A cement raw meal grinding aid and its application

Abstract

The present invention provides a cement raw meal grinding aid, which comprises spherical gypsum particles, quaternary ammonium base, polyvinylpyrrolidone, N-vinylpyrrolidone and C2-C4 polyols; the spherical gypsum particles are graded spherical gypsum particles. The present invention also provides a preparation method of the cement raw meal grinding aid, which comprises the following steps: mixing N-vinylpyrrolidone and C2-C4 polyols and stirring; adding the spherical gypsum particles, 0.1-0.5 of the quaternary ammonium base and polyvinylpyrrolidone, and then performing the first ball milling to obtain the product. The present invention also provides an application of the cement raw meal grinding aid in the grinding process of cement raw meal.

Description

Technical Field

[0001] The present invention belongs to the technical field of cement raw meal preparation, and particularly relates to a method for preparing cement raw meal. Background Art

[0002] As a major cement-producing country, China's annual cement output can reach 2 billion tons, and the annual output of clinker used for cement production is also extremely large. The cement production industry is an energy-intensive industry. Therefore, how to save energy and reduce consumption during the cement production process has become an urgent problem to be solved.

[0003] The reason why cement production has high energy consumption is that during the production process of cement clinker, it is necessary to grind the cement raw meal, and then calcine the ground raw meal at 1450°C to finally obtain cement clinker. Raw meal grinding is a process in which, under the action of external force, through impact, extrusion, grinding, etc., the stress during object deformation and the cohesion between particles are overcome to turn massive materials into fine powder. In the production process of cement raw meal, the effective energy utilization rate of the process of grinding raw meal into fine powder is very low, while the power consumption is very high. And if the raw meal fine powder is not ground sufficiently, the surface area of the obtained raw meal is small and the reaction activity is low, which will also increase the energy consumption during the clinker calcination process.

[0004] To improve the energy utilization efficiency of cement production and reduce energy consumption, adding a cement grinding aid during the cement raw meal grinding process is a feasible method.

[0005] The patent with the publication number CN114195415A discloses a cement raw meal grinding aid. The components of the grinding aid include: triethanolamine, triisopropanolamine, ethylene glycol, sugar ether, sodium acetate, calcium formate, lignin, dodecylbenzene, and water. The addition of this grinding aid greatly improves the fluidity of the cement, making the cement more suitable for casting, with less casting time and greatly improving the cement casting efficiency. At the same time, the setting time decreases, indicating that the cement has a faster action speed, so that when using this cement, the cement can quickly set and generate strength. The cement using the grinding aid of the present invention is more suitable for applications where rapid setting and initial strength generation of cement are required, such as slope protection scenarios, etc.

[0006] A cement raw material grinding aid with a publication number of CN114890695B, which comprises the following components in parts by mass: 130-170 parts of polyglycerol; 70-90 parts of polyethylene glycol dodecanamide; 50-80 parts of polyvinylpyrrolidone; 14-18 parts of sodium acetate; 8-11 parts of a conditioning aid; 1000-1100 parts of water; the mass ratio between the polyglycerol, polyethylene glycol dodecanamide, polyvinylpyrrolidone, sodium acetate and the conditioning aid is 15:8:6.5:1.6:1; the conditioning aid is prepared by mixing fatty alcohol polyoxyethylene ether, polytetrafluoroethylene emulsion and polyethylene glycol in a mass ratio of (1-1.2):(0.3-0.5):(0.8-1); the polyglycerol is prepared by mixing pentaglycerol and decaglycerol in a mass ratio of (1-1.3):(1.5-1.7). The components in the grinding aid can be fully coordinated, thereby maximizing the grinding aid effect and greatly improving the fineness and fluidity of the cement raw material particles and the strength and crack resistance of the cement product.

[0007] However, the above method has the problem of long raw material grinding time. Summary of the Invention

[0008] The first object of the present invention is to provide a cement raw material grinding aid that can greatly improve the fineness and fluidity of cement raw material particles in a relatively short time.

[0009] The second object of the present invention is to provide a preparation method of the cement raw material grinding aid.

