Low-carbon cementing material and preparation method thereof

Abstract

The invention discloses a low-carbon cementing material and a preparation method thereof, and relates to the technical field of metallurgy. The method comprises the following steps: fully mixing the industrial solid waste with metal alkaline hydroxide, silicon oxide and pulverized coal according to a certain proportion to obtain a mixed material; roasting the mixed material at a certain temperature, and grinding to obtain roasted industrial solid waste; wherein the roasting temperature is 300-1000 DEG C, and the roasting time is 1-8 hours; and adding an alkali activator into the roasted industrial solid waste, fully mixing, and then hydrating and curing to obtain the high-strength low-carbon cementing material. According to the preparation method of the low-carbon cementing material, multiple industrial solid wastes are subjected to synergistic heat treatment for preparation, the potential activity of the solid wastes is greatly excited through a method of carrying out synergistic heat treatment on the multiple solid wastes and the additive, the synergistic gelling effect among the solid wastes is exerted, the potential activity of the solid wastes can be greatly excited under the action of a conventional alkali activator and low-temperature roasting, and the low-carbon cementing material is prepared. The high-strength low-carbon cementing material is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a low-carbon gelling material and a preparation method thereof. Background Art

[0002] A large amount of solid waste is generated during the production process of the metallurgical industry. It has the disadvantages of poor activity and easy expansion when exposed to water. There is currently no effective way to deal with it. The conventional practice of enterprises is to store or use a small amount as cement filler, but the blending ratio in cement is low, and the issuance of the new national standard "General Portland Cement" (GB175-2023) has clearly restricted the application of industrial solid waste in the field of cement. Low-carbon cementitious materials are green and environmentally friendly, and they all use industrial solid waste. They can replace cement concrete as a structural building material. Studies have shown that the problem of low-carbon cementitious materials mainly focuses on how to effectively exert the synergistic effect between solid wastes. Scholars have carried out a lot of research on the above issues. Most of the research focuses on the effects of various reaction parameters such as the type and dosage of alkali activators, mechanical activation time and method, type of chemical activators and pH on the activity of materials. However, there are still problems such as single excitation means, poor activity excitation effect, low strength, high process implementation cost or low material added value, which have not been realized in engineering applications. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for preparing a low-carbon cementitious material. The method uses a variety of industrial solid wastes as raw materials, and synergistically heat-treats the various solid wastes and admixtures to exert the synergistic gelling effect between the solid wastes, thereby obtaining a high-strength low-carbon cementitious material.

[0004] The present invention adopts the following technical solutions:

[0005] A method for preparing a low-carbon gelling material, the method comprising:

[0006] The industrial solid waste is fully mixed with metal alkaline hydroxide, silicon oxide and coal powder in a certain proportion to obtain a mixed material;

[0007] The mixed material is roasted at a certain temperature and then ground to obtain roasted industrial solid waste; wherein the roasting temperature is 300-1000° C. and the roasting time is 1-8 hours;

[0008] Adding an alkali activator to the calcined industrial solid waste, fully mixing and hydrating and curing, to obtain a high-strength low-carbon cementitious material;

[0009] Among them, the amount of the metal alkaline hydroxide added to the mixed material is 5% to 30%; the amount of the silicon oxide added is 1% to 10%; the amount of the coal powder added is 1% to 5%; and the rest is industrial solid waste;

[0010] The amount of the alkali activator added and the water-cement ratio of the industrial solid waste are 0.2-0.5.

[0011] Wherein, the industrial solid waste is solid waste generated in the industrial production process, and the industrial solid waste includes CaO, SiO2 and Al2O3, wherein the mass percentage of CaO is not less than 10%, the mass percentage of SiO2 is not less than 30%, and the mass percentage of Al2O3 is not less than 20%;

[0012] And the mass percentage of Fe2O3 in the industrial solid waste is not more than 5%.

[0013] Wherein, the mass percentage of CaO in the industrial solid waste is 10-20%, the mass percentage of SiO2 is 30-35%, and the mass percentage of Al2O3 in the industrial solid waste is 25-31%. Preferably, the mass percentage of CaO in the industrial solid waste is 11-20%, the mass percentage of SiO2 is 30-33%, and the mass percentage of Al2O3 in the industrial solid waste is 25-31%. More preferably, the mass ratio of SiO2 to Al2O3 is as close to 1 as possible, and preferably the mass ratio of SiO2 to Al2O3 is 1.08-1.06.

[0014] Wherein, the water content of the industrial solid waste is below 10wt%;

[0015] And / or, the specific surface area of ​​the industrial solid waste is greater than 200m 2 / kg.

