Cradle-to-gate study of red clay for use in the ceramic industry

The ceramic tile industry is one of the most important industries in Spain, with the highest concentration of firms to be found in the province of Castellón on the Mediterranean coast. The basic input material for this industry is red clay. The aim of this study was to carry out an LCA of the process of mining, treating and marketing this clay in order to identify the stages and unit processes that have the greatest impact on the environment. This LCA examines all the stages of the red clay from cradle to the customer's gate, including the process of mining and treating the clay in the mining facilities and its later distribution to end users. Life cycle inventory (LCI): An exhaustive LCI was performed by collecting data from the mine run by Watts Blake Bearne Spain, S.A. (WBB-Spain) in Castellón. Inputs and outputs were collected for all the unit processes involved in the mining, treatment and marketing of the clay: Mining the clay, which embraces the unit processes of removing the layer of vegetation covering the chosen area, preparing the area to allow access for the firm's vehicles, and boring or blasting the place the clay is to be extracted from. Treating the clay that is mined to make the finished product, which entails all unit processes required to separate out the waste material and transport it to the tip (which will later be reconditioned), excavating and transporting the clay to the crushing plant and later storing it in heaps before delivery to customers. All the internal transport that takes place between each unit process has also considered. Distribution of the final product, where the clay is loaded onto dumper trucks and delivered to the customer. Life cycle impact assessment (LCIA): According to ISO 1404X standards, the LCIA is performed at two levels. Firstly, the emissions accounted for in the inventory stage are sorted into impact categories to obtain an indicator for each category (mandatory elements). Secondly, the weighting of environmental data to a single unit is applied (optional elements). In compliance with ISO 14042, a sensitivity analysis is performed and three different impact assessment methods (Eco-Indicator'95, Eco-Indicator'99 and EPS'2000) are applied in order to analyse their influence on the results. The processes that involve the movement of clay within the mine (excavation and loading and transport to the crushing facilities and heaps) are the ones that make the greatest contribution to impact categories for pollu