"Evaluation of LF Slag Degradation and Its Impact on Ladle Lining"

M.N. MOLINÉ; A.G. TOMBA MARTINEZ; P. G. GALLIANO

Santiago

Congreso; 16th Biennial Worldwide Congress on Refractories UNITECR?17; 2017

MgO-C and Al2O3-MgO-C bricks are widely used as working lining in the steelmaking ladles. Due to their carbon content they are particularly susceptible to high temperature oxidation. These bricks are exposed to such conditions after casting and during the ladle preheating.At the end of each heat, LF slag remains partly adhered to the walls, generating a coating that can act as a barrier, protecting the refractory to decarburization. The slag also suffers transformations during cooling such as hydration and pulverization, which can affect its protective capacity.For this reason, physico-chemical characterization of a steelmaking ladle slag and the evaluation of its integrity under different conditions are carried out in this work. The degradation of the slag by weathering is evaluated through its granulometric evolution at different times for several months. In each case, samples were also characterized by different techniques: X-ray fluorescence, X-ray diffraction and thermogravimetric analyses.At short time, degradative processes concerning CaO are observed. At longer time, degradation of MgO and changes in calcium aluminates are also detected. These transformations involve volumetric expansions and then, the slag disintegration. These changes will affect the protective capacity of the slag on preventing decarburization of working lining refractories in empty ladle conditions