Abstract: Ca-α-SiAlON/SiC powder was produced by carbothermal reduction-nitridation method and using the gold tailings from Henan Lingbao Gold Mine as the main raw material, and a proper amount of silica and calcium oxide of analytical grade as regulator. The results show that the formation of Ca-α-SiAlON is dependent on the system temperature and the amount of CaO. With the rise of reaction temperature, the reaction products are formed in sequence of SiC, α-Si₃N₄, β -Si₃N₄ and Ca-α-SiAlON. α-Si₃N₄、β-Si₃N₄ and SiC are intermittent products in synthesizing  Ca-α-SiAlON. At a sintering temperature of 1 600 ℃, a temperature retaining time of 5 h and a stoichiometrical proportion of 4.2% CaO, good Ca-α-SiAlON and SiC compound product can be obtained, with the elongated grain Ca-α-SiAlON amounting to about 72%.

Key words: Gold tailings,Ca-α-SiAlON/SiC, Carbothermal reduction-nitridation, Sintering temperature, CaO addition