With the continuous consumption of coal, the discharge of fly ash is also increasing, and the degree of environmental pollution is becoming more and more serious. In order to protect the ecological environment, it is necessary to implement sustainable development strategies. The fly ash is comprehensively utilized, and the fly ash cement is produced by producing cement clinker or mixed material, which can be reused without causing the ecological environment to be polluted. At the same time, this work also has the High economic and environmental benefits.

At this stage, in thermal power plants, the main material used for boiler fuel is pulverized coal. When all the pulverized coal is injected into the boiler, it will be fully burned, and it will be in the form of fine particle fire. , fully release the heat energy. After a period of combustion, ash will be formed. Since the ash content of the raw coal itself is not the same, in terms of the quality of the raw coal, it will normally account for 15% to 40%. The corresponding fine dust is collected through the dust collection facility of the exhaust system, which is fly ash. Fly ash does not exist in nature, but a powdery mineral resource formed by artificial intervention, which is a fuel by-product, and can also be called “regenerated mineral powdery resource”. According to the actual content of calcium oxide in fly ash, fly ash is divided into two types, namely high calcium fly ash and low calcium fly ash.

As far as fly ash is concerned, its chemical composition fluctuates very greatly, but in reality, most of them are mainly acidic oxides. In domestic fly ash, there are only two main chemical components, namely alumina and silica, which together account for about 70% to 80%. The content is 15%~40%, while silicon oxide accounts for 35%~55%. In addition, the activity of fly ash itself depends entirely on silica and alumina. The more the content of these two, the greater the activity of fly ash; at the same time, the calcium oxide component of fly ash itself also has A certain degree of activity, so it will also affect the degree of activity of fly ash.

Fly ash is mainly composed of three substances, namely crystal, glass and a small amount of unburned carbon. Among them, in the crystal, not only the component of mullite, but also the component of anorthite and the like. In fly ash, the content of aluminosilicate glass body occupies more than 50%, and is the main active part of fly ash. Based on other same conditions, if the content of glass body in fly ash is more, the fly ash itself the higher the degree of activity. In addition, the glass body inside the fly ash, whether it is the surface condition, the actual shape or the size, is closely related to its own performance.

Fly ash is used as cement admixture

1 Ordinary Portland cement with fly ash
Taking the national standards as the actual starting point and the regulations of “Portland cement and ordinary Portland cement”, not only can fly ash be mixed as a mixed material, but also 6% to 15% can be added. After that, it is still named ordinary Portland cement. In Portland cement mixed with fly ash, its own strength is much higher than that of cement without fly ash.

2 Fly ash Portland cement mixed with fly ash
It is still based on the national standard as the actual starting point, with the regulations of “slag portland cement, pozzolanic portland cement and fly ash portland cement”, and the fly ash and portland cement clinker are mixed in At the same time, a certain amount of gypsum is ground to make a hydraulic cementitious material, which is called fly ash Portland cement. In the process of mixing fly ash into it, the overall weight ratio is 20%~ 40%, so the strength of the cement increases very slowly in the early stage, and its own hardness gradually exceeds that of Portland cement after about 18 days.

3 Composite Portland Cement
According to the national standard, with “composite Portland cement” as the regulation, as far as composite Portland cement is concerned, it is not only mixed with fly ash, but also mixed with some slag, and it is mixed with 15%~50% The weight ratio was incorporated.

4 Fly ash ultrafine cement
As far as fly ash ultrafine cement is concerned, it is itself an ultrafine cement made by mixing granulated blast furnace slag with Portland cement clinker, and is U-shaped, with 30% ultrafine fly ash mixed into it. Among them, the inorganic grouting material is further made and used in the actual foundation treatment. In the whole production process of the cement, not only the original cost can be further reduced, but also the grouting performance can be greatly improved.

In the process of cement production, fly ash is used in it to make cement mixture materials, which can not only further increase the output of cement, but also regulate the actual mixing ratio, thereby regulating the actual efficacy of cement. For example, in the process of cement production, adding 12% fly ash can increase the overall output by 14.3%; if 25% fly ash is added, 10% fly ash is added at the same time. slag can increase the overall cement output by 35.2%; in addition, mixing fly ash into cement can further save energy. In the process of producing 425# two-mixed cement, the standard The input production of coal is only 138.85kg/t. In addition, the double-mixed cement itself not only has the characteristics of strong corrosion resistance, but also has a very low cost in the actual production process, and its own hydration heat is also very low. In the process of practical application, the benefits are very high. Significantly.

In the actual production process of cement, mixing fly ash into it can not only further reduce the use of clinker, but also save costs, reuse the waste, and avoid pollution to the ecological environment. The cement industry has brought greater economic benefits, so the comprehensive utilization of fly ash should be further promoted to create greater social and environmental benefits.