浸取方式对废物水泥窑共处置产品中Pb,Cd和Ni浸出的影响

模拟煅烧试验制取含Pb,Cd和Ni的水泥熟料,并将其制成混凝土样品,通过水槽浸出试验研究间歇浸取方式对混凝土中Pb,Cd和Ni释放的影响.结果表明:间歇碳化保存处理浸出液的pH为9.5～10.4,低于连续浸取处理浸出液的pH(10.3～11.0),而间歇自然保存处理的浸出液pH则与连续浸取处理浸出液的pH相近;间歇浸取过程的碳酸化作用增加了混凝土中Pb和Cd的释放,表现为间歇浸取碳化保存处理的累积浸出量最大(Pb和Cd分别为686和332 mg/m2),连续浸取处理的累积浸出量最低(Pb和Cd分别为480和203 mg/m2);间歇处理对Ni的释放影响与Pb和Cd的不同,连续浸取处理的累积浸出量最大,为155 mg/m2,而间歇碳化保存处理的累积浸出量(85 mg/m2)最小.

Influence of Leaching Mode on the Leaching of Pb, Cd and Ni in Cement Product from Co-Processing Waste in Cement Kilns

Clinker containing Pb, Cd and Ni was produced by simulating cement calcination tests, and concrete samples were also prepared. The influence of intermittent wetting on the release of Pb, Cd and Ni in concrete samples was studied via basin diffusion testing. The results showed that the leachate pH in intermittent wetting with carbonation control was in the range of 9.5 to 10.4, which was lower than that in continuous leaching control (10.3-11.0). However, the pH of continuous leaching control was close to that of intermittent wetting without carbonation control. The release amount of Pb and Cd in concrete samples was increased by the carbonation in intermittent wetting. The maximum cumulative release amount was in intermittent wetting with carbonation control (the concentrations of Pb and Cd were 686 and 332 mg/m² respectively), while the minimum cumulative release amount was in continuous leaching control (the concentrations of Pb and Cd were 480 and 203 mg/m² respectively). In contrast to the influence of intermittent wetting on the release of Pb and Cd, the release of Ni was restrained by the carbonation in intermittent wetting. The release amount in continuous leaching control was highest (155 mg/m²), while the release amount in intermittent wetting with carbonation control was lowest (85 mg/m²).