A Rapid Separation Process of Ultrafine Particles from Dilute Aqueous Suspension

Abstract

A potential rapid separation process of ultrafine particles from dilute aqueous suspensions is introduced. This process involves the separation of one or two rypes of ultrafine particles in aqueous suspension by heterocoagulation phenomena. The objective of this study was to develop a rapid separation process of hematite (a- Fe,O,: 0. 1 ~ ) particles and mixed particles of hematite and silica (SiO,: 0. 1 2 ~ ) from their aqueous suspension using a macroscopic collector (glass beads, 80~). Hematite particles were rapidly separated at an acidic condition, i.e., - pH 5. were positively charged hematite particles attached onto the negatively charged glass beads collectors. For a mixed suspension of hematite and silica particles, simultaneous separation of both silica and hematite particles occurred at an acidic condition, where both silica and glass bead were negatively charged, while hematite particles were positively charged. Attachment was possible because hematite particles acted as a bridge between silica particles and glass beads. This rapid solidliquid separation process is referred to as tumbling method. The mechanism involved in this process could be applied in the separation of ultrafine silica from geothermal effluent.