Study of Zn-Pb ore tailings and their potential in cement technology

authors	Nouairi, J; Hajjaji, W; Costa, CS; Senff, L; Patinha, C; da Silva, EF; Labrincha, JA; Rocha, F; Medhioub, M
nationality	International
journal	JOURNAL OF AFRICAN EARTH SCIENCES
author keywords	Mining rejects; Diapiric zone; Clinker; Heavy metal; Immobilisation
keywords	NORTHERN TUNISIA; MINE TAILINGS; SOILS; LEAD; METALS; ZINC
abstract	This paper describes the synthesis of sulfobelite clinkers incorporating mining rejects. The targeted Zn-Pb tailing wastes generated in the diapiric zone (NW Tunisia) were tested in clinker/cement compositions to ensure the inertization of existing hazardous heavy metals. Mineralogical composition of the two selected samples revealed calcite, dolomite, quartz, kaolinite, galena, pyrite and gypsum as crystalline phases. Vertical distributions of dominant heavy metals (Pb, Zn and Cu) in soil profiles show enrichment in the surface layers and decrease towards the depth. In sintered clinkers powders, the presence of the targeted crystalline phases (trialuminate sulphate (C4A3S), belite (C2S), and ferrite (C4AF)) are in the predicted desirable amounts. Heat flow generated during the hydration of different cement pastes showed a slower reaction for clinkers with higher amounts of C(4)A(3)S or constituted by coarser particles. After 28 days curing, the best mechanical resistance (24.34 MPa under compression) was obtained for the clinker calcined at 1350 degrees C and showing a suitable particle size distribution. Concerning heavy metals, immobilisation of 75-85% of Pb, Zn and Cu was assessed in the mortars formulated with the produced clinker/cement, posing no hazardous risks to the environment. (C) 2017 Elsevier Ltd. All rights reserved.
publisher	PERGAMON-ELSEVIER SCIENCE LTD
issn	1464-343X
year published	2018
volume	139
beginning page	165
ending page	172
digital object identifier (doi)	10.1016/j.jafrearsci.2017.11.004
web of science category	Geosciences, Multidisciplinary
subject category	Geology
unique article identifier	WOS:000424724800011