造粒体形成に及ぼす界面性状の影響

液中造粒に関する研究 (第1報)

抄録

Interfacial properties of particles-water-oil system and their effects on agglomerates formation have been studied using BaSO₄, sodium oleate (Na01) and kerosene as model particles, surface active reagent and bridging liquid, respectively. Prior to the experiments on agglomeration, adsorption isotherm for BaSO₄ /Na01 system, interfacial tension of kerosene in NaOl aqueous solution, contact angles of BaSO₄-kerosene-Na01 aqueous solution system, and zeta potential of BaSO₄and kerosene in NaOl aqueous solution were measured under the various conditions. The variations of contact angles with NaOl concentration and pH were explained in terms of the adsorption amount of oleate on BaSO₄, the interfacial tension and the potential barrier.
In addition to agglomeration experiments, phase inversion tests were also carried out. In the present system, spherical and/or lumpy agglomerates were obtained in the Na01 addition range of 2.19x10^-3-4.75x10^-3mol/lunder natural pH conditions and in the pH range of 7.3-11.9 at 3.65x10^-3mol/ lNa01 addition. And it was shown that agglomerates formation was possible within water-in-oil emulsion region in the phase inversion tests. From these results, it was found that particleparticle cohesive force due to negative capillary force was a necessary condition for agglomerates formation and contact angles on the surface of aggregate particles were more important than those on smooth surfaces.
Phase inversion method was effective for determing the best suitable reagent and its dosage for agglomeration.