Bernd Wittgens

Abstract:

The Norwegian ferro-alloy industry is a world leader in sustainable production of ferro-silicon, silicon, and manganese alloys. Even if the industry is currently operating with very low specific energy consumption, there is a considerable amount of energy available in the off-gas from the submerged arc furnaces, both in terms latent heat and unconverted chemical energy. For FeMn production, the off-gas also contains mineral rich particles which are contaminated by tar and polycyclic aromatic hydrocarbon (PAH) components. The dust particles are currently removed from the off-gas and deposited as a wet sludge waste stream. Results from recent experimental validation are presented for a new concept for off-gas processing, which enables an increased energy recovery and can facilitate future material recovery through production of tar and PAH free mineral dust. New results from a techno-economic evaluation of the concept will be presented, including ideas for material recovery from the currently unutilized waste stream. The overall objective is a maximized energy recovery and simultaneously prepare for a comprehensive reduction of waste streams.