Process Development for Gold Concentrate Recovery by Multi-stage Flotation using Optimized Conditions

Abstract

A pre-treatment method for upgrading gold from a polymetallic gold-zinc-lead ore by flotation was studied. X-ray diff raction analysis of the gold sulfi de ore showed that quartz, calcite, pyrite, sphalerite, and galena are the main constituents of the ore. The composition of the polymetallic ore contained 6.49 ppm Au, 3.48% Zn, 1.25% Pb, 17.98% Fe, and 20.36% S. Due to the complexity of the polymetallic ore, the gold recovery is generally low. The objective of this study is to develop a primary fl otation process to recover gold in a bulk sulfi de concentrate. The eff ects of particle size, collector type, fl otation time, and the slurry pH on the recoveries and grades of gold, zinc, and lead were investigated. The developed fl otation process consisted of rougher, scavenger, and cleaner stages. High recovery of gold was found to be linked with a high recovery of Pb which was achieved by the utilization of a mixture of collector AERO 7249 and PAX. The gold fl otation kinetics were fast with more than 50% of gold recovered within 5 minutes of fl otation. Under optimized fl otation conditions with rougher, scavenger, and cleaner stages, a total gold recovery of 88.36 % and a fi nal gold grade of 60.97 ppm were obtained. A total gold enrichment ratio of 9.4 was achieved, confi rming the viability of the fl otation method in upgrading the gold from the polymetallic sulfi de ore prior to further processing.