The primary emulsification to form the microballoons was studied. The effects of preparation conditions against the formation of microballoons were examined. The factors examined were metal species in the external aqueous phase, the concentrations of sodium silicate in the internal phase and Cyanex 923 as carrier. The particle size and shell thickness were found 10 mu m and 2 mu m, respectively. Since the penetration of metal species through the oil phase was promoted by the increase of carrier concentration. The formation of microballoons was completed in a short time of less than 30 min. The formation of microballoons of Co(II), Ni(II), Zn(II), Sr(II), and Cu(II) were used for removal of these metal ions.