Steel slag cement grinding aid and its preparation method and application

Abstract

The application discloses a steel slag cement grinding aid, a preparation method and application thereof, and belongs to the technical field of concrete admixtures, and comprises the following raw materials in mass fraction: 80-90% of steel slag, 4-6% of acid solution and 6-14% of magnesium aluminum silicate waste residue. The preparation method comprises the following steps: after the steel slag is crushed, the steel slag is mixed and stirred with the acid solution and the magnesium aluminum silicate waste residue to obtain the steel slag cement grinding aid. The steel slag cement grinding aid prepared by the method has low cost, is non-toxic and non-corrosive, simultaneously improves and enhances the grinding effect of cement products, provides a technical problem solving way for the waste slag discharged by a steel enterprise, achieves energy saving and emission reduction, reduces carbon emission, protects the environment, realizes comprehensive utilization of the waste slag, and is advanced in the preparation method and is widely suitable for use in cement enterprises.

Description

Technical Field

[0001] This invention belongs to the field of concrete admixture technology, and particularly relates to a steel slag cement grinding aid, its preparation method and application. Background Technology

[0002] Steel slag is a blocky, hard, and difficult-to-grind waste residue discharged from steel mills after smelting steel products at temperatures exceeding 1500 degrees Celsius. Its main chemical components and their mass fractions are: CaO 46.31%, SiO2 10.11%, Al2O3 21.42%, fCaO (free calcium oxide) 4.93%, MgO 5.61%, Fe2O3 3.11%, and SO3 1.13%. Long-term stockpiling and landfilling of this steel slag have severely polluted the environment. Currently, there are many successful research cases on developing products using steel slag, but the utilization rate is relatively low. The main reason is that steel slag blocks are large and extremely hard, making them difficult to grind for use in building materials.

[0003] Therefore, how to provide a grinding aid method for steel slag cement to improve its grinding performance and product quality is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a steel slag cement grinding aid, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A steel slag cement grinding aid comprises the following raw materials by mass fraction:

[0007] The composition consists of 80-90% steel slag, 4-6% acid solution, and 6-14% magnesium aluminum silicate waste.

[0008] Preferably, the acid solution is hydrochloric acid with a mass concentration of 36.5%.

[0009] Preferably, the steel slag cement grinding aid contains 1.46-2.19% HCl and 5.63-12.69% MgAl2SiO6 by mass.

[0010] Beneficial Effects: This invention mixes blocky, hard, and difficult-to-grind steel slag with hydrochloric acid and magnesium aluminum silicate to chemically activate the steel slag cement grinding aid. The HCl component in the hydrochloric acid and the MgAl2SiO6 component in the magnesium aluminum silicate adsorb onto the surface of the steel slag particles, reducing their surface energy and causing the near-surface lattice cracks to migrate. This allows the particles to effectively adhere to the inner walls of cracks in the steel slag material, penetrating deeper into the cracks. As cracks form and expand, the HCl and MgAl2SiO6 further promote crack expansion and prevent crack closure, thereby reducing the hardness and grinding difficulty of the steel slag particles and accelerating the particle fracture and loosening process. This results in a steel slag cement grinding aid with both particle loosening and grinding-aiding effects. Furthermore, since this invention uses steel slag, a waste slag discharged from steel enterprises, as the main raw material, it provides a solution for both environmental protection and waste slag resource utilization, making it suitable for widespread application in cement enterprises.

[0011] Furthermore, hydrochloric acid at the aforementioned concentrations exhibits a high acid-base neutralization effect. During the chemical activation of steel slag cement grinding aids, it can provide sufficient and stable H₂O. + Components, making H + It adsorbs more effectively onto the surface of steel slag particles, reducing their surface energy and significantly inducing positional migration of near-surface lattice layers. Simultaneously, this concentration of hydrochloric acid reacts better with the steel slag, promoting crack propagation and preventing crack closure, further reducing the hardness and grinding resistance of the steel slag particles, thereby improving the grinding aid effect and enhancing the performance stability of the steel slag cement grinding aid.

[0012] Preferably, the chemical composition of the steel slag includes the following substances in mass fractions:

[0013] CaO 38.21-46.31%, SiO210.11-15.12%, Al2O321.42-22.51%, fCaO 4.93-5.56%, MgO 5.61-6.02%, Fe2O33.11-3.56%, SO31.13-1.69%.

[0014] Beneficial Effects: The chemical composition of steel slag at specific mass fractions has a significant impact on the performance of steel slag cement grinding aids. A high CaO content provides an abundant calcium source for the grinding aid, which helps form a more stable mineral phase during subsequent mixing with cement and other materials, enhancing the strength and other properties of the cement. The presence of SiO2 and Al2O3 can participate in chemical reactions, regulate the pH of the grinding aid, improve the interaction between the grinding aid and steel slag particles, and further enhance the grinding effect. An appropriate amount of fCaO (free calcium oxide) can, to some extent, activate the activity of steel slag, promoting its grinding and reaction. Components such as MgO and Fe2O3 can also synergistically work with other substances to optimize the chemical composition and physical properties of the grinding aid, resulting in better performance in particle dispersion and grinding aids for steel slag cement.

[0015] Preferably, the mass fraction of MgAl2SiO6 in the magnesium aluminum silicate waste residue is 90-91%.

[0016] Beneficial effects: The high MgAl2SiO6 content (90-91%) in magnesium aluminum silicate waste provides ample active ingredients for steel slag cement grinding aids. MgAl2SiO6 can effectively adsorb onto the surface of steel slag particles, reducing the surface energy of the steel slag particles and reacting with H in acid solutions. + The synergistic effect more strongly induces the positional migration of the near-surface lattice, penetrating deep into the cracks of steel slag particles, promoting crack propagation and preventing crack closure. The high content of MgAl2SiO6 also enhances the particle dispersion effect of the grinding aid, making steel slag particles easier to disperse during grinding, reducing agglomeration, thereby improving the grinding efficiency of steel slag and enhancing the overall performance of the steel slag cement grinding aid.

[0017] A method for preparing a steel slag cement grinding aid includes the following steps:

[0018] The steel slag is crushed and then mixed with acid solution and magnesium aluminum silicate waste to obtain the steel slag cement grinding aid.

[0019] Beneficial effects: This preparation method is simple and easy to implement, requiring no complex equipment or cumbersome processes, greatly reducing production costs and time. During the mixing process, the raw materials can fully contact and react, chemically activating the steel slag and allowing the H in the acid solution to react. + The effective components in magnesium aluminum silicate waste are uniformly adsorbed on the surface of steel slag particles, realizing the position migration of the near-surface layer lattice, promoting the formation and propagation of cracks, thereby rapidly preparing a steel slag cement grinding aid with good particle dispersion and grinding aid effect, which is suitable for large-scale industrial production.

[0020] Preferably, the crushing is performed to crush the particles to a size of 1-3 mm.

[0021] Beneficial effects: The purpose of crushing is to obtain steel slag into reasonably uniform fine particles. After crushing, the fine particles are mixed and stirred to form new mineral lattice positions and new active factors or molecular clusters. The steel slag cement grinding aid product is simple, has extremely low cost, high grinding efficiency, and is easy to implement.

[0022] Preferably, the mixing time is 5-8 minutes.

[0023] Beneficial effects: Within the above range, the raw materials can be fully mixed and reacted. During this time period, the H+ in the acid solution... + The effective components in magnesium aluminum silicate waste have sufficient time to adsorb onto the surface of steel slag particles, inducing near-surface lattice migration, promoting crack propagation and preventing crack closure, thereby achieving the best grinding aid effect. At the same time, it avoids energy waste and potential over-reaction caused by excessive stirring time, improving production efficiency and reducing production costs while ensuring the performance of the grinding aid.

[0024] Application of a steel slag cement grinding aid in cement grinding aids.

[0025] Beneficial effects: The steel slag cement grinding aid of the present invention can replace commonly used liquid cement grinding aids and other grinding aid products. Compared with commonly used liquid cement grinding aids, the steel slag cement grinding aid of the present invention can significantly increase cement strength, specific surface area, reduce cement water demand, increase particle flowability and cement compatibility, and significantly improve cement production through grinding aid.

[0026] Preferably, the amount of steel slag cement grinding aid added is 0.8-1% of the cement mass.

