Ana Rosa Rabelo de Lima
Universität Duisburg-Essen
PhD candidate at the University Duisburg-Essen in the field of recycling of oxidic and metallic residues and circular economy, supervised by prof. Rüdiger Deike.She is a Brazilian Materials Engineer, with background in the Brazilian Amazon area. She got interested in man-made impacts, also due to the scenery found in that region, and started to get involved with projects related to sustainability and industrial ecology. She is now mainly involved with projects between Germany and Brazil.She is also in the student board of the ISIE student Chapter.
In order to reduce environmental burdens, technological developments are now focusing on energy productivity and resource efficiency. Metals play a pivotal role in this context because of their theoretical unlimited recyclability, without loss of quality, in virtually closed cycles. It is, in principle, possible to manufacture metal goods using secondary raw materials with marginal environmental pressure and significantly reduced specific energy consumption
To increase the number of viable recycling techniques, it is necessary to have deep understanding of the residual material quantities and compositions. This study focuses in the residual materials which occur in the manufacture and processing of alloyed steels in Brazil and Germany. These materials may be found in filter dust, slag, mill scale and overspray. They contain valuable alloying elements such as chromium, cobalt, molybdenum, nickel, niobium, vanadium and tungsten.
A physicochemical characterisation was needed to achieve an adequate evaluation of the material composition and recyclability potential. Physical parameters such as particle size, residual moisture and density have been identified. The chemical characterisation has been done using x-ray fluorescence, particularly focusing on the economically strategic elements and on the heavy metals in relation to environmental problems. The oxidized metals from the residual materials have been analysed to allow conclusions about the best reduction agent necessary for the reduction process.
This study is the foundation of a long-term project that aims to identify recycling processes that are not based on recovering metals as secondary raw materials in pure form, but as alloy briquettes, which can be reused directly in the producer’s own operations, allowing lower costs for the recycling process.
This innovative method is intended to utilize direct reduction of the oxidized metals contained in the residual material to replace the conventional and costly processes. A further benefit of the proposed method relates to the fact that some waste materials could be simply reused on site. In-process recycling using this innovative technique would bring reduced operational costs, decrease mineral extraction, and major energy savings, with related CO2 emission abatements, in metals recycle processes.
• Industrial ecology in developing countries , • Industrial symbiosis and eco-industrial development , • Sustainable business models
