Additive for adjusting coagulation time of high-calcium-based material of alkali-activated circulating fluidized bed

Abstract

The invention discloses an additive for adjusting the setting time of a high-calcium-based material of an alkali-activated circulating fluidized bed, and belongs to the technical field of solid waste recycling and building materials. The additive is prepared from the following raw materials in parts by mass: 300 to 400 parts of allyl polyoxyethylene ether, 50 to 250 parts of acrylic acid, 4 to 20 parts of sodium methacrylate sulfonate, 10 to 30 parts of chain initiator, 2 to 8 parts of chain transfer agent and 600 to 800 parts of water. By scientifically regulating and controlling the raw material composition of the additive for regulating the coagulation time of the alkali-activated circulating fluidized bed high-calcium-based material, the coagulation time of the circulating fluidized bed high-calcium-based material is effectively regulated, and a technical guarantee is provided for industrial application of circulating fluidized bed high-calcium ash.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste resource utilization and building materials, and particularly relates to an additive for adjusting the coagulation time of an alkali-stimulated circulating fluidized bed high-calcium-based material. Background Art

[0002] Circulating fluidized bed ash refers to the fly ash and bottom ash produced by the combustion of circulating fluidized bed boilers. As a special type of fly ash, circulating fluidized bed ash has irregular particle morphology and loose structure, so its utilization degree and utilization efficiency are often less than 40%. Since the combustion process of circulating fluidized bed is quite different from that of traditional pulverized coal furnace, there are a lot of calcium and sulfur components in circulating fluidized bed fly ash, which makes it fail to meet the requirements of national standard "Pozzolanic mixed materials for cement" (GB / T2847-2005) and national standard "Fly ash for cement and concrete" (GB / T 1596-2017) for fly ash. As a result, it is difficult to achieve large-scale consumption in the field of cement and concrete like pulverized coal furnace fly ash. At present, the utilization technology for circulating fluidized bed fly ash has not yet been systematic, and the ash is piled up in large quantities. It is urgent to find a suitable utilization method to realize the large-scale utilization of this type of ash. Therefore, combining the physicochemical properties of circulating fluidized bed fly ash and conducting basic research on its application in the preparation of geopolymers has far-reaching significance for the resource utilization of circulating fluidized bed fly ash, saving land and protecting the environment.

[0003] Circulating fluidized bed fly ash contains a large amount of amorphous aluminosilicate structure, which has certain volcanic ash activity and is easily chemically excited to participate in the reaction. The use of circulating fluidized bed fly ash to prepare geopolymers not only realizes the large-scale disposal of industrial solid waste, but also helps the cement industry to transform towards a green, low-carbon and sustainable direction. However, the geopolymers prepared using circulating fluidized bed fly ash have the defect that the setting time is difficult to control. Summary of the invention

[0004] In view of the above problems, the present invention provides an additive for adjusting the setting time of alkali-activated circulating fluidized bed high calcium-based materials. By scientifically regulating the raw material composition of the additive for adjusting the setting time of alkali-activated circulating fluidized bed high calcium-based materials, the setting time of the circulating fluidized bed high calcium-based materials is effectively adjusted, providing technical guarantee for the industrial application of circulating fluidized bed high calcium ash.

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

[0006] One of the technical solutions of the present invention is to provide an additive for adjusting the coagulation time of an alkali-activated circulating fluidized bed high-calcium-based material. The components include, by weight: 300 to 400 parts of allyl polyoxyethylene ether, 50 to 250 parts of acrylic acid, 4 to 20 parts of sodium methacrylate sulfonate, 10 to 30 parts of a chain initiator, 2 to 8 parts of a chain transfer agent and 600 to 800 parts of water.

[0007] Preferably, the number average molecular weight of the allyl polyoxyethylene ether is 500-1000.

[0008] Preferably, the chain initiator is 2,2'-azobisisobutyronitrile or ammonium persulfate-ascorbic acid (Vc) redox system or hydrogen peroxide (H2O2)-ascorbic acid (Vc) redox system.

[0009] Preferably, the chain transfer agent is mercaptopropionic acid, hydroquinone or n-dodecyl mercaptan.

[0010] The second technical solution of the present invention is to provide a method for preparing the additive for adjusting the coagulation time of the alkali-activated circulating fluidized bed high calcium-based material, comprising the following steps:

[0011] A chain initiator, a chain transfer agent and part of water are mixed to obtain component A; acrylic acid is used as component B; the remaining water, allyl polyoxyethylene ether and sodium methacrylate sulfonate are mixed as a base liquid; the component A and the component B are added to the base liquid at the same time, and the pH is adjusted to neutral after the reaction to obtain the additive for adjusting the coagulation time of alkali-stimulated circulating fluidized bed high-calcium-based materials.

