Effect of MgO/Al₂O₃ on Crystallization Behavior of Molten Modified Slag in Preparation Process of Blast Furnace Slag Based Cotton

In order to explore the effect of MgO/Al₂O₃ ratio on crystallization behavior of molten modified slag in the preparation progress of blast-furnace-slag-based slag fiber,theoretical crystallization temperature and species and contents of precipitated phases at different values of MgO/Al₂O₃ ratio in cooling process of modified slag were simulated by FactSage thermodynamic software.Ballast furnace slag with different values of MgO/Al₂O₃ ratio was prepared using chemical pure agents under laboratory conditions and crystallization behavior of molten modified slag with different values of MgO/Al₂O₃ ratio was analyzed by XRD and SEM.The results indicated that crystallization phenomenon occurred in modified slag with various MgO/Al₂O₃ ratio and the precipitated phases are mainly composed of akermanite(2CaO·MgO·2SiO₂) and gehlenite(2CaO·Al₂O₃·SiO₂).Theoretical crystallization temperatures of different precipitated phases and modified slag change regularly with the change of the value of MgO/Al₂O₃ ratio.When the value of MgO/Al₂O₃ ratio is 0.6,crystallization temperature of molten slag is the lowest at 1 406.83℃,at which activation energy of crystallization is at maximum value and the complete system is the most stable.