The rational utilization and effective recovery of steel slag is one of the important symbols of the improvement of modern steel industry technology.Therefore, the reduction, resource utilization and high value utilization of steel slag has become an important research topic at home and abroad.In recent years, China attaches great importance to promoting the comprehensive utilization of bulk industrial solid wastes such as steel slag. In particular, it is emphasized in the Fourteenth Five-Year Plan that the comprehensive utilization rate of newly added bulk solid wastes reaches 60% and the stock bulk solid wastes decreases in an orderly way. Steel slag, as one of the bulk solid wastes, has a low utilization rate due to its large fluctuation of chemical composition and mineral composition, slow hydration, low early strength, poor stability, low grindability and difficult pretreatment of raw materials. However, with the continuous development of science and technology, and the optimization of new equipment technology, there are new changes in the deep treatment of steel slag.
In the field of industrial solid waste, the Great Wall machinery focus on resource utilization development direction in this field, and actively explore the steel slag, water slag, slag, fly ash, coal gangue and other industrial solid waste recycling solutions, vertical grinding machine and recommend special solid waste powder production line of a complete set of solutions, the escort for the comprehensive utilization of solid waste. The steel slag powder processed by vertical mill has high activity, good quality and wide application.If it can be used in concrete production, using steel slag composite powder (fly ash, slag powder, steel slag powder) to replace 20% ~ 50% of ordinary Portland cement, can prepare good performance of C20 ~ C60 different strength grade concrete.Or the high activity mineral admixture with shrinkage compensating function can be developed by using steel slag powder, making its 28d activity index greater than 65%.When the mixing amount reaches more than 20%, the concrete can produce micro-expansion, and the expansion rate starts to stabilize in 90d, and the size is (1 ~ 3)×10-4.
In addition, the application of steel slag powder in the field of concrete production is the main way to help the steel slag powder improve the added value of finished products and realize greater value. The research shows that the water consumption of the cement paste mixed with steel slag powder at the standard consistency has little change compared with that of the benchmark cement, and at the same time, it has obvious delaying effect on the setting of the cement paste.The setting time of self-compacting concrete mixed with steel slag powder is obviously longer than that of reference self-compacting concrete, and the higher the steel slag powder content is, the longer the setting time of self-compacting concrete is.Therefore, steel slag powder is suitable for retarded self-compacting concrete.
