Powder Technology, Vol.160, No.2, 135-140, 2005
Recycling of glaze waste through hydrocyclone separation
The purpose of this work was to evaluate the applicability of hydrocyclone technology to separate glaze components for reuse in an industrial process. A laboratory size hydrocyclone system was constructed using industrial components. Preliminary work showed that clean separation of the waste into three particle size ranges; < 5, 5-20, and > 20 mu m, would allow for each component to be recycled. Hydrocyclones were used to separate particles which have different sedimentation velocities, calculated based on Stokes Law, but could not separate systems with particles that had different sizes and densities but similar sedimentation velocities. Thus, particle behavior in the system correlated to what is predicted by Stokes Law, which is based on laminar flow. The particle size distributions of the separated glaze waste shifted towards the target values of < 5, 5-20, and > 20 mu m, but were broad and overlapped slightly. A more efficient system would be required for the waste to be completely reusable. Selective agglomeration of glaze constituents was proposed to increase efficiency of separation by creating narrower, more distinct particle size distributions. Sedimentation and titration tests were used to estimate the isoelectric point of glaze constituents. Hypothetical calculations demonstrated that selective agglomeration could be used to significantly increase the sedimentation velocity of particles. (c) 2005 Published by Elsevier B.V.