Solid waste-based cementing material and preparation method thereof

Abstract

The invention relates to a solid waste-based cementing material and a preparation method thereof, belongs to the technical field of solid waste recycling, and solves the technical problems that the use effect is influenced by limited solid waste doping amount, few solid waste types and unqualified stability when the solid waste-based cementing material is prepared from the existing solid waste material. According to the solution, the solid waste-based cementing material is prepared from the following components in parts by mass: 25 to 35 parts of fly ash, 10 to 20 parts of carbide slag, 5 to 10 parts of desulfurized gypsum, 15 to 25 parts of steel slag and 25 to 35 parts of mineral slag. The method is used for preparing the solid waste-based cementing material and comprises the following steps: 1) removing iron; 2) drying; the materials obtained in the step 2 are ground through a ball mill, sampled and sealed, the materials obtained in the step 3 are put into a dry powder stirrer according to the proportion to be evenly stirred to obtain the solid waste-based cementing material.Compared with the prior art, the method has the advantages that the solid waste doping amount reaches 100%, multi-element solid waste doping is achieved, and the stability is qualified.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste recycling, and particularly relates to a solid waste-based cementitious material and a preparation method thereof. Background Art

[0002] Industrial solid waste refers to various waste residues, dusts and other solid wastes generated in industrial production activities. Among them, fly ash, coal gangue, steel slag, carbide slag, desulfurized gypsum, etc. are listed as bulk industrial solid wastes by the state. The discharge of a large amount of industrial solid wastes causes extremely strong pollution to the environment. At the same time, improper handling of problems such as the scattering during the handling, cleaning and stacking of solid wastes and the flying of dust and ash sand will also cause secondary pollution to the environment, with great harm. Many inorganic industrial solid wastes such as fly ash, desulfurized gypsum, and slag are by-products generated through high-temperature sintering or chemical reactions, and have potential chemical reaction activities, and can be used as raw materials for preparing inorganic cementitious materials.

[0003] However, there are still the following problems in the prior art for preparing solid waste-based cementitious materials using solid waste materials: First, the addition amount of solid waste is very limited, basically only maintained at about 50%-70%, and a certain amount of pure cement needs to be added to achieve the use effect. This is mainly because the activity of solid waste materials is not as easy to be stimulated as that of cement; Second, the types of solid waste are few. Most of the existing solid waste-based cementitious materials are prepared with fly ash and steel slag as the main body, supplemented by pure cement. The solid waste materials play more of a filling role, and the use value has not been fully developed; Third, the reason for the unqualified soundness of the cementitious material prepared with steel slag is that the steel slag itself contains more free calcium oxide, and the free calcium oxide is very unstable inside and is prone to digestion, which in turn causes cracks in the solid waste-based cementitious material after hardening, affecting the use effect. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art and solve the technical problems such as limited addition amount of solid waste, few types of solid waste, and unqualified soundness affecting the use effect when preparing solid waste-based cementitious materials with existing solid waste materials, the present invention provides a solid waste-based cementitious material and a preparation method thereof.

[0005] The present invention is realized through the following technical solutions.

[0006] The present invention provides a solid waste-based cementitious material, which includes 25-35 parts of fly ash, 10-20 parts of carbide slag, 5-10 parts of desulfurized gypsum, 15-25 parts of steel slag and 25-35 parts of slag by mass fraction.

[0007] Further, the grinding particle size D50 of the fly ash is 10-15 μm.

[0008] Further, the grinding particle size D50 of the carbide slag is 6 - 10 μm.

[0009] Further, the grinding particle size D50 of the desulfurized gypsum is 5 - 8 μm.

[0010] Further, the grinding particle size D50 of the steel slag is 5 - 8 μm.

[0011] Further, the grinding particle size D50 of the slag is 6 - 12 μm.

[0012] Further, for the preparation of a solid waste-based cementitious material, the following steps are included: Iron removal: Removing iron from fly ash, carbide slag, desulfurized gypsum, steel slag and slag through an iron remover; Drying: Separately drying the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 1) to a water content < 8%; Grinding: Using a ball mill to respectively grind the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 2) to obtain fly ash with a grinding particle size D50 of 10 - 15 μm, carbide slag with a grinding particle size D50 of 6 - 10 μm, desulfurized gypsum with a grinding particle size D50 of 5 - 8 μm, steel slag with a grinding particle size D50 of 5 - 8 μm and slag with a grinding particle size D50 of 6 - 12 μm, and taking samples for sealing; Mixing: Putting the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 3) into a dry powder mixer according to the ratio of 25 - 35 parts of fly ash, 10 - 20 parts of carbide slag, 5 - 10 parts of desulfurized gypsum, 15 - 25 parts of steel slag and 25 - 35 parts of slag, and mixing evenly to obtain a solid waste-based cementitious material; Testing performance: Testing the flexural strength, compressive strength and soundness performance of the solid waste-based cementitious material obtained in step 4) according to the national standard testing method for cement.

