Waste steel slag and muck mixture recycling building material

Abstract

The invention relates to a waste steel slag and muck mixture recycling building material which is composed of a waste steel slag and muck mixture, a binding material and water, and the waste steel slag and muck mixture is a steel slag and muck mixture obtained after a steel slag buried mixture is subjected to magnetic separation. According to the waste steel slag and muck mixture recycling building material, the polluted muck mixture originally needing high-cost treatment is converted into functional building materials such as standard bricks and other recycling products, and meanwhile the dual industry pain points of high pollution treatment cost and difficult historical remaining waste treatment are solved.

Description

Technical Field

[0001] This invention belongs to the field of contaminated soil treatment technology, specifically relating to the resource utilization of waste steel slag and soil mixtures for building materials. Background Technology

[0002] Decades ago, there was a lack of regulations, standards, and technical methods for the use of steel slag as building materials. It was usually discarded and buried underground in the factory area. These were considered "historical waste".

[0003] Limited by outdated production processes in the past, the quality of steel slag is inconsistent and poses a risk of pollution such as heavy metals. Furthermore, long-term underground burial has caused the remaining steel slag to become completely aged, losing the activity of fresh steel slag (similar to cement becoming ineffective after long-term storage). In addition, the aged buried steel slag has a complex and uneven composition, consisting of a mixture of remaining steel slag, soil, gravel, and other materials, with particle sizes ranging from large to small, and is not a single steel slag component.

[0004] According to the current national standards and regulations in the field of contaminated soil and groundwater remediation, this type of landfill mixture is defined as "contaminated soil" and requires special remediation. The remediation cost is several hundred yuan per cubic meter, and the amount to be treated is huge, resulting in extremely high overall economic expenditure. At the same time, the industry lacks efficient and low-cost remediation technologies for this type of waste soil mixture.

[0005] Traditional steel slag building materials use "fresh steel slag" as the core raw material (produced by steel mills, active, and in compliance with existing standards). It can be mixed with traditional cementitious materials such as cement to make bricks, and brick factories are willing to purchase it at low prices (it has both raw material value and waste disposal value). However, the above-mentioned waste landfill steel slag mixture, when processed by traditional processes, either cannot be formed or has insufficient strength after forming, and is considered "negative value" waste, which brick factories refuse to accept.

[0006] In the process of remediating such traditional contaminated sites, "magnetic separation technology" has been applied to the separation of steel slag from contaminated sites and has been applied on an engineering scale. However, if the mixture after separation is only temporarily stored by stockpiling, it will still create new waste stockpiling problems and fail to achieve the goal of site pollution remediation, further promoting the necessity of resource utilization research. Summary of the Invention

[0007] The main objective of this invention is to address the above-mentioned problems by providing a resource-based building material made from a mixture of waste steel slag and soil.

[0008] The purpose of this invention is to provide a resource-based building material made from a mixture of waste steel slag and soil. Its main feature is that it is composed of a mixture of waste steel slag and soil, cementing materials and water. The waste steel slag and soil mixture is a mixture of steel slag landfill mixture after magnetic separation.

[0009] Preferably, the weight ratio of the waste steel slag mixture to the cementitious material is 4:1 to 7:1, and the water content is 4% to 8%.

[0010] Preferably, the gelling material is a solid waste gelling material.

[0011] Preferably, the maximum particle size in the waste steel slag and soil mixture is ≤20mm.

[0012] Preferably, the building material is a building brick, which is formed by mixing and stirring the waste steel slag mixture, cementing material and water for 2 to 6 minutes and then pressing it into shape in a mold.

[0013] The waste steel slag and soil mixture of the present invention is a resource-based building material that transforms the "polluted soil mixture" that originally required high-cost treatment into a functional building material, such as standard bricks and other resource-based products, thereby solving the dual industry pain points of "high cost of pollution treatment" and "difficulty in disposing of historical waste". Attached Figure Description

[0014] Figure 1 This is a process flow diagram for preparing building bricks from waste steel slag and soil mixtures according to the present invention.

