Immobilization of Wastes by Metakaolin-Blended Cements

Metakaolin-blended cements were used to stabilize two kinds of wastes: municipal incinerator fly ash and latex waste coming from the carpet industry. The physical and chemical properties of wastes were investigated and mortars containing these wastes were cast. A blended cement containing 20% metakaolin was utilized to immobilize the incinerator fly ash which was introduced as a sand substitute in mortars. Leaching tests and microstructural investigations were carried out as well as mechanical tests. The results obtained show that metakaolin plays a beneficial effect in the stabilization of chlorides contained in such fly ash. Cements containing from 10 to 30% metakaolin were used to cast mortars, in which latex was introduced as a sand substitute. Metakaolin reacted with the calcite contained in the latex and the C3A of portland cement to form carboluminate. Leaching tests showed a good immobilization of this waste.