[0012] Preferably, the time for simultaneously adding the component A and the component B into the base liquid is 2h-4h.

[0013] Preferably, the reaction time is 2h-4h and the temperature is 35-55°C.

[0014] The third technical solution of the present invention is to provide an application of the above-mentioned additive for adjusting the coagulation time of high-calcium-based materials in an alkali-stimulated circulating fluidized bed in adjusting the coagulation time of high-calcium-based materials in an alkali-stimulated circulating fluidized bed.

[0015] The beneficial technical effects of the present invention are as follows:

[0016] The additive raw material sodium methacrylate sulfonate provided by the present invention contains sulfonic acid groups, which are anionic groups and can be complexed with calcium ions in the circulating fluidized bed high calcium ash to accelerate the hydration process of the circulating fluidized bed high calcium ash. The amount of the sulfonic acid group can be adjusted to control the coagulation time of the alkali-induced circulating fluidized bed high calcium-based material. The raw materials allyl polyoxyethylene ether and acrylic acid are used as the main chain and side chain to fill the pores of the circulating fluidized bed high calcium-based material particles to improve the compressive strength of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart for preparing an additive for adjusting the setting time of an alkali-activated circulating fluidized bed high-calcium-based material in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0019] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the 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.

[0020] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0021] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0022] The preparation flow chart of the additive for adjusting the setting time of the alkali-activated circulating fluidized bed high calcium-based material in the embodiment of the present invention is shown in Figure 1 .

[0023] Comparative Example 1

[0024] Take 59 parts of circulating fluidized bed ash and 41 parts of tap water, add water glass and sodium hydroxide to make the system's Si / Al=4.2, Na / Al=0.7, stir evenly and prepare the resulting slurry into a 25mm×50mm cylindrical specimen.

[0025] Example 1

[0026] Take the following raw materials: 380 parts of allyl polyoxyethylene ether with a number average molecular weight of 1000, 110 parts of acrylic acid, 10 parts of sodium methacrylic acid sulfonate, 14 parts of chain initiator (ammonium persulfate and ascorbic acid in a mass ratio of 2.5:1), 3.8 parts of chain transfer agent (mercaptopropionic acid) and 800 parts of deionized water;

[0027] Preparation of additives: Mix the chain initiator and chain transfer agent with 300 parts of deionized water as liquid A, acrylic acid as liquid B, mix allyl polyoxyethylene ether and sodium methacrylate sulfonate with 500 parts of deionized water, stir to form a base liquid, and then add liquid A and liquid B to the base liquid at a uniform speed through a peristaltic pump for 3 hours, keep warm for 2 hours at a temperature of 45°C, and then adjust the pH to neutral with sodium hydroxide solution to obtain an additive for adjusting the coagulation time of alkali-activated circulating fluidized bed high-calcium-based materials.

[0028] Based on the solid content of the additive for adjusting the setting time of alkali-activated circulating fluidized bed high-calcium-based materials, 1% of the additive by mass of the circulating fluidized bed ash in Comparative Example 1 was added, and the slurry was prepared in the manner of Comparative Example 1 (41 parts of water in the slurry included the deionized water contained in the additive), and the obtained slurry was prepared into a 25mm×50mm cylindrical specimen.

[0029] Example 2

[0030] The preparation method of the additive for adjusting the setting time of the alkali-activated circulating fluidized bed high calcium-based material is the same as that of Example 1.

[0031] Based on the solid content of the additive for adjusting the setting time of alkali-activated circulating fluidized bed high-calcium-based materials, 2% of the additive by mass of the circulating fluidized bed ash in Comparative Example 1 was added, and the slurry was prepared in the manner of Comparative Example 1 (41 parts of water in the slurry included the deionized water contained in the additive), and the obtained slurry was prepared into a 25mm×50mm cylindrical specimen.

[0032] Example 3

[0033] The preparation method of the additive for adjusting the setting time of the alkali-activated circulating fluidized bed high calcium-based material is the same as that of Example 1.

[0034] Based on the solid content of the additive for adjusting the setting time of alkali-activated circulating fluidized bed high-calcium-based materials, 3% of the additive by mass of the circulating fluidized bed ash in Comparative Example 1 was added, and the slurry was prepared in the manner of Comparative Example 1 (41 parts of water in the slurry included the deionized water contained in the additive), and the obtained slurry was prepared into a 25mm×50mm cylindrical specimen.

