| Popis: |
As a fundamental study with regards to the recovery of fine mineral particles by liquid-liquid extraction, the effect of sodium dodecylbenzenesulfonate (SDBS) as a surfactant has been investigated in terms of pH, SDBS concentration, zeta potential, contact angles, interfacial tensions and work of adhesion. Maximum recoveries were obtained at pH around 7 and SDBS concentration of 1 × 10⁻⁴ mol･dm⁻³. In alkaline solutions, the recovery of monazite decreased regardless of the SDBS concentration as the pH was increased above 7. An increase in the SDBS concentration up to 1 × 10⁻⁴ mol･dm⁻³ resulted in an increase in the recovery. It was considered that in the pH range below 7, an increase in the SDBS concentration brought about a higher coulombic adsorption density of the surfactant ions on the monazite particles which were charged positively, and resulted in higher recoveries. So as to examine a relationship between the oil-wettability and the recovery, contact angles and interfacial tensions were also measured in terms of pH and SDBS concentration. Based on the results obtained above, the work of adhesion was calculated. It was found that the work of adhesion was considerably related to the monazite recovery of the liquid-liquid extraction. |
