A potential rapid solid/liquid separation process of fine particles from dilute aqueous suspensions is introduced (tumbling method). This process involves the separation of one or two types of fine particles in aqueous suspension by heterocoagulation phenomena and is conducted by tumbling suspensions with a macroscopic collector such as glass beads which leads to the settling of particles with the collector. Particularly, it was found that silica (Si02: 0.12 μm) particles could effectively be collected by glass beads (80 μ.m) through a bridging effect of hematite (α-Fe203: 0.10 μm ) particles. The results were explained in terms of the DLVO theory and the efficient movement of the glass beads collector