The recovery of the waste of the secondary glass (waste3)

In Italy, the amount of glass waste reached in 2015 1.825.000 t, and 91% of this amount has been recycled. The remaining 9% that is to say 164.000 t in 2015 constitutes the waste of this process (Coreve, 2015). SASIL spa processes this waste obtaining a product named glassy sand that is now well accepted by the glass factories. In turn from this treatment SASIL generates a 3% of waste made of all the impurities usually present in a glass waste. The problem faced in this research is the recovery of the most of these impurities. The impurities are represented by ceramics, stones, magnetic and non-magnetic metals, paper, plastics, cork, oily residues, synthetic corks etc., which are not always easily removable. SASIL S.p.A. already built a treatment plant for the recovery of this waste but the its performances are not yet satisfactory. For this reason some samples were taken from different points of the plant in order to carry out particle size analysis and product characterization to define the composition of the waste and evaluate the efficiency of industrial treatments. The present work shows that the cullet waste material of scrap glass recovery treatments (waste3) is composed of exploitable product fractions with different particle sizes and physical (such as density , shape and resistance) properties. In the next step, laboratory tests were executed to achieve maximum separation efficiency and to valorise the different product fractions. On the base of laboratory results, a new treatment plant was designed and economic evaluation have been made. The materials to be trade as secondary raw materials (SRM) are about 87.5% of the total entering the plant and result to be glass, plastic lightweight, ferrous metals, non-ferrous metals, synthetic stoppers and cork stoppers.