Theoretical study and mathematical modelling on the reaction rates in the SiMn-production process

Abstract

AbstractThe reduction rate of MnO and SiO2in the furnace stage of metallurgical silicomanganese productionhas been studied to increase the current understanding of the SiMn-alloy production process.

Usingthermodynamic data and experimental values, a computational model has been constructed in MATLABR2016B, based on the general relations for the reaction rates of the most prominent reactions found inthe process.

Furthermore, general formulas for the activities of MnO, SiO2, Mn and Si, as well as thecarbon saturation in the metal, were created based of data from FACTSAGE.

The formulas for activities and carbon saturation were found to be able to replicate the values from FACT-SAGE to a very high degree for the concentrations found during the silicomanganese production process.

The model was found to be able to replicate most of the experiments to a very high degree, producingslag and metal concentrations that were within a tens of a percent of the experimental value through theapplication of our knowledge of the thermodynamics and kinetics of the system.

From the comparison of three experiments with Assmang ore and three with Comilog ore, Assmang orewas found to reduce faster and at a lower temperature compared to Comilog ore.The foaming phenomena was studied and the rate of reaction was found to increase several fold duringthe foaming.

This was believed to be due to an increased reaction area between the carbon in the cruciblewall and the coke, and the slag.HeFeMn was found to reduce the temperature at which Assmang ore and quartz starts reducing withabour 75C.