[0013] The beneficial effects achieved by the present invention are as follows: The present invention selects fly ash, carbide slag, desulfurized gypsum, steel slag and slag, and uses a five-component solid waste system to prepare a solid waste-based cementitious material, and the solid waste addition amount reaches 100%; The grinding operation is selected to stimulate the hydration performance of the raw materials, and the five-component solid waste mixing synergistic effect reacts with each other to form a strength comparable to that of cement. At the same time, the flexural strength and compressive strength after 7 days and 28 days of curing period both exceed the national standard of cement. In addition, the partial synergistic effect of the five-component solid waste system alleviates the crack problem caused by more free calcium oxide in the steel slag; In addition, the solid waste-based cementitious material prepared by the present invention partially replaces cement, which can reduce a large amount of carbon dioxide emissions. It can not only achieve large-scale digestion of industrial solid waste, but also achieve low-cost preparation of building cementitious materials.

[0014] Compared with the prior art, the present invention has the advantages of a solid waste admixture amount reaching 100%, multi-component solid waste admixture, and qualified soundness. Specific Embodiments

[0015] The present invention will be further described in detail below in conjunction with embodiments. Embodiment

[0016] A solid waste-based cementitious material, by mass fraction, includes 30 parts of fly ash, 20 parts of carbide slag, 10 parts of desulfurized gypsum, 15 parts of steel slag, and 25 parts of slag.

[0017] Among them, the grinding particle size D50 of the fly ash is 11 μm; the grinding particle size D50 of the carbide slag is 6 μm; the grinding particle size D50 of the desulfurized gypsum is 8 μm; the grinding particle size D50 of the steel slag is 8 μm; the grinding particle size D50 of the slag is 8 μm.

[0018] For preparing a solid waste-based cementitious material, the following steps are included: 1) Iron removal: Pass the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag through a magnetic separator to remove iron filings and impurities mixed in during the production process; 2) Drying: Separate and dry the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag obtained in step 1) until the water content < 8%; 3) Grinding: Use a ball mill to grind the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag obtained in step 2) respectively to obtain fly ash with a grinding particle size D50 of 11 μm, carbide slag with a grinding particle size D50 of 6 μm, desulfurized gypsum with a grinding particle size D50 of 8 μm, steel slag with a grinding particle size D50 of 8 μm, and slag with a grinding particle size D50 of 8 μm, and sample and seal; 4) Mixing: Put the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag obtained in step 3) into a dry powder mixer according to the ratio of 30 parts of fly ash, 20 parts of carbide slag, 10 parts of desulfurized gypsum, 15 parts of steel slag, and 25 parts of slag, and stir evenly to obtain a solid waste-based cementitious material; 5) Performance testing: Carry out flexural strength, compressive strength, and soundness performance tests on the solid waste-based cementitious material obtained in step 4) according to the national standard test method for cement.

[0019] The test methods for flexural strength and compressive strength are as follows: After preparing mortar materials in a mixing tank according to the ratio of solid waste-based cementitious material: standard sand: water = 450 g: 1350 g: 225 ml, load them into the test mold. After selecting the paving material, perform two operations in the vibration table vibration mode for 60 times, then remove the mold, place it in a curing room at 20°C and a humidity of more than 90% for standard curing. After 24 h, demold and soak it in normal temperature water for curing. After 7 days and 28 days of curing periods, conduct flexural strength and compressive strength tests.

[0020] In this example, the 7-day flexural strength of the solid waste-based cementitious material is 5.5 MPa, exceeding the 7-day flexural strength of 3.6 MPa of the standard 325 cement. The 7-day compressive strength of the solid waste-based cementitious material is 25.6 MPa, exceeding the 7-day compressive strength of 20.2 MPa of the standard 325 cement; the 28-day flexural strength of the solid waste-based cementitious material is 7.6 MPa, exceeding the 28-day flexural strength of 5.9 MPa of the standard 325 cement, and the 28-day compressive strength of the solid waste-based cementitious material is 37.1 MPa, exceeding the 28-day compressive strength of 32.5 MPa of the standard 325 cement.

