in our country every year is about 1. But the effective utilization rate of steel slag in our country is only about 20-30%. Why is the current utilization rate of steel slag in our country not high? Ccement. Com/richtext/IMG/le8jzjw2we1693193952191. However, this form of utilization faces the following four problems:
1. The grinding of steel slag causes great damage to the mill, shortens the maintenance cycle, reduces the grinding efficiency, and increases the equipment and maintenance costs. 2.3
. The steel slag itself is difficult to grind, so the hydraulic activity of the steel slag is often low.
4.
In the past, many comprehensive utilization methods were restricted by some of the above problems to varying degrees and were difficult to promote. To thoroughly solve the problem of steel slag pollution, it is necessary to have a subversive technology to break through the above technical bottlenecks. Shen Weiguo said that perhaps it was a coincidence that the technology of "steel slag phase separation clinker" had solved the above four problems well. The technology of "
steel slag phase separation clinker" is to put the unground steel slag into the kiln system for calcination, forming a gradient clinker containing three layers of different phases with the reconstructed steel slag as the core, the high-speed rail clinker as the transition zone and the ordinary clinker as the main body, so it is called steel slag phase separation clinker. How does this technology solve the above problems? The granular waste slag after iron separation is directly put into a kiln system for calcination, so that a grinding link is reduced, the difficulty in grinding steel slag is no longer a problem, and the energy consumption of raw material grinding can be saved.
2. that Mel point of the steel slag is low, and the free calcium in the steel slag fully reacts with the silicon, aluminum and iron component in the steel slag and the raw meal for consumption. In the trial production at Yufeng, Liuzhou, the free calcium content of the clinker after calcination is
basically 1.3. After calcination and reaction with the raw meal, part of the steel slag is transformed into clinker, part into high-speed rail clinker, and part into reconstructed steel slag. The activity of the reconstituted steel slag is more than 90%, and the strength of the phase separated clinker is higher than that of the conventional clinker.
4. Steel slag contains high content of elemental iron and ferrous iron, and has strong reducibility. The melting point of steel slag is lower than that of raw material, and it has basically melted at 1300 degrees Celsius, when the outside of steel slag has been wrapped by raw material powder. Prior to this, iron and ferrous iron were first oxidized to provide reduction protection for trivalent chromium, which had no chance to react with oxygen, and the content of water-soluble hexavalent chromium in the final fired steel slag phase separation clinker was very low. After practical application, the water-soluble hexavalent chromium in the cement and clinker of Yufeng and Bohong has been reduced.
2) the energy-saving effect is the best: the addition of the steel slag enables the original solid phase reaction to occur in the molten liquid phase of the steel slag, thereby greatly reducing the sintering temperature by 20 to 50 deg C, and the comprehensive coal blending is not changed when the steel slag is added to sinter the clinker, which is equivalent to saving the coal consumption in the same proportion. And
3) that carbon neutralization effect is the B: when the steel slag phase-separation clinker is sinter, the steel slag does not decompose calcium carbonate, which is equivalent to reducing the carbon emission.
4) The added value of the product is the highest: steel slag is converted into high-quality clinker, while other technologies convert steel slag into raw meal or auxiliary cementitious materials, and the added value is far lower than that of clinker. Steel slag phase separation clinker can be used in general cement, road cement, Shen Weiguo introduced." This technology is the technical inspiration generated by the research team of "Big Concrete World" in 2008. After 15 years of research, five postgraduates and one doctoral student have devoted themselves to technology research and development, and have formed a complete set of technology with patent technology as the core and technical secrets as the key. The results have been popularized and applied in four enterprises in South China, Southwest China and Northwest China, and remarkable economic and social benefits have been achieved. The 2022 results were reviewed by experts, and the experts agreed: "The project is highly innovative, and the overall technology has reached the international advanced level, in which the burning technology of steel slag phase separation clinker has reached the international leading level.". It is suggested to further accelerate the popularization and application and promote the efficient recycling of steel slag.
Shen Weiguo is full of expectations for the comprehensive promotion of this technology. If this technology is fully promoted and applied, it will not only convert 160 million tons of cheap steel slag into high-quality clinker at low cost every year, but also produce 132 million tons of carbon emission reduction, with considerable direct economic and environmental benefits! ccement.com/project/snjnhb2023" rel="noopener noreferrer" _ blank "" 2023 Cement'Double Carbon 'Conference and the 10th China Cement Energy Conservation and Environmental Protection Technology Exchange Conference ", At that time , Shen Weiguo , a researcher and doctoral supervisor of Wuhan University of Technology, will share the theme of "Engineering Transformation of Steel Slag Phase Separation Clinker Patent Technology" ! ccement.com/brandnewslist-1-1000121.
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