Recycling of spent FCC catalyst for the production of synthetic mullite

• Two grades of mullite with 60 and 70 wt% Al 2 O 3 were synthesized successfully. • The synthetic mullite is produced using spent FCC catalyst from Iranian plants. • Low cost of spent FCC catalyst reduces the production cost of the resulted mullite. • The resulted mullite has high quality and low price. Spent fluid catalytic cracking (FCC) catalysts were gathered from Iran’s petrochemical plants and calcined at 1250°C that led to the stabilization of V 2 O 5 in the liquid phase. Therefore, the calcining process at 1250°C converts the hazardous spent FCC catalyst to the non-hazardous aluminosilicate raw material. In this work, two grades of mullite with 60 and 70 wt.% Al 2 O 3 were synthesized successfully with the calcined spent FCC, calcined alumina and metallurgical alumina. The sintered samples had a high level of mullite phase along with high bulk density and low water absorption. Additionally, the samples that contain metallurgical alumina had a higher level of mullite phase content than the samples that contain calcined alumina. The considerable results of the synthesized mullites from this work present cost reduction of the synthetic mullite production that can consume all the spent FCC catalyst in Iran under the environmentally friendly process.