An investigation into the use of xanthate, trithiocarbonate and thiourea collectors on the flotation of sperrylite (PtAs2)

• Published in: Minerals engineering Vol. 199; p. 108103
• Main Authors: Wali, A., O'Connor, C.T., McFadzean, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2023
• Subjects: Platinum group minerals; Sperrylite; Thiourea; Trithiocarbonate; Thiourea; Trithiocarbonate; Platinum group minerals; Sperrylite
• ISSN: 0892-6875; 1872-9444
• DOI: 10.1016/j.mineng.2023.108103

[Display omitted] •At monolayer coverage, collectors do not sufficiently increase sperrylite recovery.•Increasing ionic strength or collector dosage improves sperrylite recovery.•TTC’s and xanthates are more selective for base metal sulfides than sperrylite.•ICP-MS can be successfully used to assay arsenic in place of mineralogical analysis. Sperrylite contributes about 21% to the total platinum group minerals (PGMs) found in the Platreef ore deposit. The recovery of sperrylite by flotation has been shown to be poor and the reasons for this are not well understood. Xanthate collectors have been widely used in flotation of PGM ores, especially in the recovery of PGMs associated with base metal sulfides. However, previous studies have shown that these collectors are not as successful in recovering sperrylite. This study has compared the use of xanthates with collectors with different functional groups, increased dosages, as well as high ionic strength of process water on the floatability of sperrylite. The xanthate, trithiocarbonate and thiourea collectors investigated were shown to adsorb on sperrylite to varying degrees, but at a dosage equivalent to about one pseudo-monolayer coverage they did not impart sufficient hydrophobicity to the mineral to induce significant flotation recovery, with the recoveries ranging between 15 and 18%. Increasing the dosage of a strong collector such as PAX or the ionic strength of the process water used in the flotation was shown to improve the recovery of sperrylite to 45% at 20 monolayers of PAX and 20.6% at 0.12 M ionic strength. Batch flotation tests showed that the increases in sperrylite recovery achieved under different conditions were non-selective towards sperrylite and came at the expense of an increase in total solids recovered. This investigation has provided further insights into the possible reasons for the poor floatability of sperrylite which may guide future work on improving the recovery of this economically important mineral.