Title: Exergetic considerations on the recovery of metals from waste

Authors: Franz-Georg Simon; Olaf Holm

Addresses: Division Contaminant Transfer and Environmental Technologies, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12005 Berlin, Germany ' Division Contaminant Transfer and Environmental Technologies, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12005 Berlin, Germany

Abstract: Bottom ash from municipal solid waste incineration (MSWI) consists of elemental metals in considerable amounts. The exergy of bottom ash was calculated to be some 100 kJ/mol, mainly as a result of the presence of elemental Fe and Al. From this it can be shown that the recovery of elemental metals Cu, Al and Fe is beneficial. The fine fraction <4 mm additionally contains chemically bound metals (oxides, carbonates, silicates). Separation prospects with techniques as in ore processing (flotation, density separation, bioleaching, hydrothermal solution) are discussed. Although the concentration of Cu compounds in bottom ash is in the range of today's exploited ores the economic viability of the recovery of metal compounds is uncertain. For sufficient enrichment different concerted treatment steps are required.

Keywords: bioleaching; bottom ash; cumulative energy consumption; cumulative exergy consumption; density separation; environmental technology; flotation; hydrothermal solutions; recycling technology; metals recovery; waste management; municipal solid waste; MSW incineration; MSWI; iron; copper; aluminium; oxides; carbonates; silicates.

DOI: 10.1504/IJEX.2016.075668

International Journal of Exergy, 2016 Vol.19 No.3, pp.352 - 363

Received: 10 Jan 2015
Accepted: 28 Feb 2015
Published online: 31 Mar 2016 *

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