An efficient method for recycling spent residue cat-cracking catalysts (SRC) to prepare broadly-applicable mullite-based wear-resistant ceramics

Spent residue catalysts (SRC) of fluid cat-cracking were used as raw materials for the preparation of wear-resistant ceramics. The starting material was wet-milled and then dried to obtain semi-dried powders. The resultant powder was pressed into various shapes and sintered at various temperatures (1300 to 1450 °C). The bulk density and linear shrinkage of the samples increased as the temperatures rose, while the apparent porosity and water absorption behaved in a reverse manner. Based on the results, the specimens sintered at 1450 °C appeared to be the best alternatives for the preparation of the wear-resistant ceramics. The results also revealed that pre-calcination has no significant effect on the final properties of the ceramic products. The XRD results approved that mullite is the only crystallized phase in the specimens sintered at 1450 °C. Moreover, the absence of vanadium and nickel-based phases in the XRD pattern indicated that these elements had been stabilized in the glassy phase. SEM images displayed the presence of needle-like mullite grains, in agreement with the XRD results. Additionally, SEM images illustrated that the fractures, appeared after the wear test, were inter-granular and may have been resulted from the well-controlled sintering conditions. Generally, the results of this study suggest a cleaner method for converting the SRCs to wear-resistant mullite-based ceramics with a wide range of industrial applications. Reuse of RFCC Spent Catalysts Using an Efficient Sintering Method. [Display omitted] •A promising way to overcome environmental issues concerned with spent RFCC catalysts was suggested.•As-received and calcined ceramic catalysts were recovered to produce mullite-based wear-resistant ceramics.•Optimum temperature for sintering the wear-resistant ceramics was 1450 °C without pre-calcination.•Pre-calcining had no considerable impact on the final properties of the resultant ceramics.•Saving in energy and resources, toxicity reduction, waste elimination, and cleaner production were attained.