[0035] Example 4

[0036] The preparation method of the additive for adjusting the setting time of the alkali-activated circulating fluidized bed high calcium-based material is the same as that of Example 1.

[0037] Based on the solid content of the additive for adjusting the setting time of alkali-activated circulating fluidized bed high-calcium-based materials, 4% of the additive by mass of the circulating fluidized bed ash in Comparative Example 1 was added, and the slurry was prepared in the manner of Comparative Example 1 (41 parts of water in the slurry included the deionized water contained in the additive), and the obtained slurry was prepared into a 25mm×50mm cylindrical specimen.

[0038] Example 5

[0039] The preparation method of the additive for adjusting the setting time of the alkali-activated circulating fluidized bed high calcium-based material is the same as that of Example 1.

[0040] Based on the solid content of the additive for adjusting the setting time of alkali-activated circulating fluidized bed high-calcium-based materials, 5% of the additive by mass of the circulating fluidized bed ash in Comparative Example 1 was added, and the slurry was prepared in the manner of Comparative Example 1 (41 parts of water in the slurry included the deionized water contained in the additive), and the obtained slurry was prepared into a 25mm×50mm cylindrical specimen.

[0041] The setting time of the slurry prepared in Comparative Example 1 and Examples 1-5 was measured in accordance with GB / T1346-2011 "Test method for water consumption, setting time and stability of cement standard consistency", and the measurement results are shown in Table 1; the compressive strength of the test specimens prepared in Comparative Example 1 and Examples 1-5 was measured in accordance with GB / T17671-2021 "Test method for strength of cement mortar (ISO method)", and the measurement results are shown in Table 1.

[0042] Table 1

[0043]

[0044] *Note: After verification by multiple groups of parallel tests, according to GB / T17671-2021 "Test method for strength of cement mortar (ISO method)", standard specimens (40×40×160mm) were prepared with the same ratio, and the compressive strength of the standard specimens was 2.2 times that of the cylindrical specimens used in the present invention.

[0045] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An additive for adjusting the setting time of alkali-stimulated circulating fluidized bed high calcium-based materials, characterized in that: The raw materials include, by mass, 300-400 parts of allyl polyoxyethylene ether, 50-250 parts of acrylic acid, 4-20 parts of sodium methacrylic acid sulfonate, 10-30 parts of chain initiator, 2-8 parts of chain transfer agent and 600-800 parts of water.

2. The additive for adjusting the setting time of alkali-stimulated circulating fluidized bed high calcium-based materials according to claim 1, characterized in that: The number average molecular weight of the allyl polyoxyethylene ether is 500-1000.

3. The additive for adjusting the setting time of alkali-stimulated circulating fluidized bed high calcium-based materials according to claim 1, characterized in that: The chain initiator is 2,2'-azobisisobutyronitrile or ammonium persulfate-ascorbic acid redox system or hydrogen peroxide-ascorbic acid redox system.

4. The additive for adjusting the setting time of alkali-stimulated circulating fluidized bed high calcium-based materials according to claim 1, characterized in that: The chain transfer agent is mercaptopropionic acid, hydroquinone or n-dodecyl mercaptan.

5. A method for preparing the additive for adjusting the setting time of alkali-stimulated circulating fluidized bed high calcium-based materials according to any one of claims 1 to 4, characterized in that: The following steps are involved: The chain initiator, the chain transfer agent and part of the water are mixed to obtain component A; acrylic acid is used as component B; the remaining water is mixed with allyl polyoxyethylene ether and sodium methacrylic acid sulfonate to form a base liquid; The component A and the component B are added to the base liquid at the same time, and the pH is adjusted to be neutral after the reaction, so as to obtain the additive for adjusting the coagulation time of the alkali-stimulated circulating fluidized bed high-calcium-based material.

6. The preparation method according to claim 5, characterized in that: The time for simultaneously adding the component A and the component B into the base liquid is 2h-4h.

7. The preparation method according to claim 5, characterized in that: The reaction time is 2h-4h, and the temperature is 35-55°C.

8. Use of the additive for adjusting the setting time of an alkali-stimulated circulating fluidized bed high-calcium-based material according to any one of claims 1 to 4 in adjusting the setting time of an alkali-stimulated circulating fluidized bed high-calcium-based material.

Images