Waste Sorting - CRT Glass Sorting
CRT glass is the largest item by weight. However, because of the 2 different types of glass used in CRT manufacture, the glass fractions have to be sorted to achieve a separation of the 2 type of glass, i.e. panel glass sorted from funnel glass.
Panel glass has virtually no lead content, whilst funnel glass normally has a lead content in the 20-25% range. The lead, in the form of lead oxide, is included as shielding against the X-Rays inherent in TV’s and monitors It is essential to separate the 2 qualities of glass to maximise the recycling revenues.
X-TRACT separator is able to sort the panel glass from the funnel glass. It does it by comparing their different atomic densities, and analysing the data from the X-Rays using a bi-chromatic sensor system. X-TRACT is the first industrial application for any dry mechanical density sorting.
TOMRA Sorting conducted numerous tests on mixtures of CRT glass using the X-TRACT sorter. The test material was a mixture of panel glass, funnel glass and combined pieces, above 15mm in size, from crushed TV/monitor glass. The goal was to achieve a very high degree of purity of panel glass. This was achieved. The purity of the panel glass was always above 99.9% (i.e. less than 0.1% lead content), and the recovery of panel glass was always above 90%.
Over the years, the amount of lead content used in the manufacture of both panel and funnel glass has varied. CRT glass manufactured in earlier days had panel glass with a lead content of up to 3.25% whilst funnel glass had a lead content in the 14-15% range.
The X-TRACT separator is able to identify these lower levels of lead, and sort the CRT with the lower lead content into the funnel glass fraction, thus leaving the panel glass effectively lead free. In summary, the X-Ray based sorting system developed by TOMRA Sorting has many possible applications in the recycling of CRT glass from TV sets and computer monitors. The quality of the recycled panel glass achieved is very high, and meets the glass industries stringent maximum lead content requirements for recycled glass.
With X-TRACT it is now possible to separate panel glass from funnel glass, and also to separate out glass that has a lower lead content than regular funnel glass, and higher lead content than regular panel glass.
The particle size range for the CRT glass sorting is 8 mm to 100 mm, and best sorting results are achieved with intermediate size splits.