. Gypsum is usually added to slow down the hydration rate of aluminate. Aluminate and ferrite react with gypsum to generate AFt and AFm, which is beneficial to cement strength. In order to improve cement strength, it is necessary to promote the hydration of aluminate, bainite and ferrite, and slow down the hydration of aluminate as much as possible. Therefore, chemical admixtures such as grinding aids and accelerators are very popular in the cement industry.

[0003] Triethanolamine is currently a commonly used early strength agent and grinding aid by domestic and foreign companies. It can reduce the steric hindrance between cement particles during cement grinding, prevent the aggregation of ultrafine particles, thereby reducing the electrostatic agglomeration of cement particles, improving grinding efficiency and reducing energy consumption. However, triethanolamine is relatively expensive and only improves the early strength of cement, but not significantly in the later strength. Therefore, the preparation and synthesis of new grinding aids and enhancers are currently a hot topic of research. The amino and hydroxyl groups in alkanolamines can improve the grinding performance of cement and promote the hydration of cement, and are important raw materials for the synthesis of new grinding aids and enhancers. The synthesis of grinding aids and accelerators is still in the exploratory stage, and the performance of the currently synthesized admixtures is similar to that of triethanolamine. An admixture that can both improve the grinding efficiency of cement and enhance the overall strength of cement needs to be explored.

[0004] At present, many scholars have conducted corresponding research on cement grinding aids and have achieved certain results, but there are also some defects.

[0005] Chinese patent application number 201610911194.X discloses a method for preparing a polymer grinding aid using triethanolamine, polyether monomers and sulfonic acid monomers. The disadvantages of this method are that toluene is required in the preparation process and is toxic, the cost of adjusting the pH using NaOH solution is high, and the process is relatively complicated.

[0006] The Chinese patent application number CN202110327855.5 discloses a cement grinding aid and a high early strength cement using the cement grinding aid. The grinding aid is obtained by stirring and mixing 10-20 parts of ethylene glycol, 10-20 parts of propylene glycol, 5-10 parts of rice husk ash, 10-20 parts of triethanolamine, 5-10 parts of refrigerant and 5-15 parts of sodium carbonate. This grinding aid is similar to triethanolamine, and only greatly improves the early strength of cement, but has no obvious effect on the later strength of cement. In addition, various grinding aids are simply compounded with early strength agents, without direct innovation in the field of synthesis.

[0007] The Chinese patent with application number CN202110331452.8 discloses a cement grinding aid and cement using the cement grinding aid. This method is prepared by stirring and mixing the following raw materials by mass: 10-20 parts of triisopropanolamine, 10-15 parts of ethylene glycol, and 10-15 parts of gluconic acid. This grinding aid is simply compounded with various grinding aids, and no new grinding aids are explored. In addition, the preparation of this cement requires the use of expensive raw materials such as nano-magnesium oxide, which increases the cost of use. Summary of the invention

[0008] Purpose of the invention: The technical problem to be solved by the present invention is to provide a new cement grinding enhancer and a preparation method thereof in view of the deficiencies in the prior art, so as to further improve the performance of cement while reducing the cost.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing a cement grinding aid enhancer, characterized in that it comprises the following steps:

[0011] (1) Under an inert atmosphere, 8-20 parts by weight of an alcohol amine is dissolved in 50 parts by weight of dimethyl sulfoxide to obtain a mixed solution I, and 5-10 parts by weight of a polycarboxylic acid is dissolved in 30 parts by weight of dimethyl sulfoxide to obtain a mixed solution II;

[0012] (2) under an inert atmosphere, 0.3-1.5 parts by mass of a catalyst is added to the mixed solution I to obtain a mixed solution III, and then the mixed solution II is continuously added dropwise to the mixed solution III at a pressure of 0.1-0.6 MPa for reaction at 100-150° C. for 1-12 hours, with continuous stirring during the reaction, and the mixture is cooled to room temperature to obtain a mixed solution IV;

[0013] (3) under an inert atmosphere, adding 0.2-1.2 parts by weight of an amine-dissolving agent to the mixed solution IV, stirring and mixing uniformly to obtain a mixed solution V, and then continuously stirring the mixed solution V at 60-100° C. for 1-6 hours, distilling off the solvent under reduced pressure, and cooling to room temperature to obtain a mixed solution VI;

[0014] (4) Evenly mix 10 parts by weight of the mixed solution VI with 0.1-1 parts by weight of a hydrophilic agent to obtain a product.

[0015] Preferably, the inert atmosphere used in the present invention is N2 atmosphere. The mass parts of raw materials in each step are calculated according to a unified standard.