[0010] The third object of the present invention is to provide an application of the cement raw material grinding aid.

[0011] The present invention is realized by adopting the following technical solutions:

[0012] A cement raw material grinding aid, in parts by weight, comprises 8-12 parts of spherical gypsum particles, 0.1-0.5 part of quaternary ammonium base, 0.3-0.6 part of polyvinylpyrrolidone, 30-50 parts of N-vinylpyrrolidone and 40-50 parts of C2-C4 polyol;

[0013] The spherical gypsum particles include first spherical gypsum particles with a D50 of 20-25 microns, second spherical gypsum particles with a D50 of 10-15 microns, third spherical gypsum particles with a D50 of 2-5 microns and fourth spherical gypsum particles with a D50 of 0.5-0.8 microns;

[0014] The weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles and the fourth spherical gypsum particles is 1-3:2-4:2-5:3-5.

[0015] The cement raw meal grinding aid, by weight, comprises 8-12 parts of spherical gypsum particles, 0.1-0.5 parts of quaternary ammonium base, 0.3-0.6 parts of polyvinylpyrrolidone, 30-50 parts of N-vinylpyrrolidone and 40-50 parts of glycerol;

[0016] The weight ratio of the first spherical gypsum particle, the second spherical gypsum particle, the third spherical gypsum particle and the fourth spherical gypsum particle is 1-3:2-4:2-5:3-5.

[0017] The quaternary ammonium base includes tetramethylammonium hydroxide, tetrabutylammonium hydroxide or polyethyleneimine;

[0018] The C2-C4 polyhydric alcohol includes propylene glycol, glycerol or erythritol;

[0019] The polyvinylpyrrolidone includes K30, K60 or K90.

[0020] A preparation method of the cement raw meal grinding aid comprises the following steps:

[0021] Mix N-vinylpyrrolidone and C2-C4 polyhydric alcohol and then stir;

[0022] Add the spherical gypsum particles, 0.1-0.5 parts of the quaternary ammonium base and polyvinylpyrrolidone, and then carry out the first ball milling to obtain the product.

[0023] The preparation method of the cement raw meal grinding aid comprises the step of mixing N-vinylpyrrolidone and C2-C4 polyhydric alcohol and then stirring at 35-45 °C.

[0024] The stirring speed is 30-60 r / min;

[0025] The time of the first ball milling is 20-40 min;

[0026] The ball-to-material ratio of the first ball milling is 1:2-3.

[0027] An application of the cement raw meal grinding aid is applied to the grinding of cement raw meal.

[0028] The grinding comprises the following steps:

[0029] Mix the cement raw meal raw material with a D50 of 100-150 microns and the cement raw meal grinding aid to obtain a mixture, and carry out the second ball milling on the mixture for 30-50 min to obtain a paste;

[0030] Carry out the third ball milling on the paste for 30-50 min to obtain the cement raw meal.

[0031] The weight ratio of the cement raw meal raw material to the cement raw meal grinding aid is 20-30:1;

[0032] The bulk density of the mixture is 2.3 - 2.5 g / cm 3 ;

[0033] The ball-to-material ratio of the second ball milling is 1:2 - 3.

[0034] The diameter of the grinding balls used in the second ball milling is 200 - 500 microns.

[0035] The ball-to-material ratio of the third ball milling is 1:2 - 3;

[0036] The diameter of the grinding balls used in the third ball milling is 200 - 500 microns.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. The grinding aid provided by the present invention can increase the fluidity of the raw cement particles, making the grinding opportunities for the particles tend to be equal, thus contributing to improving the grinding efficiency, increasing the content of fine particles, optimizing the particle size distribution, increasing the specific surface area, improving the dispersibility of the particles, and making the particle morphology tend to be round.

