Interaction of mullite with some polluting oxides in diesel vehicle filters

Mullite is one of the most promising substitutes for cordierite as a material for the manufacture of diesel vehicle filters. This study investigated the sensitivity of mullite to chemical attack provoked by some of the oxides present in the particulate of diesel-engine exhaust gases. Filter thermal regeneration conditions were simulated by means of heat treatments between 400 and 1000 degrees C. The following pollutants were used: V2O5, PbO, ZnO, Fe2O3, CeO2, CaCO3 and Na2CO3 (the last-mentioned as oxide generators). The results obtained were compared with those for cordierite. Mullite was less sensitive to attack than cordierite but was unable to effectively resist attack by PbO and Na2CO3. (C) 1999 Elsevier Science Ltd and Techna S.r.l. All rights reserved.