The Ingurtosu Pb-Zn mine in south-western Sardinia, exhibits three main weathering processes: 1) oxidation without acidification derived from Pb and Zn sulphides; 2) oxidation with acidification derived from Fe sulphides; 3) pH buffering due to Ca and Mg carbonate dissolution. These weathering processes are followed by adsorption of metals on iron oxyhydroxides and precipitation of hydrated sulphates (sometimes carbonates). Nearly all iron sulphides and carbonate (siderite, ankerite) grains, have alteration rims made up of iron oxyhydroxides (goethite), where Zn, Cu and Pb are adsorbed after sulphide oxidation. Moreover, the occurrence of slightly weathered clay minerals confirms the low pH values are never reached. -from Authors
Weathering of Pb-Zn mine tailings in PH buffered environment
IBBA, ANGELO;
1995-01-01
Abstract
The Ingurtosu Pb-Zn mine in south-western Sardinia, exhibits three main weathering processes: 1) oxidation without acidification derived from Pb and Zn sulphides; 2) oxidation with acidification derived from Fe sulphides; 3) pH buffering due to Ca and Mg carbonate dissolution. These weathering processes are followed by adsorption of metals on iron oxyhydroxides and precipitation of hydrated sulphates (sometimes carbonates). Nearly all iron sulphides and carbonate (siderite, ankerite) grains, have alteration rims made up of iron oxyhydroxides (goethite), where Zn, Cu and Pb are adsorbed after sulphide oxidation. Moreover, the occurrence of slightly weathered clay minerals confirms the low pH values are never reached. -from Authors
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