Heavy metals leaching in bricks made from lead and zinc mine tailings with varied chemical components
Abstract The stabilization/solidification approach has received considerable attentions for the disposal of hazardous metal-bearing mine tailings. A poor understanding of the immobilization mechanism of heavy metals in final products always restricts its practical applications. We reported that, the stabilization of toxic heavy metals (Zn, Pb, Cd and Cu) in bricks made from the lead and zinc mine tailings (LZMT) was highly dependent on the relative contents of SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO and MgO in LZMT. As the (SiO 2 +Al 2 O 3 )/(Fe 2 O 3 +CaO+MgO) ratios (SA/FCM ratios) increased, the C Pb , C Cd , or C Cu in leachates slightly decreased first and then increased. Much differently, C Zn firstly increased and then decreased, having highest C Zn (3.92mg/L at 30th day) at the SA/FCM ratios of 0.80. Compared with C Zn and C Pb , a much small C Cd and C Cu can be found. Notably, the C Zn and C Pb are also impacted by the change of SiO 2 :Al 2 O 3 ratios (and Fe 2 O 3 :CaO:MgO ratios as well). The C Pb decreased as the SiO 2 :Al 2 O 3 ratios increased from 1:0.046 to 1:1.354, while the C Zn reached a highest value at SiO 2 :Al 2 O 3 ratio of 1:0.084. The XRD analysis suggests that, the Al and Si can interact with Pb to form PbAl 2 Si 2 O 8 , which facilitates the immobilization of Pb 2+ . Excessive amount of SiO 2 and Al 2 O 3 bring the difficulties to forming stabile skeletons, resulting in the leaching of Pb readily. As for Zn, higher C Zn is generally owing to the occurrence of acid-soluble Zn 2 SiO 4 in bricks. The stabilization of Zn was achieved once Al 3+ was introduced as host to be substituted by Zn 2+ in the aluminate or aluminosilicate matrix. The findings could enrich the mechanistic understanding and pathway of heavy metals immobilization in eco-environmental products from LZMT. Highlights Impacts of SiO 2 :Al 2 O 3 and Fe 2 O 3 :CaO:MgO on metals leaching were examined. Leaching of Zn, Pb are highly depended on the chemical compositions in bricks. Presence of PbAl 2 Si 2 O 8 could facilitate the immobilization of Pb 2+ in bricks. Higher C Zn could be attributed to the formation of Zn 2 SiO 4 in bricks. Concentrations of Cd, Cu, Pb, Zn in leachate are all below the standard. Graphical abstract [DISPLAY OMISSION]
- 원문이 없습니다.
- DOI : http://dx.doi.org/10.1016/j.conbuildmat.2016.12.076
- Elsevier : 저널> 권호 > 논문
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기