[0021] The test method for soundness performance is as follows: Prepare two test cakes with a diameter of 70 - 80 mm, a central thickness of about 10 mm, thinner edges, and a smooth surface according to the standard consistency test method. Cure the test cakes in a standard curing box for 24 h. After taking out the test cakes, place them in a boiling box and boil for about 4 h under the condition that there are no cracks on the surface of the test cakes, then check whether there are cracks on the surface of the test cakes and use a ruler to test whether there is bending. If there is no such situation, it is qualified, otherwise it is unqualified. If the judgment conclusions of the two test cakes are the same, it is considered that the overall soundness is qualified.

[0022] The soundness performance test of the solid waste-based cementitious material in this example is qualified.

[0023] In this example, a five-component solid waste system is selected to prepare the solid waste-based cementitious material, and the solid waste addition amount reaches 100%. The grinding operation is selected to stimulate the hydration performance of the raw materials. The flexural strength and compressive strength after 7 days and 28 days of curing periods both exceed the national cement standards. In addition, the partial synergistic effect of the five-component solid waste system alleviates the crack problem caused by more free calcium oxide in steel slag. Example

[0024] A solid waste-based cementitious material, by mass fraction, includes 25 parts of fly ash, 20 parts of carbide slag, 10 parts of desulfurized gypsum, 15 parts of steel slag, and 30 parts of slag.

[0025] Among them, the grinding particle size D50 of the fly ash is 11 μm; the grinding particle size D50 of the carbide slag is 6 μm; the grinding particle size D50 of the desulfurized gypsum is 8 μm; the grinding particle size D50 of the steel slag is 8 μm; the grinding particle size D50 of the slag is 8 μm.

[0026] A method for preparing a solid waste-based cementitious material includes the following steps: 1) Iron removal: Pass the fly ash, carbide slag, desulfurized gypsum, steel slag and slag through a magnetic separator to remove iron filings and impurities mixed in during the production process; 2) Drying: Separate and dry the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 1) to a water content < 8%; 3) Grinding: Use a ball mill to grind the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 2) respectively to obtain fly ash with a grinding particle size D50 of 11 μm, carbide slag with a grinding particle size D50 of 6 μm, desulfurized gypsum with a grinding particle size D50 of 8 μm, steel slag with a grinding particle size D50 of 8 μm and slag with a grinding particle size D50 of 8 μm, and sample and seal them; 4) Stirring: Put the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 3) into a dry powder mixer according to the ratio of 25 parts of fly ash, 20 parts of carbide slag, 10 parts of desulfurized gypsum, 15 parts of steel slag and 30 parts of slag, and stir evenly to obtain a solid waste-based cementitious material; 5) Testing performance: Test the flexural strength, compressive strength and soundness performance of the solid waste-based cementitious material obtained in step 4) according to the national standard test method for cement.

[0027] The test methods for flexural strength and compressive strength and the soundness performance test are the same as those in Example 1. In this example, the 7-day flexural strength of the solid waste-based cementitious material is 5.1 MPa, exceeding the 7-day flexural strength of 3.6 MPa of the standard 325 cement. The 7-day compressive strength of the solid waste-based cementitious material is 22.8 MPa, exceeding the 7-day compressive strength of 20.2 MPa of the standard 325 cement. The 28-day flexural strength of the solid waste-based cementitious material is 7.3 MPa, exceeding the 28-day flexural strength of 5.9 MPa of the standard 325 cement. The 28-day compressive strength of the solid waste-based cementitious material is 33.6 MPa, exceeding the 28-day compressive strength of 32.5 MPa of the standard 325 cement.

[0028] The soundness performance test of the solid waste-based cementitious material in this example is qualified.

[0029] In this embodiment, a five-component solid waste system is selected to prepare a solid waste-based cementitious material, and the solid waste addition amount reaches 100%. The grinding operation is selected to stimulate the hydration performance of the raw materials. The flexural strength and compressive strength after the 7-day and 28-day curing periods exceed the national cement standards. In addition, the partial synergistic effect of the five-component solid waste system alleviates the crack problem caused by the relatively large amount of free calcium oxide in the steel slag. Embodiment

[0030] A solid waste-based cementitious material, by mass fraction, includes 35 parts of fly ash, 15 parts of carbide slag, 10 parts of desulfurized gypsum, 15 parts of steel slag, and 25 parts of slag.

[0031] Among them, the grinding particle size D50 of the fly ash is 11 μm; the grinding particle size D50 of the carbide slag is 6 μm; the grinding particle size D50 of the desulfurized gypsum is 8 μm; the grinding particle size D50 of the steel slag is 8 μm; the grinding particle size D50 of the slag is 8 μm.