[0039] 2. The preparation cost of the raw cement grinding aid provided by the present invention is simple, recyclable, low-cost, and has strong economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Shows the relationship diagram between the ball milling time and D50 of the raw cement in Example 1; it can be seen from the figure that after the paste is formed, due to the self-shearing of the raw material particles, the ball milling efficiency increases significantly;

[0041] Figure 2 Shows the relationship diagram between the ball milling time and D50 of the raw cement in Comparative Example 4; it can be seen from the figure that after the paste is formed, due to the too small bulk density, the ball milling efficiency does not increase significantly;

[0042] Figure 3 Shows the relationship diagram between the ball milling time and D50 of the raw cement in Comparative Example 5; it can be seen from the figure that after the paste is formed, due to the too large bulk density, the ball milling efficiency does not increase significantly. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention provides a cement raw meal grinding aid, which, by weight parts, comprises 8-12 parts of spherical gypsum particles, 0.1-0.5 part of quaternary ammonium base, 0.3-0.6 part of polyvinylpyrrolidone, 30-50 parts of N-vinylpyrrolidone and 40-50 parts of C2-C4 polyhydric alcohol; wherein, the spherical gypsum particles are used as ball milling aids to adjust the bulk density of the cement raw meal, the quaternary ammonium base and polyvinylpyrrolidone are used as dispersants, and N-vinylpyrrolidone and polyhydric alcohol are used as ball milling aids. Specifically, the spherical gypsum particles include first spherical gypsum particles with a D50 of 20-25 microns, second spherical gypsum particles with a D50 of 10-15 microns, third spherical gypsum particles with a D50 of 2-5 microns and fourth spherical gypsum particles with a D50 of 0.5-0.8 microns; and, the weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles and the fourth spherical gypsum particles is 1-3:2-4:2-5:3-5. By adjusting the bulk density of the raw materials of the cement raw meal with the above four different gypsum particles, a paste can be formed when the raw materials of the cement raw meal are ball milled, so that when the raw materials of the cement raw meal are ball milled, the relationship between the ball milling time and the particle size of the raw materials is closer to a linear relationship, thereby reducing the ball milling time. At the same time, cement raw meal with a narrower particle size distribution can also be obtained. The reason for using graded spherical gypsum particles is that during the ball milling process, the particle size of the cement raw meal raw materials will continuously decrease. After the particle size of the cement raw meal raw materials decreases, spherical gypsum particles with a smaller particle size are required to fill the gaps of the cement raw meal raw materials, so that during the ball milling process, continuous energy transfer can be achieved, and self-shearing of the cement raw meal raw materials can be realized.

[0044] Specifically, the quaternary ammonium base is selected from one of tetramethylammonium hydroxide, tetrabutylammonium hydroxide or polyethyleneimine. Other types of quaternary ammonium bases can also implement the present invention.

[0045] Specifically, the C2-C4 polyhydric alcohol is selected from one of propylene glycol, glycerol or erythritol; other types of polyhydric alcohols can also implement the present invention.

[0046] Specifically, the polyvinylpyrrolidone can be selected from one of K30, K60 or K90. Other types of polyvinylpyrrolidone can also implement the present invention.

[0047] The present invention also provides a preparation method of the cement raw meal grinding aid. Specifically, it includes the following steps:

[0048] Mix N-vinylpyrrolidone and C2-C4 polyhydric alcohol and then stir to make the solvent components evenly mixed. Then add the spherical gypsum particles, 0.1-0.5 of the quaternary ammonium base and polyvinylpyrrolidone and conduct the first ball milling to obtain a uniformly mixed cement raw meal grinding aid.

[0049] Specifically, the preparation method of the cement raw meal grinding aid includes the step of mixing N-vinylpyrrolidone with a C2-C4 polyol and stirring at 35-45°C. Stirring at this temperature allows the two to mix more quickly.

[0050] Specifically, the stirring speed is 30-60 r / min;

[0051] Specifically, the first ball milling time is 20-40 min;

[0052] Specifically, the ball-to-material ratio of the first ball milling is 1:2-3.

[0053] The present invention also provides an application of the cement raw meal grinding aid, which is applied to the grinding of cement raw meal.

[0054] Specifically, the grinding includes the following steps:

[0055] Mix a cement raw meal raw material with a D50 of 100-150 microns with the cement raw meal grinding aid to obtain a mixture, and subject the mixture to a second ball milling for 30-50 min to obtain a paste;

[0056] The weight ratio of the cement raw meal raw material to the cement raw meal grinding aid is 20-30:1;

[0057] The bulk density of the mixture is 2.3-2.5 g / cm 3 ;

[0058] The ball-to-material ratio of the second ball milling is 1:2-3.

[0059] In the above method, the essence of paste formation is the reduction of the distance between cement raw meal particles. After the paste is formed, further ball milling can achieve efficient physical self-shearing between cement raw meal particles. That is, the grinding balls are used to mechanically drive the cement raw meal particles to shear and rub against each other to achieve efficient ball milling of the cement raw meal particles. This idea uses the surface area of the cement raw meal particles as the shear working area, greatly improving the ball milling efficiency of the cement raw meal particles. This self-grinding idea belongs to a pure physical shear process, inheriting the advantages of traditional mechanical peeling strategies and not introducing impurities, thereby maximizing the physical and chemical performance indicators of the cement raw meal particles. At the same time, the self-shearing of the cement raw meal particles can also reduce the particle size distribution range of the cement raw meal particles.

[0060] To implement the above method, the present invention uses micron grinding balls as an energy conduction medium to drive the rotation of cement raw material particles; by increasing the volume of cement raw material particles in the ball milling medium and reducing the spacing between cement raw material particles, the mutual contact and shear friction of the rotating cement raw material particles are achieved; by increasing the ball milling linear velocity and improving the energy input, efficient self-shearing is successfully realized. Importantly, the bulk density of the cement raw material particles is 2.3 - 2.5 g / cm 3 to achieve the best grinding efficiency. This is because when grinding and exfoliating the cryptocrystalline graphite nanoparticles, when the bulk density is 2.3 - 2.5 g / cm 3 during the ball milling process of cement raw material particles, the particle size and ball milling time first show a parabolic shape. After the end of this parabolic process, the particle size and ball milling time will show a relatively linear relationship. In this way, the ball milling time can be shortened, and at the same time, due to the effect of self-shearing, the particle size distribution of the obtained cement raw material is also narrow.

[0061] When the density is greater than 2.5 g / cm 3 or less than 2.3 g / cm 3 the parabolic process is very long, and the ball milling and exfoliating effect will be reduced. This is because the size of the bulk density will affect the energy transfer efficiency of the grinding balls during the ball milling process. Only when the bulk density is between 2.3 - 2.5 g / cm 3 can the energy transfer efficiency from the ceramic grinding balls to the cement raw material particles reach the highest.

[0062] Specifically, the diameter of the ceramic grinding balls is 200 - 500 microns. If the diameter of the ceramic grinding balls is too large, it will exacerbate the non-uniformity of the cement raw material particles, and the spacing between the ceramic grinding balls will also increase, which is not conducive to the mutual grinding of the cement raw material particles. If the diameter of the ceramic grinding balls is too small, the energy and power may be insufficient, resulting in an extended time to form a paste and a reduction in the final efficiency.

[0063] The present invention will be further described below in conjunction with specific embodiments.

[0064] Example 1

[0065] Mix N-vinylpyrrolidone and glycerol and stir at a speed of 60 r / min at 35°C; then add spherical gypsum particles, tetramethylammonium hydroxide, and polyvinylpyrrolidone K30 and perform the first ball milling to obtain a cement raw material grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0066] In Example 1, by weight, the cement raw material grinding aid contains 8 parts of spherical gypsum particles, 0.5 part of tetramethylammonium hydroxide, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone, and 50 parts of glycerol; among them, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 20 μm, second spherical gypsum particles with a D50 of 15 μm, third spherical gypsum particles with a D50 of 5 μm, and fourth spherical gypsum particles with a D50 of 0.8 μm; the weight ratio of the first spherical gypsum particles, second spherical gypsum particles, third spherical gypsum particles, and fourth spherical gypsum particles is 1:2:5:5.

