Synthesis of single phase Ca-α-SiAlON using Y-type zeolite

Single phase Ca-α-SiAlON was synthesized for the first time by the carbothermal reduction-nitridation of a physical mixture of Y-type zeolite and CaO. Under well-optimized conditions, which included both a Si/Al ratio of 2.8 for the starting Y-type zeolite and a Ca/Al ratio of 0.63–0.75, highly crystalline, pure Ca-α-SiAlON was obtained. The formation of pure Ca-α-SiAlON was also confirmed by 27Al and 29Si MAS NMR measurements.