阅读说明：本技术 一种粉煤灰-煤渣胶凝材料及其制备方法 (Fly ash-cinder cementing material and preparation method thereof ) 是由 梁政 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种粉煤灰-煤渣胶凝材料及其制备方法,其中制备方法包括如下步骤：S1.将粉煤灰、煤渣、水泥和缓凝剂混合搅拌均匀,形成混合物；S2.将甲基丙烯酸甲酯、十二烷基苯磺酸钠和水混合,制成水乳液；S3.将S2的水乳液与S1的混合物混合搅拌,制成浆体的粉煤灰-煤渣胶凝材料。还可以进一步包括S4.将S3的浆体注入模具中,然后振实,静置成型,脱模,之后再密封养护,最后自然放置,得到固化的粉煤灰-煤渣胶凝材料。本发明将粉煤灰、煤渣制备成高性能的胶凝材料,从而资源化利用大量固体废物粉煤灰和煤渣,绿色环保。(The invention discloses a fly ash-cinder cementing material and a preparation method thereof, wherein the preparation method comprises the following steps: s1, uniformly mixing and stirring fly ash, coal slag, cement and a retarder to form a mixture; s2, mixing methyl methacrylate, sodium dodecyl benzene sulfonate and water to prepare a water emulsion; and S3, mixing and stirring the water emulsion of the S2 and the mixture of the S1 to prepare the fly ash-cinder cementing material of slurry. S4, injecting the slurry of S3 into a mould, compacting, standing for forming, demoulding, sealing and curing, and naturally standing to obtain the solidified fly ash-cinder cementing material. The fly ash and the coal cinder are prepared into the high-performance cementing material, so that a large amount of solid waste fly ash and coal cinder are recycled, and the environment is protected.)

1. The preparation method of the fly ash-cinder cementing material is characterized by comprising the following steps of:

s1, uniformly mixing and stirring fly ash, coal slag, cement and a retarder to form a mixture;

s2, mixing methyl methacrylate, sodium dodecyl benzene sulfonate and water to prepare a water emulsion;

and S3, mixing and stirring the water emulsion of the S2 and the mixture of the S1 to prepare the fly ash-cinder cementing material of slurry.

2. The method for preparing the fly ash-cinder cementing material according to the claim 1, characterized by further comprising the following steps:

and S4, injecting the slurry of the S3 into a mold, compacting, standing for forming, demolding, sealing for maintenance, and naturally standing to obtain the solidified fly ash-cinder cementing material.

3. The preparation method of the fly ash-cinder cementing material according to the claim 2, characterized in that in S4, the sealing and curing are carried out for 24-72 h.

4. The method for preparing the fly ash-cinder cementing material according to the claim 1, characterized in that in S1, the fly ash, the cinder and the cement are mixed and stirred for 1-5 min.

5. The method for preparing the fly ash-cinder cementing material according to the claim 1, wherein in S1, the cement is magnesium phosphate cement.

6. The method for preparing the fly ash-cinder cementing material of claim 5, wherein in S1, the retarder is borax.

7. The preparation method of the fly ash-cinder cementing material according to the claim 6, wherein in S1, the weight percentages of the fly ash, cinder, cement and retarder are as follows: 19% of magnesium phosphate cement, 1% of retarder, 60% of fly ash and 20% of coal cinder.

8. The method for preparing a fly ash-cinder binder according to claim 1, wherein in S2, the amount of methyl methacrylate is 30-40 wt%, the amount of sodium dodecylbenzenesulfonate is 30-40 wt%, and the amount of water is 30-40 wt%, based on the total weight of the aqueous emulsion.

9. The method for preparing the fly ash-cinder cementing material according to the claim 1, wherein the mixing weight ratio of the water emulsion in the S2 and the mixture in the S1 in the S3 is 0.16-0.2: 1.

10. a fly ash-cinder cementitious material, characterised in that it is produced by the method of producing a fly ash-cinder cementitious material according to any of claims 1 to 9.

Technical Field

The invention relates to the field of materials, and particularly relates to a fly ash-cinder cementing material and a preparation method thereof.

