A method for synergistically enhancing the activity of steel slag using silica-amyl alcohols

Abstract

This invention relates to the field of steel slag resource utilization building materials technology, and particularly to a method for synergistically enhancing the activity of steel slag using silica fume and isopropanolamine. The composite material of this invention, by weight, comprises 290-350 parts cement, 100-150 parts steel slag, 2.5-20 parts silica fume, and 0.1-0.2 parts diethanol monoisopropanolamine. The composite material obtained by this invention exhibits high early strength and good cementitious activity.

Description

Technical Field

[0001] This invention relates to the field of steel slag resource utilization building materials technology, and in particular to a method for synergistically enhancing the activity of steel slag using silica ash alcohol amine. Background Technology

[0002] Steel slag is an industrial solid waste generated during the steelmaking process. Based on 15% of crude steel production, the annual output of steel slag is approximately 70 million tons. The long-term accumulation of large amounts of steel slag not only wastes land resources but also pollutes soil and groundwater resources.

[0003] Steel slag, as a solid waste, has a similar chemical and mineral composition to silicate cement clinker and exhibits hydraulic cementitious properties. Therefore, using steel slag to replace part of the cement in the preparation of cementitious materials can not only reduce environmental pollution and energy consumption caused by cement production but also improve the utilization rate of solid wastes like steel slag. However, steel slag suffers from low cementitious activity and poor early strength, resulting in generally poor mechanical properties when used to replace part of the cement, which is not conducive to comprehensive utilization.

[0004] Patent CN115974488A improves the early strength of steel slag cement by adding nano-alumina, with a maximum 3-day strength increase of 26.26%. However, this method can only utilize steel slag as a solid waste and cannot utilize other solid wastes. Summary of the Invention

[0005] This invention provides a method for synergistically enhancing the activity of steel slag using silica fume and amines, which solves the problem of poor early strength caused by the use of steel slag as a cement admixture in the prior art, promotes the efficient utilization of steel slag, and can also utilize solid waste silica fume.

[0006] This invention provides a composite material, comprising, by weight, 290-350 parts cement, 100-150 parts steel slag, 2.5-20 parts silica fume, and 0.1-0.2 parts diethanol monoisopropanolamine. This invention utilizes the synergistic effect of silica fume and diisopropanolamine to enhance the activity of steel slag, thereby improving the early strength of steel slag cement and solving the problem of poor early strength when steel slag is used to replace part of the cement, thus improving the utilization rate of steel slag. The composite material of this invention exhibits high early strength and good cementitious activity.

[0007] Preferably, it also includes water, wherein the amount of water is 200-250 parts.

[0008] Preferably, it also includes sand, wherein the amount of sand is 1000-1600 parts.

[0009] Preferably, the composite material comprises the following raw materials: 300-330 parts cement, 110-138 parts steel slag, 3-25 parts silica fume, 0.1-0.2 parts diethanol monoisopropanolamine (DEIPA), 215-235 parts water, and 1300-1400 parts sand.

[0010] More preferably, the composite material comprises the following raw materials: 315 parts cement, 112.5 to 135 parts steel slag, 4.5 to 22.5 parts silica fume, 0.135 parts diethanolamine monoisopropanolamine (DEIPA), 225 parts water, and 1350 parts sand.

[0011] Preferably, the composite material is a mortar sample.

[0012] Preferably, in some experimental examples, the composition of the mortar sample includes cement, steel slag, silica fume, water, diethanol monoisopropanolamine, and standard sand.

[0013] Preferably, the diethanol monoisopropanolamine has a purity of 85% or higher, and more preferably 93%.

[0014] Preferably, according to GB / T 51003—2014 "Technical Specification for Application of Mineral Admixtures", the ratio of steel slag to cement is approximately 3:7.

[0015] Preferably, the water used in this invention is tap water.

[0016] According to the composite material, the steel slag is converter steel slag.

[0017] According to the composite material, the steel slag contains, by weight percentage, 11-21% SiO2, 35-46% CaO, 2-7% MgO, 15-27% Fe2O3, 2-6% Al2O3, and 0.2-0.9% SO3.

[0018] According to the composite material, the silica fume contains 85-96% SiO2, 0.6-2% CaO, 0.3-1% MgO, 0.4-1.4% Fe2O3, 0.5-1.7% Al2O3, and 0.4-1.3% SO3 by weight percentage.

