The interrelation of factors influencing the dissolution of metals in columns of mine tailings.
Mine Drainage and Surface Mine Reclamation. Volume I: Mine Water and Mine Waste. Vol. I. Pittsburgh, PA: U.S. Bureau of Mines, 1988 Apr; :210-219
The dissolution of metal species from silver mine mill tailings containing quartz (70%) and manganiferous siderite was investigated using a column leach procedure. The effects of leachant ionic strength, pH, and buffering ability were examined. The results indicated increased metal transport with increased ionic strength and decreased pH. In another test series, matched sets of columns were compared to determine the effect of leachate residence time on metal concentration. In these tests, leachate metal ion concentrations more than doubled in columns that were allowed to evaporate (wet/dry cycle) about 30% of their pore leachate volume. The pH of the leachate eluted from the dry cycle (unsaturated column) decreased while the conductance increased. Increases of five times were observed for lead and manganese, while increases of two orders of magnitude were seen for zinc and cadmium. The wet/ dry cycle effect was enhanced during subsequent cycles, but appeared not to be influenced by the addition of sodium lauryl sulfate, sodium benzoate, or phenol, which are known to inhibit microorganism involvement. Increased sensitivity to further oxidation of those columns that underwent the dry cycle became apparent through increased deviation of the ion yields from duplicate columns. The interrelation of the above factors with the composition of the tailings present adds complexity to determining dissolution mechanisms.
Metals; Silver-compounds; Quartz-dust; Mining-industry; Lead-compounds; Manganese-compounds; Zinc-compounds; Cadmium-compounds; Sodium-compounds; Phenols; Oxidation
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Mine Drainage and Surface Mine Reclamation. Volume I: Mine Water and Mine Waste