[0015] Figure 2 The image shows the compressive strength test results in Example 2. Detailed Implementation

[0016] To provide a clearer understanding of the technical content of this invention, the following embodiments are provided in detail. However, it is important to note that these descriptions are merely for further illustrating the features and advantages of this invention, and not for limiting the scope of the claims. Example

[0017] like Figure 1 As shown, the waste steel slag and soil mixture of the present invention is used to prepare resource-based building bricks. The proportions of the waste steel slag and soil mixture, cementitious materials, and water are shown in Table 2 below. The water content is the ratio of the weight of the added water to the total weight of the waste steel slag and soil mixture and cementitious materials. For example, if the total weight of the waste steel slag and soil mixture and cementitious materials is 10 kg, then 4% water content is equivalent to 0.4 kg of water.

[0018] The waste steel slag and soil mixture used was a mixture of steel slag and soil from a contaminated site left over from a steel plant, after magnetic separation. Referring to the magnetic separation method disclosed in CN120155446A, the total particle size was ≤20mm.

[0019] Conventional brick-making aggregates have corresponding standard requirements for mud content, mud lump content, and crushing value, as specified in the "Construction Gravel and Crushed Stone" (GB / T 14685-2022). In this embodiment, steel slag was used as aggregate, and the corresponding indicators were tested. Mud content: the content of clay particles with a diameter of less than 75μm in the gravel; mud lump content: the content of particles with an original diameter greater than 4.75mm in the gravel and crushed stone, which are smaller than 2.36mm after water soaking and washing; crushing value: refers to the performance index of aggregate resistance to crushing. The aggregate crushing value is used to measure the ability of stone to resist crushing under gradually increasing load. It is expressed as a percentage, which is the ratio of the weight of crushed debris to the total weight of the sample, as measured by the specified test method. The above indicators were tested according to the test methods in "Construction Gravel and Crushed Stone" (GB / T 14685-2022).

[0020] As shown in Table 1 below, the steel slag and soil mixture in this embodiment has a mud content and mud lump content that are far from meeting the standard requirements, while the crushing value of 5mm~20mm crushed stone meets the minimum requirements.

[0021] ; The gelling material used is a solid waste cementing material that meets the "Technical Standard for Application of High-Performance Concrete Made from Solid Waste".

[0022] The prepared building bricks were subjected to compressive strength testing in accordance with the provisions of GB / T 4111 "Test Methods for Concrete Blocks and Bricks", as detailed in Table 2 below. Figure 2 As shown.

[0023] ; The standard requirements for compressive strength of "Solid Concrete Bricks" (GB 21144-2023) are shown in Table 3 below.

[0024] ; As can be seen from the above examples, under the same formula, the brick strength of cementitious materials is not as good as that of all-solid-waste cementitious materials; when the material-to-slag ratio of all-solid-waste cementitious materials is greater than 1:7, the compressive strength grade can basically reach MU10; the higher the proportion of cementitious materials, the higher the brick strength, but the higher the proportion, the lower the growth rate of brick strength; the higher the water content, the higher the brick strength, but too much water will affect brick forming and demolding. In actual production, it is recommended that the water content be 4% to 8%; increasing the mixing time can slightly enhance the brick strength and make the brick quality homogeneity better. In actual production, it is recommended that the mixing time be 3 to 6 minutes; when the material-to-slag ratio is 1 / 6, the water content is 5%, and the mixing time is 3 minutes, the brick strength grade reaches MU15, and the brick making economic efficiency is the highest.

[0025] In this specification, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, this specification should be considered illustrative rather than restrictive.

Claims

1. A resource-based building material made from a mixture of waste steel slag and soil, characterized in that, It is composed of a mixture of waste steel slag and soil, cementing materials and water, wherein the waste steel slag and soil mixture is a mixture of steel slag landfill mixture after magnetic separation.

2. The resource-based building material made from waste steel slag and soil mixture according to claim 1, characterized in that, The weight ratio of the waste steel slag mixture to the cementitious material is 4:1 to 7:

1.

3. The resource-based building material made from waste steel slag and soil mixture according to claim 1, characterized in that, The cementing material mentioned is a solid waste cementing material.

4. The resource-based building material made from waste steel slag and soil mixture according to claim 1, characterized in that, The maximum particle size in the waste steel slag and soil mixture is ≤20mm.

5. The resource-based building material made from waste steel slag and soil mixture according to claim 1, characterized in that, The building material is a building brick, which is made by mixing waste steel slag and soil, cementing material and water for 2 to 6 minutes and then pressing it into shape in a mold.

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