Abstract:The mineral transition, microstructure and self-pulverization as well as the Al₂O₃ leaching performance of calcium aluminate clinkers with different P additions in CaO-Al₂O₃-SiO₂ system during high-temperature sintering were systematically studied by XRF, XRD, SEM-EDS and DSC-TG technologies. The clinkers sintered at 1350 °C mainly contain 12CaO·7Al₂O₃, CaO·Al₂O₃, β-2CaO·SiO₂ and γ-2CaO·SiO₂. The content of β-2CaO·SiO₂ increases while the content of γ-2CaO·SiO₂ decreases as the P addition increases. The self-pulverization property of clinkers deteriorates with increasing P addition. P distributes evenly in the clinkers, and inhibits the transformation of β-2CaO·SiO₂ to γ-2CaO·SiO₂. The cell volumes of 12CaO·7Al₂O₃ and CaO·Al₂O₃ decrease and increase respectively as the P addition increases, and P decreases their formation temperatures. The Al₂O₃ leaching rate of calcium aluminate clinkers decreases obviously with increasing P addition, which decreases form 95.01% to 83.84% as the P addition increases from 0 to 0.85%.

Key words: lime-sinter process; calcium aluminate; dicalcium silicate; crystal structure; self-pulverization performance; leaching