[0016] Specifically, in step (1), the alcoholamine is a primary alcoholamine or a secondary alcoholamine, specifically at least one of ethanolamine, diethanolamine, dimethanolamine, dimethylethanolamine, and diisopropanolamine, preferably diisopropanolamine; and the mass fraction of the alcoholamine is preferably 10-14 parts.

[0017] Specifically, in step (1), the polycarboxylic acid is at least one of citric acid, tartaric acid, phosphoric acid, malic acid and oxalic acid, preferably citric acid; and the mass fraction of the polycarboxylic acid is preferably 7-9 parts.

[0018] Specifically, in step (2), the catalyst is at least one of p-toluenesulfonic acid, concentrated sulfuric acid, thionyl chloride, and molecular sieves, preferably p-toluenesulfonic acid; the mass fraction of the catalyst is preferably 0.5-1 part.

[0019] Preferably, in step (2), during the reaction process, the reaction pressure is controlled to be 0.2-0.5 MPa, the reaction temperature is controlled to be 110-130° C., and the reaction time is controlled to be 3-5 h.

[0020] Specifically, in step (3), the aminolysis agent is any one of sodium ethoxide and sodium hydroxide, preferably sodium ethoxide; the weight percentage of the aminolysis agent is preferably 0.3-0.6 parts.

[0021] Preferably, in step (3), the reaction temperature is controlled at 70-90°C and the reaction time is 2-4h.

[0022] Specifically, in step (4), the hydrophilic agent is at least one of polyoxyethylene lauryl alcohol ether, glyceryl monooleate, sorbitan monolaurate, polysorbate, polyoxyethylene fatty alcohol ether, and glyceryl monoacetate, preferably polysorbate; the mass fraction of the hydrophilic agent is preferably 0.2-0.5 parts.

[0023] Furthermore, the cement grinding enhancer prepared by the above method is also within the protection scope of the present invention.

[0024] Furthermore, the present invention also claims the use of the above-mentioned cement grinding enhancer in cement clinker grinding to enhance both the grinding performance and the hydration performance of the clinker.

[0025] Beneficial effects:

[0026] (1) The cement grinding aid and enhancer prepared by the present invention uses cheaper organic acids (citric acid, phosphoric acid, folic acid, malic acid, etc.) as part of the reactants, thereby reducing the use cost of the grinding aid and enhancer. The preparation process of the present invention is simple, and the use of dimethyl sulfoxide as a solvent increases the reaction rate and product yield. The continuous addition of polyacids promotes the reaction and reduces the generation of by-products, and is easy to regulate the synthesis conditions of the reaction temperature, reaction time, and reaction pressure. The present invention also uses the mechanism of aminolysis reaction, and by adding aminolysis agents such as sodium ethoxide and sodium hydroxide, the ester by-products generated by the reaction are converted into amide main products, thereby improving the yield and purity of the grinding aid and enhancer.

[0027] (2) The cement grinding aid and enhancer prepared by the present invention is a new type of amide alcohol grinding aid and enhancer. The preparation process of the grinding aid and enhancer is simple, and the product purity after the aminolysis reaction is high. In the reaction process, an amide group is formed, and it carries more hydroxyl groups. Due to the presence of more side chains, it has a larger steric hindrance. Existing studies have shown that the more ester groups and hydroxyl groups in the grinding aid and enhancer, the better its grinding aid effect and the better the effect of improving the compressive strength of cement. The amide group and the ester group have similar structures and also have corresponding effects. Due to the increase in hydroxyl groups, the grinding aid and enhancer molecules can be more easily adsorbed on the surface of the particles, lowering the surface energy of the particles and increasing the crushing efficiency of the particles. The grinding aid and enhancer adsorbed on the surface of the particles forms a thin film on the surface, which improves the fluidity of the particles and makes the crushing force on the particles during the grinding process more uniform. This grinding aid and enhancer has a certain hydrophobicity due to its larger steric hindrance and the presence of amide groups. Therefore, this grinding aid and enhancer increases the fluidity of cement, reduces the standard viscosity water requirement, delays the initial setting time but shortens the time from initial setting to final setting, affecting the early strength of cement. After adding the hydrophilic agent, the hydrophilicity of the cement particles ground by the cement grinding enhancer is improved, the contact area and reaction rate of cement with water in the early stage are increased, and the early strength of cement is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0029] Figure 1 The present invention is a flow chart of the preparation process of the cement grinding aid enhancer.

