Rheology of Low Density Suspensions in Dense Medium Separation of Post-consumer Plastics∗

∗A Note from the Editors: Although the above paper deals with the separation of plastics, it was included in Coal Preparation because of its similarity to the densemedium separation of coal. In both cases, dense-medium separations are done using magnetite systems at low densities under dynamic conditions. Under such conditions, the viscosity and stability of the dense-medium suspension play key role in determining separation efficiency. Hence, the rheological and performance data obtained from the separation of plastics may be directly applicable to coal separation, albeit at somewhat higher medium densities.

Abstract

The aim of this paper is to investigate the feasibility of using clay suspensions in dynamic dense medium separation of post-consumer plastics. The Theological behavior of suspensions formed with different commercial clay samples was studied to ascertain that both viscosity and stability could be maintained in the range required by dense medium separation systems. Suspensions made with a selected clay sample were used in a laboratory test rig equipped with a conical cyclone and a cylindrical cyclone with peripheral underflow discharge. Preliminary separation tests were carried out using different density plastic tracers. The results with both separators demonstrated that the separation of two plastics of different densities can be obtained.

Keywords:

• Post consumer plastics
• DMS
• low density suspensions

Notes

∗A Note from the Editors: Although the above paper deals with the separation of plastics, it was included in Coal Preparation because of its similarity to the densemedium separation of coal. In both cases, dense-medium separations are done using magnetite systems at low densities under dynamic conditions. Under such conditions, the viscosity and stability of the dense-medium suspension play key role in determining separation efficiency. Hence, the rheological and performance data obtained from the separation of plastics may be directly applicable to coal separation, albeit at somewhat higher medium densities.

Additional information

Notes on contributors

P BEVILACQUA

Corresponding author. e-mail: [email protected]