Steady-State Materials and Enthalpy Balance: Applications to Ferroalloy Production and Industrial-Scale Validation

Abstract

Steady-state material and enthalpy balance models for ferroalloy production in submerged arc furnace (SAF) have been developed. Two different types of ferroalloys, used commonly in the steel industry, namely high-carbon ferromanganese and high-carbon silicomanganese, were considered, and appropriate mass and energy conservation expressions were developed considering input, output and losses of various entities to/from two different 33 MVA SAFs. Several plant-specific parameters, such as material loss due to handling, off-gases, hot metal, slag and off-gas temperatures as well as heat losses from the SAFs, were incorporated in order to develop a predictive material and energy balance framework. Embodying types of feed materials, their composition and amount together with product composition along with relevant thermodynamic data, and amount of metal and slag produced in the two processes were estimated. Similarly, external power required to produce a given amount of ferroalloy was calculated by coupling material balance with an appropriate energy balance calculation scheme. It was demonstrated that estimates of hot metal production, slag generation and external electrical energy requirement were in reasonable agreement with industrial operating data. A graphical user interface was also developed to carry out material and energy balance calculations efficiently.