[0030] Figure 2 This is the infrared spectrum of the grinding aid enhancer prepared in the embodiment of the present invention.

[0031] Figure 3 It is the compressive strength of cement mortar tested in Test Example 2.

[0032] Figure 4It is the compressive strength of cement mortar tested in Test Example 3.

[0033] Figure 5 It is the compressive strength of cement mortar tested in Test Example 4.

[0034] Figure 6 It is the compressive strength of the cement mortar tested in Test Example 5.

[0035] Figure 7 It is the compressive strength of the cement mortar tested in Test Example 6. DETAILED DESCRIPTION

[0036] The present invention can be better understood with reference to the following examples.

[0037] Example 1

[0038] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0039] Diisopropanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g, sodium ethoxide 0.3g and polysorbate 1g.

[0040] The preparation method of cement grinding enhancer in this embodiment (combined with Figure 1 shown):

[0041] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to the diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.3MPa and warm to 110°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into the diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0042] Example 2

[0043] The preparation method of the cement grinding enhancer described in this embodiment:

[0044] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.3MPa and warm to 120°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0045] Example 3

[0046] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0047] Diisopropanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g, sodium ethoxide 0.3g and polysorbate 1g.

[0048] The preparation method of the cement grinding enhancer described in this embodiment:

[0049] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.3MPa and warm to 130°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0050] Example 4

[0051] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0052] Diisopropanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g, sodium ethoxide 0.3g and polysorbate 1g.

[0053] The preparation method of the cement grinding enhancer described in this embodiment:

[0054] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.3MPa and warm to 130°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 2h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0055] Example 5

[0056] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0057] Diisopropanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g, sodium ethoxide 0.3g and polysorbate 1g.

[0058] The preparation method of the cement grinding enhancer described in this embodiment:

[0059] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.3MPa and warm to 130°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 6h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0060] Example 6

[0061] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0062] Diisopropanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g, sodium ethoxide 0.3g and polysorbate 1g.

[0063] The preparation method of the cement grinding enhancer described in this embodiment:

[0064] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.2MPa and warm to 130°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0065] Example 7

[0066] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0067] Diisopropanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g, sodium ethoxide 0.3g and polysorbate 1g.

[0068] The preparation method of the cement grinding enhancer described in this embodiment:

[0069] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. 0.6g of p-toluenesulfonic acid is added to diisopropanolamine-dimethyl sulfoxide solution and stirred evenly. Pass N2 atmosphere, pressurize to 0.4MPa and warm to 130°C, add dimethyl sulfoxide-citric acid solution to the timing dripping device and drop it into diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0070] Example 8

[0071] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0072] 12g of dimethylolamine, 8g of tartaric acid, 0.6g of concentrated sulfuric acid, 0.3g of sodium hydroxide and 1g of polyoxyethylene lauryl alcohol ether.

[0073] The preparation method of the cement grinding enhancer described in this embodiment:

[0074] Weigh 50g of dimethyl sulfoxide to dissolve 12g of dimethylamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of tartaric acid. Add 0.6g of concentrated sulfuric acid to the dimethylamine-dimethyl sulfoxide solution and stir evenly. Pass N2 atmosphere, pressurize to 0.3MPa and heat to 130°C, add dimethyl sulfoxide-tartaric acid solution to the timing dripping device and uniformly drop it into the dimethylamine-dimethyl sulfoxide solution within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium hydroxide to the three-necked flask and stir evenly, heat to 70°C and react for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polyoxyethylene lauryl alcohol ether and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0075] Example 9

[0076] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0077] Dimethylethanolamine 12g, phosphoric acid 8g, thionyl chloride 0.6g, sodium ethoxide 0.3g and monoolein 1g.

[0078] The preparation method of the cement grinding enhancer described in this embodiment:

[0079] Weigh 50g of dimethyl sulfoxide to dissolve 12g of dimethylethanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of phosphoric acid. Add 0.6g of concentrated sulfuric acid to the dimethylethanolamine-dimethyl sulfoxide solution and stir evenly. Pass N2 atmosphere, pressurize to 0.3MPa and heat to 130°C, add dimethyl sulfoxide-phosphoric acid solution to the timing dripping device and drip it into the dimethylethanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, heat to 70°C and react for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of monooleyl glycerol and stir and mix evenly to obtain the cement grinding enhancer. The entire reaction process is stirred continuously at a stirring speed of 300rpm / min.

[0080] Example 10

[0081] The amounts of the raw materials of the cement grinding enhancer described in this embodiment are:

[0082] 12g of diisopropanolamine, 8g of malic acid, 0.6g of molecular sieve 4A, 0.3g of sodium ethoxide and 1g of polyoxyethylene fatty alcohol ether.

