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12.01.2011

Befesa Zinc Freiberg investigates charcoal to reduce CO2 emissions

The Befesa Zinc Freiberg runs a plant for the treatment of zinc containing residues, mainly electric arc furnace dust, by thermal volatilisation. In the process, the zinc oxide contained in the residues will be reduced in two waelz kilns by a reduction agent, usually petrol coke, coke breeze or anthracite. As all of them are fossil fuels, whose usage leads to an enrichment of CO2 in the atmosphere, Feiberg is developing a research to replace them by renewable substances.

The use of smaller amounts of reducing agents as a means to reduce fossil CO2 emissions has been studied in the past and is already considered an optimized way. However, it breaks new ground and is currently investigating the replacement of fossil by renewable reducing agents, one of them may be charcoal.

For that reason, Befesa Zinc Freiberg conducted in June 2011 an experiment by using 500 t of charcoal and where nearly 45.500 euros were spent. This amount is the price difference between coke and the much more expensive charcoal. In the course of the experiment, no big differences in the zinc recovery between the usage of charcoal and coke could be observed. However, by using charcoal, annual emissions of greenhouse gases from the factory were reduced by 1%. The experiment will be continued next year in order to be optimised.

Befesa R & D is doing researches on pyrolysis of wood waste, for example olive stones and wood from grapevines, to produce a cheaper secondary charcoal. In the future, pyrolysed products will be used as a reducing agent in metallurgical processes and experiments in Freiberg will have been the base.

Installations of Befesa Zinc Freiberg, in Germany

Installations of Befesa Zinc Freiberg, in Germany