The importance of microsilicon powder in the application is reflected in which aspects

In the production process of ferrosilicon or silicon metal, high silica produces silicon powder in the thermal furnace. After cooling, high fine particles are formed, filtered and collected by the filter to obtain the silicon powder. Usually, silica grey is colored between light and dark grey. Silica should produce a colorless S2. Its color depends mainly on the content of carbon and iron oxide. The higher the carbon content, the darker the color. In addition, the encrypted silicon ash is darker than the natural silicon ash. The particle size of silicon powder is less than 1 m, and the average particle size is about 0.1um, which is 1 / 100 of the diameter of cement particles. Thus, the silicon powder can be highly dispersed in the concrete and filled between the cement particles to lift High density. At the same time, microsilicon powder has high activity and can be used to purify time, coke and sawdust reduction, leading to complex reactions in the smelting process. Among them, when the quartz stone and carbon are at 1750, the reduction reaction produces unstable carbon monoxide. When the temperature is above 2160, the silica is evaporated and released. When encountering air below 1100, it reacts faster with oxygen and more comprehensively with 00 kg/m3 of cement water. The initial gray-state microsilica powder is usually transported in bags. Due to its small density and low long-distance transport efficiency, it mainly combines with the hydroxide produced by artificial direct decomposition Reaction. Silicon powder is mainly provided in two forms, namely crude silicon powder and dense silicon powder.1. The original gray microsilicon powder, which is directly collected by the dust collector, has a loose volume of about 150-2 bags. The silicon powder is poured into the concrete mixer, which results in large dust and low working efficiency in the working environment.2. Encryption of silicon powder. In order to solve the problem that the original gray microsilicon powder is not suitable for long-distance transportation and low efficiency, a "silicon powder encryption technology" is developed to improve the loose density of the silicon powder. This technique enables the original gray microsilicon powder to roll aggregate into small particle masses under the action of compressed air flow, which increases the loose volume of the silicon powder to 500-700 Kg/m3, greatly easy to use; the cohesion of the encrypted silicon powder particles is weak, it is easy to disperse during the mixing process in the concrete mixer; therefore, the silicon powder particles can be put into the mixer after the aggregate feeding to ensure the dispersion and good dispersion of the dense silicon powder particles.3. The higher the content of silica, the higher the performance of silicon powder, and the lower the content of other non-silica impurities. The content of silicon ash is greater than 85%, and the carbon of silicon ash contains a part of the adsorption gas guiding agent in the concrete. Therefore, burning loss =7% (carbon and water content control) is again the fineness of silicon powder should be controlled At 45 um, the particle size should be large and the screening amount should be less than 10%. Some scholars and experts have calculated that when 15% silicon powder is replaced by cement, the ratio of cement particles to silicon powder particles in concrete is 1:2 million. Silicon ash is a kind of fine powder substance. The key to improve the strength of concrete is to improve the bonding strength between the cement slurry and the aggregate, reduce fresh water, prevent water accumulation under the surface of the aggregate, so as to improve the compactness of the boundary surface transition area, reduce the thickness of the boundary surface transition area, the particle size of silicon ash is 100 times smaller than the cement particles, and fill the gap between the cement particles. Its effect with the cement particles filled in The effect is the same between the aggregates, increasing the compactness of the concrete. However, one of the prerequisites for silicon powder in these actions is the good dispersion in concrete. Add a small amount of silicon ash in concrete, and combined with efficient water reducing agent, can improve the physical and mechanical properties of concrete, such as significantly reduce the concrete separation and bleeding, effectively improve the pumping performance of concrete, significantly improve the concrete early, late strength, reduce chloride ion permeability, effectively improve the concrete chemical corrosion resistance and wear resistance, prevent concrete separation in the process of underwater construction. In conclusion, silicon powder has been widely used for high durability and high strength In concrete. In fact, the application of silicon powder in concrete dates back to Norway in the 1940s. In the late 1970s, northern Europe and North America also made great progress in the application of silicon powder in concrete. In the early 1980s, China has done a lot of research work on silicon powder concrete, and it has been widely used in water conservancy projects and achieved good results. The Ministry of Water Resources also promulgated the Interim Provisions on the Quality Standards of Hydraulic Concrete. In addition, the application of silicon powder in concrete is strongly driven by technological progress and social and economic factors, and the durability of concrete is paid more and more attention. Practice table Ming, in the harsh environment, ordinary concrete engineering may be seriously damaged in a short time, thus threatening the quality of the project and greatly reducing the service life of the project. However, meet the requirements of high performance concrete is prepared by cement, silicon ash, fly ash and water reducing agent, and has been successfully applied in all kinds of engineering, greatly promoted the progress of shotcrete technology, greatly reduce the shotcrete rebound, make the construction efficiency doubled, the concrete performance is significantly improved, the flexibility, rapidity and economy of concrete construction to a new level. Influence of silica ash on the properties of hardened concrete: cement slurry and bone The thickness of the interface transition zone between materials is about 5um, which is the weak link in concrete. When silica mortar is mixed, the microstructure of the transition area of the aggregate interface is similar to that of the slurry and dense and uniform. Silicon ash of hardened concrete performance improvement mainly due to the improvement of interface structure and composition, and between the slurry and aggregate bonding strength, thus eliminating the problem of "weak connection", the concrete has the characteristics of composite materials, the aggregate particles in concrete, not just the inert filler. Adding silicon ash to the concrete can improve the impermeability of the concrete and effectively improve the coagulation Chemical corrosion resistance of the soil. However, there is also a disadvantage, that is, the concrete added with silica ash is easy to absorb water during the maintenance period, and must be kept in time to prevent cracking. The above mainly introduces the performance of concrete mixed with silicon powder. In the future production and construction, more industries or fields will involve silicon powder. It can be seen that the importance of microsilicon powder in the application is reflected in the above content