[0083] The preparation method of the cement grinding enhancer described in this embodiment:

[0084] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diisopropanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of malic acid. Add 0.6g of concentrated sulfuric acid to the diisopropanolamine-dimethyl sulfoxide solution and stir evenly. Pass N2 atmosphere, pressurize to 0.3MPa and warm to 130°C, add dimethyl sulfoxide-malic acid solution to the timing dripping device and drop it into the diisopropanolamine-dimethyl sulfoxide solution at a uniform speed within 1h, continue to react for 4h, and cool to room temperature after the reaction. Then add 0.3g of sodium ethoxide to the three-necked flask and stir evenly, warm to 70°C for reaction for 2h, remove dimethyl sulfoxide and water by reduced pressure distillation after the reaction is completed, and cool to room temperature. Then add 1g of polyoxyethylene fatty alcohol ether and stir and mix evenly to obtain the cement grinding enhancer. The whole reaction process is continuously stirred at a stirring speed of 300rpm / min.

[0085] Comparative Example 1:

[0086] Triethylamine is used as a cement grinding enhancer in the prior art.

[0087] Comparative Example 2:

[0088] In the prior art, diethanol monoisopropanolamine is used as a cement grinding enhancer.

[0089] Comparative Example 3:

[0090] Diethanolamine 12g, citric acid 8g, p-toluenesulfonic acid 0.6g and polysorbate 1g.

[0091] The preparation method of the cement grinding enhancer described in this embodiment:

[0092] Weigh 50g of dimethyl sulfoxide to dissolve 12g of diethanolamine, and weigh 30g of dimethyl sulfoxide to dissolve 8g of citric acid. Add 0.6g of p-toluenesulfonic acid to the diethanolamine-dimethyl sulfoxide solution and stir evenly. Pass N2 atmosphere, pressurize to 0.3MPa and heat to 130°C, add dimethyl sulfoxide-citric acid solution to diethanolamine-dimethyl sulfoxide solution, continue to react for 6h, cool to room temperature after the reaction, and remove dimethyl sulfoxide and water by vacuum distillation. Then add 1g of polysorbate and stir and mix evenly to obtain the cement grinding enhancer. The entire reaction process is stirred continuously at a stirring speed of 300rpm / min.

[0093] Test Example 1:

[0094] Combination Figure 2 , is the infrared spectrum of the cement grinding enhancer prepared in Example 3 of the present invention. As shown in the figure, carboxylic acid has a wavelength of 1689-1758 cm -1 The C=O absorption peak at 1549cm -1 and 1300cm -1The NH bending vibration peak and CN stretching vibration peak belonging to the secondary amine group also disappeared, indicating that diisopropanolamine and citric acid were completely reacted. -1 A new absorption peak appeared nearby, which is the strong absorption peak of C=O in tertiary amide amine. -1 The peaks appearing nearby are the stretching vibration peaks of the CO bonds in tertiary alcohols. 1490-1350cm -1 and 1250-1140cm -1 The absorption peaks at 1770-1720cm are the bending vibration peaks of CH and the stretching vibration peaks of CC on the carbon chain, while the absorption peaks at 1770-1720cm -1 No characteristic C=O absorption peak of ester group was observed. This indicates that the diisopropanolamine and citric acid in the grinding aid enhancer synthesized in Example 3 were completely reacted, and no ester group was generated but only amide group was generated.

[0095] Existing studies have shown that the more molecular polar groups there are and the stronger the polarity of the groups, the more obvious the effect of improving the compressive strength of cement. The ability of organic grinding aids to promote cement hydration comes from its complexing ability to various ions in cement, and the stronger the polarity of the organic grinding aids and the more complex the molecular structure, the stronger its complexing ability. The grinding aid prepared by the present invention has a large number of polar group amide groups and hydroxyl groups, so it has a strong complexing ability for important ions [Ca], [Al], [Fe], [Si] and [S] in cement. Since the grinding aid enhancer increases the ion saturation in the cement pore solution, according to the principle of solubility equilibrium, it will promote the dissolution of C3S, C2S, C3A, C4AF and gypsum in cement, and increase the number of ions in cement that can undergo hydration reactions. The increase in the total number of ions in the cement pore solution will promote the hydration reaction of the ions to generate more CSH, AFt and AFm faster, so as to improve the compressive strength of cement. The grinding aid enhancer is represented by DC, and the chemical equation for promoting the cement hydration reaction is as follows:

