Juergen Antrekowitsch

Abstract:

The industrial sector “metal production” is still one of the biggest emitters of fossil based anthropogenic carbon dioxide. While carbon carriers are often used as source of energy, also the chemical process, the reduction, in many cases requires carbon. [1] Examples are various shaft furnace technologies, rotary kilns, rotary hearth furnaces etc. Especially iron industry as well as zinc and copper recycling, lead and tin metallurgy and others consume huge amounts of carbon for reduction. Fresh biomass contains far too many volatiles and does not offer appropriate mechanical properties. Also standard pyrolysis produces a type of charcoal, which is still too reactive because of remaining volatiles and high porosity. The Chair of Nonferrous Metallurgy, Montanuniversitaet Leoben, has started to develop special charcoals out of various types of wood based biomass that offer characteristics which are closer to the one of metallurgical coke than common charcoals. These reducing agents were tested for zinc recycling in rotary kilns as well as in molten slags for other recycling processes. The tests done in lab- and technical scale showed promising results regarding a possible replacement of fossil carbon carriers by special pyrolyzed biomass. The paper describes advantages and disadvantages of the utilization of biomass in the above mentioned field. Furthermore, availability and differences in the quality of wooden biomass with focus on metallurgical application is discussed as well as the utilization of the generated pyrolysis gas [2, 3]. In general, it can be summarized that the use of special pyrolyzed biomass as reducing agent for different metallurgical processes is possible from the technical point of view and can contribute to minimize the CO2-emission from fossil carbon carriers. Especially in times of high CO2-credit prices such concepts for metal production can be also realized economically.