阅读说明：本技术 利用废弃混凝土和钢渣制备的高活性混合材及其制备方法和应用 (High-activity mixed material prepared from waste concrete and steel slag, and preparation method and application thereof ) 是由 任雪红 张文生 叶家元 张洪滔 董刚 于 2020-06-05 设计创作，主要内容包括：本发明涉及一种利用废弃混凝土和钢渣制备的高活性混合材及其制备方法和应用,该制备方法包括以下步骤：将废弃混凝土破碎至最大粒径15mm以下；将破碎后的混凝土进行铺设,使得其高度不超过最大粒径5mm,1min内将1500℃以上的高温熔融态钢渣倒入,通过熔体流动与混凝土颗粒充分接触混合,保温热闷5-30min；将得到的物料进行速冷；将冷却的物料粉磨,磁力选铁,直至其最可几粒径达到100μm以下时,筛除125μm以上的粗颗粒,继续粉磨直至粉料细度为80μm筛余3％以下,即可得到所述高活性混合材。本发明以废弃混凝土和热态钢渣为原料,同时利用了两种工业固废,节约了资源能源,保护了环境,具有很高的环境效益和经济效益。(The invention relates to a high-activity mixed material prepared from waste concrete and steel slag, a preparation method and application thereof, wherein the preparation method comprises the following steps: crushing the waste concrete to the maximum grain diameter of below 15 mm; paving the crushed concrete to ensure that the height of the concrete does not exceed 5mm of the maximum particle size, pouring high-temperature molten steel slag with the temperature of more than 1500 ℃ within 1min, fully contacting and mixing the slag with concrete particles through melt flow, and insulating and hot-sealing for 5-30 min; rapidly cooling the obtained material; and grinding the cooled material, magnetically selecting iron until the particle size of most particles reaches below 100 mu m, screening out coarse particles with the particle size of above 125 mu m, and continuously grinding until the fineness of the powder is below 80 mu m and the screen residue is below 3%, thus obtaining the high-activity mixed material. The invention takes the waste concrete and the thermal steel slag as raw materials, simultaneously utilizes two industrial solid wastes, saves resource and energy, protects the environment and has high environmental benefit and economic benefit.)

1. The preparation method of the high-activity mixed material is characterized by comprising the following steps of:

1) crushing the waste concrete to the maximum grain diameter of below 15 mm;

2) paving the concrete crushed in the step 1) to ensure that the height of the concrete does not exceed 5mm of the maximum particle size, pouring high-temperature molten steel slag with the temperature of more than 1500 ℃ within 1min, fully contacting and mixing the steel slag with concrete particles through melt flow, and insulating and hot-sealing for 5-30 min;

3) quickly cooling the material obtained in the step 2);

4) grinding the material cooled in the step 3), selecting iron by magnetic force until the particle size of most probable particle size reaches below 100 mu m, screening out coarse particles with the particle size of above 125 mu m, and continuously grinding until the fineness of the powder is below 3% of the screen residue with the particle size of 80 mu m, thus obtaining the high-activity mixed material.

2. The method of claim 1, wherein the waste concrete is 20 to 80% by weight of the total weight of the waste concrete and the high-temperature molten steel slag.

3. The method for preparing a highly reactive admixture according to claim 1, wherein in step 2), the concrete is laid on the bottom of a cylindrical pit, a slag pan or a refractory crucible.

4. The method for preparing a highly reactive admixture according to claim 3, wherein in step 2), heat-insulating refractory bricks having a thickness of 10mm or more are provided on the outer periphery of the slag pit.

5. The method for preparing a high-activity mixed material according to claim 1, wherein in the step 3), the rapid cooling mode is fan cooling; the rotating speed of the electric fan is not lower than 500 revolutions per minute.

6. The method for preparing the highly active admixture according to claim 1, wherein in the step 4), the material cooled in the step 3) is ground for 2-20 min, iron is selected by magnetic force, and then the grinding is continued for 2-30 min, and the iron is selected by magnetic force until the content of metal iron is below 1% and the most probable particle size reaches below 100 μm, particles above 125 μm are screened out, and the grinding is continued until the fineness of the powder is below 80 μm and the screen residue is below 3%, so that the highly active admixture is obtained.

