The roasted ore is dissolved in autoclave at 200 ~ C for 60 min. The Influence of roasting temperature on bauxite dissolution performance is shown in Fig. 3. It can be seen from Fig. 3 that the increase of calcination temperature can significantly improve the dissolution rate of alumina. 11 with the increase of calcination temperature, the change of alumina dissolution rate first increases and then decreases.  When the roasting temperature is higher than 585 ~ C, the dissolution rate begins to decrease.  When the roasting temperature is lower than 535c, the dissolution rate increases with the increase of roasting temperature, and decreases when the roasting temperature is higher than 535oc.The results show that there is a suitable temperature range for activation roasting, in which the chemical reaction activity of ore increases with the increase of temperature, and the dissolution performance is obviously improved.  However, if the roasting temperature is too high, the chemical activity of the ore will be reduced and the dissolution performance of the ore will be deteriorated.