Recovery of Glazing Ceramic Sludge in Construction Materials Fernanda Andreola, Luisa Barbieri, and Isabella Lancellotti Dipartimento di Ingegneria dei Materiali e dell’Ambiente, Università di Modena e Reggio Emilia, Via Vignolese, 905/a, 41100 Modena, Italy. E-mail: <andreola.fernanda@unimore.it>, <luisa.barbieri@unimore.it>, <isabella.lancellotti@unimore.it > ABSTRACT Ceramic glazing sludge deriving from the purification process of waste-water obtained by the glazing tile phase was mixed in equal proportion with glass cullet in order to obtain a high sintered product suitable to be used as floor /wall covering tiles. The characterization of fired samples includes the evaluation of both sintering parameters: water absorption, linear shrinkage and apparent density according to the ISO rules and sintering temperatures estimated by optical heating microscope. Satisfactory results were achieved from technological tests and SEM analysis showed a dense microstructure with crystalline phases similar to commercial glass- ceramic, identified by X ray diffraction. Besides, the obtainment of these products was achieved with energy saving due to the lower firing temperatures (about 1000°C) with respect to commercial products for floor/wall covering (about 1200°C). INTRODUCTION Italy is the 3 rd largest floor and wall tile producer in the world, where the 80% of the total national production is manufactured in Sassuolo-Scandiano Ceramic District (mostly localized in a 300 km 2 area) in the Northest Italy (Modena and Reggio Emilia). The floor and wall ceramic tiles industry represents a secure reference for the Italian economy with a production of about 600 million of m 2 [27° National Statistical Report, Confindustria Ceramica 2006]. The ceramic residues coming from tiles industry are due to the process and purification treatments and can be classified in two different ways as a function of both their production process and physical state. One group is composed of unfired rejects coming from steps prior firing (pressing, drying, glazing, etc.) and the other one consists in fired rejects, derived from tile selection, polishing, etc. The latter group includes residues as dust, solid and sludge (water content ranging from 40 to 80 wt%). Furthermore, the production process generates a series of sludge derived from water purification (clarification and glazing sludge) and the purification of firing and atomization gases (exhausted lime). At present, the current industrial reintroduction of