[0027] Beneficial Effects: Adding the steel slag cement grinding aid obtained in this invention to cement products in a certain proportion can provide external factors or molecular clusters to neutralize unsaturated valence bonds on the cross-sections of cement particles, eliminate or weaken the attraction between the cross-sections of cement particles, and prevent fine cement powder from adhering to the surface of coarse particles or agglomerating together, thereby improving grinding efficiency. Simultaneously, the surface-active components of the steel slag cement grinding aid form a monomolecular adsorption film on the surface of cement particles, reducing particle agglomeration and adhesion between particles and grinding mill baffles and liners, thus improving the flowability of cement products. This significantly increases the speed at which materials continuously pass through the mill, improving the grinding effect of cement products. Experimental results show that directly adding 0.8-1% of the steel slag cement grinding aid provided in this invention to cement grinding production improves the grinding and strengthening effect of cement, and is non-toxic and non-corrosive, helping to increase cement yield and quality, and further reducing cement production costs.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] The steel slag cement grinding aid prepared by the method provided in this invention is low in cost, non-toxic, and non-corrosive. It also improves the surface activity of cement particles, forming a monomolecular adsorption film on the particle surface, reducing particle agglomeration and adhesion between particles and grinding mill baffles and liners. This improves the flowability of cement products, significantly increasing the speed at which materials continuously pass through the mill, and enhancing the grinding effect of cement products. The technical effect of the steel slag cement grinding aid of this invention is superior to common commercially available liquid grinding aids. It also provides a new solution for the disposal of steel slag waste from steel enterprises, achieving energy conservation, emission reduction, carbon emission reduction, environmental protection, and comprehensive utilization of waste resources. Furthermore, the advanced preparation method is widely applicable to cement enterprises. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0032] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels;

[0033] The main chemical composition of the steel slag is as follows: CaO 46.31%, SiO2 10.11%, Al2O3 21.42%, fCaO 4.93%, MgO 5.61%, Fe2O3 3.11%, SO3 1.13%;

[0034] The mass fraction of MgAl2SiO6 in the magnesium aluminum silicate waste residue is 90.6%;

[0035] The concentration of hydrochloric acid is 36.5%.

[0036] The commercially available grinding aid was purchased from Anhui Tianchang Technology Co., Ltd.

[0037] Unless otherwise specified, room temperature or normal temperature in the embodiments of the present invention refers to 25±3℃.

[0038] Example 1

[0039] A method for preparing a steel slag cement grinding aid includes the following steps:

[0040] Steel slag waste is crushed into fine particles of 1-3mm using a crusher. Then, by mass fraction, steel slag (80%), hydrochloric acid (6%), and magnesium aluminum silicate waste (14%) are added to a mixer and mixed for 5 minutes to obtain the steel slag cement grinding aid product.

[0041] The obtained steel slag cement grinding aid contains 2.19% HCl by mass (i.e., the concentration of hydrochloric acid used is 36.5%) and 12.68% MgAl2SiO6 by mass (i.e., the mass fraction of MgAl2SiO6 in magnesium aluminum silicate waste is 90.57%).

[0042] The obtained steel slag cement grinding aid was used to directly replace the liquid cement grinding aid on the market as a cement grinding aid. The dosage was 0.8% and 1% of the cement mass. It was used to prepare cement for grinding. The quality technical indicators of the cement product were tested according to the technical requirements of the national standard GB / T175-2023 General Cement Standard. The specific surface area, standard consistency, setting time, mortar fluidity, compatibility, strength and grinding efficiency of the cement after grinding were tested. The test results are shown in Table 1.

[0043] Table 1. Comparison of Physical Properties and Grinding Efficiency of Steel Slag Cement Grinding Aids and Commercial Liquid Grinding Aids

[0044]

[0045] As shown in Table 1, the steel slag cement grinding aid obtained in this invention can significantly improve cement grinding efficiency. Compared with commercially available grinding aids, Example 1 increases hourly output by 64-75 tons, increases specific surface area by 101-124 g / kg, reduces water demand by 20-40%, increases mortar fluidity by 103-110 mm, increases compatibility by 65-80 mm, and advances setting time by approximately 10-20 minutes. Furthermore, it increases cement flexural and compressive strength at 3 days and 28 days by 0.6-0.8 MPa, 0.7-1.0 MPa, 7.0-9.1 MPa, and 4.1-8.4 MPa, respectively. Compared with cement products without grinding aids, Example 1 increases hourly output by 70-80 tons and increases specific surface area by 111-130 m² / kg. 2 / kg, reducing water demand by 20-40%, increasing mortar fluidity by 100-105mm, increasing compatibility by 60-75mm, and advancing setting time by approximately 0-5 minutes. Furthermore, it increases cement flexural and compressive strength by 0.4-0.8MPa, 0.7-1.0MPa, 7.0-9.1MPa, and 4.1-8.4MPa at 3 days and 28 days, respectively, far exceeding the product quality and hourly output of cement produced without grinding aids and with commercially available liquid grinding aids.

