Remediation of asbestos containing materials by Joule heating vitrification performed in a pre-pilot apparatus

A remediation method for asbestos containing materials based on vitrification by joule heating is presented. Crystal phase transformations of several asbestos minerals were investigated. The vitrification technology on a pre-pilot scale was applied to cement-asbestos pipes containing simultaneously chrysotile and crocidolite. The progressive heating up to 1600 degrees C led to the complete melting of fibrous minerals and the rapid cooling of the melt formed a monolithic glass. Mineralogical (XRD) and morphological (SEM) analysis showed absence of crystalline phases within the glass. The external part of the joule heated volume was not melted but lacked asbestos because of an irreversible thermal conversion of asbestos and silicate minerals into high temperature silicates (enstatite and diopside). An absolute filter integrated in the gas effluent treatment system avoided the release of asbestos fibres during the vitrification process. This process assured the complete remediation of asbestos containing materials and its scaling up to the Held application could be a suitable industrial treatment of tons of material. (C) 2008 Elsevier B.V. All rights reserved.