Surface chemistry investigation of froth flotation products of lead-zinc sulfide ore using ToF-SIMS and multivariate analysis

Abstract

In complex flotation circuits of lead-zinc sulfide ore, selective adsorption of flotation reagents (e.g., collectors, depressants, and regulators) and solution components onto different mineral surfaces are involved. This work aimed to study the surface chemistry differences between minerals in lead concentrate and those in tailings by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and multivariate analysis to understand the flotation behavior of minerals. Specifically, multivariate curve resolution-alternating least squares (MCR-ALS) and principal component analysis (PCA) were used to process ToF-SIMS image datasets of flotation products to enhance mineral identification. The results show that MCR-ALS was more successful than PCA in identifying minerals of ToF-SIMS images from flotation products. Further PCA of the spectra obtained from the specific mineral surfaces in the lead concentrate and tailings revealed surface chemistry reasons for the poor mineral separation. The main finding of this study was that the adsorption of lead ions onto the surfaces of sphalerite, pyrite, calcite, and quartz was an important reason for the failed separation of these minerals from galena in high-alkaline lime systems. The surface chemical evidence provided by this study helps to better understand the selective separation mechanism of lead-zinc sulfide ores.