Effect of Glycerol Mechanical Excitation on the Phase Evolution and Hydration Activity of Steel Slag

Abstract

During the slow cooling process of steel slag, the crystals of inert mineral phases (C₂F, RO phases) and active mineral phases (C₂S, C₃S) adhere and grow, and the irregular interlocking, embedding, filling, stacking, and coating between mineral phases seriously affect the hydration activity of active mineral phases in steel slag. Therefore, this article selects glycerol (C₃H₈O₃) as a grinding aid to mechanically excite steel slag, exploring the mineral phase evolution and hydration activity excitation mechanism of steel slag under different process parameters. C₃H₈O₃ mechanical excitation refined the steel slag particles, increased porosity, increased specific surface area, and caused peeling behavior between the rough surface active mineral phases (C₂S, C₃S) of the steel slag particles and the smooth surface inert mineral phase C₂F with sharp angular protrusions. When the addition amount of C₃H₈O₃ is 0.24 wt% and the ball milling time is 90 minutes, the mechanical excitation effect of steel slag is the best. The total mass fraction of C₂S and C₃S increases by 14.3 wt%, while the mass fraction of C₂F decreases by 19.3 wt%. The mechanical excitation of C₃H₈O₃ can cause the steel slag to germinate cracks at the interface of each phase, and a porous honeycomb structure composed of calcium hydroxide (CH) and calcium silicon hydrogel (C-S-H) appears during the hydration process, producing a large number of acicular ettringite (AFt), effectively improving the early hydration activity of steel slag.