Steel slag, slag grinding activator and preparation method and application thereof

Abstract

The application discloses a steel slag and slag grinding aid activator and belongs to the technical field of building materials. The steel slag and slag grinding aid activator comprises the following raw materials in percentage by mass: grinding modifier 40-60%, grinding dispersant 2-15% and inorganic salt 35-45%. The grinding modifier is composed of ethylenediamine tetramethylene phosphonic acid, triethanolamine, zinc bromide and hydroquinone in a mass ratio of (30-40):(50-60):(1-5):(1-5). The grinding dispersant is naphthalene sulfonate formaldehyde condensate or / and triisopropanolamine. The inorganic salt comprises sodium sulfate and sodium carbonate. The grinding aid activator can significantly improve the grinding efficiency of the steel slag and slag composite system, enhance the early strength of the system and improve the volume stability of the system.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a steel slag and ore slag grinding aid activator, its preparation method and application. Background Technology

[0002] Slag is a byproduct of the ironmaking process in blast furnaces, produced by the reaction of impurities such as silica and alumina with lime, accounting for 25-30% of iron production. Steel slag is a solid waste generated in large quantities during steelmaking, produced by extracting impurities with lime, accounting for 8-15% of crude steel production. Effectively utilizing slag and steel slag in the production of building materials is one of the effective means of large-scale disposal of metallurgical solid waste. In recent decades, slag has gradually become a major mineral admixture in concrete production, while the comprehensive utilization rate of steel slag needs to be improved due to its poor hydration properties and uncertain stability.

[0003] The main components of steel slag include calcium oxide, silicon dioxide, aluminum oxide, iron oxide, ferric oxide, magnesium oxide, manganese oxide, and phosphorus pentoxide. Its mineral crystals are dense, primarily composed of tricalcium silicate, followed by dicalcium silicate, RO phase (a broad solid solution formed mainly of FeO, MgO, and other divalent metal oxides such as MnO), dicalcium ferrite, and free calcium oxide. The large grain size results in slow hydration and low hydration activity. Furthermore, steel slag has high strength and a hard texture, making it difficult to grind. The powder formed has a crystalline or glassy core. In the later stages of grinding, the amorphous layer on the particle surface thickens, preventing direct grinding action on the particle interior and increasing the grinding difficulty. Simultaneously, the continuous collisions and compression between particles easily cause agglomeration of fine particles, further increasing the grinding challenge. In addition, the free calcium oxide and free magnesium oxide contained in steel slag have micro-expansion properties, which can affect the stability of the system and easily lead to volume expansion during hydration, resulting in reduced early strength and ultimately limiting the application of steel slag in mortar and concrete.

[0004] The main raw materials of existing grinding aids are amines, alcohols (such as ethylene glycol and glycerol), lignin sulfonates, fatty acids and their salts, and alkyl sulfonates. The main function of these grinding aids is to improve particle dispersibility and reduce agglomeration, thereby improving powder performance. For example, Chinese patent CN113003981B discloses a grinding aid for ultrafine composite mineral admixtures and its preparation method, with modified polyhydroxy alcohol amines, sugars, and inorganic salts as the main raw materials. This grinding aid can effectively reduce the specific surface energy of ultrafine admixture particles and reduce agglomeration. However, the shortcomings of low early strength and poor volume stability of steel slag after hydration have not been improved. Related research shows that there is a synergistic hydration effect between steel slag and blast furnace slag. Mixing and grinding steel slag and blast furnace slag will increase the application of steel slag in the concrete industry. Therefore, the development of low-cost, high-performance grinding aids for steel slag and blast furnace slag that can effectively eliminate the micro-expansion of steel slag is urgently needed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a grinding aid activator for steel slag and ore slag, which can significantly improve the grinding efficiency of the steel slag and ore slag composite system, enhance the early strength of the system, and also improve the volume stability of the system.

[0006] To achieve the above objectives, the following technologies are employed:

[0007] A grinding aid activator for steel slag and mineral slag comprises the following raw materials in the following mass percentages: 40-60% grinding aid modifier, 2-15% grinding aid dispersant, and 35-45% inorganic salt; wherein the grinding aid modifier is composed of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in a mass ratio of (30-40):(50-60):(1-5):(1-5); wherein the grinding aid dispersant is naphthalenesulfonate formaldehyde condensate and / or triisopropanolamine; and wherein the inorganic salt includes sodium sulfate and sodium carbonate.

