A fundamental study of solid mixing was carried out using a newly developed measuring system which employs an optical method. The reflective properties of light for the particle bed and the magnitude of output fluctuation have been measured under static and vibrating conditions to evaluate their degree of mixing in a state of motion. The influence of a number of probes inserted into the particle bed on the mixing index was also examined.
The concentration change with time measured at the six local positions in a high speed agitator-type mixer and the mixing curves based on these concentration variations showed different patterns according to the operating conditions and the combination of the physical properties of the particles.
Eight typical cases of mixing were introduced, and the mechanisms of mixing and/or demixing, segregation, phenomena, the coating process and the electrostatics effect on the mixing were discussed.