Manufacture of ceramic bodies by using a mud waste from the TiO2 pigmentindustry

Abstract

The main objective of this paper is focused in the use of a waste generated by the TiO2 pigment industry, ilmenite mud (MUD), on the production of ceramic bodies. These ceramic bodies were produced from mixtures of a commercial red stoneware mixture (RSM) with different concentrations of mud (3, 5, 7, 10, 30 and 50 wt.%). The samples were sintered to simulate a fastfiring process. The sintering behaviour of the fired samples was evaluated by linear shrinkage, means of water absorption, apparent porosity and bulk density. Both green powder and fired samples were characterised by means of X-ray diffraction (XRD), differential scanning calorimetry (DSC/TG), field emission scanning electron microscopy (FESEM) and bending strength measurements. Moreover, the activity concentrations of radionuclides were measured by highresolution low-background gamma spectrometry, because this mud is a NORM (Naturally Occurring Radioactive Material) waste. Finally, the TCLP leaching test (Toxicity Characteristic Leaching Procedure, USEPA) was performed to assess the risks of use tiles from an environmental perspective. The results demonstrated that MUD can be successfully valorised in the manufacture of red stoneware ceramic bodies with similar or even better technological properties than commercialmaterials used currently.