Preparation and properties analysis of sediment ceramsite with high efficiency phosphorus removal

The main purpose of the research is to develop ceramsite with high efficiency phosphorus (P) removal from dredged sediment of a river. Single factor and orthogonal experiments L9(34) were conducted to investigate the effects of pore-forming agent, concrete, sintering temperature and holding time on characteristics of ceramsite. Furthermore, reuse of the disused ceramiste was studied. Results showed that the optimum conditions for the sintering process were obtained with a pore-forming agent-6.0 g, concrete-6.0 g, a sintering temperature of 1 060℃, and a holding time of 15 min. Properties of the ceramsite were as follows:void fraction 60.20%, water absorption 38.75%, breaking and wear rate 2.14%, solubility in hydrochloric acid 1.60%, silt carrying capacity 0.77%, apparent density 1 280 kg·m-3, and piled density 510 kg·m-3, which met the standard for an artificial ceramsite filter material for water treatment. When the initial P concentration was 10.0 mg·L-1, a P removal efficiency of 95.55% was obtained with the ceramsite. The disused ceramsite could be reused using 2.0 mol·L-1 NaOH. Thus, the dredged sediment is an alternative raw materials for the ceramsite filter with high efficiency phosphorus removal.