[0067] Then, the cement raw material with a D50 of 100 μm and the cement raw material grinding aid are mixed at a ratio of 20:1 to obtain a mixture with a bulk density of 2.3 g / cm 3 and the mixture is subjected to a second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 μm. The paste is subjected to a third ball milling for 30 min to obtain the cement raw material. The conditions of the third ball milling are the same as those of the second ball milling.

[0068] Example 2

[0069] N-vinylpyrrolidone and glycerol are mixed and stirred at a speed of 30 r / min at 45°C; then, spherical gypsum particles, tetramethylammonium hydroxide, and polyvinylpyrrolidone K60 are added and the mixture is subjected to a first ball milling to obtain the cement raw material grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:3, and the ball milling time is 20 min.

[0070] In Example 2, by weight, the cement raw material grinding aid contains 12 parts of spherical gypsum particles, 0.6 part of tetramethylammonium hydroxide, 0.3 part of polyvinylpyrrolidone, 30 parts of N-vinylpyrrolidone, and 40 parts of glycerol; among them, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 25 μm, second spherical gypsum particles with a D50 of 15 μm, third spherical gypsum particles with a D50 of 2 μm, and fourth spherical gypsum particles with a D50 of 0.5 μm; the weight ratio of the first spherical gypsum particles, second spherical gypsum particles, third spherical gypsum particles, and fourth spherical gypsum particles is 3:4:2:3.

[0071] Then, the cement raw material with a D50 of 150 μm and the cement raw material grinding aid are mixed at a ratio of 20:1 to obtain a mixture with a bulk density of 2.3 g / cm 3 and the mixture is subjected to a second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:3; the diameter of the grinding balls used in the second ball milling is 300 μm. The paste is subjected to a third ball milling for 30 min to obtain the cement raw material. The conditions of the third ball milling are the same as those of the second ball milling.

[0072] Example 3

[0073] Mix N-vinylpyrrolidone with glycerol and stir at a speed of 60 r / min at 35 °C; then add spherical gypsum particles, PEI and polyvinylpyrrolidone K90 and conduct the first ball milling to obtain the cement raw meal grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0074] In Example 3, by weight, the cement raw meal grinding aid contains 10 parts of spherical gypsum particles, 0.5 part of PEI, 0.4 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone and 50 parts of propylene glycol; among them, the spherical gypsum particles contain the first spherical gypsum particles with D50 of 23 microns, the second spherical gypsum particles with D50 of 15 microns, the third spherical gypsum particles with D50 of 5 microns and the fourth spherical gypsum particles with D50 of 0.8 microns; the weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles and the fourth spherical gypsum particles is 2:2:5:5.

[0075] Then mix the cement raw meal raw material with D50 of 100 microns and the cement raw meal grinding aid in a ratio of 25:1 to obtain a mixture with a bulk density of 2.3 g / cm 3 and conduct the second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:3; the diameter of the grinding balls used in the second ball milling is 250 microns. Conduct the third ball milling on the paste for 30 min to obtain the cement raw meal. The conditions of the third ball milling are the same as those of the second ball milling.

[0076] Example 4

[0077] Mix N-vinylpyrrolidone with glycerol and stir at a speed of 50 r / min at 35 °C; then add spherical gypsum particles, tetraethylammonium hydroxide and polyvinylpyrrolidone K30 and conduct the first ball milling to obtain the cement raw meal grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0078] In Example 4, by weight, the cement raw meal grinding aid contains 8 parts of spherical gypsum particles, 0.5 part of tetraethylammonium hydroxide, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone and 50 parts of glycerol; among them, the spherical gypsum particles contain the first spherical gypsum particles with D50 of 20 microns, the second spherical gypsum particles with D50 of 12 microns, the third spherical gypsum particles with D50 of 5 microns and the fourth spherical gypsum particles with D50 of 0.6 microns; the weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles and the fourth spherical gypsum particles is 3:2:4:5.

