Leaching of potential hazardous elements of coal cleaning rejects.
The geochemical characteristics of coal cleaning rejects (CCR) in Santa Catarina State, Brazil, were investigated. Around 3.5 million ton/year of coal waste are dumped in Santa Catarina State. Coal beneficiation by froth flotation results in large amounts of CCR composed of coaly and mineral matter, the latter characterised by the occurrence of sulphide minerals and a broad array of leachable elements. The total and leachable contents of more than 60 elements were analysed. Atmospheric exposure promotes sulphide oxidation that releases substantial sulphate loads as well as Ca2+, K+, Mg2+, Cl- and Al3+. The metals with the most severe discharges were Zn, Cu, Mn, Co, Ni and Cd. Most trace pollutants in the CCR displayed a marked pH-dependent solubility, being immobile in near-neutral samples. The results highlight the complex interactions among mineral matter solubility, pH and the leaching of potentially hazardous elements.
Silva
Luis F O
LF
Catarinense Institut of Environmental Research and Human Development-IPADHC, Capivari de Baixo, Santa Catarina, Brazil.
Izquierdo
Maria
M
Querol
Xavier
X
Finkelman
Robert B
RB
Oliveira
Marcos L S
ML
Wollenschlager
Marcus
M
Towler
Mark
M
Pérez-López
Rafael
R
Macias
Felipe
F
D001938:Brazil; D003031:Coal; D004784:Environmental Monitoring / Q000379:methods*; D008906:Mining
D003031:Coal