The use of secondary raw materials is gaining more and more importance in the industry. High quality requirements on the side of the producing industry meet varying qualities on the side of the processing industry. In order to further increase the share of secondary raw materials, reliable information about their qualitative properties is required. Representative sampling in the course of cullet delivery is an option for the glass industry, but the effort involved is currently still high and difficult to implement, which is why there is a need for a suitable industrially feasible incoming inspection procedure for quality assurance. In the course of the present work, cullet sampling was carried out according to two different methods, the first representative according to LAGA PN 98 but costly, the second simplified and adapted to the operational conditions of the glass manufacturer Stoelzle. The samples were sieved to determine the particle size distribution. The resulting fine and medium fractions (< 1 mm and, 1 - 6.3 mm, respectively) were subsequently annealed to determine the organic content. In the coarse fraction (6.3 - 20 mm), the organic content was determined by separating and weighing the light fraction that floated up during washing of the cullet. In the very coarse fraction (> 20 mm), the organic content was determined by manual sorting and weighing. The determination of the proportions of cullet in the different colors was carried out by sensor-based sorting (VIS) of the washed coarse fraction and classification of the cullet at particle/single grain level according to the learned color classes (brown, olive, white, green, light green, yellow and pink, CSF and blue). Finally, the fine and coarse fractions were analyzed by X-ray fluorescence analysis (XRF) to assess chemical composition. By comparing the evaluation results of the representative sampling and the simplified sampling procedure, it was shown by means of variance analyses that the implementation of a simplified sampling procedure does not provide the same but similar results. The simplified sampling procedure is characterized by a significantly lower proportion of the coarse fraction in the sampled material. The increased proportion of the fine fraction and the accumulation of impurities in it lead to a higher calculated total impurity content compared to representative sampling when the simplified method and continued analysis are carried out. Finally, a procedure for incoming goods inspection integrated into the operational process is proposed.
|Translated title of the contribution||Development of a process for the inspection of incoming cullet|
|Award date||21 Oct 2022|
|Publication status||Published - 2022|
Bibliographical noteembargoed until 06-09-2025
- quality inspection