TECHNOLOGICAL CHARACTERIZATION OF RIACHO DOS MACHADOS GOLD ORE FOR CYANIDE LEACHING AND STUDY OF THE UTILIZATION OF OXIDIZING-AGENTS

This work evaluates the behavior in the cyanide leaching of primary go ld ore from Riacho dos Machados, central Brazil. The parameters studie d were: extraction of gold/silver in different ore sizes to determine the exposition of precious metals; rare of extraction in bottle roll t ests with crushed and ground ores; and the effect of addition of oxidi sing agents (air, oxygen and hydrogen peroxide) on gold/silver leachin g. The run of mine ore contains about 7 ppm of gold and 2 ppm of silve r. The gold/silver particles are of microscopic and submicroscopic siz es and 90% of the gold was extractable. The use of oxygen and hydrogen peroxide mixed with air increased the rate of gold dissolution. (C) 1 997 Published by Elsevier Science Ltd.