[0079] Then mix the cement raw meal raw material with D50 of 100 microns and the cement raw meal grinding aid in a ratio of 27:1 to obtain a mixture with a bulk density of 2.4 g / cm3 The mixture is subjected to a second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 microns. The paste is subjected to a third ball milling for 30 min to obtain raw cement. The conditions of the third ball milling are the same as those of the second ball milling.

[0080] Example 5

[0081] N-vinylpyrrolidone and glycerol are mixed and stirred at a speed of 60 r / min at 35 °C; then spherical gypsum particles, tetramethylammonium hydroxide and polyvinylpyrrolidone K30 are added and then subjected to a first ball milling to obtain a grinding aid for raw cement. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0082] In Example 5, by weight, the grinding aid for raw cement contains 10 parts of spherical gypsum particles, 0.4 part of tetramethylammonium hydroxide, 0.4 part of polyvinylpyrrolidone, 45 parts of N-vinylpyrrolidone and 45 parts of glycerol; among them, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 22 microns, second spherical gypsum particles with a D50 of 13 microns, third spherical gypsum particles with a D50 of 5 microns and fourth spherical gypsum particles with a D50 of 0.8 microns; the weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles and the fourth spherical gypsum particles is 3:2:5:4.

[0083] Then, the raw cement raw material with a D50 of 100 microns and the grinding aid for raw cement are mixed at a ratio of 23:1 to obtain a bulk density of 2.5 g / cm 3 The mixture is subjected to a second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 microns. The paste is subjected to a third ball milling for 30 min to obtain raw cement. The conditions of the third ball milling are the same as those of the second ball milling.

[0084] Comparative Example 1

[0085] N-vinylpyrrolidone and glycerol are mixed and stirred at a speed of 60 r / min at 35 °C; then spherical gypsum particles, tetramethylammonium hydroxide and polyvinylpyrrolidone K30 are added and then subjected to a first ball milling to obtain a grinding aid for raw cement. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0086] In Comparative Example 1, based on parts by weight, the cement raw material grinding aid contains 8 parts of spherical gypsum particles, 0.5 part of quaternary ammonium base, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone, and 50 parts of glycerol; among which, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 20 microns, second spherical gypsum particles with a D50 of 15 microns, and third spherical gypsum particles with a D50 of 5 microns; the weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, and the third spherical gypsum particles is 1:2:5.

[0087] Then, the cement raw material with a D50 of 100 microns and the cement raw material grinding aid are mixed at a ratio of 20:1 to obtain a mixture with a bulk density of 2.3 g / cm 3 and the mixture is subjected to a second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 microns. The paste is subjected to a third ball milling for 30 min to obtain the cement raw material. The conditions of the third ball milling are the same as those of the second ball milling.

[0088] Comparative Example 2

[0089] N-vinylpyrrolidone and glycerol are mixed and stirred at a speed of 60 r / min at 35 °C; then spherical gypsum particles, tetramethylammonium hydroxide, and polyvinylpyrrolidone K30 are added and the mixture is subjected to a first ball milling to obtain the cement raw material grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0090] In Comparative Example 2, based on parts by weight, the cement raw material grinding aid contains 8 parts of spherical gypsum particles, 0.5 part of quaternary ammonium base, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone, and 50 parts of glycerol; among which, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 20 microns and second spherical gypsum particles with a D50 of 15 microns; the weight ratio of the first spherical gypsum particles to the second spherical gypsum particles is 1:2.

[0091] Then, the cement raw material with a D50 of 100 microns and the cement raw material grinding aid are mixed at a ratio of 20:1 to obtain a mixture with a bulk density of 2.3 g / cm 3 and the mixture is subjected to a second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 microns. The paste is subjected to a third ball milling for 30 min to obtain the cement raw material. The conditions of the third ball milling are the same as those of the second ball milling.

[0092] Comparative Example 3

[0093] Mix N-vinylpyrrolidone and glycerol and stir at a speed of 60 r / min at 35°C; then add spherical gypsum particles, tetramethylammonium hydroxide and polyvinylpyrrolidone K30 and conduct the first ball milling to obtain the cement raw material grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0094] In Comparative Example 3, based on parts by weight, the cement raw material grinding aid contains 8 parts of spherical gypsum particles, 0.5 part of quaternary ammonium base, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone and 50 parts of glycerol; among them, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 20 microns.

