Recycling of EOL CRT glass into ceramic glaze formulations and its environmental impact by LCA approach |
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Authors: | Fernanda Andreola Luisa Barbieri Anna Corradi Anna Maria Ferrari Isabella Lancellotti Paolo Neri |
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Institution: | (1) Dipartimento di Ingegneria dei Materiali e dell’Ambiente, Università di Modena e Reggio Emilia, Via Vignolese 905, 41100 Modena, Italy;(2) Dipartimento di Scienze e Metodi dell’Ingegneria, Università di Modena e Reggio Emilia, Via Fogliani 1, 42100 Reggio Emilia, Italy;(3) PROT-INN, C.R. ENEA, Via Martiri di Monte Sole, Bologna, Italy |
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Abstract: | Background, Aims and Scope The interest in recycling materials at the end of their life is growing in the industry in general. As regards the Wastes
of Electrical and Electronic Equipment (WEEE), an appreciable increase of these materials has been noticed in the last decades,
117 · 103 tons of WEEE have been produced in Italy in 2002 according to Ecohitech 1] and the increase in this kind of waste is three
times higher than that of the municipal waste according to the FISE ASSOAMBIENTE report 2]. Within WEEE, End-of-Life Cathode
Ray Tube (EOL CRT) glass, the main part of TV sets and PC monitors, is here analysed using both a technical approach to establish
a possible reuse of the glass in a open-loop recycling field (ceramic industry) and a methodology (LCA) capable of providing
environmental evaluations.
Methods The technological characterization was performed by chemical resistance tests (UNI EN ISO 10545-13), staining tests (UNI EN
ISO 10545-14) with blue methylene and potassium permanganate (KMnO4), and surface abrasion tests (UNI EN ISO 10545-7). The LCA study was conducted using the SimaPro 5.0 software and Eco-Indicator
99 as an evaluation method.
Results and Discussion The good technical results, reached by using cleaned EOL CRT panel glass inside a ceramic glaze formulation instead of a commercial
frit, are supported by the environmental impact evaluation, which shows a decrease of the overall potential damage (measured
in Points) of 36% and, in particular, a reduction of 53% in ‘Human health’, 31% in ‘Eco-system quality’ and 24% in ‘Resources’.
Conclusions This study has demonstrated that this new, open-loop recycling strategy for the CRT glass significantly reduces the environmental
impact of the ceramic glaze production process. In fact, in all damage categories examined in this study, there is a minor
impact. An improvement is evident in the respiratory inorganics sub-category related to the lowering of dusts mainly and to
a lesser amount with NOx and SOx in the climate change sub-category, due mainly to the reduction of CO2 emission correlated to the avoided combustion of the mixture which feeds melting furnaces in the frit production. Thus, the
damage decrease in ‘Ecosystem quality’ is prevalently due to the lower NOx emissions by the kilns in the frit production that is evident in the acidification/eutrophication sub-category. Finally,
the significant saving in the ‘Resource’ category is principally linked to the fossil fuels sub-category, thanks to the methane
saving which stokes the melting furnaces.
Perspectives Furthermore, the decrease in CO2 emission (94.4%) evident in the climate change sub-category is a very important topic because it is in line with the Kyoto
protocol (1997), where significant efforts have been exerted for the reduction of the green house gases emission, notably
CO2. The CO2 emission is correlated to the combustion of the mixture which feeds melting kilns in the frit production, therefore the recycling
of secondary raw materials, already in a glass state, can reduce the emissions of this gas. This reduction can be termed as
environmental credit and it is an example of an allocation of environmental loads in a open-loop recycling, where waste from
one industrial system are used as raw materials in another product system. |
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Keywords: | Cathode ray-tube glass ceramic glaze life cycle assessment recycling |
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