Abstract: The serious interface emulsion created in the copper solvent extraction operation of Dexing Copper Mine influences adversely the whole bioleaching-solvent extraction-electrowinning process. To solve this problem the stability of interfacial emulsion was researched. It is discovered that limited coalescence of emulsion droplets takes place during the emulsion storage, which results in the stabilization of average diameter of droplets at 13~14μm. Droplets can not coalesce and the emulsion can keep along-term. Sulfate precipitation is promoted in interfacial region where the medium dielectric constant is relatively lower due to the effect of electrical double layer. The sedimentation of precipitates on droplet interface makes the interfacial skins become more and more thick and the coalescence become more and more difficult. Interfacial effects make the colloids of Fe(OH)3 and SiO2 in aqueous phase polymerize continuously, so that the emulsion gelates gradually. As a result limited coalescence of droplets takes place. Calculated interfacial solubility of some sulfates is lower by about 10 times than that in continuous body phase.
Mechanism of limited coalescence of interfacial emulsion in copper solvent extraction
Abstract:
The serious interface emulsion created in the copper solvent extraction operation of Dexing Copper Mine influences adversely the whole bioleaching-solvent extraction-electrowinning process. To solve this problem the stability of interfacial emulsion was researched. It is discovered that limited coalescence of emulsion droplets takes place during the emulsion storage, which results in the stabilization of average diameter of droplets at 13~14?μm. Droplets can not coalesce and the emulsion can keep a long-term. Sulfate precipitation is promoted in interfacial region where the medium dielectric constant is relatively lower due to the effect of electrical double layer. The sedimentation of precipitates on droplet interface makes the interfacial skins become more and more thick and the coalescence become more and more difficult. Interfacial effects make the colloids of Fe (OH) 3 and SiO 2 in aqueous phase polymerize continuously, so that the emulsion gelates gradually. As a result limited coalescence of droplets takes place. Calculated interfacial solubility of some sulfates is lower by about 10 times than that in continuous body phase.