Lime mud is a kind of solid waste in the papermaking industry,which has been a source of serious environmental pollution.Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C.The objective of this study was to explore the efficiency of Ca^(2+) and OH-release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments,X-ray diffraction(XRD) and scanning electron microscopy(SEM).The results show that Ca^(2+) and OH-were released from the ceramsites due to the dissolution of anorthite,gehlenite and available lime.It is also concluded that gehlenite had stronger capacity for Ca^(2+) and OH-release compared with anorthite.The Ca^(2+) release could be fit well by the Avrami kinetic model.Increases of porosity,dosage and temperature were associated with increases in the concentrations of Ca^(2+) and OH-released.Under different conditions,the ceramsites could maintain aqueous solutions in alkaline conditions(p H = 9.3–10.9) and the release of Ca^(2+) was not affected.The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%,respectively.The final p H values of both phosphorus and copper ions solutions changed slightly.The reuse of lime mud in the form of ceramsites is an effective strategy.
展开▼
