Peculiarities of the phase composition formation of steelmaking slags and evaluation of the possibility of obtaining mineral binders with low CO2 generation on their basis

The article presents the results of analysis of steelmaking slags formation. It is shown that currently two methods of steel refining are used in the steelmaking industry – oxidative and reducing. The method of oxidative refining is implemented in electric arc furnaces (EAF), and is primarily aimed at extracting phosphorus from the steel being smelted. Reducing refining is implemented in the ladle-furnace unit (LF) and is aimed at removing sulfur from steel. The features of these processes affect the formation of the phase composition of steelmaking slags. Under conditions of oxidative refining, wustite FeO, magnetite Fe 3 O 4 , larnite β-2CaO·SiO 2 and merwinite 3CaO·MgO·2SiO 2 are formed in EAF slags, and under conditions of reducing refining in LF slags, mayenite 12CaO·7Al 2 O 3 , periclase MgO, low–temperature modification of dicalcium silicate – γ-2CaO·SiO 2 , CaS and FeO. Of the minerals in the composition of EAF slags and LF slags, mayenite 12CaO·7Al 2 O 3 and larnite β-2CaO·SiO 2 have hydraulic activity. Based on the theoretical analysis of the formation of sulfated hydraulically active phases, the possibility of imparting properties of mineral binders to steelmaking slags by grinding without their additional thermal preparation is shown.