Production of Silicomanganese from Comilog Ore - Reduction Behavior

Abstract

The reduction behavior of silicomanganese (SiMn) charges based on Comilog ore was investigated. The charges were heated up to to different temperatures by using a thermogravimetric graphite tube furnace. The weight loss during heating was measured and compared with slag and metal compositions for each sample for investigating the reduction for the charges. The aim was to investigate the reduction rates for silicon and manganese in SiMn production, and to find out if limestone added as a flux has positive impact on the degree of reduction for silicon and manganese.

For investigating the slag and metal compositions for the samples it was used SEM (EDS) and EPMA.

It was found that the slag in SiMn charges will foam at high temperature when heating rate of 4.5 °C/minute. The temperature for this foaming was 1600 °C for SiMn charge with limestone and 1650 °C for charge without limestone.

The MnO reduction will start at 1400 °C in SiMn charges, and the reduction of silica will start occur at 1550 °C in SiMn charges. These temperatures was found to be the same for SiMn charges both with and without limestone.

The SiMn charges was found to have a liquid slag phase at 1250 °C according to the binary phase diagram for MnO-SiO2.

SiMn charge with limestone added as a flux had higher degree of reduction of both manganese and silicon than SiMn charge without limestone.