%0 Journal Article
%T Dependence of solubility and stability of calcium arsenates on pH value<br>砷酸钙化合物的溶解度及其稳定性随pH值的变化
%A ZHU Yinian
%A ZHANG Hua
%A LIANG Yanpeng
%A LIU Huili
%A ZHANG Xuehong
%A <br>朱义年
%A 张华
%A 梁延鹏
%A 刘辉利
%A 张学洪
%J 环境科学学报
%D 2005
%I 
%X The effect of pHand Ca/As ratio on the lime precipitation of arsenic-containing wastewater was studied in detail by both precipitation and dissolution experiments. For the precipitation under Ca/As=1.5 and 1.67, the residual arsenic concentration reached the lowest value at pH 7.0, and then increased slowly with the increasing pHvalues. The residual arsenic concentration after precipitation under Ca/As=2.0 and 4.0 decreased quickly with the pHincrease. There was no great difference between the experimental results for Ca/As=2.0 and 4.0. The composition and structure of the calcium arsenate compounds, which precipitated from the mixing of As solution with Ca(OH)2 slurry, depended on the pHand the Ca/As molar ratio. The particle size of the solids precipitated at high pHand high Ca/As ratio was much finer than for the low-pHand low-Ca/As precipitated solids. Ca3(AsO4)2·3H2O, Ca3(AsO4)2·2.25H2O, Ca5(AsO4)3OH and (Ca4(OH)2(AsO4)2·4H2O) were identified in the experiment over a wide range of pHand for Ca/As molar ratios between 1.0 and 4.0. Based on the analytical results,their solubility products were calculated as Ksp of 10-21.14, 10-21.40, 10-40.12 and 10-27.49, respectively.
%K lime precipitation
%K calcium arsenates
%K solubility
%K stability
%K pH value<br>石灰沉淀
%K 砷酸钙
%K 溶解度
%K 稳定性
%K pH值
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=3FF3ABA7486768130C3FF830376F43B398E0C97F0FF2DD53&cid=A7CA601309F5FED03C078BCE383971DC&jid=03A55E61A8750ACAC6AF81EF9E2AC838&aid=FA0E011AB661E5B8&yid=2DD7160C83D0ACED&vid=C5154311167311FE&iid=59906B3B2830C2C5&sid=1396DEC9DD671DC4&eid=14DD4EE1ABB958C5&journal_id=0253-2468&journal_name=环境科学学报&referenced_num=5&reference_num=35