Enhanced flocculation and sedimentation of copper tailings by polycarboxylate ether superplasticizer

The problem of tailings handling and disposal has gradually attracted significant attention around the world. Most studies focus on the tailings' settling efficiency; however, more attention should be paid to the sediment of tailings which may seriously affect the storage capacity and service life of tailings dams. Therefore, this study aimed to use the polycarboxylate ether/ester (PCE) superplasticizer first time as a mineral surfactant to improve both the settling and the sediment properties of copper tailings. In this purpose, the effects of non-ionic polyacrylamides (NPAM) molecular weight (MW) and PCE dosage on the settlement performance of the tailings were studied. The results showed that, with the synergism of PCE and NPAM, the initial sedimentation rate (ISR) could be increased by up to 2.3 times and the final sediment volume could be reduced by 6.0 %. The floc size and morphology analysis inferred that tailing particles formed larger and more compact flocs after adding PCE. The investigations on the tailings' wettability and electrical property indicated that PCE could weaken the hydrophilicity and neutralize the negative charges on the particles surface. This research demonstrates that PCE surfactant is conducive to rapid settling and densely stacking, which may provide a great promising reagent for solid-liquid separation of tailings.