Weathering Processes in a Lignite Mine Spoil Treated with a CaCo3-Rich Waste Slurry under Two Moisture Programmes

Authors: Seoane S.¹; Leirós M.C.²

Source: Water, Air, and Soil Pollution, Volume 119, Numbers 1-4, April 2000 , pp. 59-74(16)

Publisher: Springer

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Abstract:

Chemical processes affecting the acidity of a sulphide-rich lignite mine spoil treated with high or low doses of a CaCO_3-rich industrial waste slurry were studied in the laboratory under two moisture programmes (cycles of alternate waterlogging and drying, and percolation) so as to determine the slurry dose neutralizing spoil acidity and the possible detrimental effects of high doses. The most important acidity-reducing process was the dissolution of applied calcium carbonate, and CaCO_3 consumption was greater under percolation conditions than under waterlogging and drying conditions. The most important acidity-increasing process was the oxidation of sulphides, which was again more intense under percolation. Under waterlogging and drying conditions, the formation of hydroxysulphates may also have contributed to acidification.

Keywords: acidification; chemical weathering; liming; mine spoil

Language: English

Document Type: Regular paper

Affiliations: 1: Universidad de Santiago de Compostela, Departamento de Edafología y Química Agrícola, Escuela Politécnica Superior, Campus Universitario, 27002, Lugo, Spain (author for correspondence, e-mail: seoane@lugo.usc.es) 2: Universidad de Santiago de Compostela, Departamento de Edafología y Química Agrícola, Facultad de Farmacia, Campus Sur, 15706, Santiago de Compostela, Spain

Publication date: 2000-04-01