24-10-2012, 11:20 AM
Evaluation of a Method Using Colloidal Gas Aphrons to Remediate Metals-Contaminated Mine Drainage Waters
ABSTRACT
Experiments were conducted in which three selected metals-contaminated mine drainage water samples were treated by
chemical precipitation followed by flotation using colloidal gas aphrons (CGAs) to concentrate the precipitates. Drainage
water samples used in the experiments were collected from an abandoned turn-of-the-century copper mine in south-central
Wyoming, an inactive gold mine in Colorado’s historic Clear Creek mining district, and a relatively modern gold mine near
Rapid City, South Dakota. The copper mine drainage sample was nearly neutral (pH 6.5) while the two gold mine samples
were quite acidic (pH(approx)2.5). Metals concentrations ranged from a few mg/L for the copper mine drainage to several
thousand mg/L for the sample from South Dakota. CGAs are emulsions of micrometer-sized soap bubbles generated in a
surfactant solution. In flotation processes the CGA microbubbles provide a huge interfacial surface area and cause minimal
turbulence as they rise through the liquid. CGA flotation can provide an inexpensive alternative to dissolved air flotation