[0096] According to the theory that the mineral phase is completely dissolved in the initial stage of hydration, the mineral phase will first form ions in the water phase, and then the ions will react with each other to form hydration products. Grinding aids will chelate with the metal ions dissolved in cement, thereby increasing the solubility of [Ca], [A1] and [Fe]:

[0097] 3CaO·SiO2+nH2O→xCaO·2SiO2·yH2O+(3-x)Ca 2+ +2(3-x)OH -

[0098] 2(2CaO·SiO2)+nH2O→xCaO·2SiO2·yH2O+(2-x)Ca 2+ +2(2-x)OH -

[0099]

[0100]

[0101] nDC+Ca 2+ →[nDC-Ca] 2+

[0102]

[0103]

[0104] In the above reaction, the mineral phases C3S, C2S, C3A, and C4AF are first dissolved into ions, and then DC chelates with Ca2+, Al(OH)4-, and Fe(OH)63- ions. According to Le Chatelier's principle, the reaction moves forward until a new dissolution equilibrium constant K value is reached. Therefore, DC promotes the dissolution of the mineral phase and increases the content of various dissolved metal ions in the solution.

[0105] Calcium hydroxide is the main product of cement hydration and plays a vital role in the strength development of cement. The grinding aid prepared by the present invention affects the crystallization and morphology of calcium hydroxide in cement. Since this grinding aid has a large steric hindrance and a strong complexing ability to [Ca], the grain size of calcium hydroxide generated by cement hydration becomes smaller, and part of amorphous calcium hydroxide is generated. Small-sized calcium hydroxide is usually embedded in the hydrated gel or fills part of the gelling pores, thereby improving the compressive strength and other working properties of cement. And amorphous calcium hydroxide can also play a similar role to CSH, gluing the particles together. And because the grinding aid prepared by the present invention promotes the generation of CSH, AFt and AFm and the small-sized and amorphous calcium hydroxide, the pore volume and pore size of cement are reduced, thereby improving the compressive strength of cement.

[0106] Test Example 2:

[0107] In order to compare and illustrate the grinding effect of the grinding aid enhancers prepared by synthesis at different temperatures in each embodiment and the cement grinding aid enhancer of the comparative example, each grinding aid enhancer was subjected to a grinding test and a cement mortar strength test according to the following method, and the test steps are as follows:

[0108] (1) The grinding aid enhancer described in Example 1-3 and the grinding aid enhancer described in Comparative Example 1-2 are prepared into a grinding aid enhancer solution with an effective concentration of 50% for later use; the cement clinker is crushed to a particle size of less than 4.5 mm for later use; the desulfurized gypsum is dried at 45°C for 3 hours for later use; the mineral powder is taken out for later use; and a batching test is carried out at 5 kg / mill.

[0109] (2) Accurately weigh 3750g of cement clinker, 1000g of mineral powder and 250g of desulfurized gypsum and mix them evenly. Use an analytical balance to accurately weigh 3.00g of grinding aid enhancer solution, and use a spray bottle to evenly spray it on the mixed cement clinker. Grind for 30 minutes, grind out for 5 minutes, sieve and mix evenly to obtain the ground sample, seal the sample for storage and mark it. Test the specific surface area and 45μm sieve residue of the sample, and conduct a cement mortar strength test. The specific surface area and 45μm sieve residue of the sample are shown in Table 1, and the 3d, 7d and 28d compressive strength of the cement mortar are shown in Table 1. Figure 3 shown.

[0110] As can be seen from Table 1, the specific surface area and 45 μm sieve residue of the cement grinding aid prepared by each embodiment of the present invention are better than those of the blank group, Comparative Example 1 and Comparative Example 2. Therefore, the grinding aid prepared by the present invention has a better grinding effect on cement than the blank group, Comparative Example 1 and Comparative Example 2, and meets the requirements of the grinding aid standard GB / T26748-2011. Figure 3 It can be seen that the cement grinding aid enhancer prepared by each embodiment of the present invention has higher compressive strength of cement mortar at 3d, 7d and 28d after cement grinding than the blank group, Comparative Example 1 and Comparative Example 2. With the increase of synthesis temperature, the grinding aid enhancer has a small improvement in the grinding effect of cement and the compressive strength of mortar. The above data show that the new cement grinding aid enhancer prepared by the present invention has a significant grinding effect on cement and significantly improves the compressive strength of cement mortar, and is a cement grinding aid enhancer with excellent performance.

