New Glass recycling plant for Cape Town.
Permission to use this article from The Engineering News magazine vol 24 No 43 (Nov 5 –11 2004) was received. Article by Abdul Cook.
R15m glass-recycling plant opens in Cape Town.
A glass recycling plant was commissioned in June by Consol Glass in Belville, Cape Town. "This plant provides exceptional quality, removes contanimants like ceramics, stones, porcelain, and metals, and makes conttainer glass more recyclable downstream by saving time and cost", claims head of the glass recycling for Consol Jaco Human (below).
With about 700,00t of glass being placed in the consumer market, of which only 22% is recovered for recycling, a new method based on international best practises was introduced to increase the recycling rate of post-consumer waste glass in particular.
The new Cape Town plant uses optoelectronic tachnology developed by Binder+Co of Austria, to automatically separate cullet (used glass) from nonglass elements in the waste stream and to separate the clean cullet into different colours.
Using a high-resolution camera system the plant is able to recognise a wide spectrum of colours, forms and structures. The cullet is separated according to colour in one work step, while impurities are removed. The machines use optoelectronic detection equipment and the technology is based on infrared-sensitive cameras to detect contaminents in the cullet stream. the cullet stream is separated into three main colour streams; flint, amber and green.
The system also allows for the refinement of certain colours for example, dead leaf green, is removed from the green cullet stream. "The colour purity on flint for example is 99% correct", says Human.
The detection equipment is linked to a blow-out mechanism that uses compressed air to remove contaminants from the cullet stream. The Clarity-Plus machine has almost no moving parts apart from the electromagnetic blow-out valve mechanism and the processes are therfore largely automated.