Preparation and microscopic structure control of fine particle materials by using emulsion liquid membrane system as a microreactor

摘要

Fine particle materials were prepared by using an emulsion liquid membrane (ELM, water-in-oil-in-water (W/O/W) emulsion) system. Metal ions were extracted from the external water phase into the organic membrane phase containing extractant (cation carrier), and then stripped into the internal water phase to make submicro-or micron-sized oxalate, carbonate and phosphate particles, of which the size, morphology and crystal structure were well-controlled. As case studies, the preparation of well-difined spherical oxalate particles of rare earth metals, spherical calcium carbonate particles of hollow structure, spherical calcium phosphate particles, composite Sr-Pb oxalate particles, acicular Co ferrite and Ni ferrite fine particles, and rare earth oxide spherical phosphor particles was demonstrated, and the properties and functions of the internal water phase as a microreactor are discussed.