[0019] According to the composite material, the cement is silicate cement.

[0020] Preferably, the cement is a special reference cement for testing concrete admixtures, model: PI 42.5 silicate cement.

[0021] The present invention also provides a method for preparing the composite material, wherein the raw materials of the composite material further include sand, and the method for preparing the composite material includes the following steps: mixing and adding the raw materials, stirring, stirring evenly after adding sand, and preparing a mortar sample.

[0022] Preferably, the method for preparing the composite material includes the following steps:

[0023] a. Mix diethanol monoisopropanolamine with water until homogeneous to obtain the first mixture;

[0024] b. Mix the cement and steel slag evenly to obtain a second mixture;

[0025] c. Mix the first mixture, the second mixture, and silica fume, then add sand to obtain the composite material.

[0026] According to the preparation method of the composite material, the first mixture is poured into a stirrer, silica fume is added, then the second mixture is added, and after mixing evenly, sand is added and the mixture is stirred evenly to finally obtain the corresponding composite material.

[0027] Preferably, after adding the second mixture, stir for 30 seconds and then feed the sand.

[0028] The product obtained by the above preparation method is a mortar sample. The water-cement ratio of the mortar sample is selected as 0.5.

[0029] Preferably, the stirrer is a mixing pot.

[0030] Preferably, the mixing pot and mixing blades are moistened with a wet cloth, and diethanol monoisopropanolamine is mixed with water to obtain a first mixture. Then, the mixture is poured into the mixing pot, silica fume is added, and then a second mixture of cement and steel slag is added to the first mixture. The mixture is stirred to obtain a mortar test block of steel slag cement composite cementitious material with silica fume and diethanol monoisopropanolamine.

[0031] Preferably, the first mixture is poured into a mixing pot, silica fume is added, and then the second mixture is added. The mixture is stirred for 30 seconds, sand is added, and stirring is continued until homogeneous, finally yielding the corresponding mortar sample.

[0032] According to the preparation method of the composite material, the sand is standard sand.

[0033] The present invention also provides the application of the composite material in the field of construction.

[0034] The beneficial effects of this invention are:

[0035] (1) The composite material described in this invention has high early strength and good gelling activity.

[0036] (2) This invention incorporates diethanol monoisopropanolamine and silica fume into steel slag cement composite cementitious material. The complexation and solubilization effect of diethanol monoisopropanolamine promotes the dissolution of calcium ions and other ions in steel slag, and the pozzolanic activity of silica fume reacts with the hydration product Ca(OH)2 and the micro-aggregate filling effect effectively improve the strength of steel slag cement composite cementitious system, especially the early compressive strength.

[0037] (3) The preparation method of the composite material of the present invention is simple and convenient for industrial use.

[0038] (4) The improvement of early strength of steel slag cement by the present invention is beneficial to the use of steel slag with higher admixture in cementitious materials, and is of great significance to improving the comprehensive utilization rate of steel slag.

[0039] (5) The diethanol monoisopropanolamine selected in this invention has low toxicity and is added in very small amounts in the system. It can also utilize solid waste silica fume, which has little harm to the environment and low cost, and is in line with the current development trend of low carbon and environmental protection in the cement industry. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention.

[0041] Figure 1 The graph shows the test results of the compressive strength of the mortar samples prepared in Experimental Examples 1 to 7 of this invention at different ages according to GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)". Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] The main chemical components of steel slag and silica fume in the embodiments of the present invention are shown in Table 1.

[0044] Table 1

[0045]

[0046] Experimental Example 1

[0047] The raw materials for the mortar sample in this embodiment are 315g of cement, 135g of steel slag, 225g of water, and 1350g of standard sand.

[0048] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 135g steel slag, 225g water, and 1350g standard sand. Mix the cement and steel slag evenly and then pour them into the water. Follow the mortar preparation method to obtain mortar sample block 1 of steel slag cement composite cementitious material.

[0049] The mortar sample had a 3-day compressive strength of 18.28 MPa and an activity index of 65.73%.

[0050] Experiment Example 2

[0051] The raw materials for the mortar sample in this embodiment are 315g of cement, 135g of steel slag, 0.135g of diethanolamine monoisopropanol (DEIPA), 225g of water, and 1350g of standard sand.

[0052] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 135g steel slag, 0.135g diethanolmonoisopropanolamine (DEIPA), 225g water, and 1350g standard sand. Mix the diethanolmonoisopropanolamine and water evenly to obtain the first mixture. Then, add the second mixture (obtained by evenly mixing cement and steel slag) to the first mixture. Follow the mortar preparation method to obtain mortar sample 2 of the steel slag cement composite cementitious material with added diethanolmonoisopropanolamine.

[0053] The mortar sample had a 3-day compressive strength of 22.28 MPa and an activity index of 80.12%.

[0054] Experimental Example 3

[0055] The raw materials for the mortar sample in this embodiment are 315g of cement, 130.5g of steel slag, 4.5g of silica fume, 0.135g of diethanolamine monoisopropanol (DEIPA), 225g of water, and 1350g of standard sand.

[0056] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 130.5g steel slag, 4.5g silica fume, 0.135g diethanolmonoisopropanolamine (DEIPA), 225g water, and 1350g standard sand. Mix the diethanolmonoisopropanolamine and water evenly to obtain the first mixture. Add silica fume, and then add the second mixture (obtained by evenly mixing cement and steel slag) to the first mixture. Follow the mortar preparation method to obtain mortar sample block 3 of the steel slag cement composite cementitious material containing silica fume and diethanolmonoisopropanolamine.

[0057] The mortar sample had a 3-day compressive strength of 24.71 MPa and an activity index of 88.85%.

[0058] Experiment Example 4

[0059] The raw materials for the mortar sample in this embodiment are 315g of cement, 126g of steel slag, 9g of silica fume, 0.135g of diethanolamine monoisopropanol (DEIPA), 225g of water, and 1350g of standard sand.

[0060] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 126g steel slag, 9g silica fume, 0.135g diethanolmonoisopropanolamine (DEIPA), 225g water, and 1350g standard sand. Mix the diethanolmonoisopropanolamine and water evenly to obtain the first mixture. Add silica fume, and then add the second mixture (obtained by evenly mixing cement and steel slag) to the first mixture. Follow the mortar preparation method to obtain mortar sample block 4 of the steel slag cement composite cementitious material containing silica fume and diethanolmonoisopropanolamine.

[0061] The mortar sample had a 3-day compressive strength of 24 MPa and an activity index of 86.30%.

[0062] Experimental Example 5

[0063] The raw materials for the mortar sample in this embodiment are 315g of cement, 121.5g of steel slag, 13.5g of silica fume, 0.135g of diethanolamine monoisopropanol (DEIPA), 225g of water, and 1350g of standard sand.

[0064] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 121.5g steel slag, 13.5g silica fume, 0.135g diethanolmonoisopropanolamine (DEIPA), 225g water, and 1350g standard sand. Mix the diethanolmonoisopropanolamine and water evenly to obtain the first mixture. Add silica fume, and then add the second mixture obtained by evenly mixing cement and steel slag to the first mixture. Follow the mortar preparation method to obtain mortar sample block 5 of steel slag cement composite cementitious material with added silica fume and diethanolmonoisopropanolamine.

[0065] The mortar sample had a 3-day compressive strength of 23.74 MPa and an activity index of 85.36%.

[0066] Experimental Example 6

[0067] The raw materials for the mortar sample in this embodiment are 315g of cement, 117g of steel slag, 18g of silica fume, 0.135g of diethanolamine monoisopropanol (DEIPA), 225g of water, and 1350g of standard sand.

[0068] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 117g steel slag, 18g silica fume, 0.135g diethanolmonoisopropanolamine (DEIPA), 225g water, and 1350g standard sand. Mix the diethanolmonoisopropanolamine and water evenly to obtain the first mixture. Add silica fume, and then add the second mixture (obtained by evenly mixing cement and steel slag) to the first mixture. Follow the mortar preparation method to obtain mortar sample block 6 of steel slag cement composite cementitious material containing silica fume and diethanolmonoisopropanolamine.

[0069] The mortar sample had a 3-day compressive strength of 23.06 MPa and an activity index of 82.92%.

[0070] Experimental Example 7

[0071] The raw materials for the mortar sample in this embodiment are 315g of cement, 112.5g of steel slag, 22.5g of silica fume, 0.135g of diethanolamine monoisopropanol (DEIPA), 225g of water, and 1350g of standard sand.

