Composite superfine slag powder and preparation method thereof

Abstract

The invention relates to the technical field of building materials, in particular to composite superfine slag powder and a preparation method thereof. The superfine slag powder is prepared from the following raw material components in percentage by weight: 5%-10% of desulfurized gypsum, 45%-55% of blast furnace water granulated slag, 15%-20% of blast furnace slag, 10%-20% of fly ash and 1%-5% of an exciting agent. The superfine slag powder disclosed by the invention is high in strength and good in water absorption-water release performance, and can greatly reduce cracking, improve the strength, reduce carbonization and remarkably improve the comprehensive performance of concrete after being added into the concrete. The preparation method disclosed by the invention is simple to operate, energy-saving, efficient and environment-friendly, can effectively improve the quality of the product and improve the performance of the product, and has obvious social, economic and environment-friendly benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, in particular, especially relates to a composite type of slag powder and a preparation method thereof. BACKGROUND

[0002] Slag powder is a micron-sized powder material made of industrial solid waste such as metallurgy and power, and has potential cementitious activity. Slag powder is widely used in the field of building materials, and can be used as a cement admixture or a concrete additive to reduce the amount of cement and improve the material density and erosion resistance, which has economic and environmental benefits and meets the development trend of green building materials.

[0003] In recent years, with the promotion of the concept of green building, slag powder as a typical material for recycling of industrial solid waste, related research focuses on improving its activity and optimizing the performance of concrete. The existing technology mainly tries to enhance the activity and functionality of slag powder by improving the grinding process, adjusting the particle size distribution or adding chemical activators, and some research also tries to compound slag powder with other mineral admixtures to improve the overall performance of concrete. However, the slag powder on the market still has many shortcomings. In terms of strength performance, its early strength development is slow, which is difficult to meet the rapid construction demand; the water absorption and water release performance is poor, which cannot provide effective internal curing for concrete, resulting in shrinkage and cracking of concrete due to water imbalance; the particle morphology is irregular, which is difficult to effectively improve the structure of the concrete interfacial transition zone. In addition, the single slag powder has a limited cement replacement rate when applied in concrete, which is difficult to achieve the dual goals of high performance and low carbon emission, limiting its large-scale application in high-performance concrete. SUMMARY The purpose of the present application is to provide a composite type of slag powder and a preparation method thereof, which has high strength, good water absorption and water release performance, and can significantly reduce cracking, improve strength, reduce carbonation and significantly improve the overall performance of concrete when added to concrete.

[0004] In order to achieve the above purpose, the technical scheme of the present application is as follows: In one aspect, the present application provides a composite type of slag powder, and the weight percentage of each component of the slag powder is as follows: desulfurization gypsum 5% to 10%, high-temperature water slag 45% to 55%, blast furnace slag 15% to 20%, fly ash 10% to 20%, and activator 1% to 5%.

[0005] In the above technical scheme, further, the activator is CaO.

[0006] In the above technical scheme, further, the specific surface area of the slag powder is 400 to 550 m 2 / kg.

[0007] Another aspect of the present application provides a preparation method of the composite slag powder, comprising the following steps: (1) drying treatment of the blast furnace slag, the blast furnace slag, and the fly ash; (2) crushing treatment of the dried blast furnace slag, the blast furnace slag, and the fly ash, and grading treatment of the crushed materials; (3) mixing of the materials with a particle size of ≤2 mm with the desulfurization gypsum and the activator, and ball milling of the mixture in a ball mill, and re-crushing of the materials with a particle size of >2 mm; (4) obtaining of the composite slag powder from the ball-milled micro powder after steam curing.

[0008] In the above technical solution, further, in step (1), the drying temperature is 110-130℃, and the drying time is 30-40 min.

[0009] In the above technical solution, further, in step (3), the ball milling speed is 20-30 r / min.

[0010] The present application has the following beneficial effects: 1. The composite slag powder has high strength, good water absorption and water release performance, and is spherical, and has the effects of adjusting water, improving interface, and internal curing when used in concrete. 2. The composite slag powder can significantly reduce cracking, improve strength, reduce carbonation, and significantly improve the comprehensive performance of concrete when added to concrete, and can save cement, reduce cost and carbon emission.

[0011] 3. The preparation method is simple in operation, energy-saving, efficient and environmentally friendly, can effectively improve the quality and performance of the product, and has obvious social, economic and environmental benefits. DETAILED DESCRIPTION

[0012] The following examples can make those skilled in the art more fully understand the present application, but do not limit the present application in any way.

[0013] Example 1 A composite slag powder, the weight percentage of each component of the raw material is: desulfurization gypsum 10%, blast furnace slag 45%, blast furnace slag 20%, fly ash 20%, and CaO 5%.

