pH effect on adsorption and performance of xanthate, dithiocarbamate and s-triazine collectors on sperrylite mineral surface

Abstract

The pH effect in minerals flotation is of key significance in maximizing the recovery of platinum group minerals (PGMs). The computational simulations, microcalorimetry and microflotation experimental approaches were utilised to determine the performance of sodium normal butyl xanthate (SNBX), sodium normal butyl dithiocarbamate (SNBDTC) and sodium 2,6-dithio-4-butylamino-1,3,5-triazine (SDTBAT), xanthate (NBX), dithiocarbamate (NBDTC) and s-triazine (DTBAT) collectors onto sperrylite mineral surface under neutral, alkaline and acidic conditions. Computationally, it was observed that on dry surface under neutral and alkaline conditions the collectors preferred bidentate (SNBX and SNBDTC) and tridentate (SDTBAT) adsorption modes. Under acidic conditions all three collectors preferred the monodentate adsorption mode. The adsorption energies for dry and hydrated surfaces showed that SDTBAT bind stronger under neutral adsorption, which was in agreement with the microcalorimetry heats of adsorptions. In alkaline conditions for dry and hydrated surface, the SNBX gave the most exothermic adsorption energy. Under acidic conditions on both dry and hydrated surface, the HNBDTC gave strong adsorption energy. The alkaline and acidic conditions were in agreement with the microflotation recoveries at pH = 9 and pH = 4, respectively. The study clearly demonstrated that sperrylite floats better under acidic conditions using dithiocarbamate collector with higher recoveries of 48.16 %.