[0111] Table 1 Test results of specific surface area and 45μm sieve residue of grinding aids synthesized at different temperatures

[0112]

[0113] Test Example 3:

[0114] In order to compare and illustrate the grinding aid effect of the grinding aid enhancer prepared in different times in each embodiment and the cement grinding aid enhancer of the comparative example, each grinding aid enhancer was subjected to a grinding test and a cement mortar strength test according to the following method, and the test steps are as follows:

[0115] (1) The grinding aid enhancers described in Examples 4, 3 and 5 and the grinding aid enhancers of Comparative Examples 1-2 are prepared into a grinding aid enhancer solution with an effective concentration of 50% for later use; the cement clinker is crushed to a particle size of less than 4.5 mm for later use; the desulfurized gypsum is dried at 45° C. for 3 h for later use; the mineral powder is taken out for later use; and a batching test is carried out at 5 kg / mill.

[0116] (2) Accurately weigh 3750g of cement clinker, 1000g of mineral powder and 250g of desulfurized gypsum and mix them evenly. Use an analytical balance to accurately weigh 3.00g of grinding aid enhancer solution, and use a spray bottle to evenly spray it on the mixed cement clinker. Grind for 30 minutes, grind out for 5 minutes, sieve and mix evenly to obtain the ground sample, seal the sample for storage and mark it. Test the specific surface area and 45μm sieve residue of the sample, and conduct a cement mortar strength test. The specific surface area and 45μm sieve residue of the sample are shown in Table 2, and the 3d, 7d and 28d compressive strength of the cement mortar are shown in Table 2. Figure 4 shown.

[0117] It can be seen from Table 2 that the specific surface area and 45 μm sieve residue of the cement grinding aid prepared by each embodiment of the present invention are better than those of the blank group, Comparative Example 1 and Comparative Example 2. Therefore, the grinding aid prepared by the present invention has a better grinding effect on cement than the blank group, Comparative Example 1 and Comparative Example 2, and meets the requirements of the grinding aid standard GB / T26748-2011. Figure 4 It can be seen that the cement grinding enhancer prepared in each embodiment of the present invention has higher compressive strength of cement mortar at 3d, 7d and 28d after cement grinding than the blank group, Comparative Example 1 and Comparative Example 2. With the increase of synthesis time, the grinding enhancer has a small improvement in the grinding effect of cement and the compressive strength of mortar.

[0118] Table 2 Effect of grinding aids synthesized at different times on specific surface area and 45 μm sieve residue

[0119]

[0120]

[0121] Test example 4:

[0122] In order to compare and illustrate the grinding aid effect of the grinding aid enhancer prepared in different times in each embodiment and the cement grinding aid enhancer of the comparative example, each grinding aid enhancer was subjected to a grinding test and a cement mortar strength test according to the following method, and the test steps are as follows:

[0123] (1) The grinding aid enhancers described in Examples 6, 3 and 7 and the grinding aid enhancers of Comparative Examples 1-2 are prepared into a grinding aid enhancer solution with an effective concentration of 50% for later use; the cement clinker is crushed to a particle size of less than 4.5 mm for later use; the desulfurized gypsum is dried at 45° C. for 3 h for later use; the mineral powder is taken out for later use; and a batching test is carried out at 5 kg / mill.

[0124] (2) Accurately weigh 3750g of cement clinker, 1000g of mineral powder and 250g of desulfurized gypsum and mix them evenly. Use an analytical balance to accurately weigh 3.00g of grinding aid enhancer solution, and use a spray bottle to evenly spray it on the mixed cement clinker. Grind for 30 minutes, grind out for 5 minutes, sieve and mix evenly to obtain the ground sample, seal the sample for storage and mark it. Test the specific surface area and 45μm sieve residue of the sample, and conduct a cement mortar strength test. The specific surface area and 45μm sieve residue of the sample are shown in Table 3, and the 3d, 7d and 28d compressive strength of the cement mortar are shown in Table 3. Figure 5 shown.

[0125] It can be seen from Table 3 that the specific surface area and 45 μm sieve residue of the cement grinding aid prepared by each embodiment of the present invention are better than those of the blank group, Comparative Example 1 and Comparative Example 2. Therefore, the grinding aid prepared by the present invention has a better grinding effect on cement than the blank group, Comparative Example 1 and Comparative Example 2, and meets the requirements of the grinding aid standard GB / T26748-2011. Figure 5 It can be seen that the cement grinding enhancer prepared in each embodiment of the present invention has higher compressive strength of cement mortar at 3d, 7d and 28d after cement grinding than the blank group, Comparative Example 1 and Comparative Example 2. With the increase of synthesis pressure, the grinding enhancer has a small improvement in the grinding effect of cement and the compressive strength of mortar.

