Title: Roman and modern slag at S. Domingos mine (IPB, Portugal): compositional features and implications for their long-term stability and potential reuse

Authors: A. Mateus, A. Pinto, L.C. Alves, J.X. Matos, J. Figueiras, N.R. Neng

Addresses: Faculdade de Ciencias, Departamento de Geologia and CeGUL, Universidade de Lisboa, Ed. C6, Piso 4, Campo Grande, 1749-016 Lisboa, Portugal. ' CREMINER, Faculdade de Ciencias, Universidade de Lisboa, Ed. C6, Piso 4, Campo Grande, 1749-016 Lisboa, Portugal. ' Departamento de Fisica, Instituto Tecnologico e Nuclear, Estrada Nacional nº10, 2686-953 Sacavem, Portugal. ' Laboratorio Nacional de Geologia e Energia, U.I. Recursos Minerais e Geofísica, R. Frei Amador Arrais 39 r/c Ap. 104, 7801-902 Beja, Portugal. ' Faculdade de Ciencias, Departamento de Geologia and CREMINER, Universidade de Lisboa, Ed. C6, Piso 4, Campo Grande, 1749-016 Lisboa, Portugal. ' Faculdade de Ciencias, Departamento de Quimica e Bioquimica, Universidade de Lisboa, Ed. C8, Piso 2, Campo Grande, 1749-016 Lisboa, Portugal

Abstract: S. Domingos ores have been exploited for Cu and S from antiquity to 1966. Slag is composed of Fe-, Ca-, Zn- and Pb-rich silicate glass, fayalite, hedenbergite, Fe-spinel, and blebs of Fe-, Cu-, Zn- (and Pb-)sulphides, minor sulphosalts and Cu-Zn-Pb-iss with evidence for low-T exsolution and reactions. Silicates and oxides often crystallised far from equilibrium out of undercooled melts. Weathering leads to Fe-(hydro)oxide + digenite ±Fe-, Cu- and Pb-sulphate, Ca, Zn and Pb loss from glass and acid drainage. The slag is an excellent aggregate raw material but its chemical instability calls for preliminary processing, which might lead to economic metal recovery.

Keywords: metal-rich slag; long-term slag stability; slag reuse potential; ore processing waste; Portugal; aggregate raw material; chemical instability; copper; sulphur; metal recovery.

DOI: 10.1504/IJEWM.2011.040971

International Journal of Environment and Waste Management, 2011 Vol.8 No.1/2, pp.133 - 159

Published online: 27 Jun 2011 *

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