Self-organization of recent rhythmic iron-manganese precipitations in underground mines in the Harz mountains

Abstract

A recent early diagenetic banded iron-manganese mud has been forming underground in a closed lead-zinc mine for approximately 40 years. The processes leading to the banded structure of the precipitate were studied during a period of 2 years. Therefore, 19 physical and chemical parameters were measured regularly in short intervals. The resulting time series were analysed with respect to the data sets of the monthly chemical analyses of the descendent mine water, the daily rainfall and the mineral content. The results reveal that the precipitated material undergoes internal self-organization due to interaction of redox, colloidchemical, microbial, electrical and ripening processes, and not exclusively produced by seasonal fluctuations of material input. Thus, the primary banding of the material, caused by externally forced fluctuations of the redox conditions within the mine water, is reorganized after a short time. The finally observed bands are controlled by non-linear coupling of reaction and transport processes within the mud. A genetic model for the banded mineralization was developed and verified by numerical simulation.

Removal of critical metals from waste water by zero-valent iron

“…A third group of papers investigated the incorporation of Al (Cismasu et al, 2012), Ga (Xu et al, 2007), Ge (Liang et al, 2008), In (Chou et al, 2009), Nd (Nagano et al, 1999) and Nb (Oliveira et al, 2009) in the (crystal) structure of ferrihydrite, goethite, hematite (a-Fe 2 O 3 ), or amorphous iron hydroxides. A fourth process is co-precipitation of separate phases like beryllium hydroxide (Be(OH) 2 ) (Burguera et al, 2000) and birnessite (MnO 2 $ H 2 O) (Dietrich and Jacob, 1996) together with ferrihydrite and/or other iron hydroxides.…”