Alternative technological approach for synthesis of ceramic pigments by waste materials recycling

Alternative technological approach is proposed enabling utilization of raw materials from an oil refinery, such as waste guard layers from reactors. Reagent grade and purified MgO, Cr2O3, Fe2O3, and nitric acid (HNO3), were used as additional precursors. The homogeneous mixtures obtained were formed into pellets and sintered at different temperatures. The main phase was proved by X-ray phase analysis (XRD) and compared to ICPDS database. The main phase in the ceramics synthesized was solid solution of spinel MgAl2O4 and magnesiochromite. These minerals are classified as chromspinelide MgCrt(2)Al(0.4)Fe(0.4)O(4) and alumochromite MgCrt(2)Al(0.4)Fe(0.4)O(4). Additional SEM observations, combined with EDX analysis were performed, evincing agglomeration at lower temperatures, followed by agglomerate crumbling, at elevated calcination temperature. The complete transformation of initial precursors into the final ceramic compounds was found to occur at 800 degrees C - 1 h. The ceramic samples synthesized had high density of 1.72-1.93 g/cm(3) and large absorption area - 32.93% which is probably due to the high porosity of the sample. (C) 2016 SECV. Published by Elsevier Espana, S.L.U.