Background

Fly ash and cinder are the main solid waste produced by burning coal in a thermal power plant. The fly ash is collected by a dust collector, while the coal slag is discharged from the bottom. China is a big country consuming coal resources, and the coal consumption is increased by 0.6 percent in the same ratio in 2020, accounting for 56.8 percent of the total energy consumption. At present, the utilization rate of the coal cinder is relatively low, the coal cinder is mainly used for cement, concrete and the like, and is rarely used for making bricks and roadbed cushions. If the coal cinder can be fully utilized, the accumulation and the abandonment of the coal cinder can be slowed down, the land occupation and the pollution of sulfur-containing gas to the atmospheric environment are reduced, and even spontaneous combustion and fire generation can be realized. However, the coal cinder is far inferior to the coal ash in the use of cement concrete. In the United states, the fly ash is mainly used in the related aspects of concrete, the utilization rate can reach about half, and the utilization rate of the coal cinder is very little in all aspects and is only one fifth of the fly ash. In China, only a small part of cement production enterprises use coal cinder as a cement paste mixing raw material, and reports of the application of the coal cinder in various projects are few.

Cinder, also known as slag. The coal slag is mainly generated by coal burning of power plants, industries, boilers and the like. Both fly ash and coal slag are solid wastes generated by burning coal. At present, the utilization rate of the slag is also low generally, and the slag is generally applied to brick making and paving. The general chemical composition of the coal cinder is shown in the following table 1. The mineral composition mainly comprises: anorthite, quartz, magnetite and pyrite, a large amount of silicon-containing glass and active SiO₂. Active Al₂0₃Has potential pozzolanic activity and can be used as a cement mineral admixture.

TABLE 1 main chemical composition of cinder

Fly ash is a tiny soot particle produced from the combustion of a fuel. The particle size is generally 1 to 100 μm, and is also called soot. The fly ash is formed by feeding coal powder into a high-temperature furnace, absorbing heat on a hot surface under the suspension combustion condition and then cooling. Due to surface tension, most fly ash is spherical, smooth in surface and small in micropores. Some of the particles are adhered by colliding with each other in a molten state, and thus, they become honeycomb-shaped composite particles having rough surfaces and many edges. The chemical composition of the fly ash is shown in table 2. It is related to the composition of the coal, the particle size of the coal particles, the boiler type, the combustion conditions and the collection method, etc.

TABLE 2 fly ash main chemical composition

The fly ash and the cinder are used as main byproducts of the fire coal, can be used as solid waste and can also be used as a resource. The fly ash and the coal cinder have similar chemical compositions and mineral phases and can also have complementary properties. It is necessary to explore the application of the fly ash and the coal cinder in the gelling system and improve the application of the gelling system.

The green cementing material technology can utilize a large amount of industrial solid wastes, and reduces the development and utilization of natural resources. It can effectively reduce and slow down the pollution and safety risk of solid waste to the environment. The technology of the gelled material can realize green development of industry and can play a role in promoting the construction of ecological civilization. The research on the resource utilization of industrial solid wastes and the development of green cementing materials also conforms to the national and local industrial policies.

Disclosure of Invention

In view of the above, the present invention provides a fly ash-cinder cementing material and a preparation method thereof, which improves various performances of a fly ash-cinder cementing system, and prepares a cementing material with low cost and high performance, wherein the prepared cementing material not only makes full use of solid waste, but also reduces stacking of fly ash and cinder and pollution to the environment.

The adopted technical scheme is as follows:

the invention relates to a preparation method of a fly ash-cinder cementing material, which comprises the following steps:

s1, uniformly mixing and stirring fly ash, coal slag, cement and a retarder to form a mixture;

s2, mixing methyl methacrylate, sodium dodecyl benzene sulfonate and water to prepare a water emulsion;

and S3, mixing and stirring the water emulsion of the S2 and the mixture of the S1 to prepare the fly ash-cinder cementing material of slurry.

Further, still include:

and S4, injecting the slurry of the S3 into a mold, compacting, standing for forming, demolding, sealing for maintenance, and naturally standing to obtain the solidified fly ash-cinder cementing material.