[0072] The preparation process of the mortar sample is as follows: Weigh the following raw materials: 315g cement, 112.5g steel slag, 22.5g silica fume, 0.135g diethanolmonoisopropanolamine (DEIPA), 225g water, and 1350g standard sand. Mix the diethanolmonoisopropanolamine and water evenly to obtain the first mixture. Add silica fume, and then add the second mixture obtained by evenly mixing cement and steel slag to the first mixture. Follow the mortar preparation method to obtain mortar sample block 7 of steel slag cement composite cementitious material with added silica fume and diethanolmonoisopropanolamine.

[0073] The mortar sample had a 3-day compressive strength of 23.75 MPa and an activity index of 85.40%.

[0074] The mortar samples prepared by the methods shown in Examples 1-7 were tested for compressive strength at different ages according to GB / T17671-2021 "Test Methods for Strength of Cement Mortar (ISO Method)". The test results are as follows: Figure 1 As shown.

[0075] from Figure 1 It can be seen that the strength of the mortar sample obtained by the preparation method described in this invention is improved, especially the early compressive strength.

[0076] When 0.03% diethanol monoisopropanolamine was added, the 3-day compressive strength increased by 21.9%, and the activity index was 80.11%, which was 14.38% higher than that of Experimental Example 1.

[0077] When silica fume and diethanol monoisopropanolamine were added simultaneously, the 3-day strength of each group was improved compared to that of diethanol monoisopropanolamine alone. The 3-day compressive strength of the mortar sample in Example 3 increased by 6.43 MPa, with an activity index of 88.85%, compared to 23.12% in Experiment 1. This indicates that the addition of silica fume monoisopropanolamine resulted in a greater improvement in compressive strength compared to the addition of diethanol monoisopropanolamine alone. The increase in 3-day compressive strength after adding silica fume monoisopropanolamine ranged from 26.15% to 35.18%, and the increase in activity index ranged from 17.19% to 23.12%.

[0078] This invention utilizes the synergistic effect of silica fume and isopropanolamine to promote the dissolution of ions in steel slag. Simultaneously, silica fume reacts with calcium ions to generate CSH gel and promptly consumes hydration products, promoting the continued hydration reaction and further enhancing the activity of steel slag. This invention can significantly improve the early strength of steel slag cement. The raw materials of this invention include cement, steel slag, silica fume, diethanolmonoisopropanolamine, water, and standard sand. Adding and stirring these raw materials according to the steps yields the corresponding proportion of mortar. The preparation method is simple and suitable for industrial production.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite material that utilizes silica-alkanolamine to synergistically enhance the activity of steel slag, characterized in that, By weight, its raw materials are 290-350 parts cement, 100-150 parts steel slag, 2.5-20 parts silica fume, 0.1-0.2 parts diethanol monoisopropanolamine, 1000-1600 parts sand and 200-250 parts water.

2. The composite material for synergistically enhancing the activity of steel slag using silica-alkanolamine as described in claim 1, characterized in that, The steel slag is converter steel slag.

3. The composite material for synergistically enhancing the activity of steel slag using silica-alkanolamine as described in claim 1 or 2, characterized in that, By weight percentage, the steel slag contains 11-21% SiO2, 35-46% CaO, 2-7% MgO, 15-27% Fe2O3, 2-6% Al2O3, and 0.2-0.9% SO3.

4. The composite material for synergistically enhancing the activity of steel slag using silica-alkanolamine as described in claim 1, characterized in that, By weight percentage, the silica fume contains 85-96% SiO2, 0.6-2% CaO, 0.3-1% MgO, 0.4-1.4% Fe2O3, 0.5-1.7% Al2O3, and 0.4-1.3% SO3.

5. The composite material for synergistically enhancing the activity of steel slag using silica-alkanolamine as described in claim 1, characterized in that, The cement is silicate cement.

6. A method for preparing the composite material according to any one of claims 1-5, characterized in that, Includes the following steps: a. Mix diethanol monoisopropanolamine with water until homogeneous to obtain the first mixture; b. Mix the cement and steel slag evenly to obtain a second mixture; c. Mix the first mixture, the second mixture, and silica fume, then add sand to obtain the composite material.

7. The application of the composite material according to any one of claims 1-5 in the field of construction.

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