[0014] The chemical components (%) of the desulfurization gypsum in this example are: crystal water 19.7%, SO344.73%, SiO21.68%, CaO31.38%, MgO 0.12%, Fe2O30.48%, and Al2O30.76%.

[0015] The method for preparing the composite slag powder comprises the following steps: (1) Drying the blast furnace slag, blast furnace slag and fly ash at a drying temperature of 110°C and a drying time of 30 minutes; (2) Crush the dried blast furnace slag, blast furnace slag and fly ash, and perform classification on the crushed materials; (3) The materials with particle size ≤ 2 mm are mixed with desulfurized gypsum and activator CaO, and then put into ball mill for ball milling at a speed of 30 r / min. The materials with particle size > 2 mm are crushed again; (4) The ball-milled micropowder is steam-cured to obtain composite slag micropowder.

[0016] Example 2 A composite slag micropowder, the weight percentages of the raw material components of which are: desulfurized gypsum: 5%, blast furnace slag: 55%, blast furnace slag: 20%, fly ash: 19%, and CaO: 1%.

[0017] The chemical composition (%) of the desulfurization gypsum in this embodiment is: crystal water 19.7%, SO3 44.73%, SiO2 1.68%, CaO 31.38%, MgO 0.12%, Fe2O3 0.48%, Al2O3 0.76%.

[0018] The method for preparing the composite slag powder comprises the following steps: (1) Drying the blast furnace slag, blast furnace slag and fly ash at a drying temperature of 130°C and a drying time of 40 minutes; (2) Crush the dried blast furnace slag, blast furnace slag and fly ash, and perform classification on the crushed materials; (3) The materials with particle size ≤ 2 mm are mixed with desulfurized gypsum and activator CaO, and then put into ball mill for ball milling at a speed of 40 r / min. The materials with particle size > 2 mm are crushed again; (4) The ball-milled micropowder is steam-cured to obtain composite slag micropowder.

[0019] Example 3 A composite slag micropowder, the weight percentages of the raw material components of which are: desulfurized gypsum: 10%, blast furnace slag: 50%, blast furnace slag: 15%, fly ash: 20%, and CaO: 5%.

[0020] The chemical composition (%) of the desulfurization gypsum in this embodiment is: crystal water 19.7%, SO3 44.73%, SiO2 1.68%, CaO 31.38%, MgO 0.12%, Fe2O3 0.48%, Al2O3 0.76%.

[0021] The preparation method of the composite type slag powder comprises the following steps: (1) drying treatment of the blast furnace slag, the blast furnace slag and the fly ash, the drying temperature is 130 DEG C, and the drying time is 40 min; (2) crushing treatment of the dried blast furnace slag, the blast furnace slag and the fly ash, and grading treatment of the crushed materials; (3) mixing of the materials with particle size of 2 mm or less with the desulfurization gypsum and the activator CaO, and entering the ball mill for ball milling, the ball milling speed is 40 r / min, and the materials with particle size of more than 2 mm are crushed again; (4) obtaining of the composite type slag powder after steam curing of the ball-milled micro powder.

[0022] The test results of the concrete added with the examples 1-3 and the ordinary concrete are shown in table 1.

[0023] Table 1

[0024] The test shows that the 3-day strength, the 7-day strength and the 28-day strength of the concrete test piece are all higher than the strength of the ordinary concrete test piece.

[0025] The above examples are only the preferred examples of the present application, and are not the limitation to the embodiments. The protection scope of the present application should be limited by the scope defined by the claims. Other different forms of changes or variations can be made on the basis of the above description. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A composite slag powder, characterized in that: The weight percentages of the raw material components of the slag fine powder are: desulfurized gypsum: 5%-10%, blast furnace slag: 45%-55%, blast furnace slag: 15%-20%, fly ash: 10%-20%, and activator: 1%-5%.

2. The composite slag powder according to claim 1, characterized in that: The activator is CaO.

3. The composite slag powder according to claim 1, characterized in that: The specific surface area of ​​the slag powder is 400~550m 2 / kg.

4. A method for preparing the composite slag powder according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (1) Drying blast furnace slag, blast furnace slag and fly ash; (2) Crush the dried blast furnace slag, blast furnace slag and fly ash, and perform classification on the crushed materials; (3) Materials with a particle size of ≤2mm are mixed with desulfurization stone and activator and put into ball mill for ball milling. Materials with a particle size of >2mm are crushed again; (4) The ball-milled micropowder is steam-cured to obtain composite slag micropowder.

5. The preparation method according to claim 3, characterized in that In step (1), the drying temperature is 110-130°C and the drying time is 30-40 minutes.

6. The preparation method according to claim 3, characterized in that In step (3), the ball milling speed is 20-30 r / min.

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