Gel material, industrial solid waste solidified immature soil material containing gel material and preparation method of gel material

Abstract

The invention provides a gel material, an industrial solid waste solidified immature soil material containing the gel material and a preparation method of the industrial solid waste solidified immature soil material, and belongs to the technical field of building materials.The industrial solid wastes such as desulfurized gypsum, carbide slag, slag powder and red mud are used for forming a full-solid-waste gel system, and the full-solid-waste gel system is mixed with immature soil, a water reducing agent and water; the high-flow-state and high-performance industrial solid waste solidified raw soil material suitable for pouring construction can be prepared on the premise of not additionally introducing an additive through a two-step method of ageing coating and stirring. The industrial solid waste solidified immature soil material has the advantages of being good in workability, high in mechanical property, good in durability, environmentally friendly, low in cost and simple in preparation process, use of the industrial solid waste solidified immature soil material in areas with relatively short resources and relatively backward economy is promoted, and the industrial solid waste solidified immature soil material can be used for treating engineering slurry and is applied to filling projects such as pipe galleries, temporary ground hardening and roads.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and in particular relates to a gel material, an industrial solid waste solidified raw soil material containing the gel material, and a preparation method thereof. Background Art

[0002] Raw earth materials refer to building materials that use raw earth as the main raw material and can be used for house construction without roasting and only simple processing. Raw earth materials have outstanding heat storage properties, making the interior of the house warm in winter and cool in summer; they can be made from local materials and adapted to local conditions, and are renewable; the processing process is low-energy and pollution-free. It is estimated that its processing energy consumption and carbon emissions are 3% and 9% of clay bricks and concrete, respectively. However, the disadvantages of raw earth materials are also very significant. They have poor mechanical properties, insufficient seismic resistance, poor water resistance, and lack of resistance to freezing, thawing and wind erosion. Therefore, their use and development are greatly restricted, and they are gradually replaced by concrete, masonry, and steel in house construction. On the other hand, raw earth materials are usually used in construction in the form of adobe and rammed earth. This ramming molding process is time-consuming and labor-intensive, and is not suitable for construction in narrow or irregular spaces.

[0003] At present, raw soil reinforcement materials are still mainly cement, lime, polyphosphate, polyquaternary ammonium salt, water glass and other materials. The production of these materials is a high-energy consumption and high-carbon emission process, which will greatly reduce the green and environmentally friendly characteristics of raw soil building materials. At the same time, a large number of industrial solid wastes with potential hydraulic activity in my country, such as desulfurized gypsum, carbide slag, slag powder and red mud, are produced and stored in large quantities every year at a scale of hundreds of millions of tons. Among them, desulfurized gypsum is an industrial byproduct gypsum obtained by coal or oil industrial enterprises after treating sulfur dioxide in flue gas. The main component is calcium sulfate dihydrate CaSO4·2H2O; carbide slag is the waste residue after calcium carbide is hydrolyzed to obtain acetylene gas, and the main components are calcium hydroxide and water; slag powder is the waste residue produced by the smelting of pig iron in steel plants, which is dried and ground, and is mainly composed of CaO, MgO, SiO2 and Al2O3; red mud is an industrial solid waste discharged when the aluminum industry extracts alumina, and is also mainly composed of Al2O3, SiO2, Fe2O3 and CaO. If these industrial solid wastes can be used as reinforcing materials for raw soil and a high-performance, high-fluidity raw soil material suitable for pouring construction can be developed, the raw soil material will have the advantages of high mechanical properties, good durability, green environmental protection, low cost and simple preparation process. This can promote its use in areas where resources are relatively scarce and the economy is relatively backward. This technology can also be used to process engineering mud and apply it to filling projects such as pipeline corridors, temporary ground hardening, and roads. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a gel material, an industrial solid waste solidified soil material containing the same, and a preparation method thereof. Based on the combined use of the full solid waste gelling system and the "two-step method" preparation process of aging, coating and stirring, a high-performance, high-fluidity industrial solid waste solidified soil material is finally prepared without the introduction of additional additives.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] A gel material, wherein the raw materials include, by weight:

[0008] 4-6 parts of desulfurized gypsum, 8-10 parts of carbide slag, 10-12 parts of slag powder and 6-9 parts of red mud.

[0009] Preferably, the average particle size of the desulfurized gypsum is less than 50 μm.

