This work describes an investigation on the ceramic encapsulation of mineral residues, and refractories residues in special, by a chemically bonded ceramic technique, using a new binder system based on potassium and magnesium phosphate. This process shows as advantage to the conventional chemically bonded ceramics based on Portland and high alumina cements a less permeable and soluble structure, which is more compatible with the treatment of noninert and even more environmentally dangerous residues. The mechanical strength developed by this ceramic, with cold crushing strength above 40 MPa after 24 h of curing, allows its use in a great variety of applications. The development of high mechanical strength within a short period of curing makes possible some uses where conventional binders have limitation. The efficacy of the encapsulating concrete was demonstrated by chemical, physical, mineralogical and microstructural characterization methods and also assessed by standardized leaching tests. (c) 2007 Elsevier Ltd. All rights reserved.