A slag grinding aid and a method for preparing the same

Abstract

The application provides a slag grinding aid and a preparation method thereof, and the slag grinding aid comprises the following components in percentage by mass: 2-8% of polyaluminum, 20-40% of methoxy polyethylene glycol derivative, 1-5% of phosphate, and the rest is water. The slag grinding aid can improve the grindability and activity of the slag, and can significantly increase the content of 0-3 mu m particles in the slag.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a slag grinding aid and its preparation method. Background Technology

[0002] Slag is a waste product generated during iron and steel smelting. Its glassy structure, formed through rapid water quenching at high temperatures, makes it unstable and possesses significant potential chemical energy. However, the glassy structure is very dense, resulting in low reactivity and preventing direct application in building materials such as cement and concrete. While ground slag powder exhibits better reactivity, its poor grindability is due to the large amount of glass in it.

[0003] With the continuous development of my country's national economic construction, the demand for mineral powder, as a high-quality concrete admixture and cementitious material, is increasing. Mineral powder, as an admixture, not only reduces production costs but also has considerable economic value. Furthermore, it can utilize slag resources to address environmental issues. However, the high power consumption and difficulty in grinding ultrafine slag have become a bottleneck restricting the development of the slag powder industry.

[0004] Due to its unique glassy structure, slag differs significantly from crystalline clinker in properties. Slag lacks stress concentration points, making it more difficult to grind. While clinker requires deagglomeration, slag requires disrupting its surface silica-oxygen network structure. Therefore, grinding aids used in cement may not be suitable for slag. Existing grinding aids, when added to the slag grinding process, can address the agglomeration around slag particles, but they do not improve the grindability of the slag particles themselves, resulting in a less than ideal grinding effect. Therefore, exploring slag grinding aids to address the aforementioned problem of difficult slag grinding is of significant research and application value. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a slag grinding aid and its preparation method. The slag grinding aid can improve the grindability and activity of slag, and the preparation method is simple.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] In a first aspect, the present invention provides a slag grinding aid, comprising, by mass percentage, the following components: 2% to 8% polyaluminum, 20% to 40% methoxy polyethylene glycol derivative, 1% to 5% phosphate, and the remainder being water.

[0008] Furthermore, the methoxy polyethylene glycol derivative is any one or a combination of several of methoxy polyethylene glycol amine, methoxy polyethylene glycol azide, and methoxy polyethylene glycol maleamide.

[0009] Furthermore, the phosphate is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate.

[0010] Furthermore, the slag grinding aid comprises, by weight percentage, the following components: 3%–7% polyaluminum, 25%–35% methoxy polyethylene glycol derivative, 2%–4% phosphate, and the remainder being water.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned slag grinding aid, wherein each component is weighed according to the mass percentage, and the components are stirred and mixed to obtain the above-mentioned slag grinding aid.

[0012] Furthermore, the stirring conditions are: a rotation speed of 300–450 r / min and a stirring time of 20–35 min.

[0013] Thirdly, the present invention provides a method for using the above-mentioned slag grinding aid, wherein the dosage of the above-mentioned slag grinding aid is 0.03% to 0.1% of the slag mass.

[0014] The principle of this invention is as follows:

[0015] Polyaluminum is cross-linked polymerized through hydroxyl groups, resulting in a large number of hydroxyl groups in the molecule. During slag grinding, the oxygen atoms in the hydroxyl groups can be adsorbed at the interface of slag particle fracture, acting as a "wedge" to cause the surface lattice position to migrate, reducing the strength and hardness of the particles and shielding the charge on the fracture surface of the slag particles, thus aiding grinding. Subsequently, aluminum hydroxyl ions are adsorbed on the surface of slag particles, accelerating the aluminum polymerization reaction of the slag, crystallizing and precipitating a loose silicon-aluminum phase, weakening and softening the glassy structure of the slag, enhancing the grindability of the slag, and reducing the "shielding effect" of the slag surface products. This enhances the ion migration ability and distance on the slag surface, promoting the continuous hydration of the slag.

[0016] The methoxy polyethylene glycol derivative has a hydrophobic polymethyl structure on one side and contains nitrogen on the other, exhibiting excellent surface activity, reducing surface tension, and significantly increasing polar surface energy. The repulsion between particles with the same charge prevents them from approaching each other and agglomerating. The methyl structure, exposed outside the slag particles, shields the cross-sectional charge of the particles, and its strong steric hindrance further reduces the aggregation of finely ground particles, improving grinding efficiency. The presence of unshared electron pairs on the nitrogen atom promotes complexation between the compound and metal ions in the slurry, increasing the solubility of metal ions in the slurry and accelerating their diffusion. This accelerates the dissolution rate of intermediate minerals and enhances the slag activity.