[0046] Example 2

[0047] A method for preparing a steel slag cement grinding aid includes the following steps:

[0048] Steel slag waste is crushed into fine particles of 1-3mm using a crusher. Then, by mass fraction, steel slag (85%), hydrochloric acid (5%), and magnesium aluminum silicate waste (10%) are added together to a mixer and mixed for 6 minutes to obtain the steel slag cement grinding aid product.

[0049] The obtained steel slag cement grinding aid contains 1.83% HCl and 9.1% MgAl2SiO6 by mass.

[0050] The obtained steel slag cement grinding aid was used to directly replace the liquid cement grinding aid on the market as a cement grinding aid. The dosage was 0.8% and 1% of the cement mass. It was used to prepare cement for grinding. The quality technical indicators of the cement product were tested according to the technical requirements of the national standard GB / T175-2023 General Cement Standard. The specific surface area, standard consistency, setting time, mortar fluidity, compatibility, strength and grinding efficiency of the cement after grinding were tested. The test results are shown in Table 2.

[0051] Table 2. Comparison of Physical Properties and Grinding Efficiency of Steel Slag Cement Grinding Aids and Commercial Liquid Grinding Aids

[0052]

[0053] As shown in Table 2, the steel slag cement grinding aid obtained in this invention has good grinding enhancement and yield-increasing effects on cement. Compared with commercially available grinding aids, Example 2 can significantly increase the specific surface area of ​​cement by 76-116 m². 2 / kg, reducing cement water demand by 25-45%, increasing fluidity by 123-125mm, compatibility by 80-105mm, and setting time by approximately 15-30 minutes. Simultaneously, it increases cement flexural strength by 0.6-1.2MPa at 3 days and 0.7-1.3MPa at 28 days, increases compressive strength by 6.8-10.9MPa at 3 days and 4.8-9.5MPa at 28 days, and increases hourly output by 74-84 tons. Compared to cement products without grinding aids, Example 2 significantly increases the specific surface area of ​​cement by 94-130m². 2 / kg, reducing cement water demand by 25-45%, increasing fluidity by 118-120mm, compatibility by 80-95mm, and setting time by approximately 15-20 minutes. Simultaneously, it increases cement flexural strength by 0.5-1.2MPa at 3 days and 0.7-1.2MPa at 28 days, increases compressive strength by 7.0-9.2MPa at 3 days and 5.2-9.6MPa at 28 days, and increases hourly output by 79-89 tons.

[0054] Example 3

[0055] A method for preparing a steel slag cement grinding aid includes the following steps:

[0056] Steel slag waste is crushed into fine particles of 1-3mm using a crusher. Then, by mass fraction, steel slag (90%), hydrochloric acid (4%), and magnesium aluminum silicate waste (6%) are added to a mixer and mixed for 8 minutes to obtain the steel slag cement grinding aid product.

[0057] The obtained steel slag cement grinding aid contains 1.46% HCl and 5.43% MgAl2SiO6 by mass.

[0058] The obtained steel slag cement grinding aid was used to directly replace the liquid cement grinding aid on the market as a cement grinding aid. The dosage was 0.8% and 1% of the cement mass. It was used to prepare cement for grinding. The quality technical indicators of the cement product were tested according to the technical requirements of the national standard GB / T175-2023 General Cement Standard. The specific surface area, standard consistency, setting time, mortar fluidity, compatibility, strength and grinding efficiency of the cement after grinding were tested. The test results are shown in Table 3.

[0059] Table 3 Comparison of Physical Properties and Grinding Efficiency of Steel Slag Cement Grinding Aids and Commercially Available Liquid Grinding Aids for Different Cement Types

[0060]

[0061] As shown in Table 3, the steel slag cement grinding aid obtained by this invention has the characteristics of strong adaptability, stable performance, and significant grinding aid and strengthening effects. Compared with commercially available grinding aids, Example 2 can increase the specific surface area by 82-103 m². 2 / kg, reducing cement water demand by 30-45%, increasing mortar fluidity by 114-124mm and compatibility by 76-94mm, advancing setting time by approximately 4-15 minutes, increasing cement strength by 0.9-1.3MPa and 0.8-1.1MPa at 3 days and 28 days respectively, increasing cement compressive strength by 8.9-11.1MPa and 6.2-9.6MPa at 3 days and 28 days respectively, and increasing hourly output by 83-93 tons; compared to cement products without grinding aids, Example 3 can increase specific surface area by 100-120m². 2 / kg, reducing cement water demand by 30-45%, increasing mortar fluidity by 113-123mm and compatibility by 70-85mm, advancing setting time by approximately 5-20 minutes, increasing cement strength by 0.8-1.1MPa and 0.8-1.0MPa at 3 days and 28 days respectively, increasing cement compressive strength by 8.9-11.0MPa and 6.1-9.2MPa at 3 days and 28 days respectively, and increasing hourly output by 83-93 tons.

