Relationship between properties of oil/water emulsion and agglomeration of carbonate minerals

In this study, a modification of oil agglomeration processes of dolomite and magnesite particles has been proposed. In this method the emulsion of kerosene with dodecylammonium hydrochloride (DDAHCl) was added to the minerals suspension. The experimental results have demonstrated that the agglomeration was governed by the properties of oil/water interface such as zeta potential and interfacial tension (γo/w). Addition of cationic surfactant to the emulsion changed the zeta potential value from negative to positive, which resulted in enhanced the adhesion of the oil droplets to negatively charged particles, according to the DLVO theory. The presence of cationic surfactant has an effect on the size of the agglomerate. At the high DDAHCl concentration (21 mg/gsolid) the recovery and diameter of agglomerates slightly decreased, and finally a paste was formed. It results from decrease of the value of γo/w leading to the formation of weaker liquid bridges between solid particles. This explanation was supported by AFM measurements of adhesion forces.

Figure optionsDownload as PowerPoint slideResearch highlights▶ An initial increase in DDAHCl concentration in system at a constant NaOl concentration resulted in an increase of agglomeration recovery. ▶ When the DDAHCl concentration was too large, the agglomeration diminishes up to the paste formation. ▶ The size of feed particles plays a crucial role in agglomeration process. ▶ Agglomeration of dolomite and magnesite strongly depends on pH of suspension in system containing cationic and anionic surfactants. ▶ The properties of kerosene/water emulsion affect the recovery of agglomeration process and the size of agglomerates.