7. The high-activity mixed material is characterized in that the activity index of the high-activity mixed material is more than 80%, and the content of metallic iron is less than 1 wt%.

8. The highly active admixture according to claim 7, wherein the highly active admixture is produced by the method according to any one of claims 1 to 6.

9. A cement comprising the highly reactive admixture according to claim 8 or 9.

10. The cement of claim 9, wherein the cement comprises, in weight percent: 60% -92% of cement clinker; 0.5 to 5 percent of natural dihydrate gypsum; 5 to 38 percent of high-activity mixed material.

Technical Field

The invention relates to the technical field of recycling of waste concrete and steel slag, in particular to a high-activity mixed material prepared from waste concrete and steel slag, and a preparation method and application thereof.

Background

China is the biggest country for producing and using cement concrete in the world. Along with the social development, the quantity of the waste concrete is increased year by year in the demolition of various buildings. It is expected that in the near future, China will soon become the country with the largest amount of waste concrete. However, most of the waste concrete in China is treated by landfill, and the environmental pressure is increasingly prominent. Meanwhile, few existing application methods or researches for recycling waste concrete mostly stay in the recycling stage of aggregate, and the high-value-added cementitious component in the concrete cannot be efficiently utilized. The method is a great waste of resources or energy sources, and is also a reason that the prior waste concrete has low recycling rate, high cost and limited popularization and application.

Waste concrete of any age contains a certain amount of unhydrated cement minerals. In addition, the hydrated mineral hydration products in the concrete are treated again, so that partial restoration of the gelling activity of the hydrated mineral hydration products can be realized, and in addition, the limestone aggregate can also form minerals with certain gelling activity after physical and chemical reactions. At present, the cement industry in China is under unprecedented resource, energy and environment pressure, and a new effective concrete recycling treatment and reutilization technology is formed by treatment through certain physical and chemical means, so that the green, low-carbon, environment-friendly and sustainable development of the cement industry is certainly and greatly promoted.

Disclosure of Invention

In view of the above, the main objective of the present invention is to provide a high-activity admixture prepared from waste concrete and thermal steel slag, and a preparation method and an application thereof, wherein the high-activity admixture is prepared by reactivating the waste concrete by using the waste heat of the molten steel slag.

The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme.

The preparation method of the high-activity mixed material provided by the invention comprises the following steps:

1) crushing the waste concrete to the maximum grain diameter of below 15 mm;

2) paving the concrete crushed in the step 1) to ensure that the height of the concrete does not exceed 5mm of the maximum particle size, pouring high-temperature molten steel slag with the temperature of more than 1500 ℃ within 1min, fully contacting and mixing the steel slag with concrete particles through melt flow, and insulating and hot-sealing for 5-30 min;

3) quickly cooling the material obtained in the step 2);

4) grinding the material cooled in the step 3), selecting iron by magnetic force, screening out coarse particles with the particle size of more than 125 microns when the particle size of the most probable particle size reaches below 100 microns, and continuously grinding until the fineness of the powder is below 3% of the screen residue with the particle size of 80 microns, thus obtaining the high-activity mixed material.

The object of the present invention and the technical problems solved thereby can be further achieved by the following technical measures.

Preferably, in the method for preparing the high-activity admixture, the weight ratio of the waste concrete to the molten steel slag is 20 to 80%.

Preferably, in the preparation method of the high-activity admixture, the waste concrete accounts for 20-75% of the total weight of the waste concrete and the high-temperature molten steel slag, and more preferably 20-50%.

Preferably, in the method for preparing the high-activity mixed material, in the step 2), the concrete is laid on the bottom of the cylindrical slag pit or the refractory crucible.

Preferably, in the preparation method of the high-activity mixed material, in the step 2), heat-insulating refractory bricks with the thickness of more than 10mm are arranged on the periphery of the slag pit.

Preferably, in the method for preparing the high-activity mixed material, in the step 3), the rapid cooling method is fan cooling.

Preferably, in the preparation method of the high-activity mixed material, in the step 3), the rotation speed of the electric fan is not lower than 500 rpm.