[0017] Free metal ions in phosphates can enter the lattice pores or replace ions in the lattice, further distorting the mineral lattice, accelerating the breaking of chemical bonds within the mineral material, reducing particle agglomeration, and improving the grinding effect.

[0018] The oxygen atoms in the polyaluminum in the grinding aid adsorb onto the surface of slag particles, while the hydroxyl groups act as bridges, connecting the methoxy polyethylene glycol derivative and phosphate to adsorb onto the slag particle surface. The synergistic effect of these three components enhances the grinding performance of the system and improves the grindability of the slag. The polyaluminum in the system weakens the "masking effect" of the slag surface products, enhances the ion migration ability and distance on the slag surface, and promotes the continuous hydration of the slag. The methoxy polyethylene glycol derivative can form water-soluble chelates with the cations in the slag hydration system, forming many fusible points on the slag surface, resulting in a faster reaction rate and improved density. The phosphate breaks the chemical bonding bonds of the slag components, Si-O-Si and Ca-O, forming colloidal structural units with lower stability. The accumulation of these lower-stability colloidal structural units forms aggregates, which in turn form a denser structure. The synergistic effect of these three components enhances the activity of the slag.

[0019] The beneficial effects of this invention are as follows:

[0020] 1) The slag grinding aid provided by this invention has a synergistic effect of polyaluminum, methoxy polyethylene glycol derivative and phosphate, which can eliminate the agglomeration around slag particles, destroy the glassy structure of slag, improve the grindability of slag particles, and have excellent grinding aid effect. It can significantly increase the content of 0-3μm particles in slag.

[0021] 2) The synergistic effect of polyaluminum, methoxy polyethylene glycol derivatives and phosphate in the slag grinding aid provided by the present invention enhances the ion migration ability and distance on the slag surface, promotes the continuous hydration of slag, and thus forms a denser structure and improves the activity of slag.

[0022] 3) The raw materials of the slag grinding aid of the present invention are simple and readily available, and the preparation method is simple, efficient, safe and environmentally friendly, with good controllability and easy to industrialize. Detailed Implementation

[0023] The principles and features of the present invention are described below with reference to specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0024] It should be noted that, in the description of the embodiments of this application, the term "some specific embodiments" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same implementation or instance. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0025] This invention provides a slag grinding aid, comprising the following components by mass percentage: 2%–8% polyaluminum, 20%–40% methoxy polyethylene glycol derivative, 1%–5% phosphate, and the remainder being water.

[0026] In some specific embodiments, the methoxy polyethylene glycol derivative is any one or a combination of several of methoxy polyethylene glycol amine, methoxy polyethylene glycol azide, and methoxy polyethylene glycol maleamide.

[0027] In some specific embodiments, the phosphate is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate.

[0028] In some specific embodiments, the slag grinding aid comprises, by weight percentage, the following components: 3%–7% polyaluminum, 25%–35% methoxy polyethylene glycol derivative, 2%–4% phosphate, and the remainder being water.

[0029] The present invention provides a method for preparing the above-mentioned slag grinding aid, wherein each component is weighed according to the mass percentage, and the components are stirred and mixed to obtain the above-mentioned slag grinding aid.

[0030] Preferably, the stirring conditions are: a rotation speed of 300-450 r / min and a stirring time of 20-35 min.

[0031] The present invention also provides a method for using the above-mentioned slag grinding aid, wherein the dosage of the above-mentioned slag grinding aid is 0.03% to 0.1% of the slag mass.

[0032] Based on the above embodiments, the present invention provides the following specific examples to further illustrate the invention. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following examples, unless otherwise specified, are generally performed according to the manufacturer's recommended conditions. Unless otherwise stated, percentages and parts are calculated by mass.

[0033] Example 1

[0034] 77g of water, 2g of polyaluminum, 20g of methoxy polyethylene glycolamine, and 1g of sodium tripolyphosphate were added sequentially into a container and stirred at 300r / min for 20min to obtain the grinding aid that improves the grindability and activity of slag.

[0035] Example 2

[0036] 73g water, 2g polyaluminum, 20g methoxy polyethylene glycol amine, and 5g sodium tripolyphosphate were added sequentially into a container and stirred at 450r / min for 35min to obtain the grinding aid that improves the grindability and activity of slag.

[0037] Example 3

[0038] 71g of water, 8g of polyaluminum, 20g of methoxy polyethylene glycol azide, and 1g of sodium hexametaphosphate were added sequentially into a container and stirred at 300r / min for 20min to obtain the grinding aid that improves the grindability and activity of slag.

[0039] Example 4

[0040] 67g of water, 8g of polyaluminum, 20g of methoxy polyethylene glycol maleamide, and 5g of sodium hexametaphosphate were added sequentially into a container and stirred at 300r / min for 20min to obtain the grinding aid that improves the grindability and activity of slag.

