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The biggest challenge for our society, in order to foster the sustainable circular economy, is the efficient recycling of wastes from industrial, commercial, domestic and other streams. The transition to a circular economy is the goal of the European Commission’s Circular Economy Action, which was first launched in 2015. In 2020 the above action plan announced initiatives along the entire life cycle of the product, with the aim to make sustainable products the norm in the EU. Therefore, it is anticipated that the above action will result in an increase in Europe’s economic competitiveness, sustainability, resource efficiency and resource security. Within this context, the suitability of ferroalumina as a raw material in the blast furnace is investigated. Ferroalumina is the product of the high-pressure filter press dewatering process of the Greek red mud generated during the production of alumina by means of the Bayer cycle. Ferroalumina is a low-cost raw material and its possible charging in the blast furnace and/or steelmaking aggregates is a step towards industrial symbiosis, where the wastes, namely by-products, of an industry or an industrial process, become the raw materials for another. In the present work the effect of ferroalumina addition as a raw material was examined by smelting ferroalumina, blast furnace-slag, lime and scrap at 1550°C in a graphite crucible and a constant slag basicity. The increase of the alumina content in the slag improves the desulfurization capacity. Moreover, the silicon exchange between slag and metal was examined. The results indicate that the alkalis’ capacity of the slag increases with the addition of ferroalumina. The analysis of the finally obtained slag suggests that it could be suitable for utilization in slag-cement production.

Purpose During steel plate and long-product production, numerous imperfections and defects appear that deteriorate product quality and consequently reduce revenue. The purpose of this paper is to provide a practical overview of typical defects (surface and internal) that occur and their root causes. Design/methodology/approach The data presented here derive from the quality department and from more than 50 technical reports of ELKEME S.A. on the last decade’s production of steel making companies STOMANA S.A. and SIDENOR S.A., with emphasis on the defects occurred in some of the products of the Bulgarian plant. Stereoscopic observations of surface defects, light optical metallography, and scanning electron microscopy with EDS represent the most used techniques to characterize defected macro-/micro-areas and microstructures. Findings In general, the most commonly encountered defects from semi-finished (billets, blooms, and slabs) and final (round bar and plate) steel products are as follows: network cracks, porosity, gas holes, shrinkage, shell, slivers, casting powder entrapment, ladle slag entrapment, other non-metallic inclusions, low hot ductility, centerline segregation cracking, macro- and micro-segregation, and mechanical defects (scratches, transverse cracks, and seams). Practical implications External and internal quality improvement can reduce the production cost (Euro/ton). Social implications Improvement of the quality of industrial plates and long products increases the safety of the further-produced constructions and systems such as bridges, cranes, heavy equipment, automobile parts, etc. Originality/value Root cause analysis and categorization of the most commonly encountered defects can pave the way to production process improvements that directly affect final product quality and the overall per ton production cost. The benefits of this work obviously affect all steel producers/processers, and also society through the safety increase achieved by the quality improvement in the steel products used in constructions and automobile parts.

Summary Forest biomass is used to produce bioenergy that comes from many sources such as trees of harvestable age or killed trees by disturbances, material from stand thinning, harvest residues, and by-products of industrial forest processes. The Region of Western Macedonia in Greece has a considerable potential of forest biomass but lacks in wood resources management and exploitation. This lack constitutes a deterrent for potential bioenergy investments. The present study identifies five pilot concepts based upon regional needs to be developed in order to raise awareness and to attract the attention of stakeholders. These pilot plans aim to identify concrete measures for wood mobilization and to explain their applicability under different conditions. As a result, decision-makers from administrations, industry, and forestry practitioners will be helped to make sound choices and implement appropriate actions with respect to all aspects of sustainable wood mobilization, while ensuring sustainable forest management. These five pilot applications are described as follows: biomass investor's toolkit; development of a traceability procedure for biomass energy chain; guide for educating personnel in timber harvesting, safety, and precaution measures; development of a guide/toolkit for the next generation forest management plans; and overview of options for utilization of biomass ashes. Copyright © 2015 John Wiley & Sons, Ltd.

This work simulates the Suralaya Power Plant Unit 6 boiler located at Cilegon, Banten, in Indonesia for two thermal loads, i.e., 600 and 400 MW under as-found (normal) and reduced-oxygen co...