Construction of an experimental unit for the mechanical colour sorting of non-crushed recycled container glass

Abstract

The continuous growth of container glass recycling requires additional measures for the colour separation of waste glass. This paper presents the results of a research programme partly financed by the Umweltbundesamt (Federal Office for the Environment), Berlin, which deals with the mechanical colour separation of recycled container glass. It was the task of this research programme to develop and build a pilot unit which would function under operational conditions. For economic reasons and in order to limit the technological input, the process is designed for the sorting of whole bottles and large pieces of cullet. Before starting colour sorting, small pieces of glass are screened off. The larger material is aligned in the conveyor direction and is fed in single file to the colour recognition and ejector systems. After colour recognition by a light transmission measurement, the bottles or glass pieces are separated according to colour, in free fall, by mechanical ejection of the samples. The colours flint, amber, green and opaque are differentiated.