Effect of MnO2 doping on mineral formation and hydration properties of restructured steel slag.

In this paper, addressing issues of the steel slag cementing, such as low activity and poor stability problem, calcium, aluminum and other components were introduced to reconstruct the steel slag with adding different proportions of MnO₂ and analyzed using XRD, EDS, heat of hydration and activity index. And the study focuses on the effect of MnO₂ doping on mineral formation and mechanical properties of reconstructed steel slag. The results show that at high temperatures, the doping of MnO₂ can improve the ease of burning of reconstituted steel slag, and the effect of increasing the doping is significant. The incorporation of MnO₂ promotes the formation of C4AF minerals, reduces the content of MgO, and has little influence on the formation of C₂S. Mn³⁺ is easy to replace Fe³⁺ in C4AF to form solid solution. MnO₂ can obviously promote the hydration of reconstructed steel slag, which shows that the acceleration period is advanced and the induction period is shortened. The gelling activity index increased firstly and then decreased with the increase of MnO₂ dosage. When the dosage was 2.0%,the gelling activity was the best, the 90d compressive strength was 104.95 MPa, and the activity index was about 100%. [ABSTRACT FROM AUTHOR]