[0062] Comparative Example 1

[0063] A method for preparing a steel slag cement grinding aid, differing from Example 1 only in that magnesium aluminum silicate waste slag is replaced with aluminum ash slag, includes the following steps:

[0064] Steel slag waste is crushed into fine particles of 1-3mm using a crusher. Then, by mass fraction, steel slag (80%), hydrochloric acid (6%), and aluminum ash slag (14%) are added to a mixer and mixed for 5 minutes to obtain the steel slag cement grinding aid product.

[0065] Comparative Example 2

[0066] A method for preparing a steel slag cement grinding aid, differing from Example 1 only in that hydrochloric acid is replaced with 36.5% sulfuric acid, includes the following steps:

[0067] Steel slag waste is crushed into fine particles of 1-3mm using a crusher. Then, by mass fraction, steel slag (80%), sulfuric acid (6%), and magnesium aluminum silicate waste (14%) are added together to a mixer and mixed for 5 minutes to obtain the steel slag cement grinding aid product.

[0068] Comparative Example 3

[0069] A method for preparing a steel slag cement grinding aid, differing from Example 1 only in that a portion of the magnesium aluminum silicate waste slag is replaced with aluminum ash slag, includes the following steps:

[0070] Steel slag waste is crushed into fine particles of 1-3mm using a crusher. Then, by mass fraction, steel slag (80%), hydrochloric acid (6%), magnesium aluminum silicate waste (10%), and aluminum ash (4%) are added to a mixer and mixed for 5 minutes to obtain the steel slag cement grinding aid product.

[0071] Technical effects:

[0072] The grinding aids obtained from Comparative Examples 1-3 were used to directly replace liquid cement grinding aids on the market as cement grinding aids, with an addition amount of 0.8% and 1% of the cement mass, respectively. They were used to prepare cement for grinding. The quality technical indicators of the cement products were tested according to the technical requirements of the national standard GB / T175-2023 General Cement Standard, including specific surface area, standard consistency, setting time, mortar fluidity, compatibility, strength, and grinding efficiency after cement grinding. The test results are shown in Table 4.

[0073] Table 4. Comparison of Physical Properties and Grinding Efficiency of Steel Slag Cement Grinding Aids and Commercial Liquid Grinding Aids

[0074]

[0075] A comparison of Table 4 with Tables 1-3 shows that the steel slag cement grinding aid prepared by Comparative Example 1 using 80% steel slag, 6% hydrochloric acid, and 14% aluminum ash; Comparative Example 2 using 80% steel slag, 6% sulfuric acid, and 14% magnesium aluminum phosphate ash; and Comparative Example 3 using 30% steel slag, 6% hydrochloric acid, 10% magnesium aluminum phosphate ash, and 4% aluminum ash has a technical effect far lower than that of the present invention, but is comparable to the technical effect of grinding aids on the market.

[0076] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A steel slag cement grinding aid, characterized in that, Raw materials including the following mass fractions: Steel slag 80-90%, acid solution 4-6%, and magnesium aluminum silicate waste slag 6-14%; The acid solution is hydrochloric acid with a mass concentration of 36.5%; The steel slag cement grinding aid contains 1.46-2.19% HCl and 5.63-12.69% MgAl2SiO6 by mass.

2. The preparation method of the steel slag cement grinding aid as described in claim 1, characterized in that, Includes the following steps: The steel slag is crushed and then mixed with acid solution and magnesium aluminum silicate waste to obtain the steel slag cement grinding aid.

3. The method for preparing a steel slag cement grinding aid according to claim 2, characterized in that, The crushing refers to crushing to a particle size of 1-3 mm.

4. The method for preparing a steel slag cement grinding aid according to claim 2, characterized in that, The mixing and stirring time is 5-8 minutes.

5. The application of the steel slag cement grinding aid as described in claim 1 in cement grinding aids.

6. The application according to claim 5, characterized in that, The amount of steel slag cement grinding aid added is 0.8-1% of the cement mass.

Images