[0126] Table 3 Effect of grinding aids synthesized under different pressures on specific surface area and 45 μm sieve residue

[0127]

[0128]

[0129] Test Example 5:

[0130] In order to compare and illustrate the grinding effect of the grinding aid enhancer synthesized in the embodiment and the cement grinding aid enhancer of the comparative example at different dosages, each grinding aid enhancer was subjected to a grinding test and a cement mortar strength test at different dosages according to the following method, and the test steps are as follows:

[0131] (1) The grinding aid enhancer described in Example 3 and the grinding aid enhancer described in Comparative Examples 1-2 are prepared into a grinding aid enhancer solution with an effective concentration of 50% for later use; the cement clinker is crushed to a particle size of less than 4.5 mm for later use; the desulfurized gypsum is dried at 45°C for 3 h for later use; the mineral powder is taken out for later use; and a batching test is carried out at 5 kg / mill.

[0132] (2) Accurately weigh 3750g of cement clinker, 1000g of mineral powder and 250g of desulfurized gypsum and mix them evenly. Use an analytical balance to accurately weigh 2.00g, 3.00g and 4.00g of grinding aid enhancer solution, and use a spray bottle to evenly spray it on the mixed cement clinker. Grind for 30 minutes, grind out for 5 minutes, sieve and mix evenly to obtain the ground sample, seal the sample for storage and mark it. Test the specific surface area and 45μm sieve residue of the sample, and conduct a cement mortar strength test. The specific surface area and 45μm sieve residue of the sample are shown in Table 4, and the 3d, 7d and 28d compressive strength of the cement mortar are shown in Table 4. Figure 5 shown.

[0133] As can be seen from Table 4, the specific surface area and 45 μm sieve residue of cement after grinding prepared by Example 3 of the present invention are better than those of the blank group, Comparative Example 1 and Comparative Example 2 at different yields, indicating that the grinding aid enhancer prepared in the present invention has a better grinding effect on cement than the blank group, Comparative Example 1 and Comparative Example 2. The grinding effect of the grinding aid enhancer increases with the increase in the amount of the grinding aid enhancer, and all meet the requirements of the grinding aid standard GB / T26748-2011. Figure 6 It can be seen that the cement grinding aid enhancer prepared in Example 3 of the present invention has higher compressive strength of cement mortar at 3d, 7d and 28d after cement grinding at different dosages than the blank group, Comparative Example 1 and Comparative Example 2. As the dosage of the grinding aid enhancer increases, the compressive strength of cement also increases. The above data show that the new cement grinding aid enhancer prepared in the present invention has a significant grinding effect on cement at different dosages, and significantly improves the compressive strength of cement mortar, and the effect increases with the increase in the dosage of the grinding aid enhancer.

[0134] Table 4 Test results of specific surface area and 45μm sieve residue of different grinding aids

[0135]

[0136]

[0137] Test Example 6:

[0138] In order to compare and illustrate the grinding aid effect of the grinding aid enhancer prepared in different times in each embodiment and the cement grinding aid enhancer of the comparative example, each grinding aid enhancer was subjected to a grinding test and a cement mortar strength test according to the following method, and the test steps are as follows:

[0139] (1) The grinding aid enhancers described in Examples 3, 8, 9 and 10 and the grinding aid enhancers of Comparative Examples 1-3 are prepared into a grinding aid enhancer solution with an effective concentration of 50% for later use; the cement clinker is crushed to a particle size of less than 4.5 mm for later use; the desulfurized gypsum is dried at 45° C. for 3 h for later use; the mineral powder is taken out for later use; and a batching test is carried out at 5 kg / mill.

[0140] (2) Accurately weigh 3750g of cement clinker, 1000g of mineral powder and 250g of desulfurized gypsum and mix them evenly. Use an analytical balance to accurately weigh 3.00g of grinding aid enhancer solution, and use a spray bottle to evenly spray it on the mixed cement clinker. Grind for 30 minutes, grind out for 5 minutes, sieve and mix evenly to obtain the ground sample, seal the sample for storage and mark it. Test the specific surface area and 45μm sieve residue of the sample, and conduct a cement mortar strength test. The specific surface area and 45μm sieve residue of the sample are shown in Table 5, and the 3d, 7d and 28d compressive strength of the cement mortar are shown in Table 5. Figure 7 shown.

