Addendum to “Process development for elemental recovery from PGM tailings by thermochemical treatment: preliminary major element extraction studies using ammonium sulphate as extracting agent” [Waste Manage. 50 (2016) 334–345]

Abstract

In a recent paper, a promising two-stage process for the extraction of major elements from Platinum Group Metals (PGM) was presented (Mohamed et al., 2016). This process involved solid-solid thermochemical treatment of tailings with ammonium sulphate (stage one), followed by an optimised acid dissolution step (stage two). The inclusion of a control experiment for the optimal dissolution procedure was however overlooked. The new set of data delivered by the control experiment reveals that (i) most of the silicon and calcium are extracted via the acid leaching step, (ii) aluminium and magnesium are extracted at each stage of the process, and (iii) the thermochemical step is the main contributor to chromium and iron extraction. The conclusion of the previous paper (Mohamed et al., 2016), whereby thermochemical treatment with ammonium sulphate represents a promising technology for extracting valuable elements from South African PGM tailings, withstands