Preferably, in the preparation method of the high-activity mixed material, in the step 4), the material cooled in the step 3) is ground for 2-20 min, iron is selected by magnetic force, then the material is ground for 2-30 min, iron is selected by magnetic force, when the most probable particle size reaches below 100 μm, coarse particles of particles above 125 μm are screened out, and grinding is continued until the fineness of the powder is below 80 μm and the screen residue is below 3%, so that the high-activity mixed material can be obtained. The circular mode of grinding and magnetic iron selection is selected, so that the grinding efficiency is improved, and the energy consumption is saved.

Preferably, in the method for preparing the highly active mixed material, the step 4) further includes a step of beating the cooled material into pieces before grinding.

The purpose of the invention and the technical problem to be solved can be realized by adopting the following technical scheme.

According to the high-activity mixed material provided by the invention, the activity index of the high-activity mixed material is more than 80%, and the content of metallic iron is less than 1 wt%.

Preferably, in the highly active admixture, the highly active admixture is prepared by any one of the methods described above.

The purpose of the invention and the technical problem to be solved can be realized by adopting the following technical scheme.

According to the cement provided by the invention, the cement comprises the high-activity admixture.

Preferably, in the cement, the cement comprises, by weight: 60% -92% of cement clinker; 0.5 to 5 percent of natural dihydrate gypsum; 5 to 38 percent of high-activity mixed material.

Preferably, in the cement, the cement comprises, by weight: 80% of cement clinker; 5% of natural dihydrate gypsum; 15% of high-activity mixed material.

By the technical scheme, the high-activity mixed material prepared from the waste concrete and the steel slag, and the preparation method and the application thereof at least have the following advantages:

1. according to the preparation method and the application of the high-activity mixed material, the high-added-value gelling component in the waste concrete is effectively recycled, the cement consumption is reduced, and the low-carbon sustainable development of the cement industry is promoted.

2. The preparation method and the application of the high-activity mixed material effectively play the waste heat of the steel slag, do not need an additional heat source, and have the advantages of energy conservation, environmental protection and low economic cost.

3. The preparation method and the application of the high-activity mixed material take the waste concrete and the thermal steel slag as raw materials, simultaneously utilize two industrial solid wastes, save resource and energy, protect the environment and have high environmental benefit and economic benefit.

4. The preparation method and the application of the high-activity mixed material provided by the invention have the advantages that the waste concrete components are effectively activated and utilized by virtue of the steel slag treatment process at the tail end of the steel industry, no additional equipment or technology is needed, the preparation method is simple, convenient, rapid and strong in applicability, and the preparation method is widely suitable for steel manufacturers.

5. The preparation method and the application of the high-activity mixed material provide a new way for the resource utilization of steel slag in China, expand the resource and recycling utilization rate of the steel slag and can greatly promote the sustainable development of the steel industry.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

Drawings

Fig. 1 is an XRD pattern of the highly active admixture M1 prepared in example 1 of the present invention.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description will be given to the specific embodiments, structures, characteristics and effects of the highly reactive admixture prepared by using waste concrete and steel slag and the preparation method and application thereof according to the present invention with reference to the preferred embodiments.

The following materials or reagents, unless otherwise specified, are all commercially available.

The invention provides a preparation method of a high-activity mixed material, which comprises the following steps:

1) crushing the waste concrete to the maximum grain diameter of below 15 mm;

2) paving the concrete crushed in the step 1) to ensure that the height of the concrete does not exceed 5mm of the maximum particle size, pouring high-temperature molten steel slag with the temperature of more than 1500 ℃ within 1min, fully contacting and mixing the steel slag with concrete particles through melt flow, and insulating and hot-sealing for 5-30 min;

3) quickly cooling the material obtained in the step 2);

4) grinding the material cooled in the step 3), selecting iron by magnetic force, screening out coarse particles with the particle size of more than 125 microns when the particle size of the most probable particle size reaches below 100 microns, and continuously grinding until the fineness of the powder is below 3% of the screen residue with the particle size of 80 microns, thus obtaining the high-activity mixed material.