[0141] It can be seen from Table 5 that the specific surface area and 45 μm sieve residue of the cement grinding aid prepared by each embodiment of the present invention are better than those of the blank group, Comparative Example 1, Comparative Example 2 and Comparative Example 3. Therefore, the grinding aid prepared by the present invention has a better grinding effect on cement than Comparative Example 1, Comparative Example 2 and Comparative Example 3, and all meet the requirements of the grinding aid standard GB / T26748-2011. Figure 7 It can be seen that the cement grinding enhancer prepared in each embodiment of the present invention has higher compressive strength of cement mortar at 3d, 7d and 28d after cement grinding than the blank group, Comparative Example 1, Comparative Example 2 and Comparative Example 3. With the increase of synthesis time, the grinding enhancer has a small improvement in the grinding effect of cement and the compressive strength of mortar.

[0142] Table 5 Effect of grinding aids synthesized at different times on specific surface area and 45 μm sieve residue

[0143]

[0144] The present invention provides a cement grinding enhancer and its preparation method and application ideas and methods. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for preparing a cement grinding enhancer, characterized in that: The steps include: (1) Under an inert atmosphere, 8-20 parts by weight of an alcohol amine is dissolved in 50 parts by weight of dimethyl sulfoxide to obtain a mixed solution I, and 5-10 parts by weight of a polycarboxylic acid is dissolved in 30 parts by weight of dimethyl sulfoxide to obtain a mixed solution II; (2) Under an inert atmosphere, 0.3-1.5 parts by mass of a catalyst is added to the mixed solution I to obtain a mixed solution III, and then the mixed solution II is continuously added dropwise to the mixed solution III at a pressure of 0.1-0.6 MPa for reaction at 100-150° C. for 1-12 hours, with continuous stirring during the reaction, and the mixed solution is cooled to room temperature to obtain a mixed solution IV; (3) Under an inert atmosphere, 0.2-1.2 parts by weight of an amine-dissolving agent is added to the mixed solution IV and stirred to obtain a mixed solution V. The mixed solution V is then stirred and reacted at 60-100° C. for 1-6 hours. The solvent is removed by distillation under reduced pressure and cooled to room temperature to obtain a mixed solution VI. (4) Evenly mix 10 parts by weight of the mixed solution VI with 0.1-1 parts by weight of a hydrophilic agent to obtain a product; In step (1), the alcoholamine is a primary alcoholamine or a secondary alcoholamine, specifically at least one of ethanolamine, diethanolamine, dimethanolamine, dimethylethanolamine, and diisopropanolamine; In step (1), the polycarboxylic acid is at least one of citric acid, tartaric acid, phosphoric acid, malic acid, and oxalic acid; The catalyst is at least one of p-toluenesulfonic acid, concentrated sulfuric acid, thionyl chloride and molecular sieve; The aminolysis agent is any one of sodium ethoxide and sodium hydroxide.

2. The method for preparing a cement grinding aid enhancer according to claim 1, characterized in that: In step (1), the mass fraction of the alcohol amine is 10-14 parts.

3. The method for preparing a cement grinding aid enhancer according to claim 1, characterized in that: In step (1), the mass fraction of the polycarboxylic acid is 7-9 parts.

4. The method for preparing a cement grinding aid enhancer according to claim 1, characterized in that: In step (2), the mass fraction of the catalyst is 0.5-1 part.

5. The method for preparing a cement grinding aid enhancer according to claim 1, characterized in that: In step (2), during the reaction process, the reaction pressure is controlled to be 0.2-0.5 MPa, the reaction temperature is controlled to be 110-130° C., and the reaction time is controlled to be 3-5 h.

6. The method for preparing the cement grinding aid enhancer according to claim 1, characterized in that: In step (3), the mass fraction of the aminolysis agent is 0.3-0.6 parts.

7. The method for preparing a cement grinding aid enhancer according to claim 1, characterized in that: In step (3), the reaction temperature is controlled at 70-90°C and the reaction time is 2-4h.

8. The method for preparing a cement grinding aid enhancer according to claim 1, characterized in that: In step (4), the hydrophilic agent is at least one of polyoxyethylene lauryl alcohol ether, glyceryl monooleate, sorbitan monolaurate, polysorbate, polyoxyethylene fatty alcohol ether, and glyceryl monoacetate; the mass fraction is 0.2-0.5 parts.

9. The cement grinding enhancer prepared by the method according to any one of claims 1 to 8.

10. Use of the cement grinding aid enhancer according to claim 9 in cement clinker grinding to simultaneously enhance the grinding performance and hydration performance of the clinker.

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