[0008] For steel slag and ore slag systems, the grinding aid dispersant naphthalene sulfonate formaldehyde condensate and / or triisopropanolamine in this invention can adsorb onto the surface of steel slag and ore slag, weakening the surface energy of the particles, maintaining a relative balance of residual valence bonds and charges on the crack surface, reducing the hardness and strength of the particle surface, and facilitating grinding. Simultaneously, the grinding aid dispersant also forms an adsorption film on the surface of steel slag and ore slag, reducing particle adhesion and agglomeration, and improving grinding efficiency. Furthermore, the grinding aid dispersant can further penetrate into the fine cracks of steel slag and ore slag, making the cracks difficult to heal, and continuing to penetrate into the interior of the cracks as grinding progresses, causing the cracks to expand continuously, effectively promoting the miniaturization of steel slag and ore slag particles. The addition of inorganic salts, on the one hand, can be adsorbed onto the surface of steel slag and ore slag through physical adsorption, improving their rheology and dispersibility, and increasing particle grinding efficiency; on the other hand, it can also effectively improve the early strength of the steel slag and ore slag system. In the early stage of synergistic hydration of steel slag and ore slag, the dissolution of active minerals in steel slag and ore slag will cause the pH value of the entire system to continuously increase, and the Ca in the system... 2+ Will react with OH - It combines and crystallizes in the form of Ca(OH)₂, aggregates, and coats the surface of unhydrated particles, forcing the hydration of steel slag and mineral slag to stop. Inorganic salts sodium sulfate and sodium carbonate contain SO₄²⁻. 2- and CO3 2- Ca 2+ This process consumes the calcium oxide, preventing the formation of Ca(OH)₂ crystals and allowing the hydration process of steel slag and ore slag to continue, promoting the forward hydration reaction of the system. The grinding aid modifier is a specific blend of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone. Under the catalysis of zinc bromide, ethylenediaminetetramethylenephosphonic acid and triethanolamine undergo esterification, altering the symmetrical molecular structure of triethanolamine and grafting strongly polar "COO" ester bonds onto the triethanolamine molecule. The formation of these ester bonds makes it easier for the unshared pair of electrons on the N atom in triethanolamine to form covalent bonds with calcium ions in free calcium oxide. Ultimately, the calcium ions coordinate with the N atom in triethanolamine and the O atom in the ester bonds, forming a relatively stable chelate. The addition of the grinding aid modifier effectively reduces the content of free calcium oxide in the steel slag and ore slag system, significantly improving the problem of poor volume stability of steel slag.

[0009] This invention uses grinding modifiers, grinding dispersants and inorganic salts in a specific ratio, which not only significantly improves the powdering efficiency of the steel slag and ore slag composite system, but also enhances the early strength of the system and improves the volume stability of the system.

[0010] Preferably, the preparation method of the grinding aid modifier includes the following steps:

[0011] S1. Weigh out ethylenediaminetetramethylenephosphonic acid, triethanolamine and hydroquinone according to the proportion, mix them evenly, stir and heat to 100-125℃;

[0012] S2. Add zinc bromide to the mixture obtained in step S1 and continue stirring for 4 to 8 hours;

[0013] S3. Cool the solution obtained in step S2 to 28-34°C and adjust the pH of the solution to 6-8 to obtain the grinding aid dispersant.

[0014] More preferably, the stirring rate in step S2 is 800-1200 rpm.

[0015] Preferably, the mass ratio of sodium sulfate to sodium carbonate in the inorganic salt is (1-30):(1-5).

[0016] More preferably, the inorganic salt further includes calcium chloride, and the mass ratio of sodium sulfate, sodium carbonate and calcium chloride is (1-30):(1-5):(0.2-1).

[0017] More preferably, the mass ratio of sodium sulfate, sodium carbonate and calcium chloride in the inorganic salt is 17.75:3.75:1.

[0018] More preferably, the inorganic salt further includes sodium chloride, and the mass ratio of sodium sulfate, sodium carbonate and sodium chloride is (1-30):(1-5):(0.2-1).

[0019] Adding chloride salts such as calcium chloride or sodium chloride to inorganic salts can react with calcium hydroxide in steel slag and slag systems to form calcium chlorate, which is not easily soluble in water. This further reduces the concentration of calcium hydroxide in the system, promotes the normal progress of the hydration reaction, and improves the early strength of the system.

