Synthesis of Calcium Hexaluminate from waste slag of aluminum and oyster shell

Waste aluminum slag and oyster shell were used as raw materials to synthesize calcium hexaluminate (CA6). The effects of different source materials of CaO and sintering temperature on the structures and properties of CA6 were investigated, respectively. The results show that compared to calcium oxide, oyster shell can lower the formation temperature of CA6, hence CA6 can be detected at 1300 ℃ by using oyster shell as the starting raw materials. Increasing the sintering temperature can promote the crystal growth. CA6 crystals show typical platelet shape, and its optimum sintering temperature falls in the 1450～1550 ℃ region. The bulk density is 1.54～ 1.83 g/cm3 , the apparent porosity is 44.1～55.2% and the flexural strength is 10.8～25.3 MPa.