Laboratory scale evaluation of hyperspectral imaging sorting of refurbishment plasterboard waste

At present, post-consumer plasterboard waste sorting is carried out manually by operators, which is time consuming and can be costly. In this work, a hyperspectral imaging system has been evaluated for automatic plasterboard waste sorting. Segregated plasterboard samples were crushed and sieved to obtain gypsum particles less than 250 microns, which were characterised through X-ray fluorescence to determine their chemical purity levels. It was found that the chemical purity of gypsum from refurbishment plasterboard waste obtained with the laboratory scale HSI-based sorting system was close to 96 wt%. Refurbishment plasterboard waste particles < 10 mm in size were not processed with the HSI-based sorting system because the manual processing of these particles at laboratory scale would have been very time-consuming. Since refurbishment plasterboard waste particles < 10 mm in size contained very small amounts of impurities, the segregated gypsum obtained from this unprocessed material had a chemical purity similar to that of the sorted plasterboard. The combination of unprocessed refurbishment plasterboard waste < 10 mm with sorted plasterboard ≥ 10 mm in size would lead to a plasterboard recovery yield above 98 wt%.