Abstract:The electrochemical behavior of Mengzi lead-silver-zinc ore flotation system was studied. Based on the electrochemical characteristics of sulfide mineral flotation system, a stage potential control flotation was developed with the main parameters of pulp potential(φp), pH value and collector dosage. Using N,N’ diphenylamino-dithiolphosphoric acid(NNDDC) as a collector, which has good selectivity for galena flotation at pH 8.8 and pulp potential 330 mV, DDTC is used as secondary collector to improve both the grade and recovery of Pb and Ag. The pulp potential values significantly influence the floatability of practical minerals and single minerals when using NNDDC as the collector. The flotation recovery of galena reaches 85% at about 0.3 V and pH8.8. With the usage of pulp potential control during grinding and flotation, the new pulp electrochemical technology for Mengzi lead-silver-zinc ore flotation was developed. The results show that the grades of Pb and Ag of galena concentrate are 55% and 1 800 g/t, respectively, while the recoveries of Pb and Ag are 86.5% and 65%, respectively, the grade of Zn of marmatite concentrate is 42.5%, and the recovery of Zn is 91.25%.

Key words: flotation; pulp potential; N,N’ diphenylamino-dithiolphosphoric acid; lead-silver-zinc ores