Corrosive electrochemistry of jamesonite
(1. School of Minerals Processing and Bioengineering, Central South University,
Changsha 410083,China;
2. Department of Chemistry and Material Science, Hengyang Normal University,
Hengyang 421008, China)
Changsha 410083,China;
2. Department of Chemistry and Material Science, Hengyang Normal University,
Hengyang 421008, China)
Abstract: The corrosive electrochemistry of jamesonite (Pb4FeSb6S14) was studied by the electrochemical methods of cyclic voltammetry, polarization, and AC impedance. The electrochemical processes of jamesonite were controlled by the corrosive reactions, growth of the metal-deficient and sulfur-riched layer, passivation and breakdown of elemental sulfur film on the electrode surface. The corrosive potential(φcorr) moves negatively, its corrosive current increases, and hydroxyl action becomes stronger with the rising pH value. The charge transfer resistance increases and the capacitance decreases due to the gradual growth of the metal-deficient and sulfur-riched layer on the mineral surface from -378 to 122mV (vs SHE). Element sulfur layer is formed at the potential of 122mV. The charge transfer resistance increases and its capacitance rises slowly due to the gradual breakdown of sulfur film at voltage from 222mV to 422mV. S2O2-3 and SO2-4 ions occur when the electrode potential is over 422mV. Under basic condition, the hydrophobic hydroxyl precipitate occurs on jamesonite surface, so that its collectorless floatability is poor. Under the condition of pH 6.86, it can be deduced that the potential range of collectorless floatability of jamesonite is from 22 to 422mV due to the passive action of the hydrophilic sulfur on jamesonite surface, and its optimum range of floatable potential is between 122 and 322mV.
Key words: jamesonite; electrochemistry; potential-controlled flotation