不同材料对铅锌冶炼渣中Zn、Cd和As的稳定化效应

采用典型硫化物、含磷材料、含钙碱土类材料、黏土矿物等，对2种含锌（Zn）、镉（Cd）复合污染废渣进行稳定化，考察了各种材料对废渣中共存砷（As）的作用效应，利用H₂SO₄-HNO₃浸提法评估稳定化效果，以GB 18598—2001《危险废物填埋污染控制标准》为达标限值，达到高效安全处置废渣的目的。1号废渣稳定化结果表明:Na₂S·9H₂O、Na₃PO₄·12H₂O、CaO、MgO、钠基膨润土均适用于废渣Zn和Cd的稳定处理，但含磷材料的施加使As浸出有所检出。2号废渣结果表明:各材料对Zn、Cd、As的综合稳定效果顺序为Na₂S·9H₂O > Na₃PO₄·12H₂O > （NH₄）₂HPO₄，Na₃PO₄·12H₂O和（NH₄）₂HPO₄对Zn的稳定率虽高，但易使As活化；MgO优于CaO，1% MgO对Zn、Cd、As的稳定率分别达到86.99%、91.37%、90.88%。优选MgO和Na₂S·9H₂O作为2种废渣的稳定化材料。研究可为国内含Zn、Cd、As废渣的高效稳定化技术提供数据支持。

EFFECT OF DIFFERENT IMMOBILIZING MATERIALS ON ZN,CD AND AS IN LEAD-ZINC SMELTING SLAGS

Several materials such as typical sulfides, phosphorus-containing, calcium-containing, magnesium-containing, clay minerals were used to immobilize two kinds of slags containing zinc (Zn) and cadmium (Cd), respectively. The effects of different materials on the coexistence of arsenic(As) in slags were also investigated. The immobilization effect was evaluated by H₂SO₄-HNO₃ leaching method. China national standard, GB 18598—2001 was taken as the standard requirement. Finally, the purpose of efficient and safe disposal of waste slags can be achieved. The results of immobilization of No.1 slag showed that: Na₂S·9H₂O, Na₃PO₄·12H₂O, CaO, MgO, bentonite had obvious immobilization effect on Zn and Cd, but the application of phosphorus-containing materials made As leaching detected. The results of No.2 slag showed that the immobilization effects of Zn, Cd and As were Na₂S·9H₂O>Na₃PO₄·12H₂O>(NH₄)₂HPO₄, Na₃PO₄·12H₂O and (NH₄)₂HPO₄ were easy to activate As, although they had high immobilization efficiency on Zn; MgO showed better performance than CaO, and the MgO immobilization rates for Zn, Cd, As reached 86.99%, 91.37%, 90.88% respectively at 1% dosage. MgO and Na₂S·9H₂O were the best immobilizing materials. This study could provide data support for efficient immobilization technology of slags containing Zn, Cd and As in China.