[0020] Preferably, the steel slag or ore slag grinding aid activator comprises the following raw materials in the following mass percentages: 50%–60% grinding aid modifier, 2%–7% grinding aid dispersant, and 37%–45% inorganic salt.

[0021] Preferably, the steel slag or ore slag grinding aid activator comprises the following raw materials in the following mass percentages: 55% grinding aid modifier, 5% grinding aid dispersant, and 40% inorganic salt.

[0022] Another object of the present invention is to provide a method for preparing the steel slag and ore slag grinding aid activator as described in any of the above claims, comprising the following steps: weighing the grinding aid modifier, grinding aid dispersant and inorganic salt in proportion, and mixing them evenly to obtain the steel slag and ore slag grinding aid activator.

[0023] The present invention also aims to provide the application of the steel slag and slag grinding aid activator described in any of the above claims in grinding steel slag and slag, wherein the dosage of the steel slag and slag grinding aid activator is 0.8% to 1.2% of the total mass of steel slag and slag.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] (1) The steel slag and slag grinding aid activator of the present invention can significantly improve the grinding efficiency of the steel slag and slag composite system, enhance the early strength of the system, and also improve the volume stability of the system.

[0026] (2) The preparation process of the steel slag and slag grinding aid activator of the present invention is simple, does not require ultra-high temperature or high pressure environment processing, and is low cost. Detailed Implementation

[0027] The technical solution 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.

[0028] Unless otherwise specified, the grinding aid modifiers in the following examples and comparative examples were prepared according to the following preparation method:

[0029] S1. Weigh out ethylenediaminetetramethylenephosphonic acid, triethanolamine and hydroquinone according to the proportion, mix them evenly, stir and heat to 100-125℃;

[0030] S2. Add zinc bromide to the mixture obtained in step S1, and continue stirring at 800-1200 rpm for 4-8 hours;

[0031] S3. Cool the solution obtained in step S2 to 28-34°C and adjust the pH of the solution to 6-8 to obtain the grinding aid dispersant.

[0032] The preparation method of the steel slag and ore slag grinding aid activator is as follows: weigh the grinding aid modifier, grinding aid dispersant and inorganic salt according to the proportion, and mix them evenly.

[0033] Example 1

[0034] This embodiment provides a grinding aid activator for steel slag and mineral slag, specifically comprising the following raw materials by mass percentage: 50% grinding aid modifier, 5% triisopropanolamine, and 45% inorganic salt; wherein the mass ratio of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in the grinding aid modifier is 35:55:3:3; the inorganic salt is sodium sulfate, sodium carbonate, and calcium chloride, with a mass ratio of sodium sulfate, sodium carbonate, and calcium chloride of 14:3:1.

[0035] Example 2

[0036] This embodiment provides a grinding aid activator for steel slag and mineral slag, specifically comprising the following raw materials by mass percentage: 51% grinding aid modifier, 4% triisopropanolamine, and 45% inorganic salt; wherein the mass ratio of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in the grinding aid modifier is 40:50:2:4; the inorganic salts are sodium sulfate and sodium carbonate, with a mass ratio of sodium sulfate to sodium carbonate of 6:3.5.

[0037] Example 3

[0038] This embodiment provides a grinding aid activator for steel slag and mineral slag, specifically comprising the following raw materials by mass percentage: 51% grinding aid modifier, 4% triisopropanolamine, and 45% inorganic salt; wherein the mass ratio of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in the grinding aid modifier is 30:50:1:2; the inorganic salts are sodium sulfate and sodium carbonate, with a mass ratio of sodium sulfate to sodium carbonate of 13:5.

[0039] Example 4

[0040] This embodiment provides a grinding aid activator for steel slag and mineral slag, specifically comprising the following raw materials by mass percentage: 53% grinding aid modifier, 4.5% triisopropanolamine, and 42.5% inorganic salt; wherein the mass ratio of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in the grinding aid modifier is 40:50:1:1; the inorganic salts are sodium sulfate and sodium carbonate, with a mass ratio of sodium sulfate to sodium carbonate of 12:5.

[0041] Example 5

[0042] This embodiment provides a grinding aid activator for steel slag and mineral slag, specifically comprising the following raw materials by mass percentage: 55% grinding aid modifier, 5% naphthalene sulfonate formaldehyde condensate, and 40% inorganic salt; wherein the mass ratio of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in the grinding aid modifier is 40:60:5:5; the inorganic salt is sodium sulfate, sodium carbonate, and calcium chloride, and the mass ratio of sodium sulfate, sodium carbonate, and calcium chloride is 17.75:3.75:1.

