Leaching of alumina and iron oxide from red mud

In order to recycle aluminum and iron in red mud,and solve the problems that red mud pollutes the environment and occupies large areas of land,the processes of extracting alumina and iron oxide from wast red mud with hydrochloric acid is investigated by studying the influences of baking of red mud,liquid-solid ratio of hydrochloric acid to red mud,the concentration of hydrochloric acid,reaction time,reaction temperature,ways of extracting on the leaching ratios of alumina and iron oxide.The results showed that the red mud does not need to be baked.The leaching ratios of alumina and iron oxide reach 89.00% and 98.39% respectively under the conditions that the liquid-solid ratio of hydrochloric acid to red mud is 4∶1,the concentration of hydrochloric acid is 6 mol/L,the reaction time is 60 minutes,the reaction temperature is about 109 ℃,and the way of extracting is two-step extracting.