Relevance of size and shape in cullet sorting

The waste management is transforming in a more and more complex effort, with environmental and economic relief. The urban solid wastes are mainly produced in the final phase of the consumption, particularly by the food packaging increasing. As concerns materials recovery and recycling, a key condition for the development of selective wastes collection is the capability of recycling plants. The limitation in the use of the secondary raw materials, in fact, is due to their quality, however lower than the primary raw materials one. In the case of cullets, it is necessary to assure a high quality level. The technological characteristics of the glass produced by using recycled materials are deeply influenced by the chemical composition of cullets and the presence of extraneous items in the recycled mixture. The recognition of cullets produced by crushing is important in order to recycle the glass for the industrial uses. The aim of this work is to evaluate the correspondence between the characteristics of cullets and the characteristics of the corresponding original bottles, in order to identify in cullets the physical and mechanical properties of glass that constitutes the bottles. A feasible analytical procedure able to associate the cullets characteristics to the original bottles, independently from the effect produced during the crushing, has been pointed out.