Abstract:The effect of digestion temperature on digestion and settling properties of gibbsite and boehmite hybrid bauxite were studied applying gibbsite and boehmite hybrid bauxite as objects. The results of digestion tests show that gibbsite can be completely dissolved in a short time at 145 ℃, and the alumina digestion rate drops with the prolongation of digestion time. When increasing the digestion temperature to 240 ℃ above, the alumina digestion rate of boehmite rises significantly, but alkali consumption increase at the same time. The settling test results show that the settling performance of red mud from high temperature dissolving pulp is significantly better than that from low temperature dissolving pulp. When reaching the same settling rate, the amount of flocculant added is reduced by about 50%.