The Properties of Carbon Blends in Submerged arc Furnaces

Charcoal was investigated as a renewable reducing agent to replace fossil fuel reductants in the metallurgical industry. Since a stepwise transition from fossil fuel-based reductants to renewable charcoal is expected, three charcoal blending ratios (20, 40 and 60%) were analysed. A procedure to determine the mechanical, chemical and electrical properties of carbon blends for submerged arc furnaces (SAF) was developed and evaluated by the stated three blending ratios of charcoal and metallurgical coke. The samples were investigated after heat treatment under pyrolysis and CO2 gasification conditions. The higher reactive carbon material (charcoal) was consumed by the Boudouard reaction, reducing its mechanical stability and affecting the generation of fines in consecutive analyses, e.g. the mechanical strength to withstand abrasion decreased. Chemical analysis showed only minor interaction between the carbon materials under pyrolysis conditions. The electrical resistivity of the carbon bed was mainly affected by the heat-treatment temperature and volume fraction of the carbon materials, in which a linear interpolation resulted in an acceptable accuracy. A volume fraction of at least 40% conductive material (coke) was required to enable an electrical conduction through the packed bed.