[0095] Then mix the cement raw material with a D50 of 100 microns and the cement raw material grinding aid in a ratio of 20:1 to obtain a mixture with a bulk density of 2.3 g / cm 3 and conduct the second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 microns. Conduct the third ball milling on the paste for 30 min to obtain the cement raw material. The conditions of the third ball milling are the same as those of the second ball milling.

[0096] Comparative Example 4

[0097] Mix N-vinylpyrrolidone and glycerol and stir at a speed of 60 r / min at 35°C; then add spherical gypsum particles, tetramethylammonium hydroxide and polyvinylpyrrolidone K30 and conduct the first ball milling to obtain the cement raw material grinding aid. Among them, the ball-to-material ratio of the first ball milling is 1:2, and the ball milling time is 40 min.

[0098] In Comparative Example 4, based on parts by weight, the cement raw material grinding aid contains 8 parts of spherical gypsum particles, 0.5 part of quaternary ammonium base, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone and 50 parts of glycerol; among them, the spherical gypsum particles contain first spherical gypsum particles with a D50 of 20 microns, second spherical gypsum particles with a D50 of 15 microns, third spherical gypsum particles with a D50 of 5 microns and fourth spherical gypsum particles with a D50 of 0.8 microns; the weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles and the fourth spherical gypsum particles is 1:2:5:5.

[0099] Then mix the cement raw material with a D50 of 100 microns and the cement raw material grinding aid in a ratio of 15:1 to obtain a mixture with a bulk density of 2.0 g / cm 3 and conduct the second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling is 1:2; the diameter of the grinding balls used in the second ball milling is 200 microns. Conduct the third ball milling on the paste for 30 min to obtain the cement raw material. The conditions of the third ball milling are the same as those of the second ball milling.

[0100] Comparative Example 5

[0101] N-vinylpyrrolidone and glycerol were mixed and stirred at a speed of 60 r / min at 35 °C; then spherical gypsum particles, tetramethylammonium hydroxide, and polyvinylpyrrolidone K30 were added and then subjected to the first ball milling to obtain a cement raw meal grinding aid. Among them, the ball-to-material ratio of the first ball milling was 1:2, and the ball milling time was 40 min.

[0102] In Comparative Example 5, by weight, the cement raw meal grinding aid contained 8 parts of spherical gypsum particles, 0.5 part of quaternary ammonium base, 0.6 part of polyvinylpyrrolidone, 50 parts of N-vinylpyrrolidone, and 50 parts of glycerol; among them, the spherical gypsum particles contained first spherical gypsum particles with a D50 of 20 μm, second spherical gypsum particles with a D50 of 15 μm, third spherical gypsum particles with a D50 of 5 μm, and fourth spherical gypsum particles with a D50 of 0.8 μm; the weight ratio of the first spherical gypsum particles, second spherical gypsum particles, third spherical gypsum particles, and fourth spherical gypsum particles was 1:2:5:5.

[0103] Then, the cement raw meal raw material with a D50 of 100 μm and the cement raw meal grinding aid were mixed at a ratio of 35:1 to obtain a mixture with a bulk density of 2.7 g / cm 3 and the mixture was subjected to the second ball milling for 30 min to obtain a paste; the ball-to-material ratio of the second ball milling was 1:2; the diameter of the grinding balls used in the second ball milling was 200 μm. The paste was subjected to the third ball milling for 30 min to obtain the cement raw meal. The conditions of the third ball milling were the same as those of the second ball milling.

[0104] The following table shows the particle sizes of the cement raw meal finally obtained by applying the cement raw meal grinding aids prepared in Examples 1-5 and Comparative Examples 1-5 to raw meal grinding. It can be seen from the following table that the average particle size of the cement raw meal prepared in Examples 1-5 is smaller, and at the same time, the particle size distribution range is very narrow. While the average particle size of the cement raw meal prepared in Comparative Examples 1-5 is larger, and at the same time, the particle size distribution range is wide. It can be seen from the data of Comparative Examples 1-3 that due to the insufficient grading of the spherical gypsum particles, the energy transfer process is interrupted, so that the cement raw meal raw material is difficult to be ground fine and evenly.

