Glass - Back to the Future!

Presenting Author:
Stefano Ceola

article posted 22 March 2016

Stefano Ceola was born in Vicenza, Italy on the 6th of November 1974. He earned a MSc Degree in 2000 in Chemistry with a Thesis on the Study of Liquid Crystal behavior under strong Magnetic field with EPR Spectroscopy. In 2000 started his PhD program, devoted to the investigation of photo-physical behavior of organic molecules for organic-based photo-voltaic device, in parallel with the development of new Photo-Magnetic Resonance Techniques. During the PhD he was awarded of a “Young Researcher” grant 2001, issue by University of Padua, Italy. In early 2004 he earned the PhD Degree and started his work as Researcher at the Physics Department in Leiden University, working in the development of magnetic resonance techniques related to ab initio quanto-mechanical calculation on biological molecules.
In 2006 he started a PostDoc grant issued by University of Padua for the Measurement of intramolecular distance in biological Macromolecule related to Photo-system II, at the Biology Department. In 2008 he decided to switch from Academic Research to Industrial Applied Research and started working in Stazione Sperimentale del Vetro, SSV. In this company he started to work in defect analysis related to Industrial glass production issues. Actually he is active in Technical Assistance to Glass Industry and in the SSV R&D team. He took part in several Conferences and Seminar, as speaker and with poster. He is co-author of 22 scientific refereed paper published in International Journals.

Glass Cullet: Quality Assesment and Rejects Overview

Nicola Favaro & Stefano Ceola*
Stazione Sperimentale del Vetro, Via Briati 10, 30141 Venice, ITALY

Nowadays cullet is one of the main raw materials for the glass industry in Europe. In 2015 Europe hit 73% of glass cullet recycled, with furnaces producing green colored glasses with more than 90% recycling rate.
Because of cullet increase in the furnace, glass producers have experienced an increase of defects in the final glass container. As a matter of fact cullet comes from waste, either mono-material or multi-material and it can be possibly contaminated by ceramic, stones, glass-ceramic, etc. These issues are actually managed mainly by the application of improved sorting technologies in the cullet treatment plant and with a proper, updated set of Technical Specifications.
Following the high demand for clean flint cullet, the recyclers have installed new color sorting machines able to produce high quality colored and no-colored flow from the mixed color cullet. The introduction of such machine has a positive impact on the amount of cullet recycled, however some unexpected contraindications have been registered. The redox of the cullet fed is strongly impacted by the relative amount of the different colors. Small variation can modify the redox of the batch, introducing instability on the glass color, especially in case of reduced glasses (amber and UVAG). The demand for a ever better cullet, in terms of redox stability, lead content and minimization of CSP stones in the produced glass container, has lead to an increase of rejects in cullet’s life cycle.
The paper will provide an overview of the main processes applied in Europe to sort cullet and the strategies applied to improve the total amount and quality of recoverable glass. At the end, the SSV analytical approach for quality monitoring and assessment will be described.