阅读说明：本技术 一种蒸汽与二氧化碳耦合养护粉煤灰加气砌块的工艺 (Process for maintaining fly ash aerated building block by coupling steam and carbon dioxide ) 是由 袁静娟 葛春亮 张威 徐灏 徐承亮 程露莹 周志杰 于 2021-09-15 设计创作，主要内容包括：本发明涉及一种蒸汽与二氧化碳耦合养护粉煤灰加气砌块的工艺,包括步骤：粉煤灰加气砌块在静养室静停养护,直至达到切割强度,对粉煤灰加气砌块进行切割,切割后的粉煤灰加气砌块进入养护釜；在养护釜中对切割后的粉煤灰加气砌块进行蒸压养护。本发明的有益效果是：本发明使用蒸汽蒸压和二氧化碳矿化两种养护技术耦合对粉煤灰加气砌块进行养护。相比单一蒸压养护技术,蒸压养护可以使粉煤灰转变为托勃莫来石交联结构,为粉煤灰加气砌块提供基础框架,二氧化碳矿化养护可以快速生成碳酸凝胶,填充空隙,进一步增强粉煤灰加气砌块强度,并减少蒸汽消耗和提高生产效率,并实现了二氧化碳的固化封存,减少温室气体排放。(The invention relates to a process for curing fly ash aerated building blocks by coupling steam and carbon dioxide, which comprises the following steps: statically maintaining the fly ash aerated building block in a static maintaining chamber until the cutting strength is reached, cutting the fly ash aerated building block, and feeding the cut fly ash aerated building block into a maintaining kettle; and (4) performing autoclaved curing on the cut fly ash aerated building blocks in a curing kettle. The invention has the beneficial effects that: the invention uses two curing technologies of steam pressure and carbon dioxide mineralization to couple to cure the fly ash aerated building block. Compared with a single autoclaved curing technology, the autoclaved curing can convert the fly ash into a tobermorite cross-linked structure, a basic frame is provided for the fly ash aerated block, carbon dioxide mineralized curing can quickly generate carbonic acid gel to fill gaps, the strength of the fly ash aerated block is further enhanced, steam consumption is reduced, production efficiency is improved, carbon dioxide is cured and sealed, and greenhouse gas emission is reduced.)

1. A process for curing fly ash aerated building blocks by coupling steam and carbon dioxide is characterized by comprising the following steps:

step 1, statically maintaining the fly ash aerated building block (1) in a static maintenance room until the cutting strength is reached, cutting the fly ash aerated building block (1), and feeding the cut fly ash aerated building block (1) into a maintenance kettle (2);

step 2, performing autoclaved curing on the cut fly ash aerated building block (1) in a curing kettle (2): steam (3) enters the curing kettle (2) from an air passage at the bottom of the curing kettle (2), and after the steam (3) is introduced, the fly ash aerated building block (1) is subjected to a constant temperature process for a fixed time in the curing kettle (2), and then autoclaved curing is completed; the fly ash in the fly ash aerated block is converted into trabecite with a cross-linked structure;

step 3, performing carbon dioxide mineralization curing on the fly ash aerated building block (1) subjected to autoclaved curing in a curing kettle (2): carbon dioxide enters the curing kettle (2) from an air passage at the top of the curing kettle (2), and after the carbon dioxide is introduced, the coal ash aerated building block (1) is subjected to a constant pressure process for a fixed time in the curing kettle (2) to finish mineralization curing; in the mineralization process, carbon dioxide and alkaline substances in the fly ash aerated building blocks react rapidly to generate carbonic acid gel, and the carbonic acid gel gradually fills gaps inside the fly ash aerated building blocks (1).

2. The process for curing the fly ash aerated block by coupling the steam and the carbon dioxide according to claim 1, which is characterized in that: in the step 1, the mass fraction of the fly ash in the fly ash aerated building block (1) is 30-80%.

3. The process for curing the fly ash aerated block by coupling the steam and the carbon dioxide according to claim 1, which is characterized in that: the autoclaved curing time in the step 2 is 4-6 hours, the carbon dioxide mineralized curing time in the step 3 is 2-4 hours, and the sum of the autoclaved curing time and the carbon dioxide mineralized curing time is not more than 8 hours.

4. The process for curing the fly ash aerated block by coupling the steam and the carbon dioxide according to claim 1, which is characterized in that: and 2, during the autoclaved curing, the temperature of the steam (3) in the constant temperature process is 170-200 ℃, and the pressure is 0.8-1.6 MPa.

5. The process for curing the fly ash aerated block by coupling the steam and the carbon dioxide according to claim 1, which is characterized in that: in the step 3, the concentration of carbon dioxide introduced for mineralization and maintenance of the carbon dioxide is not lower than 80 percent, and the pressure in the constant pressure process in the maintenance process is 0.5 MPa-2 MPa.