[0105] D50 / μm D90 / μm D10 / μm D90 - D10 / μm Example 1 5 12 20 8 Example 2 6 15 25 10 Example 3 5 13 22 9 Example 4 4 12 19 15 Example 5 7 16 22 6 Comparative Example 1 20 12 38 26 Comparative Example 2 22 11 44 33 Comparative Example 3 28 10 46 36 Comparative Example 4 21 12 47 35 Comparative Example 5 30 14 52 38

Claims

1. A cement raw material grinding aid, characterized in that: By weight, it includes 8-12 parts of spherical gypsum particles, 0.1-0.5 parts of quaternary ammonium base, 0.3-0.6 parts of polyvinylpyrrolidone, 30-50 parts of N-vinylpyrrolidone, and 40-50 parts of C2-C4 polyol; The spherical gypsum particles include first spherical gypsum particles with a D50 of 20-25 μm, second spherical gypsum particles with a D50 of 10-15 μm, third spherical gypsum particles with a D50 of 2-5 μm, and fourth spherical gypsum particles with a D50 of 0.5-0.8 μm; The weight ratio of the first spherical gypsum particles, the second spherical gypsum particles, the third spherical gypsum particles, and the fourth spherical gypsum particles is 1-3:2-4:2-5:3-5.

2. The cement raw material grinding aid according to claim 1, characterized in that: By weight, it includes 8-12 parts of spherical gypsum particles, 0.1-0.5 parts of quaternary ammonium base, 0.3-0.6 parts of polyvinylpyrrolidone, 30-50 parts of N-vinylpyrrolidone, and 40-50 parts of glycerol.

3. The cement raw meal grinding aid according to claim 1, characterized in that: The quaternary ammonium base is selected from one of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, or polyethyleneimine; The C2-C4 polyol is selected from one of propylene glycol, glycerol, or pentaerythritol; The polyvinylpyrrolidone is selected from one of K30, K60, or K90.

4. The preparation method of the cement raw material grinding aid according to claim 1, characterized in that: It includes the following steps: Mix N-vinylpyrrolidone and C2-C4 polyol and then stir; Add the spherical gypsum particles, 0.1-0.5 of the quaternary ammonium base, and polyvinylpyrrolidone, and then perform the first ball milling to obtain the product.

5. The preparation method of the cement raw material grinding aid according to claim 4, characterized in that: It includes the step of mixing N-vinylpyrrolidone and C2-C4 polyol and then stirring at 35-45 °C.

6. The preparation method of the cement raw material grinding aid according to claim 4, characterized in that: The stirring speed is 30-60 r / min; The time of the first ball milling is 20-40 min; The ball-to-material ratio of the first ball milling is 1:2-3.

7. The application of the cement raw material grinding aid according to claim 1, characterized in that: It is applied to the grinding of cement raw materials.

8. The application of the cement raw material grinding aid according to claim 7, characterized in that: The grinding includes the following steps: Mix the cement raw material with a D50 of 100-150 μm and the cement raw material grinding aid to obtain a mixture, and perform the second ball milling on the mixture for 30-50 min to obtain a paste; Perform the third ball milling on the paste for 30-50 min to obtain cement raw materials.

9. The application of the cement raw material grinding aid according to claim 8, characterized in that: The weight ratio of the cement raw material to the cement raw material grinding aid is 20-30:1; The bulk density of the mixture is 2.3 - 2.5 g / cm 3 ; The ball-to-material ratio of the second ball milling is 1:2-3; The diameter of the grinding balls used in the second ball milling is 200-500 μm; The ball-to-material ratio of the third ball milling is 1:2-3; The diameter of the grinding balls used in the third ball milling is 200-500 μm.

Images