Characterisation of acid pollutant emissions in ceramic tile manufacture

One of the environmental impacts associated with ceramics manufacture is the air emission of acid compounds stem from the presence of impurities in the raw materials and/or fuels. The present study was undertaken to identify the significant gaseous pollutants of an acid nature, to determine their concentrations, and to obtain the characteristic emission factors in spray dryers and firing kilns. The results show that, in spray dryers, the emission levels of the different acid pollutants are far below the current emission limit values applied in the European Union (EU). In firing kilns, the most significant acid pollutant emissions, compared with the recommended EU emission limit values (ELV-BAT), correspond to HF and HCl emissions, indicating that these emissions need to be corrected by appropriate cleaning systems before such emissions are released into the air. On the other hand, the results indicate that SO(2) and NO(x) emissions in the Castellon industrial ceramic sector lie below the ELV-BAT proposed in the European ceramic industry BREF, owing to the widespread use of natural gas as fuel and of raw materials with reduced sulphur contents.