Life cycle assessment comparison between zircon and alumina sand applied to ceramic tiles

The goal of the study is to assess and compare the use of opacifier (whitener) materials zircon sand and alumina applied in ceramic tiles production. This study provides a comparison using a cradle-to-gate life cycle assessment (LCA) approach, giving an overview of the differences from an environmental perspective between these materials in body mixtures to obtain tiles with a high degree of whiteness. This ISO compliant study is backed by an independent critical review panel and presents the first European-representative LCA comparison between zircon and alumina, using primary data from industry. A super white (with CIELab coordinate L*>85) ceramic tile can be produced using zircon or alumina as opacifier, with different mixtures. For zircon data, a previous ISO reviewed LCA and its associated paper has been used. This data comes from Zircon Industry Association members. For alumina, the eco-profile of alumina and bauxite developed by the European Aluminium has been used and is available in the "Environmental Profile Report for the European Aluminium Industry". This study considers the use phase of the compared materials as whiteners. Milling phase data was collected from specific producers and tile mixture preparation data was taken from wider industrial bodies. Sensitivity and scenario analysis were used to understand the main differences between mixtures and influences between materials. Comparing the use of zircon sand with alumina in different ceramic mixtures, the primary result is that tiles using zircon had lower environmental burdens for almost all the analysed impact potentials. The alumina mixtures investigated show about 20% higher Global Warming Potential (GWP), Eutrophication Potential (EP), Acidification Potential (AP), Photochemical Ozone Creation Potential (POCP), Abiotic Depletion Element and Fossil Potential (ADPe/f) and Primary Energy Demand (PED). The Ozone Depletion Potential (ODP) is the only potential impact that is similar for zircon mixtures and alumina mixtures. The milling process is not negligible for all the impact categories considered in this study. The results of the study show that main differences between zircon and alumina mixtures are closely tied to the environmental performance of regional grid electricity generation. This study quantifies and compares the environmental impacts associated with the production of super-white ceramic tile mixture with two different whiteners: zircon and alumina. With this study, ceramic tile producers are given a tool to guide their choices in opacifier material selection, using a rational, scientific and peer-reviewed methodology, ensuring objective comparison between two materials.