The Buoyancy Weighing Method is a new measurement method of particle size distribution. Using the buoyancy weighing method, we measured the particle size distributions of the spherical glass beads, standard powders standardized by Japanese Industrial Standards, magnesite and soft-burned magnesia for measuring the mineral particles. The particle size distribution of glass beads could be measured by a buoyancy weighing method. The particle size distribution of non-spherical particles, which were the silica sand, calcium carbonate (heavy), magnesite and sof-burned magnesia, could be measured using a buoyancy weighing method. The particle size distributions measured by the buoyancy weighing method were close to those measured by the other sedimentation methods and the laser diffraction/scattering method. The particle diameter could measure 5 μm in 2 h of measuring time by the buoyancy weighing method.