[0010] Preferably, the CaO content in the carbide slag is greater than 60%, and the average particle size is less than 8 μm.

[0011] Preferably, the specific surface area of ​​the slag powder is ≥400m 2 / kg, 28d activity index ≥95%.

[0012] Preferably, the red mud is Bayer process red mud, with a pH value of less than 12.5 and an average particle size of less than 15 μm.

[0013] Beneficial effects: The present invention limits the particle size and specific surface area of ​​each raw material in order to ensure its gelling activity; controls the CaO content in carbide slag to be greater than 60% in order to have sufficient calcium in the system; controls the pH value of red mud in order to control the alkali content of the system. The four components of industrial solid waste desulfurization gypsum, carbide slag, slag powder and red mud are synergistically compounded to form a full solid waste gelling system. The gelling system uses calcium silicate (CSH) gel, calcium aluminosilicate (CASH) gel and ettringite (AFt) as the main hydration products, which can greatly improve the mechanical properties of raw soil materials and durability such as water resistance and freeze-thaw resistance.

[0014] The second technical solution of the present invention:

[0015] A high-performance, high-fluidity raw soil material for solidifying industrial solid waste, the raw materials of which include raw soil, a water reducing agent and water, and also include the above-mentioned gel material.

[0016] Preferably, the raw materials include, by weight:

[0017] 65-75 parts of raw soil, 4-6 parts of desulfurized gypsum, 8-10 parts of carbide slag, 10-12 parts of slag powder, 6-9 parts of red mud, 0.3-0.6 parts of water reducer and 28-31 parts of water.

[0018] The third technical solution of the present invention:

[0019] The method for preparing the above-mentioned high-performance, high-fluidity industrial solid waste solidified raw soil material comprises the following steps: aging, coating and stirring the raw materials to prepare the industrial solid waste solidified raw soil material.

[0020] Preferably, the preparation method comprises the following steps:

[0021] (1) 20 wt.% of the cementitious material is mixed with the raw soil and stirred for 3-5 minutes, then 30 wt.% of water is added, stirring is continued for 5-7 minutes, and then curing is performed;

[0022] (2) The powdery material obtained after curing is mixed with the remaining cementitious material, the remaining water and the water reducing agent, and stirred for 5-7 minutes to obtain the high-performance, high-fluidity industrial solid waste solidified raw soil material.

[0023] Beneficial effects: The present invention proposes a "two-step" preparation process, which is divided into two steps: aging and coating, and re-stirring. In the aging and coating step, part of the pre-added gelling material can form a gel coating layer on the surface of the raw soil particles, which can enhance the tight bonding between the soil particles on the one hand, and reduce the contact area between the raw soil particles and their adsorption of water on the other hand, thereby releasing more free water in the system, improving the fluidity of the raw soil material, and making the prepared solidified raw soil material more suitable for pouring construction.

[0024] Preferably, the maintenance operation is:

[0025] Place under sealed conditions at a temperature of 20±2℃ and relative humidity greater than 95% for 3 days.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The present invention utilizes industrial solid wastes such as desulfurized gypsum, carbide slag, slag powder and red mud to form a full solid waste gelling system, replacing the currently commonly used cement, lime, polyphosphate, polyquaternary ammonium salt and water glass, while improving the mechanical properties and durability of raw soil materials, it has significant low-carbon environmental protection benefits and cost advantages; and adopts a "two-step" preparation process of aging coating-re-mixing to pre-form a gel coating layer on the surface of raw soil particles, release more free water, and prepare a highly fluid solidified raw soil material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 This is a flow chart for preparing a high-performance, high-fluidity industrial solid waste solidified raw soil material of the present invention;

[0030] Figure 2 The flow state diagram of the solidified raw soil material prepared in the embodiment and the comparative example;

[0031] in, Figure 2 (a) is Example 1, (b) is Comparative Example 1, and (c) is Comparative Example 2. DETAILED DESCRIPTION

[0032] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0033] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0034] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0035] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0036] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0037] All raw materials used in the examples of the present invention are commercially available.

[0038] Unless otherwise specified, the “parts” used in the embodiments of the present invention are “parts by weight”.

[0039] The technical solution of the present invention is further illustrated by the following embodiments.

[0040] The preparation flow chart of the high-performance, high-fluidity industrial solid waste solidified raw soil material of the present invention is shown in Figure 1 .