Further, in S4, sealing and maintaining are carried out for 24-72 h.

Further, in S1, the fly ash, the cinder and the cement are mixed and stirred for 1-5 min.

Further, in S1, the cement is magnesium phosphate cement.

Further, in S1, the retarder is borax.

Further, in S1, the weight percentages of the fly ash, the cinder, the cement, and the retarder are as follows: 19% of magnesium phosphate cement, 1% of retarder, 60% of fly ash and 20% of coal slag.

Further, in S2, methyl methacrylate is used in an amount of 30 wt% to 40 wt%, sodium dodecylbenzenesulfonate is used in an amount of 30 wt% to 40 wt%, and water is used in an amount of 30 wt% to 40 wt%, based on the total weight of the aqueous emulsion.

Further, in S3, the mixing weight ratio of the aqueous emulsion in S2 to the mixture in S1 is 0.16 to 0.2: 1.

The fly ash-cinder cementing material is prepared by the preparation method of the fly ash-cinder cementing material in any scheme.

The invention has the beneficial effects that:

(1) the fly ash and the coal cinder are prepared into the cementing material, so that a large amount of solid waste, namely the fly ash and the coal cinder, is recycled.

(2) Determining the relative optimal weight ratio of the cementing material: the mixing amount of the magnesium phosphate cement is 19 percent, the mixing amount of the retarder is 1 percent, the mixing amount of the fly ash is 60 percent and the mixing amount of the coal cinder is 20 percent.

(3) The coal cinder has the characteristic of promoting coagulation, and the coagulation promoting effect is stronger when the mixing amount is larger. The fly ash is just opposite, and the fly ash can be matched with each other.

(4) The high-performance cementing material can be prepared by blending the coal cinder and the fly ash and utilizing the high activity of the coal cinder and the favorable influence of the fly ash on the fluidity.

(5) A certain amount of retarder is advantageous with respect to setting time and also with respect to compressive strength.

Drawings

FIG. 1 is a graph showing the results of experiments on the effect of different amounts of fly ash and cinder on cement strength in example 5.

FIG. 2 is an SEM image of the effect on cement of different amounts of fly ash and cinder from example 5.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only preferred embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

A preparation method of a fly ash-cinder cementing material comprises the following steps:

s1, mixing and stirring the fly ash, the coal slag, the magnesium phosphate cement and the retarder for 1-5min, and uniformly stirring to form a mixture; the retarder is borax. Wherein, based on the total weight of the mixture, the weight percentages of the fly ash, the cinder, the cement and the retarder are as follows: 19% of magnesium phosphate cement, 1% of retarder, 60% of fly ash and 20% of coal cinder.

S2, mixing methyl methacrylate, sodium dodecyl benzene sulfonate and water to prepare a water emulsion;

s3, mixing the water emulsion of S2 with the mixture of S1 in a weight ratio of 0.18: 1, mixing and stirring to prepare the fly ash-cinder cementing material of slurry. Wherein the amount of methyl methacrylate is 35 wt%, the amount of sodium dodecylbenzenesulfonate is 35 wt% and the amount of water is 30 wt%, based on the total weight of the aqueous emulsion.

Example 2

Referring to embodiment 1, the present invention is different from embodiment 1 in that it further includes, in addition to embodiment 1:

s4, injecting the slurry of the S3 into a mold, compacting, standing for forming, demolding, sealing and maintaining for 24-72h, and naturally standing to obtain the solidified fly ash-cinder cementing material.

Example 3 Effect of fly ash dosage on fluidity

Referring to example 1, the effect of the amount of fly ash on the change in the properties of the fly ash-cinder binder was investigated using a univariate control method. The following table 3 shows that the amount of the fly ash is changed from 40-80% in a gradient way, and other amounts are fixed.

