Flotation Mechanism of Lead-Activated Cassiterite with Ricinoleic Acid as a Collector

This paper investigates the flotation of cassiterite (SnO₂) from ore using ricinoleic acid (RA) as a collector which is cheap and environmentally friendly. It is shown that the flotation is significantly enhanced by the activation of lead cations at pH 8. The flotation results are explained and supported by further studies to determine the changes in surface properties (hydrophobicity and surface potentials) and adsorption of RA and lead cations using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and FTIR. The results of surface (zeta) potential measurements and TOF-SIMS indicate that the amount of RA anions on the Pb-activated SnO₂ surface was higher than that on the natural SnO₂ surface. The XPS results revealed that RA anions were bound to the Sn atoms on the natural SnO₂ surface. In contrast, RA anions reacted with the Pb atoms instead of Sn atoms on the activated SnO₂ surface, improving the floatability of Pb-activated SnO₂. Pb(RA)₂ precipitation occurred on the Pb-activated surface, and H bonds were formed between two RA anions in Pb(RA)₂, which lead to a tighter assembly of collector species on the SnO₂ surface. The outcomes of this research shed light on the application of the cost-effective and environmentally friendly RA collector in cassiterite flotation.