[0043] Example 6

[0044] This embodiment provides a grinding aid activator for steel slag and mineral slag, specifically comprising the following raw materials by mass percentage: 50% grinding aid modifier, 5% naphthalene sulfonate formaldehyde condensate, and 45% inorganic salt; wherein the mass ratio of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in the grinding aid modifier is 38:56:3:4; the inorganic salt is sodium sulfate, sodium carbonate, and calcium chloride, with a mass ratio of sodium sulfate, sodium carbonate, and calcium chloride of 11.5:2.5:1.

[0045] Comparative Example 1

[0046] This comparative example provides a steel slag and ore slag grinding aid activator, whose raw material composition is basically the same as that of Example 5. The difference is that the raw material does not contain a grinding aid modifier, and the excess part is added to the naphthalene sulfonate formaldehyde condensate, that is, 60% naphthalene sulfonate formaldehyde condensate and 40% inorganic salt.

[0047] Comparative Example 2

[0048] This comparative example provides a steel slag and ore slag grinding aid activator, whose raw material composition is basically the same as that of Example 5, except that the raw material does not contain a grinding aid dispersant, and the excess part is added to the inorganic salt, that is, 55% grinding aid modifier and 45% inorganic salt.

[0049] Comparative Example 3

[0050] This comparative example provides a steel slag and ore slag grinding aid activator, whose raw material composition is basically the same as that of Example 5, except that: the raw material does not contain inorganic salts, and the excess part is added to the grinding aid modifier, that is, 95% grinding aid modifier and 5% naphthalene sulfonate formaldehyde condensate.

[0051] Comparative Example 4

[0052] This comparative example provides a grinding aid activator for steel slag and mineral slag, whose raw material composition is basically the same as that of Example 5. The difference is that the grinding aid modifier does not contain ethylenediaminetetramethylenephosphonic acid, the total amount remains unchanged, and the excess part is evenly distributed to the other three components in proportion, namely, the mass ratio of triethanolamine, zinc bromide and hydroquinone is 60:5:5.

[0053] Application examples

[0054] The steel slag and slag grinding aids prepared in each example and comparative example were added to the steel slag and slag system at a ratio of 1% of the total mass of the system. The mass ratio of steel slag to slag in the system was 9:1. After grinding for 60 minutes, the ground steel slag and slag were mixed with cement samples at a mass ratio of 3:7 according to GB / T 20491-2006. The 3-day compressive strength was measured according to GB / T17671 and compared with the blank group without the steel slag and slag grinding aids. The 3-day compressive strength growth rate (ratio to the blank group data) was measured. At the same time, the specific surface area of ​​the steel slag and slag obtained in Example 5 and each comparative example, as well as the blank group, was measured according to GB / T 8074, and the stability was measured according to GB / T 1346. The results are shown in the table below.

[0055] Table 1. Test results of the 3d compressive strength growth rate of the tested samples.

[0056] Example 1 139.31％ Example 2 134.57％ Example 3 137.12％ Example 4 135.00％ Example 5 142.37％ Example 6 133.74％ Comparative Example 1 125.23％ Comparative Example 2 132.29％ Comparative Example 3 110.93％ Comparative Example 4 133.64％

[0057] Table 2 Results of specific surface area and volumetric stability tests on the tested samples

[0058] Blank group 261.93 3.68mm Example 5 351.53 0.53mm Comparative Example 1 331.21 1.93mm Comparative Example 2 301.21 1.33mm Comparative Example 3 342.59 0.59mm Comparative Example 4 333.68 1.68mm

[0059] As can be seen from the data in Table 1 above, the 3-day compressive strength of the steel slag and ore activator systems prepared in each embodiment is significantly enhanced compared to the system without grinding aid, with an increase of more than 1.3 times, reaching a maximum of 1.42 times. This indicates that the steel slag and ore activator of the present invention can significantly improve the early strength of the steel slag and ore slag composite system. As can be seen from the data in Table 2, the specific surface area of ​​the steel slag and ore slag system prepared in Example 5 is significantly increased compared to the blank group without grinding aid, increasing by 1.3 times. The volume stability also decreases from 3.68 mm to 0.53 mm, indicating that the steel slag and ore activator of the present invention can significantly improve the grinding effect of the steel slag and ore slag composite system and improve the volume stability of the system.

