Change of Ca occurrence state in carbonation process of LF refining slag

      In order to improve utilization efficiency of LF refining slag, the change of Ca occurrence state during carbonation of refining 

slag was studied. The carbonation experiments were carried out to determine the process parameters:temperature of 20 ℃, liquid-

solid ratio of 5, aeration volume of 600 mL/min, rotation speed of 700 rad/min and particle size of less than 88 μm. Under the 

above conditions, the carbonation effect is the best, the concentration changes of Ca^2+, HCO3^-, CO3^2- under different pH 

conditions was explored. XRD, SEM, TG-DTA and FT-IR were used to characterize the refining slag before and after carbonation.

 XRD analysis shows that intensity of f-CaO, Ca2SiO4 and Ca3Al2(SiO4)3 and diffraction peaks become weak after carbonation, 

and the main product is CaCO3;DG-DTA analysis shows that weight loss rate of carbonated products reaches 13.35% at 600-800 

℃. SEM analysis shows that the generated CaCO3 particles aggregate and adhere to the surface of the refined slag particles;FT-

IR shows that after carbonation, a large amount of carbonate is produced, and most of them are in the form of calcite.