Acid Mine Drainage as a Lixiviant for Leaching Carbonate-hosted Zinc Sulfide Ores from East and Central Tennessee.
Proceeds 1990 :199-205
Column and shakeflask tests by the U.S. Bureau of Mines indicated that acidic effluents from weathering coal waste piles are excellent low-cost lixiviants for leaching carbonate-hosted sphalerite ores. These effluents contain acidity, ferric iron, and iron- and sulfur- oxidizing bacteria, the components necessary for effective leaching of metal sulfide ores. Carbonate surfaces exposed to these effluents quickly developed a passivated layer of gypsum and amorphous ferric iron compounds that inhibited acid consumption. Noncarbonate minerals, including sphalerite, chert, and barite, remained uncoated and were thus available to leaching action. The tests to date have shown up to 85-pct zinc recovery over a 20-day period for minus 200-mesh ore.
Proceeds, 1990 National Symp. on Mining, Lexington, Kentucky, 5/14-18/90. Univ, Kentucky, PP. 199-205