[0060] Comparing the data from Comparative Examples 1, 3, and 5, it can be seen that the steel slag / slag system obtained without a grinding aid modifier exhibits poorer volume stability and significantly reduced 3-day compressive strength. Conversely, when the grinding aid activator does not contain inorganic salts, the 3-day compressive strength of the resulting steel slag / slag system is significantly reduced, but still higher than the control group without the grinding aid activator. This is because the grinding aid modifier not only improves volume stability but also synergistically enhances the early strength of the system with the inorganic salts. Comparing the data from Comparative Examples 2 and 5, it can be seen that the steel slag / slag system obtained without a grinding aid dispersant exhibits significantly reduced specific surface area and significantly worse volume stability. This is because the grinding aid dispersant not only significantly improves the grinding effect of the steel slag / slag composite system but also synergistically enhances the volume stability of the system with the grinding aid activator.

[0061] Furthermore, comparing the data from Comparative Example 4 and Example 5, it can be seen that the steel slag and ore slag systems prepared without ethylenediaminetetramethylenephosphonic acid (EDTA) exhibit significantly poorer volume stability. This is because without EDTA, triethanolamine cannot form ester bonds, and its N and O atoms have weaker binding forces with calcium ions in free calcium oxide, resulting in an inefficient chelation of calcium ions. Consequently, many free calcium oxides remain in the steel slag and ore slag systems, leading to poor volume stability of the system.

[0062] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A grinding aid activator for a mixture of steel slag and mineral slag, characterized in that, The raw materials comprise the following percentages by weight: 40-60% grinding aid modifier, 2-15% grinding aid dispersant, and 35-45% inorganic salts; the grinding aid modifier is composed of ethylenediaminetetramethylenephosphonic acid, triethanolamine, zinc bromide, and hydroquinone in a mass ratio of (30-40):(50-60):(1-5):(1-5); the grinding aid dispersant is naphthalenesulfonate formaldehyde condensate and / or triisopropanolamine; the inorganic salts include sodium sulfate and sodium carbonate. The preparation method of the grinding aid modifier includes the following steps: S1. Weigh out ethylenediaminetetramethylenephosphonic acid, triethanolamine and hydroquinone according to the proportion, mix them evenly, stir and heat to 100-125℃; S2. Add zinc bromide to the mixture obtained in step S1 and continue stirring for 4 to 8 hours; S3. Cool the solution obtained in step S2 to 28-34°C and adjust the pH of the solution to 6-8 to obtain the grinding aid modifier. The mass ratio of sodium sulfate to sodium carbonate in the inorganic salt is (1-30):(1-5).

2. The grinding aid activator for a mixture of steel slag and mineral slag according to claim 1, characterized in that, The inorganic salt also includes calcium chloride, and the mass ratio of sodium sulfate, sodium carbonate and calcium chloride is (1-30):(1-5):(0.2-1).

3. The grinding aid activator for a mixture of steel slag and mineral slag according to claim 2, characterized in that, The mass ratio of sodium sulfate, sodium carbonate, and calcium chloride in the inorganic salt is 17.75:3.75:

1.

4. The grinding aid activator for a mixture of steel slag and mineral slag according to claim 1, characterized in that, The inorganic salt also includes sodium chloride, and the mass ratio of sodium sulfate, sodium carbonate and sodium chloride is (1-30):(1-5):(0.2-1).

5. The grinding aid activator for a mixture of steel slag and mineral slag according to claim 1, characterized in that, The raw materials include the following percentages by weight: 50%–60% grinding aid modifier, 2%–7% grinding aid dispersant, and 37%–45% inorganic salts.

6. The grinding aid activator for a mixture of steel slag and mineral slag according to claim 1, characterized in that, The raw materials include the following percentages by weight: 55% grinding aid modifier, 5% grinding aid dispersant, and 40% inorganic salt.

7. The method for preparing the grinding aid activator of the steel slag and ore slag mixture according to any one of claims 1 to 6, characterized in that, Includes the following steps: Weigh out the grinding aid modifier, grinding aid dispersant and inorganic salt in proportion, and mix them evenly to obtain the steel slag and ore activator.

8. The application of the grinding aid activator of the steel slag and ore slag mixture according to any one of claims 1 to 6 in the grinding of steel slag and ore slag, characterized in that, The grinding aid activator in the steel slag and slag mixture is added at a rate of 0.8% to 1.2% of the total mass of steel slag and slag.