The work presents the results of application of natural clinoptilolite for immobilization of heavy metal cations (Ag+, Pb2+, Cd2+ and Cr3+) from aqueous solutions and uses zeolite to prepare autoclaved building composites. Sorption has been conducted on sodium form of natural clinoptilolite originated from Poland. Clinoptilolite (sodium form containing heavy metal cations) has been applied to obtain new building materials which have good physical properties. Samples produced by autoclaving process showed relatively low bulk density (about 1.35 g/cm(3)). The compressive strength depended on the amount of CaO in the initial mixture. Its maximum value was about 40 MPa. The influence of heavy metal cations on the compressive strength values was insignificant (except for the Cr3+ ions). However, all the cations modified the microstructure and the ordered state of C-S-H phase. Efficiency of Ag+, Cd2+ and Pb2+ ions immobilization on the mineral matrix was shown. In the work, results of IR spectroscopy, atomic absorption spectroscopy (AAS) studies, X-ray diffraction analysis, SEM observations and technological investigations are presented. (C) 2009 Elsevier B.V. All rights reserved.