Dispersion-Flocculation Behavior of Fine Lead Particles in an Organic Solvent

Abstract

Methyl ethyl ketone (MEK) is a good solvent for polyvinyl chloride (PVC) and it has been proposed for use in PVC recycling. In the recycling process, fine particles of 3PbO·PbSO 4 ·H 2 O, used as a thermal stabilizer in PVC products, are dispersed and not dissolved in the solvent. To establish methods for removing of 3PbO·PbSO 4 ·H 2 O particles from the solvent, factors affecting the dispersion-flocculation behavior of the particles in MEK were investigated. The zeta potential and particle distribution of 3PbO·PbSO 4 ·H 2 O particles in MEK solutions containing known amounts of H 2 O were measured. Above 5 vol%H 2 O in MEK solutions, the zeta potential of 3PbO·PbSO 4 ·H 2 O particles approached zero and the flocculation of particles was achieved. In addition, it was found that Pb 2+ and Cl - affect the zeta potential of the particles. These results indicate that the dispersion-flocculation behavior of lead particles can be influenced by the concentration of H 2 O, Pb 2+ , and Cl - in MEK.