Sedimentation and separation of red mud produced in treatment process of Guizhou diasporic bauxite with low and medium grade by lime Bayer process

The experimental investigation about settlement and separation performance of red mud generated from lime Bayer process using diasporic bauxite from Guizhou province with low and medium grade(alumina-silica ratio is 5.48) was performed. The effects of diluted desilication time, diluted slurry's mass concentration and flocculants on the settlement and separation process of red mud were investigated. The results indicate that the suitable desilication time for diluted slurry whose Al2O3 mass concentration and solid content are controlled to be about 165 g/L and 85 g/L respectively is 2-3 h. When flocculant type CM180 with 210 g/t dosage is added to the desilicated red mud slurry, the average settling rate of red mud in initial 5 min and 10 min can reach 19.0 and 12.1 mm/min respectively, and the liquid solid compression ratio of red slurry can reach 5.29.