Study on Sedimentation Performance of Different Flocculants in Sub-molten Salt System

Sedimentation performance of the slurry obtained from the treatment of Bayer red mud through sub-molten salt process was studied by means of cylinder measuring.Sedimentation velocity of slurry,clarity of solution and boundary surface were selected as parameters to evaluate the sedimentation performance with adding of a series of organic polymer flocculants including Nalco-9779,BASF-HP20,Lcb8,L1bb and 90HS,etc.The results show that Nalco-9779 is the optimum one.In addition,the effects of sedimentation time,temperature,dosage of flocculants and concentration of alkaline medium on the sedimentation performance of Nalco-9779 were investigated in detail.The optimum process conditions for slurry treatment mentioned above with use of the flocculants of Nalco-9779 including time of 10 min,temperature of 100 ℃,Na2O concentration of less than 540g/L() and flocculants dosage of 160 g per ton red mud.