In recent years, the amount of steel slag produced has increased rapidly with the rapid development of the iron and steel industry. As steel slag cannot be processed in time, a large amount of steel slag takes up land, pollutes the environment, and is mostly abandoned. However, steel slag contains a large amount of available components such as slag steel, calcium oxide, iron and magnesium oxide, which can effectively realize the goal of resource recycling of steel slag.
Steel slag is divided into three types: electric furnace steel slag, open hearth steel slag and converter steel slag. The comprehensive utilization of steel slag mainly involves: pretreatment, recovery of valuable components, use as building materials, metallurgy, agriculture, etc., of which building materials account for about 40%; At the same time, the research of steel slag pretreatment accounts for about 32%, and more and more attention is paid to the pretreatment work in the early stage, so as to be more conducive to the performance of the products prepared in the later stage.
At present, steel slag is commonly used to grind steel slag into fine powder through a steel slag vertical mill
, because grinding is not only a process of particle reduction, but also accompanied by changes in crystal structure and surface physical and chemical properties, and the activity of the powdered steel slag after grinding can be greatly improved. improve. The main technical requirements of steel slag powder include specific surface area, density, moisture content, free calcium, sulfur trioxide, alkalinity coefficient, activity index, and stability. According to the activity, it is divided into first and second levels.
There are two main ways for the comprehensive utilization of steel slag as a secondary resource. One is to be recycled in the plant as a smelting solvent, which can not only replace limestone, but also can recover a large amount of metallic iron and other useful elements from it; the other is as a road building material , Building materials or raw materials for agricultural fertilizers.
Steel slag as a cement admixture has long been listed in the national standard. It is ground by a steel slag vertical mill to produce steel slag powder as a cement admixture. When the specific surface area of steel slag powder is above 400m2/kg, when it is used with slag powder, its activity is fully activated; when its specific surface area is above 450m2/kg, similar to slag powder, steel slag powder products have a good market prospect.