[0041] The technical solution of the present invention is further illustrated by the following embodiments.

[0042] The raw materials and properties used in the following examples and comparative examples of the present invention are as follows:

[0043] Raw soil: Clay, liquid limit (WL17) is 32.1%, plastic limit (WP) is 17.9%

[0044] Raw materials in cementitious materials: desulfurized gypsum with an average particle size of 43.26 μm; calcium carbide slag with an average particle size of 6.87 μm and a CaO content of 64%; a specific surface area of ​​432 m 2 / kg, slag powder with an activity index of 98% at 28d; red mud with an average particle size of 13.82μm.

[0045] Water reducing agent: Polycarboxylate water reducing agent Point-TS8.

[0046] Water: tap water.

[0047] Examples 1-4

[0048] In Examples 1-4, the raw material types and amounts of the high-performance, high-fluidity industrial solid waste solidified raw soil materials are shown in Table 1.

[0049] The specific preparation method is divided into two steps:

[0050] (1) Mix 20% of the cementitious materials (desulfurized gypsum, carbide slag, slag powder and red mud) with the raw soil and stir for 5 minutes, then add 30% of water and continue stirring for 5 minutes to obtain a wet powdery material. Then, seal the powdery material and place it under standard curing conditions of a temperature of 20±2°C and a relative humidity greater than 95% for 3 days;

[0051] (2) The powdered material after standing, the remaining 80% of the total mass of the cementitious material (desulfurized gypsum, carbide slag, slag powder and red mud), the remaining 70% of the total mass of water and the water reducing agent are mixed and stirred for 5 minutes to obtain a high-performance, high-fluidity industrial solid waste solidified raw soil material.

[0052] Table 1 Proportion of high-performance, high-fluidity industrial solid waste solidification raw soil materials (by mass)

[0053]

[0054] Comparative Example 1

[0055] The difference from Example 3 is that no industrial solid waste-based cementitious material is used, and PO 42.5 ordinary Portland cement in equal parts by weight is used as the cementitious material. Other conditions are the same as those in Example 3.

[0056] Comparative Example 2

[0057] The difference from Example 3 is that, during the preparation process, the solid waste-based cementitious materials (desulfurized gypsum, carbide slag, slag powder and red mud), raw soil, water and water reducing agent are directly mixed and stirred for 5 minutes.

[0058] Comparative Example 3

[0059] The difference from Example 3 is that only desulfurized gypsum and slag powder are used as cementitious materials, and the amounts thereof are 12 and 21 (by mass fraction), respectively. Other conditions are consistent with those of Example 3.

[0060] Effect verification

[0061] The high-performance, high-fluidity industrial solid waste solidified soil materials (hereinafter referred to as solidified soil materials) prepared in the above Examples 1-4 and the solidified soil materials prepared in Comparative Examples 1-3 were tested for performance, and the test results are shown in Table 2; the performance test method is as follows:

[0062] (1) Fluidity: Refer to the standard (GB / T 8077-2012) "Test method for homogeneity of concrete admixtures", use a conical fluidity test mold with an upper diameter of 36 mm, a lower diameter of 60 mm, and a height of 60 mm, and test on a glass plate. While the slurry is being stirred, the glass plate and the test mold are both wetted (the surface is wet but there is no obvious water mark) and placed on a horizontal table. After the slurry is stirred, fill the mold immediately, scrape it flat with a scraper, lift the mold vertically upward, and open the jump platform. After 25 jumps, measure the net slurry diameters in the vertical directions, and take the average value as the fluidity value of the sample.

[0063] (2) Compressive strength test: A cubic specimen of 40 × 40 × 160 mm was prepared and the compressive strength was tested at 7, 14 and 28 days under standard curing conditions of 20 ± 2 °C and relative humidity greater than 95%. The loading rate was 2.4 kN / s.

[0064] (3) Water softening coefficient test: The water softening coefficient of the solidified raw soil material is calculated by the following formula:

[0065] K=f / F×100%

[0066] Wherein, f is the compressive strength of the solidified soil material in the water-saturated state (MPa), and F is the compressive strength of the solidified soil material in the dry state (MPa).

