Zircon mineral solids concentrated from Athabasca oil sands froth treatment tailings: Surface chemistry and flotation properties

Zircon mineral solids concentrated from Athabasca oil sands froth treatment tailings were compared by X-ray photoelectron spectroscopy, infrared spectroscopy, and collector-assisted froth flotation before and after surface cleaning in a low temperature, radio-frequency oxygen plasma. Plasma cleaning was effective at removing a surface bound layer of organic matter having chemical markers consistent with bituminous fractions. Specifically, the observation of long-chain aliphatics, ester and ether linkages, aromatic indicators, and hydroxyls in the absence of carboxylic acid groups, suggested the surface organic layer was representative of asphaltene or resin. Supporting this interpretation was the identification of pyrrolic and thiophenic chemical states. Plasma degradation of the hydrocarbon component transformed the zircon particles from hydrophobic to hydrophilic as evidenced by their recovery in water/ethanol froth flotation tests. The cleaned zircon particles were subsequently collected in the froth using dodecylamine. This work explains the surface conditions responsible for the reporting of zircon to the froth treatment tailings and demonstrates the efficacy of plasma cleaning as a means to condition zircon for coupling with collector agents. A physical model of surface adsorption is discussed and process implications are considered.