Abstract: A novel micronization technique using solventing-out crystallization was described for the preparation of submicron BaSO₄ particles. The submicron BaSO₄ particles were characterized by transmission electron microscope (TEM),
scanning electron microscope (SEM), laser diffraction-based particle size analyzer and X-ray diffraction (XRD). The product was obtained as spherical particles with mean sizes from 160--750 nm. The effects of feed mode, feed
concentration, feed rate, agitation intensity and crystallization temperature in the solventing-out process were investigated. A well-efficiency dispersant was selected. The experimental results indicate that lower crystallization
temperature, reversed feed mode, higher feed rate, controlling solution concentration to a certain extent and faster agitation rate will lead to producing smaller BaSO₄ particles. Furthermore, the purity of submicron BaSO₄ particles
prepared by solventing-out crystallization is upon to 99.7%, and it indicates that the solventing-out crystallization is not only a micronization technique but also an excellent purification process.

Key words: barium sulfate, solventing-out, submicro-particles, crystalline