[0041] Example 5

[0042] 57g of water, 2g of polyaluminum, 40g of methoxy polyethylene glycolamine, and 1g of sodium tripolyphosphate were added sequentially into a container and stirred at 400r / min for 25min to obtain the grinding aid that improves the grindability and activity of slag.

[0043] Example 6

[0044] 53g of water, 2g of polyaluminum, 40g of methoxy polyethylene glycol amine azide, and 5g of sodium tripolyphosphate were added sequentially into a container and stirred at 400r / min for 35min to obtain the grinding aid that improves the grindability and activity of slag.

[0045] Example 7

[0046] 51g of water, 8g of polyaluminum, 40g of methoxy polyethylene glycolamine, and 1g of sodium tripolyphosphate were added sequentially into a container and stirred at 350r / min for 30min to obtain the grinding aid that improves the grindability and activity of slag.

[0047] Example 8

[0048] 47g of water, 8g of polyaluminum, 40g of methoxy polyethylene glycol amine, and 5g of sodium hexametaphosphate were added sequentially into a container and stirred at 325r / min for 22min to obtain the grinding aid that improves the grindability and activity of slag.

[0049] Example 9

[0050] 62g of water, 5g of polyaluminum, 30g of methoxy polyethylene glycolamine, and 3g of sodium tripolyphosphate were added sequentially into a container and stirred at 375r / min for 33min to obtain the grinding aid that improves the grindability and activity of slag.

[0051] Example 10

[0052] 70g water, 3g polyaluminum, 25g methoxy polyethylene glycol amine, and 2g sodium pyrophosphate were added sequentially into a container and stirred at 350r / min for 30min to obtain the grinding aid that improves the grindability and activity of slag.

[0053] Example 11

[0054] 54g water, 7g polyaluminum, 35g methoxy polyethylene glycolamine, 2g sodium tripolyphosphate, and 2g sodium hexametaphosphate were added sequentially into a container and stirred at 350r / min for 30min to obtain the grinding aid that improves the grindability and activity of slag.

[0055] Example 12

[0056] 54g water, 7g polyaluminum, 35g methoxy polyethylene glycolamine, 2g sodium tripolyphosphate, 1g sodium hexametaphosphate, and 1g sodium pyrophosphate were added sequentially into a container and stirred at 350r / min for 30min to obtain the grinding aid that improves the grindability and activity of slag.

[0057] Comparative Example 1

[0058] Repeat Example 2, replacing an equal amount of phosphate with water, while keeping other conditions unchanged, to obtain Mixture 1.

[0059] Comparative Example 2

[0060] Repeat Example 4, replacing an equal amount of the methoxy polyethylene glycol derivative with water, while keeping other conditions unchanged, to obtain mixture 2.

[0061] Comparative Example 3

[0062] Repeat Example 5, replacing an equal amount of polyaluminum with water, while keeping other conditions unchanged, to obtain mixture 3.

[0063] The slag grinding aids prepared in Examples 1-12, the mixtures prepared in Comparative Examples 1-3, and a commercially available slag grinding aid were tested and evaluated.

[0064] 1. Referring to the test methods in GB / T 12957-2005 "Test Method for Activity of Industrial Waste Slag Used in Cement Admixtures", 5 kg of slag raw material was added to a small test mill. Before grinding, a slag grinding aid was added to the slag raw material, and the grinding time was fixed at 30 min. Further comparative evaluations were conducted with polyaluminum, methoxy polyethylene glycol derivatives, phosphates, a commercially available slag grinding aid, and a blank sample without slag grinding aid. The dosage of each slag grinding aid was 0.05% (percentage of total slag mass). Particle size distribution tests were performed on the milled samples using a particle size analyzer. The results are shown in Table 1.

[0065] Table 1 Particle size distribution of samples after milling

[0066]

[0067] As shown in Table 1, the slag grinding aid prepared in this invention significantly increased the particle content in the 0–3 μm range during slag grinding compared to the control group. This increase in particle content in the 0–3 μm range indicates that the grinding aid prepared in this invention, which enhances the grindability and activity of slag, effectively improves the grindability of the slag.

[0068] In the IGC test, the acid and base components of the polar surface energy of the pulverized slag particles were determined by the basic probe molecule ethyl acetate (EtOAc, γp-=0, γp+=475.67mJ / m2) and the acidic probe molecule dichloromethane (DCM, γp-=124.58mJ / m2, γp+=0), which have known characteristic parameters. The polar surface energy can be obtained by summing them. The results are shown in Table 2.

