Study on the matching rules and control mechanisms between flocculants and slurry settlement characteristics

In order to realise efficient, economic, low carbon and environmentally friendly slurry disposal, floc sedimentation velocity ( S f ), supernatant volume ( V s ), water content of bottom mud ( W b ), supernatant turbidity ( N s ) and pH value were determined by slurry sedimentation tests, specific resistance tests, and water quality analysis. Orthogonal tests were performed to analyze the matching rule and control mechanism between flocculants and the slurry settlement characteristics. The results show that polyaluminum chloride (PAC) and polyferric chloride (PFC) had a low dose and a fast sedimentation rate. The sedimentation effect of 20 ionic degree cationic polyacrylamide (CPAM-20) in organic flocculant is the best. Although flocculants can shorten the sedimentation time, excessive flocculants can also weaken the slurry separation effect. The sedimentation efficiency of organic flocculants is higher than that of inorganic flocculants, but it is easy to form foam on the supernatant surface. For the composite flocculants, the sensitivity sequence of S f , V s and W b is PAC>CPAM-20>PFC. PAC plays a controlling role in the sedimentation effect of the slurry.