摘要：The formation kinetics and mechanism of tricalcium aluminate hydrate and calcium oxalate in dilute sodium aluminate solution and sodium oxalate solution were studied respectively based on the lime causticization, and the optimal co.ditions for removing the oxalate in dilute sodium aluminate solution as well as the mechanism were finally *** formation processes of tricalcium aluminate hydrate and calcium oxalate are mainly co.trolled by the chemical reaction and the inner diffusion respectively,and the co.responding reaction rate equations as well as the apparent activation energy were calculated. The hydrocalumite with a spatially interleaved structure will form in dilute sodium aluminate solution with sodium oxalate, greatly removing the oxalate impurity by absorption. Calcium oxalate can be co.verted to tricalcium aluminate hydrate with the increasing reaction time. The oxalate causticization efficiency and the alumina loss rate can be over 90% and below 31% respectively when reacted at 50℃ with a stirring rate of 200 r/min.