[0067] (4) Freeze-thaw resistance test: Referring to GB / T 50082-2009 "Test methods for long-term performance and durability of ordinary concrete", the 28-day-old specimens were immersed in water at room temperature for 4 days, taken out and the surface moisture was wiped off, and the specimens were placed in the center of the freeze-thaw box and frozen at -17±2℃ for 4 hours, then taken out and placed in a water tank with a water temperature of 8±2℃ for 4 hours. This is one freeze-thaw cycle, and the test is completed after 25 cycles. The mass loss rate after the freeze-thaw cycle test is calculated as follows:

[0068] Δω n =(G0-G n ) / G0×100%

[0069] Where G0 is the average mass of the specimen after 25 freeze-thaw cycles, g; G n is the average mass of the comparison specimens, g.

[0070] Table 2 Performance test results of high-performance and high-fluidity industrial solid waste solidification raw soil materials

[0071]

[0072]

[0073] Conclusion: From the data in Table 2, it can be seen that the fluidity of the industrial solid waste solidified soil material prepared by the embodiment of the present invention is greater than 250mm, and there is no water seepage phenomenon, indicating that it has good working performance and is suitable for pouring construction; in addition, the compressive strength of the solidified soil material prepared by the present invention is more than 5MPa at 7d age, and reaches 15MPa at 28d, the water softening coefficient is greater than 90%, and the mass loss rate of freeze-thaw cycles is less than 6%. Therefore, the industrial solid waste solidified soil material prepared by the embodiment of the present invention has good working performance, high compressive strength, and excellent water resistance and freeze-thaw resistance.

[0074] The cement-solidified raw soil material prepared in Comparative Example 1 has a fluidity and compressive strength similar to those of the industrial solid waste-solidified raw soil material, but its water resistance and freeze-thaw resistance are worse than those of the industrial solid waste-solidified raw soil material prepared in the embodiment of the present invention; and the production of cement is a high-energy consumption process and does not have low-carbon characteristics; the solidified raw soil material prepared in Comparative Example 2 using a direct mixing process has low fluidity and a slow hardening rate compared to the embodiment, and still does not have hardening strength after 7 days, and its water resistance and freeze-thaw resistance are both poor.

[0075] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A gel material, characterized in that: The raw materials include, by weight: 4-6 parts of desulfurized gypsum, 8-10 parts of carbide slag, 10-12 parts of slag powder and 6-9 parts of red mud.

2. The gel material according to claim 1, characterized in that: The average particle size of the desulfurized gypsum is less than 50 μm.

3. The gel material according to claim 1, characterized in that: The CaO content in the carbide slag is greater than 60%, and the average particle size is less than 8 μm.

4. The gel material according to claim 1, characterized in that: The specific surface area of ​​the slag powder is ≥400m 2 / kg, 28d activity index ≥95%.

5. The gel material according to claim 1, characterized in that: The red mud is Bayer red mud, has a pH value of less than 12.5, and an average particle size of less than 15 μm.

6. A high-performance, high-fluidity raw soil material for industrial solid waste solidification, the raw materials of which include raw soil, a water reducing agent and water, characterized in that: The raw materials also include the gel material described in any one of claims 1-5.

7. The high-performance, high-fluidity industrial solid waste solidified soil material according to claim 6, characterized in that: In terms of weight, the raw materials include: 65-75 parts of raw soil, 4-6 parts of desulfurized gypsum, 8-10 parts of carbide slag, 10-12 parts of slag powder, 6-9 parts of red mud, 0.3-0.6 parts of water reducer and 28-31 parts of water.

8. A method for preparing a high-performance, high-fluidity industrial solid waste solidified soil material as claimed in claim 6 or 7, characterized in that: The raw materials are subjected to aging, coating and stirring treatments to prepare the industrial solid waste solidified raw soil material.

9. The method for preparing high-performance, high-fluidity industrial solid waste solidified raw soil material according to claim 8, characterized in that: The following steps are involved: (1) 20 wt.% of the cementitious material is mixed with the raw soil and stirred for 3-5 minutes, then 30 wt.% of water is added, stirring is continued for 5-7 minutes, and then curing is performed; (2) Mixing the powdery material obtained after curing with the remaining cementitious material, the remaining water and the water reducing agent, and stirring for 5-7 minutes to obtain the industrial solid waste solidified raw soil material.

10. The method for preparing high-performance, high-fluidity industrial solid waste solidified soil material according to claim 9, characterized in that: The maintenance operation in step (1) is as follows: Place under sealed conditions at a temperature of 20±2℃ and relative humidity greater than 95% for 3 days.

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