The test method of the fluidity of the cementing material is as follows:

the fluidity test method is carried out according to GB/T2419-2005 'cement mortar fluidity determination method', and the test equipment and parameters are as follows: a metal truncated cone circular die with a cylinder size of 36mm by 60mm was used, the cone was placed in the center of the glass and wiped clean with a damp cloth. Taking a certain amount of sample, testing according to a standard specified method, in order to reduce the testing error and improve the testing accuracy, lifting the circular cone mould to start timing, letting the circular cone mould flow for about 30s, measuring the diameters in two vertical directions, and then taking an average value as the fluidity index of the slurry to be accurate to mm.

TABLE 3 Effect of fly ash dosage on fluidity

As can be seen from the above table, the amount of the fly ash is gradually increased, and the fluidity of the fly ash-cinder cementing material is gradually increased. The fly ash contains a large amount of spherical glass bodies with smooth surfaces in the structure, and the surfaces are smooth, so that the aim of improving the fluidity of slurry is fulfilled.

Example 4 Effect of the amount of cinder used on the fluidity

Referring to example 1, the effect of the amount of cinder on the performance of the fly ash-cinder cementitious material was studied using a univariate control method. Test methods for cement fluidity refer to example 3.

The following table 4 shows that the amount of the cinder is changed from 0 to 40 percent in a gradient way, and the other amounts are fixed.

TABLE 4 influence of the amount of cinder on the fluidity

As can be seen from the above table, the fluidity of the fly ash-cinder cementing material gradually decreases with the increase of the cinder dosage. In addition to high carbon content, the coal slag may have a rough surface and increased friction, which reduces its fluidity.

Example 5 Effect of fly ash and cinder dosage on Strength

Referring to example 2, the effect of different amounts of fly ash and cinder on the strength of the fly ash-cinder cementitious material was tested.

The method for testing the mechanical property (strength) of the cementing material comprises the following steps:

the compressive strength of the sample under curing was measured and the detailed operation was carried out as follows: firstly, cleaning the compression-resistant clamp and the pressurizing plate, and attaching the left end of the test piece to the positioning center of the clamp. The tester was then started until the test piece failed and the value recorded. The instrument is as follows: TYE-300 type pressure tester.

Microscopic testing of the cement, Scanning Electron Microscopy (SEM) analysis method:

a scanning electron microscopy spectrometer (SEM-EDS) of model EM-30PLUS manufactured by Europe and Inc. was used. The SEM can observe the microstructure change and whether the physical changes such as gaps appear in the preparation process of the cementing material. And then amplifying, collecting and re-imaging the information to achieve the purpose of characterizing the microscopic morphology of the substance. This experiment was performed using a small sample in a field emission scanning electron microscope model Sigma-500. The voltage in the selected detection parameters is 30.0KV, the highest magnification can be magnified by 2 ten thousand times, and the sample is tested by a scanning electron microscope.

The different amounts of fly ash and cinder are shown in table 5. The test results are shown in fig. 1 and 2.

TABLE 5 influence of different amounts of fly ash and cinder on the strength of cementitious Material

Remarking: the water-cement ratio refers to the weight ratio of the aqueous emulsion to the mixture.

As can be seen from FIG. 1, the compressive strength is the best when the amount of cinder is 20%, the amount of fly ash is 60%, and the amount of magnesium phosphate cement is 19% and the amount of retarder is 1%. When the mixing amount of the coal slag is more than 20 percent, the compressive strength is obviously reduced. The compression strength can be improved by adding a small amount of coal slag, and the more the coal slag is added, the stronger the coal slag is not.

As can be seen from FIG. 2, when the amount of the coal slag is very small or even not, a large gap exists. Along with the increase of the mixing amount of the coal cinder, the gap is reduced, and the compressive strength is increased. When the amount of the coal slag is more than 20%, gaps are filled and many crystals are generated. The compressive strength begins to decrease.

In addition, a certain amount of retarder is advantageous with respect to setting time and also with respect to compressive strength. The setting time of the cementing material is increased along with the increase of the amount of borax, and the reason is that the addition of the borax increases the pH value of the system, reduces the temperature and reacts on the surface of MgO particles to generate magnesium borate complex, prolongs the MgO dissolving time and reduces the hydration severity. And the appropriate amount of borax can improve the compressive strength of the cementing material. Wherein the magnesium phosphate cement contains MgO and monopotassium phosphate.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.