Technical Field

The invention belongs to the field of maintenance of fly ash aerated building blocks, and particularly relates to a process for maintaining fly ash aerated building blocks by coupling steam and carbon dioxide.

Background

The fly ash aerated building block is a novel wall building material, and has gradually become a leading product in the building material industry of China due to the advantages of light volume weight, high thermal insulation performance, good sound absorption effect, high fireproof performance, high earthquake resistance level, convenient construction and the like. The strength of the fly ash aerated building block is formed mainly by the autoclaved curing process in the production process, and SiO in the fly ash is in the environment of high temperature, high pressure and high alkalinity₂The glass body structure of (A) is destroyed, activated SiO₂And Ca (OH)₂The reaction generates tobermorite to form a cross-linking structure, thereby increasing the overall strength of the concrete. Because the strength of the crystal in the later-stage aerated building block is slowly enhanced, the general autoclaved curing needs 10-12 hours, the production efficiency is greatly reduced, the energy consumption in the curing process is high, and the energy consumption for curing one fly ash aerated building block is 2500kJ, which accounts for 15-25% of the total cost.

Carbon dioxide mineralization curing is a concrete curing technology emerging at present. The carbon dioxide can react with alkaline oxides (such as CaO, MgO and the like) in the concrete to generate carbonic acid gel, and the carbonic acid gel fills gaps inside the aerated building blocks, so that the strength of the aerated building blocks is enhanced. The carbonation reaction can be carried out at normal temperature, the reaction is rapid, the reaction can be completed within two hours basically, in addition, the technology can also realize the solidification and sealing of carbon dioxide, and the emission of greenhouse gases is reduced. Therefore, by adopting the carbon dioxide mineralization technology, the energy consumption in the production process of the fly ash aerated building block can be reduced, the production efficiency is improved, carbon dioxide can be solidified and sealed, and economic benefits and environmental benefits are achieved.

However, more than 60% of the raw materials of the fly ash aerated building block are pulverized coal ash, and if only carbon dioxide is adopted for mineralization maintenance, the fly ash aerated building block can be maintainedThe mechanical property of the fly ash is reduced mainly because the SiO in the fly ash is reduced after the autoclaved curing process is lost₂The structure of the glass body can not be damaged, so that the trabecite structure can not be formed, and the overall strength of the fly ash aerated building block is reduced.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a process for curing fly ash aerated building blocks by coupling steam and carbon dioxide.

The process for curing the fly ash aerated building block by coupling steam and carbon dioxide specifically comprises the following steps:

step 1, statically maintaining the fly ash aerated building block in a static maintenance chamber until the cutting strength is reached, cutting the fly ash aerated building block, and feeding the cut fly ash aerated building block into a maintenance kettle;

step 2, performing autoclaved curing on the cut fly ash aerated building blocks in a curing kettle: steam enters the curing kettle from an air passage at the bottom of the curing kettle, and after the steam is introduced, the fly ash aerated building block is subjected to a constant temperature process for a certain time in the curing kettle, so that autoclaved curing is completed; the fly ash in the fly ash aerated block is converted into trabecite with a cross-linked structure;

step 3, performing carbon dioxide mineralization curing on the fly ash aerated building block subjected to autoclaved curing in a curing kettle: carbon dioxide enters the curing kettle from an air passage at the top of the curing kettle, and after the carbon dioxide is introduced, the coal ash aerated building block is subjected to a constant pressure process for a certain time in the curing kettle to complete mineralization curing; in the mineralization process, carbon dioxide and alkaline substances in the fly ash aerated building blocks react rapidly to generate carbonic acid gel, gaps inside the fly ash aerated building blocks are filled gradually, and finally the fly ash aerated building blocks meet the requirements of national standard strength.

Preferably, in the step 1, the mass fraction of the fly ash in the fly ash aerated building block is 30-80%.

Preferably, the duration of the autoclaved curing in the step 2 is 4-6 hours, the duration of the carbon dioxide mineralized curing in the step 3 is 2-4 hours, and the sum of the autoclaved curing duration and the carbon dioxide mineralized curing duration is not more than 8 hours.

Preferably, the steam temperature in the steam pressure curing in the step 2 is 170-200 ℃, and the pressure is 0.8-1.6 MPa.

Preferably, the concentration of carbon dioxide introduced in the step 3 for mineralization curing of carbon dioxide is not lower than 80%, and the pressure in the curing process is 0.5 MPa-2.0 MPa.

