Investigation on Stabilization of Ladle Furnace Slag with Different Additives

Ladle furnace slag disintegrates into fine powder during cooling due to phase transformations of di-calcium silicate. This creates an adverse impact on working conditions and the environment by dust generation. In this paper, a short overview on different studies to overcome the disintegration problem is provided. An attempt was also made to study the effects of several different additives and their mixtures on disintegration of slag. Phase equilibria calculations were carried out for some additives using FactSage® to understand the phase changes in the slag. Based on the phase equilibria calculations and literature data, initial laboratory experiments were conducted at 1650 °C with different additives such as boric acid, aluminium, and fly ash. Slag samples were analyzed with X-ray fluorescence and X-ray powder diffraction for chemical and phase analysis before and after treatment. The disintegration of slag can be prevented either by addition of 0.5 wt% or more of boric acid or 9 wt% of aluminium or 6 wt% of fly ash or 4–8 wt% fly ash along with 0.125–0.25 wt% of boric acid in slag. Based on the optimized conditions, industrial trials were conducted.