[0016] Wherein, the metal alkaline hydroxide is one or more of KOH, NaOH, BaOH2, Ca(OH)2, Mg(OH)2, Zn(OH)2 or Sr(OH)2.

[0017] The silicon oxide is one or a mixture of silicon monoxide, silicon dioxide or disilicate.

[0018] Wherein, the particle size of the silicon oxide is in the range of 1 to 100 nm.

[0019] Wherein, the coal powder particle diameter ranges from 0 to 1000 μm, and the carbon content is >80%;

[0020] And / or, the particle size of the industrial solid waste is 40 to 150 microns.

[0021] Wherein, the alkaline activator is a sodium silicate solution with a modulus range of 0.5~3.

[0022] The curing process of the low-carbon cementitious material is as follows: temperature 10-30°C, humidity 80-100%, and curing time 3-28 days.

[0023] A low-carbon gelling material is prepared by adopting the above method.

[0024] The beneficial effects of the present invention are:

[0025] The preparation method of the low-carbon cementitious material of the present invention adopts the synergistic heat treatment of multiple industrial solid wastes. By using the method of synergistic heat treatment of multiple solid wastes and admixtures, the potential activity of the solid waste is greatly stimulated, and different types of solid wastes and matching proportions are selected to give play to the synergistic gelling effect between the solid wastes. Under the action of conventional alkali activators and low-temperature roasting, the potential activity of the solid waste can be greatly stimulated to obtain a high-strength low-carbon cementitious material. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the compressive strength results of the low-carbon cementitious materials prepared in Examples 1 to 4.

[0027] Figure 2 Schematic diagram of the compressive strength results of the low-carbon cementitious materials prepared in Example 1, Comparative Example 1, Comparative Example 2, Example 5 and Example 6. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] The embodiments of the present invention are described in detail below. The embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] In this embodiment, two kinds of industrial solid wastes are selected to prepare low-carbon cementitious materials.

[0032] Among them, the composition of industrial solid waste 1 is: CaO 35wt%, SiO2 25wt%, Al2O3 15wt%, SO3 5wt%, Fe2O33 wt%, Na2O 2%; the composition of industrial solid waste 2 is: CaO 5wt%, SiO2 35wt%, Al2O3 35wt%, SO3 5wt%, Fe2O35 wt%.

[0033] Industrial solid waste 1 and industrial solid waste 2 were dried at 100°C for 24 hours, then ground and passed through a 120-mesh sieve. Industrial solid waste 1 and industrial solid waste 2 were fully mixed at a ratio of 1:1, and 5% Ba(OH)2, 10% silicon oxide and 5% coal powder were added. After being fully mixed with the above industrial solid waste, they were placed in a high-temperature furnace for heat treatment. The high-temperature furnace was heated to 700°C at a rate of 5°C / min, and then cooled with the furnace after isothermal treatment for 2 hours. After taking out the sample, it was ground to obtain a specific surface area of ​​300cm 2 / g of calcined industrial solid waste; add sodium silicate alkali activator with a modulus of 1 to the calcined industrial solid waste at a water-cement ratio of 0.3, mix well and place the above materials in a 4×4×4 cm 3 The low-carbon cementitious material was obtained after curing in a standard curing box for 28 days.

[0034] Example 2

[0035] The preparation method is basically the same as that of Example 1, except that the ratio of industrial solid waste 1 to industrial solid waste 2 is reduced from 1:1 to 1:2.

[0036] Example 3

[0037] The preparation method is basically the same as that of Example 1, except that the ratio of industrial solid waste 1 to industrial solid waste 2 is reduced from 1:1 to 1:3.

[0038] Example 4

[0039] The preparation method is basically the same as that of Example 1, except that the ratio of industrial solid waste 1 to industrial solid waste 2 is reduced from 1:1 to 1:4.

[0040] Comparative Example 1

[0041] The preparation method is basically the same as that of Example 1, except that the ratio of the added Ba(OH)2, silicon oxide and coal powder is reduced from 5%, 10% and 5% to 0%.

[0042] Example 5

[0043] The preparation method is basically the same as that of Example 1, except that the ratio of Ba(OH)2, silicon oxide and coal powder is adjusted from 5%, 10% and 5% to 10%, 6% and 2%. The compressive strength of the low-carbon cementitious materials prepared in Examples 1, 2, 3, 4, 5 and Comparative Example 1 is shown in FIG. Figure 1 and Figure 2 As shown. Figure 1 It can be seen that as the ratio of industrial solid waste 1 and industrial solid waste 2 decreases, the compressive strength of low-carbon cementitious materials shows a downward trend. When the ratio is 1:4, the compressive strength reaches a maximum value of 97.1 MPa, far exceeding the strength range of C80 ultra-high strength cement concrete. Figure 2 It can be seen that compared with the low-carbon cementitious material added with Ba(OH)2, silicon oxide and coal powder, the compressive strength of the low-carbon cementitious material without additives is lower.

