摘要
磷石膏(PG)和铜尾渣(CSS)是磷化工和有色冶炼行业中产生的两种固废,含有大量可迁移性有害物质,在堆存过程中能对环境造成污染。向PG、CSS混合渣中添加CaO作为额外钙源、NaOH作为激发剂,加入约30%(质量分数)的水,搅拌均匀,通过机械压模制成固结体(PG-S),经过抗压测试和毒性浸出试验,结果表明:PG-S抗压强度可达到14.8 MPa;PG中的主要污染物PO_(4)^(3-)、F^(-)的固定率分别达到99.87%和92.13%,重金属锌、铅等有害物质的浸出浓度均能满足《污水综合排放标准》(GB 8978—1996)要求,实现了对PG、CSS的高效耦合固定/稳定化处理。通过XRD、SEM表征分析证明PG、CSS中的有害物质通过生成不溶物和胶凝包裹吸附而被固定。
Phosphogypsum(PG)and copper smelter slag(CSS)are solid wastes produced from phosphorus chemical industries and nonferrous metal smelting industries.PG mainly consists of CaSO_(4)·2H_(2)O with harmful impurities such as residual acids,phosphate,fluorides,and trace metals(e.g.,Cr,As and Cd).CSS contains large amounts of heavy metals such as lead and zinc.The soluble portions of the harmful substances in PG and CSS may enter the environment and cause serious pollution problems.In this study,NaOH and CaO were added as activators and additional calcium sources in mixed slag of PG and CSS with water to produce cemented blocks(named PG-S).Unconfined compressive strength(UCS)test and leaching test show that the compressive strength of PG-S reaches 14.8 MPa,and the stabilization efficiency of PO_(4)^(3-) and F^(-) in PG are 99.87% and 92.13%,respectively.The concentrations of heavy metal zinc,lead and other harmful substances in the leaching solution meet the requirements of"integrated wastewater discharge standard"(GB 8978—1996)of China.The stabilization/solidification(S/S)of PG and CSS using the proposed method shows high efficiency and feasibility.Through XRD and SEM analysis,the stabilized wastes show structures similar to C-S-H,ettringite,Zn_(3)(PO_(4))_(2)(H_(2)O)_(4),Pb_(10)(PO_(4))_(6)(OH)_(2) and CaF_(2).On this basis,the possible mechanism of the stabilization/solidification process is:the harmful substances in PG and CSS may be stabilized/solidified by formation of insoluble substances and adsorption of cementitious substances.
作者
王维
许向群
李杰
郭莉
陈荣升
杜冬云
WANG Wei;XU Xiangqun;LI Jie;GUO Li;CHEN Rongsheng;DU Dongyun(Hubei Province Engineering Research Center for Control and Treatment of Heavy Metal Pollution,College of Resources and Environmental Science,South-Central University for Nationalities,Wuhan 430074,China;Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education,South-Central University for Nationalities,Wuhan 430074,China;Hubei Dajang Environmental Technology Co.,Ltd.,Huangshi 435005,China)
出处
《硅酸盐通报》
CAS
北大核心
2021年第5期1601-1609,共9页
Bulletin of the Chinese Ceramic Society
基金
湖北省重大科技创新项目(2019ACA156)
湖北省重点研发计划(2020BCB062)。
关键词
磷石膏
铜尾渣
固定化
废物处理
活化
phosphogypsum
copper smelter slag
immobilization
waste treatment
activation
