Effect of contact angle, surface tension and zeta potential on oil agglomeration of celestite

• The oleate adsorption onto the celestite surfaces increased the hydrophobicity.
• The oil agglomeration decreased with decreasing contact angle and surface tension.
• The celestite surfaces became more negative owing to sodium oleate adsorption.
• The agglomeration efficiency did not decrease with increasing surface charge.
• The γc-a values were slightly greater than the γc values of celestite.

The influences of contact angle, surface tension and zeta potential on oil agglomeration recovery of celestite mineral have been investigated in the present work. Therefore, celestite mineral in methanol–water suspension was agglomerated by the use of oil (kerosene) in the presence of sodium oleate as a surfactant. The zeta potential values of celestite surfaces were measured depending on pH and sodium oleate concentration. The zeta potential values of celestite surfaces became negative even more owing to the sodium oleate adsorption. However, this phenomenon did not affect the oil agglomeration recovery at all. It was found that both increasing contact angle and surface tension raised the oil agglomeration recovery of celestite mineral. Eventually, the agglomeration degree of celestite mineral in the suspension was not lower than a particular surface tension value corresponding to the critical solution surface tension for oil agglomeration (γc-a). The γc-a values were slightly greater than the critical surface tension of wetting (γc) values.