[0044] Example 6

[0045] The preparation process of this embodiment is the same as that of embodiment 1.

[0046] The difference is that the ratio of Ba(OH)2, silicon oxide and coal powder is adjusted from 5%, 10% and 5% to 30%, 1% and 1%; at the same time, the roasting temperature is adjusted to 300℃ and the roasting time is 8h. After measurement, the compressive strength of this embodiment is 63.4MPa.

[0047] Example 7

[0048] The preparation process of this embodiment is the same as that of embodiment 1.

[0049] The difference is that the calcination temperature is adjusted to 1000°C and the calcination time is 1h.

[0050] Comparative Example 2

[0051] The preparation process of this embodiment is the same as that of embodiment 1.

[0052] The difference is that the content of Fe2O3 in industrial solid waste is 10%. After measurement, the compressive strength of the sample prepared in Comparative Example 2 is 30.5 Mpa, which is much lower than 65.8 Mpa in Example 1. This shows that the mass percentage of Fe2O3 in the industrial solid waste should not be too large, and the inventor believes that it should not be greater than 5%.

[0053] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0054] The parts not described in detail in the present description belong to the known technology in the art. The above embodiments are provided only for the purpose of describing the present invention, but not to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a low-carbon gelling material, characterized in that: The method comprises: The industrial solid waste is fully mixed with metal alkaline hydroxide, silicon oxide and coal powder in a certain proportion to obtain a mixed material; The mixed material is roasted at a certain temperature and then ground to obtain roasted industrial solid waste; wherein the roasting temperature is 300-1000° C. and the roasting time is 1-8 hours; Adding an alkali activator to the calcined industrial solid waste, fully mixing and hydrating and curing, to obtain a high-strength low-carbon cementitious material; Among them, the amount of the metal alkaline hydroxide added to the mixed material is 5% to 30%; the amount of the silicon oxide added is 1% to 10%; the amount of the coal powder added is 1% to 5%; and the rest is industrial solid waste; The amount of the alkali activator added and the water-cement ratio of the industrial solid waste are 0.2-0.

5.

2. The method for preparing a low-carbon cementitious material according to claim 1, characterized in that: The industrial solid waste is solid waste generated in the industrial production process, and the industrial solid waste includes CaO, SiO2 and Al2O3, wherein the mass percentage of CaO is not less than 10%, the mass percentage of SiO2 is not less than 30%, and the mass percentage of Al2O3 is not less than 20%; And the mass percentage of Fe2O3 in the industrial solid waste is not more than 5%.

3. The method for preparing a low-carbon gelling material according to claim 2, characterized in that: The mass percentage of CaO in the industrial solid waste is 10-20%, the mass percentage of SiO2 is 30-35%, and the mass percentage of Al2O3 in the industrial solid waste is 25-31%.

4. The method for preparing a low-carbon cementitious material according to claim 1, characterized in that: The water content of the industrial solid waste is below 10wt%; And / or, the specific surface area of ​​the industrial solid waste is greater than 200m 2 / kg.

5. The method for preparing a low-carbon cementitious material according to claim 1, characterized in that: The metal alkaline hydroxide is one or more of KOH, NaOH, BaOH2, Ca(OH)2, Mg(OH)2, Zn(OH)2 or Sr(OH)2.

6. The method for preparing a low-carbon cementitious material according to claim 1, characterized in that: The silicon oxide is one or a mixture of silicon monoxide, silicon dioxide or bisilicate.

7. The method for preparing a low-carbon cementitious material according to claim 1, characterized in that: The particle size of the silicon oxide is in the range of 1 to 100 nm.

8. The method for preparing a low-carbon cementitious material according to claim 1, characterized in that: The coal powder particles have a diameter range of 0-1000 μm and a carbon content of >80%; And / or, the particle size of the industrial solid waste is 40 to 150 microns.

9. The method for preparing a low-carbon gelling material according to claim 1, characterized in that: The alkaline activator is a sodium silicate solution with a modulus range of 0.5 to 3.

10. The method for preparing a low-carbon cementitious material according to any one of claims 1 to 9, characterized in that: The curing process of the low-carbon cementitious material is as follows: temperature 10-30° C., humidity 80-100%, and curing time 3-28 days.

11. A low-carbon cementitious material, characterized in that: The method is prepared by any one of claims 1 to 10.

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