[0032] For the preparation of a solid waste-based cementitious material, the following steps are included: 1) Iron removal: Pass the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag through a magnetic separator to remove the iron filings and impurities mixed in during the production process; 2) Drying: Separate and dry the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag obtained in step 1) to a water content of <8%; 3) Grinding: Use a ball mill to grind the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag obtained in step 2) respectively to obtain fly ash with a grinding particle size D50 of 11 μm, carbide slag with a grinding particle size D50 of 6 μm, desulfurized gypsum with a grinding particle size D50 of 8 μm, steel slag with a grinding particle size D50 of 8 μm, and slag with a grinding particle size D50 of 8 μm, and take samples for sealing; 4) Stirring: Put the fly ash, carbide slag, desulfurized gypsum, steel slag, and slag obtained in step 3) into a dry powder mixer according to the ratio of 35 parts of fly ash, 15 parts of carbide slag, 10 parts of desulfurized gypsum, 15 parts of steel slag, and 25 parts of slag, and stir evenly to obtain a solid waste-based cementitious material; 5) Performance testing: Carry out flexural strength, compressive strength, and soundness performance tests on the solid waste-based cementitious material obtained in step 4) according to the national cement standard test method.

[0033] The testing methods for flexural strength, compressive strength, and soundness performance are the same as those in Example 1. In this example, the 7-day flexural strength of the solid waste-based cementitious material is 5.2 MPa, exceeding the 7-day flexural strength of 325 standard cement, which is 3.6 MPa. The 7-day compressive strength of the solid waste-based cementitious material is 22.9 MPa, exceeding the 7-day compressive strength of 325 standard cement, which is 20.2 MPa. The 28-day flexural strength of the solid waste-based cementitious material is 7.5 MPa, exceeding the 28-day flexural strength of 325 standard cement, which is 5.9 MPa. The 28-day compressive strength of the solid waste-based cementitious material is 34.2 MPa, exceeding the 28-day compressive strength of 325 standard cement, which is 32.5 MPa.

[0034] The soundness performance test of the solid waste-based cementitious material in this example is qualified.

[0035] In this example, a five-component solid waste system is selected to prepare the solid waste-based cementitious material, and the solid waste addition amount reaches 100%. The grinding operation is selected to stimulate the hydration performance of the raw materials. The flexural strength and compressive strength after 7-day and 28-day curing periods both exceed the national cement standards. In addition, the partial synergistic effect of the five-component solid waste system alleviates the crack problem caused by the relatively high content of free calcium oxide in steel slag.

[0036] The embodiments of the present invention have been described in detail above in conjunction with the examples. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, the embodiments can still be modified. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A solid waste-based cementitious material, characterized in that: It comprises 25-35 parts of fly ash, 10-20 parts of carbide slag, 5-10 parts of desulfurized gypsum, 15-25 parts of steel slag and 25-35 parts of slag by mass fraction.

2. The solid waste-based cementitious material according to claim 1, wherein: The grinding particle size D50 of the fly ash is 10-15 μm.

3. The solid waste-based cementitious material according to claim 1, characterized in that: The grinding particle size D50 of the carbide slag is 6-10 μm.

4. A solid waste-based cementitious material according to claim 1, characterized in that: The grinding particle size D50 of the desulfurized gypsum is 5-8 μm.

5. The solid waste-based cementitious material according to claim 1, wherein: The grinding particle size D50 of the steel slag is 5-8 μm.

6. The solid waste-based cementitious material according to claim 1, wherein: The grinding particle size D50 of the slag is 6-12 μm.

7. A preparation method of a solid waste-based cementitious material, characterized in that: A method for preparing a solid waste-based cementitious material as described in any one of claims 1-6, comprising the following steps: 1) Iron removal: Removing iron from fly ash, carbide slag, desulfurized gypsum, steel slag and slag by an iron remover; 2) Drying: Separately drying the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 1) until the water content is <8%; 3) Grinding: Using a ball mill to separately grind the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 2) to obtain fly ash with a grinding particle size D50 of 10-15 μm, carbide slag with a grinding particle size D50 of 6-10 μm, desulfurized gypsum with a grinding particle size D50 of 5-8 μm, steel slag with a grinding particle size D50 of 5-8 μm and slag with a grinding particle size D50 of 6-12 μm, and sampling and sealing; 4) Mixing: Placing the fly ash, carbide slag, desulfurized gypsum, steel slag and slag obtained in step 3) into a dry powder mixer according to the ratio of 25-35 parts of fly ash, 10-20 parts of carbide slag, 5-10 parts of desulfurized gypsum, 15-25 parts of steel slag and 25-35 parts of slag, and mixing evenly to obtain a solid waste-based cementitious material; 5) Testing performance: Testing the flexural strength, compressive strength and soundness performance of the solid waste-based cementitious material obtained in step 4) according to the national standard testing method for cement.