Recycling of the product of thermal inertization of cement–asbestos for various industrial applications Alessandro F. Gualtieri a, * , Carlotta Giacobbe a , Lorenza Sardisco a , Michele Saraceno a , Magdalena Lassinantti Gualtieri b , Gigliola Lusvardi c , Cinzia Cavenati d , Ivano Zanatto d a Dipartimento di Scienze della Terra, Università di Modena e R.E., Via S. Eufemia 19, I-41100 Modena, Italy b Dipartimento Ingegneria dei Materiali e dell’Ambiente, Università di Modena e Reggio Emilia, Via Vignolese 905/a, I-41100 Modena, Italy c Dipartimento di Chimica, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 183, I-41100 Modena, Italy d ZETADI S.r.l., Via dell’Artigianato 10, Ferno (VA), Italy article info Article history: Received 10 April 2010 Accepted 8 July 2010 Available online 13 August 2010 abstract Recycling of secondary raw materials is a priority of waste handling in the countries of the European community. A potentially important secondary raw material is the product of the thermal transformation of cement–asbestos, produced by prolonged annealing at 1200–1300 °C. The product is chemically com- parable to a Mg-rich clinker. Previous work has assured the reliability of the transformation process. The current challenge is to find potential applications as secondary raw material. Recycling of thermally trea- ted asbestos-containing material (named KRYAS) in traditional ceramics has already been studied with successful results. The results presented here are the outcome of a long termed project started in 2005 and devoted to the recycling of this secondary raw materials in various industrial applications. KRYAS can be added in med- ium-high percentages (10–40 wt%) to commercial mixtures for the production of clay bricks, rock-wool glasses for insulation as well as Ca-based frits and glass–ceramics for the production of ceramic tiles. The secondary raw material was also used for the synthesis of two ceramic pigments; a green uvarovite-based pigment [Ca 3 Cr 2 (SiO 4 ) 3 ] and a pink malayaite-based pigment [Ca(Sn,Cr)SiO 5 ]. The latter is especially interesting as a substitute for cadmium-based pigments. This work also shows that KRYAS can replace standard fillers in polypropylene plastics without altering the properties of the final product. For each application, a description and relevant results are presented and discussed. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction As a result of the increased need for alternative solutions to dis- posal in landfills or controlled dumping sites, recycling of both haz- ardous and non-hazardous wastes as secondary raw materials is becoming increasingly important. Recycling is promoted by the re- cent European Directive 2008/98/EC of 19-11-2008. In Italy, recy- cling is prompted by the Italian D.Lgs 152, 03-04-2006 ‘‘Codice ambientale”. Thus, the time has come to find suitable and econom- ically viable recycling solutions. Important hazardous wastes in Italy are asbestos-containing materials (ACM). Although asbestos is banned in Italy since 1992, industrial manufacture products containing asbestos may still be easily found in the environment. For example, approximately 2 bil- lion m 2 of cement–asbestos slates still cover roofs of industrial plants and civil buildings (Gualtieri and Elmi, 2006). Although slates in good condition with no signs of surface degradation is not necessarily an acute health hazard (Gualtieri et al., 2009), they have to be removed sooner or later as physical-chemical degrada- tion of the slates in the outdoor environment will eventually result in the release of asbestos fibers (Babic, 2006; Dias et al., 2008). The awareness of the health-threat of asbestos has prompted policy of abatement and disposal of ACM, such as cement–asbes- tos, in controlled landfills. However, this cannot be regarded as the ultimate solution as a zero risk of fiber dispersion in air and water cannot be guaranteed. Besides that, the disposal in con- trolled landfills and their maintenance for an indefinite time is rather expensive. An alternative solution is the thermal transfor- mation of ACM into supposedly non-hazardous products, and safe recycling as secondary raw material (Abruzzese et al., 1998; Bor- deres, 2000; Downey and Timmons, 2005; Leonelli et al., 2006; Gualtieri et al., 2008a). This alternative to landfill disposal is a via- ble solution in Italy thanks to the law no. 248 (D.M. 19/07/2004) which legitimates the thermal destruction of asbestos containing wastes and the recycling of the product of transformation. Recently, an industrial process for the thermal destruction of asbestos containing wastes, mainly cement–asbestos, has been developed and patented (Gualtieri and Zanatto, 2007; Gualtieri et al., 2008a). Sealed packages of cement–asbestos slates are 0956-053X/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.wasman.2010.07.006 * Corresponding author. Tel.: +39 059 2055810; fax: +39 059 2055887. E-mail address: alessandro.gualtieri@unimore.it (A.F. Gualtieri). Waste Management 31 (2011) 91–100 Contents lists available at ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman