<p>One of the ways to decrease CO₂ emissions is to decrease energy consumption; however, metallurgical reactors are approaching the theoretical limits. In this scenario, it is important to have a better understanding of the process phenomena. Slag foaming in the EAF is one of the most important techniques to decrease energy consumption; however, in the past, most of the research work has not only employed conditions which are far away from the industrial practice but also the application of a conventional foaming index which is inaccurate to describe the real slag foaming process. This work has investigated slag foaming that results from one of the reactions zones, the slag/metal interface, that produce CO bubbles by reaction between FeO and C in the liquid metal. This is the first investigation that quantifies the slag foaming height due to CO bubbles generated at the slag metal interface, as a function of time, changing slag FeO, slag basicity and C in the molten metal. The variables include changes in the initial concentration of FeO (from 20 to 40 pct), slag basicity (from 1.5 to 2.3), and carbon dissolved in the molten metal (2 and 4 pct). The results clearly identify optimum values in the concentration of FeO and slag basicity. Using dimensional analysis, an equation has been developed to predict a dimensionless foam height which depends on the slag physical properties (viscosity, density, and initial height) as well as slag chemical properties (FeO and basicity) and carbon concentration in the molten metal.</p>