Investigation on Applicability of Lime as Desulfurization Agent for Molten Cast Iron

Abstract

In this study, the prospective application of lime as a desulfurization agent for the cast-iron industry is technically examined. This investigation encompasses a series of laboratory experiments conducted under atmospheric conditions, mirroring industrial settings by exploring two distinct methods for introducing lime powder onto and into molten cast iron using surface addition and gas injection techniques. Deoxidation agents (FeSi, SiC, and Al) are also incorporated to enhance the lime-based desulfurization results. Based on the findings of this study, it is indicated that lime can be a reliable cast-iron desulfurization agent by reaching an end-sulfur concentration of <0.015 wt%, thus providing an opportunity for a sustainable alternative for the foundry industry. In this study, it is also revealed that adding a small quantity of Al is more effective at enhancing desulfurization results than Si due to its role in increasing the proportion of liquid slag during desulfurization. However, caution is advised regarding the limit of aluminum concentration in cast iron (0.1 wt%), and treatment temperatures should be kept above 1400 °C to prevent counterproductive effects and undesirable defects in the product.