Dual Leaching Method for Recovering Silver and Manganese from Domestic Manganiferous Silver Deposits

摘要

A dual leaching method that offers the potential for the economic recovery of the silver and manganese contained in some domestic manganiferous silver deposits was studied. The method consists of an initial leach of manganese with aqueous sulfur dioxide (SO2) followed first by a neutralization rinse, and then by a second leach with cyanide solution for the extraction of silver. Refractory silver in these ores was either (1) intimately associated with the manganese, (2) chemically resistant to cyanide leaching, or (3) rendered inaccessible to cyanide leach solution by the surrounding manganese mineralization. Less than 10 pct of the silver was extracted when minus 2.5-plus 1.3-cm ore pieces were leached directly with cyanide. However, extractions of 25 to 82 pct of the silver and 65 to 96 pct of the manganese were attained in laboratory column-leach tests using the dual leaching method on equivalent-sized ore pieces from seven domestic deposits.