[0069] Table 2 Average Polar Surface Energy of Samples

[0070] serial number <![CDATA[Average polar surface energy / (mJ·mm -2 )]]> blank sample 16.9336 Polyaluminum 21.3956 Methoxylated polyethylene glycolamine 28.4357 phosphate 27.0124 Commercially available slag grinding aids 27.3025 Example 1 32.1923 Example 2 31.8645 Example 3 31.9275 Example 4 30.9586 Example 5 32.1811 Example 6 31.5876 Example 7 32.1052 Example 8 30.6953 Example 9 31.5275 Example 10 32.0154 Example 11 32.8846 Example 12 32.2014 Comparative Example 1 30.1020 Comparative Example 2 30.2411 Comparative Example 3 29.9869

[0071] As can be seen from Table 2, the slag grinding aid prepared in this invention significantly increased the average polar surface energy of the slag compared with the blank group, indicating that the slag grinding aid prepared in this invention effectively improved the grinding performance of the slag.

[0072] 2. Take the prepared pulverized slag, add water to prepare a slurry with a water-cement ratio of 0.28, place the slurry in a sealed container, stir with a magnetic stirrer for 60 min, then centrifuge at 3000 r / min for 10 min. Take the supernatant and filter it through a 0.22 μm filter membrane. Then add nitric acid to adjust the pH of the solution to 5-6. Use a Thermo Fisher|iCAP PRO X inductively coupled plasma atomic emission spectrometer to determine the aluminum ion concentration in the solution. The pulverized slag included is the blank group without grinding aid, and the pulverized slag obtained by grinding with the slag grinding aid prepared in Examples 1-12, the mixture prepared in Comparative Examples 1-3, and a commercially available slag grinding aid, respectively. The aluminum ion concentration in the liquid phase of the slurry during the hydration process of the slag was measured, and the results are shown in Table 3.

[0073] Table 3 Aluminum ion concentration in samples

[0074] serial number Aluminum ion concentration / mmol / L blank sample 0.05 Polyaluminum 0.06 methoxy polyethylene glycol derivatives 0.08 phosphate 0.07 Commercially available slag grinding aids 0.07 Example 1 0.21 Example 2 0.18 Example 3 0.17 Example 4 0.19 Example 5 0.16 Example 6 0.18 Example 7 0.15 Example 8 0.17 Example 9 0.21 Example 10 0.26 Example 11 0.22 Example 12 0.21 Comparative Example 1 0.13 Comparative Example 2 0.11 Comparative Example 3 0.14

[0075] As can be seen from Table 3, the slag grinding aid prepared in this invention significantly increased the concentration of aluminum ions in the liquid phase of the slurry during slag hydration compared with the blank group. The increased concentration of aluminum ions in the liquid phase of the slurry during slag hydration indicates that the slag grinding aid prepared in this invention effectively promotes the dissolution and hydration of metal ions in the mineral phase of slag.

[0076] 3. Referring to the test method in GB / T 12957-2005 "Test Method for Activity of Industrial Waste Residue Used in Cement Blends", 30% mineral powder was added to silicate cement. The activity level was determined by comparing the 28-day compressive strength of the mineral powder with that of the silicate cement. The results are shown in Table 4.

[0077] Table 4 Sample Activity

[0078]

[0079]

[0080] As can be seen from Table 4, the slag grinding aid of the present invention can significantly improve the activity of slag compared with the blank control.

[0081] Compared with the comparative example, the slag grinding aid of the present invention, when used for slag grinding, has higher content of 0-3μm particles, average polar surface energy, aluminum ion concentration and activity in the slag, indicating that the synergistic effect between the components of the slag grinding aid of the present invention can improve the grindability and activity of the slag.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A slag grinding aid, characterized in that, By mass percentage, it includes the following components: Polyaluminum 2%~8%; 20%~40% methoxy polyethylene glycol derivatives; Phosphate 1%~5%; The rest is water; The methoxy polyethylene glycol derivative is any one or a combination of several of methoxy polyethylene glycol amine, methoxy polyethylene glycol azide, and methoxy polyethylene glycol maleamide. The phosphate is one or a combination of sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate.

2. The slag grinding aid according to claim 1, characterized in that, By mass percentage, it includes the following components: Polyaluminum 3%~7%; 25%~35% methoxy polyethylene glycol derivatives; Phosphate 2%~4%; The rest is water.

3. The method for preparing the slag grinding aid according to claim 1 or 2, characterized in that, Weigh each component according to its mass percentage, stir and mix them thoroughly to obtain the slag grinding aid.

4. The method for preparing the slag grinding aid according to claim 3, characterized in that, The stirring conditions are: a rotation speed of 300~450 r / min and a stirring time of 20~35 min.

5. The method of using the slag grinding aid according to claim 1 or 2, characterized in that, The dosage of the slag grinding aid is 0.03% to 0.1% of the slag mass.

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