Analysis of alkylxanthate collectors on sulphide minerals and flotation products by headspace analysis gas-phase infrared spectroscopy (HAGIS)

Direct surface analysis by infrared spectroscopy is a useful technique for detection of xanthate species on sulphide minerals, However, infrared detec tion limits require xanthate dosages that are often one or two orders of ma gnitude higher than are used in practice. This paper presents an alternativ e approach to the analysis of collectors on mineral surfaces. A novel gas-p hase infrared technique (HAGIS) has been applied to the indirect analysis o f ethylxanthate on lead, zinc and copper sulphide mineral surfaces and also on flotation products from copper-zinc and lead-zinc ores at xanthate conc entrations which are comparable to those used in the mineral processing ind ustry. HAGIS relies on the detection of the gas-phase species generated by the thermal decomposition of xanthates adsorbed on mineral surfaces. In thi s study, the primary decomposition products generated under an air atmosphe re include carbonyl sulphide (COS), carbon dioxide (CO2), carbon disulphide (CS2) and ethanol. The amounts of these species were compared with product distributions observed for the decomposition of known ethylxanthate comple xes. Correlations between the decomposition species provide evidence for th e speciation of the collector in the flotation product. The decomposition s pecies can be readily detected from xanthate dosages that are much lower th an are the detection limits of traditional, direct surface analysis techniq ues. (C) 1999 Published by Elsevier Science Ltd All rights reserved.