Oil agglomeration of metal-bearing shale in the presence of mixed cationic-anionic surfactants

Abstract

This paper reports oil agglomeration of fine metal-bearing shale particles in the presence of cationic (dodecylamine hydrochloride) and anionic (sodium dodecyl sulfate) surfactants and their mixture. The experimental results demonstrated that there was a strong relationship between zeta potential, hydrophobic coagulation, oil agglomeration and particle hydrophobicity in the presence of cationic surfactant, whereas shale neither coagulated nor agglomerated in the presence of anionic surfactant. Addition of either anionic or cationic surfactant in emulsification of a bridging oil increased the size of agglomerates and reduced the concentration of surfactant used in the suspension. The results pointed to synergism between cationic and anionic surfactants in oil agglomeration. Based on the results obtained from this study, the mechanism of oil agglomeration of shale in the presence of ionic surfactants and their mixture was elucidated.