In order to produce mineralic bodies of high porosity, usable inter alia as adsorbers, purifiers and catalyst carriers, a predominantly mineralic mass with organic admixtures--both preferably obtained from industrial waste products--are subjected to a three-phase treatment. In a first phase, the mass is heated in an inert or reducing atmosphere to a sintering temperature between about 1000.degree. C. and 1350.degree. C. whereby the organic constituents are carbonized and partly penetrate the consolidating mineralic structure. In a second phase, still under the same nonoxidizing atmosphere and at the sintering temperature referred to, the mineralic structure is sintered into a coherent matrix. In a third phase, with reduction of the temperature to a lower level between about 600.degree. and 1000.degree. C. and exposure to the atmosphere, the carbonaceous substances occluded in the mineralic skeleton are burned off to increase its porosity.