转炉渣诱导磷酸钙结晶法去除和回收废水中磷的研究

Removal and recovery phosphorus from wastewater by converter slag-seeded crystallization of calcium phosphate

以转炉渣为晶种材料,利用批次结晶沉淀实验,研究不同的反应条件对诱导磷酸钙结晶法去除和回收废水中磷的影响。结果表明,最优反应条件为:pH=9.5,Ca/P摩尔比2∶1,转炉渣用量1.7 g/L,反应时间3 h,在此条件下,碳酸根对反应的影响甚小,对养猪场废水和污泥浓缩池上清液的处理,最高去除率分别达到95.36%和96.54%;转炉渣循环利用10次,回收磷的效果仍然很好。运用扫描电子显微镜(SEM)、X射线能谱仪(EDS)和X射线衍射仪(XRD)等测试手段对在最优工艺条件下重复使用10次的转炉渣进行了表征,证明回收的磷主要以羟基磷灰石(HAP)形态存在。

With converter slag used as a seed crystal,the effects of the reaction conditions on induced crystallization of calcium phosphate for removal and recovery of phosphorus from wastewater were investigated by batch experiments.Results indicated that pH value of 9.5,Ca/P molar ratio of 2,seed concentration of 1.7 g/L,reaction time of 3 h seemed to be the favorable conditions.Under the optimal reaction conditions,carbonate concentration had a little effect on the precipitation of calcium phosphate,and the P removal efficiencies of the swine farm wastewater and the concentrated sludge supernate were 95.36% and 96.54%,respectively.After used for ten times,converter slag as a seed crystal material for phosphorus recovery was still satisfactory.Characteristics of the products were determined by such analytical techniques as scanning electron microscopy（SEM）,energy dispersive X-ray spectroscopy（EDS） and powder X-ray diffraction（XRD）.The results showed that the main recovered product was hydroxyapatite.