The invention has the beneficial effects that: the invention discloses a process for curing a fly ash aerated block by coupling steam and carbon dioxide. Compared with a single autoclaved curing technology, the autoclaved curing can convert the fly ash into a tobermorite cross-linked structure, a basic frame is provided for the fly ash aerated block, carbon dioxide mineralized curing can quickly generate carbonic acid gel to fill gaps, the strength of the fly ash aerated block is further enhanced, steam consumption is reduced, production efficiency is improved, carbon dioxide is cured and sealed, and greenhouse gas emission is reduced.

Drawings

FIG. 1 is a process flow diagram of steam and carbon dioxide coupled curing of fly ash aerated building blocks.

Description of reference numerals: fly ash aerated building blocks 1, a curing kettle 2, steam 3 and carbon dioxide 4.

Detailed Description

The present invention will be further described with reference to the following examples. The following examples are set forth merely to aid in the understanding of the invention. It should be noted that, for a person skilled in the art, several modifications can be made to the invention without departing from the principle of the invention, and these modifications and modifications also fall within the protection scope of the claims of the present invention.

Example one

The embodiment of the application provides a process for curing fly ash aerated building blocks by coupling steam and carbon dioxide, which comprises the following steps:

step 1, statically maintaining the fly ash aerated building block 1 in a static maintaining chamber until the cutting strength is reached, cutting the fly ash aerated building block 1, and feeding the cut fly ash aerated building block 1 into a maintaining kettle 2;

step 2, performing autoclaved curing on the cut fly ash aerated building block 1 in a curing kettle 2: because the density of the steam is less than that of the air, the steam 3 enters the curing kettle 2 from an air passage at the bottom of the curing kettle 2, after the steam 3 is introduced, the fly ash aerated block 1 releases the pressure to the atmospheric pressure after undergoing a constant temperature process for a certain time in the curing kettle 2, and the autoclaved curing is completed; SiO in fly ash aerated building block₂The tobermorite reacts with alkaline substances and is converted into a cross-linked structure, so that a basic frame is provided for the fly ash aerated building block 1;

step 3, in a curing kettle 2, performing carbon dioxide mineralization curing on the fly ash aerated building block 1 which is subjected to autoclaved curing: because the density of the carbon dioxide is greater than that of the air, the carbon dioxide enters the curing kettle 2 from an air passage at the top of the curing kettle 2, and after the carbon dioxide is introduced, the fly ash aerated building block 1 releases pressure to atmospheric pressure after undergoing a constant pressure process for a certain time in the curing kettle 2, so that carbon dioxide mineralization curing is completed; in the curing process, carbon dioxide and alkaline substances in the fly ash aerated block react rapidly to generate carbonic acid gel, and the carbonic acid gel fills gaps inside the fly ash aerated block 1 to further enhance the strength of the fly ash aerated block;

example two

On the basis of the first embodiment, the second embodiment of the present application provides an application of the process for curing the fly ash aerated block by coupling steam and carbon dioxide in the first embodiment in a curing kettle:

as shown in fig. 1, the curing kettle includes two gas inlet pipes, one being a steam inlet pipe and the other being a carbon dioxide inlet pipe.

The cutting strength is achieved through static maintenance in a static maintenance chamber, the cut aerated building block enters a maintenance kettle, and the mass fraction of the fly ash in the aerated building block is 30-80%. Firstly, carrying out autoclaved curing for 4-6 hours, wherein steam enters from the bottom of a curing kettle because the density of the steam is less than that of air, the temperature of the autoclaved curing is 170-200 ℃, and the pressure is 0.8-1.6 MPa; maintaining the curing kettle at a specific pressure, releasing the pressure to atmospheric pressure after a constant temperature process for a certain time, and completing the autoclaved curing process, wherein the curing time is not more than 6 hours;

then carrying out carbon dioxide mineralization maintenance for 2-4 hours, wherein carbon dioxide with the concentration not lower than 80% enters from the top of the maintenance kettle due to the fact that the density of the carbon dioxide is larger than that of air, the pressure of the mineralization maintenance is within 0.5-2.0 MPa, the maintenance kettle is maintained at a specific pressure, after a constant pressure process of a certain time, the pressure is released to the atmospheric pressure, and the mineralization maintenance process is completed; the total curing time does not exceed 8 hours.

The curing time of the single steam curing fly ash aerated building block is generally 12 hours. The qualification rate of the single carbon dioxide mineralized and cured fly ash aerated building block is generally about 92 percent. Compared with the single steam autoclaved curing fly ash aerated building block, the embodiment reduces the steam energy consumption by 50 percent, improves the production efficiency by 33.3 percent, and realizes the curing and sealing of carbon dioxide. Compared with the single carbon dioxide curing fly ash aerated building block, the product percent of pass obtained by the curing process is about 98 percent (B06 grade products meet the standard of GB 11968-2020), and the invention improves the product percent of pass by 6 percent.