The effect of using sodium di-methyl-dithiocarbamate as a co-collector with xanthates in the froth flotation of pentlandite containing ore from Nkomati mine in South Africa

Sodium ethyl and potassium amyl xanthates are commonly used in bulk and selective froth flotation of pentlandite ores respectively. Pulp pH plays a significant role in pentlandite flotation and xanthates are sensitive to pH. Consequently, more stable collectors have to be used in the froth flotation of pentlandite ores. The dithiocarbamates are possible replacement as they are believed to be stable in a wider range of pH and their use yields a faster flotation rates than xanthates. However, it may be uneconomical to use dithiocarbamates as pure collectors due to their cost. The present study explored feasibility of using di-C1-DTC to replace or partially replace PAX and SEX in nickel flotation. The tested molar ratios were 90:10 and 70:30; with xanthates as the abundant constituent in all the mixtures. This study showed that the using di-C1-DTC as co-collector was beneficial as the mixtures 30di-C1-DTC:70SEX and 10di-C1-DTC:90PAX improved nickel recovery and grade respectively. Furthermore, there were no significant differences in cumulative mass and water recoveries obtained with all the mixtures therefore differences in nickel recoveries were due to the differences in the selectivity properties of the collectors and not physical processes viz. physical entrapment and hydraulic entrainment.