Institute of Environmental Science & Engineering, School of Metallurgical Science and Engineering, Central South University, 410083, Changsha, Hunan, China.
Environ Sci Pollut Res Int. 2013 Sep;20(9):6050-8. doi: 10.1007/s11356-013-1643-8. Epub 2013 Mar 26.
Floatation tailings (FT) are the main by-products of the hydrothermal sulfidation-flotation process. FT (FT1 and FT2) were obtained by treating two different neutralization sludges (NS) (NS1 and NS2). This paper quantitatively evaluated the environmental risks of heavy metals (Zn, Cd, Cu, Pb, and As) in FT versus NS. The total concentration and leaching rates (R 2) of heavy metals in FT were much lower than those in NS, demonstrating that the hydrothermal sulfidation-flotation process was able to effectively suppress the mobility and leachability of heavy metals. The BCR-three sequence leaching procedure of FT confirmed that all metals were transformed into more stable forms (residue and oxidizable forms) than were found that in NS. The potential ecological risk index indicated that the overall risks caused by heavy metals decreased significantly from 6627.59 and 7229.67 (very serious risk) in NS1 and NS2, respectively, to 80.26 and 76.27 (low risk) in FT1 and FT2, respectively. According to the risk assessment code, none of the heavy metals in FT posed significant risk to the natural environment except Zn (with low risk). In general, the risk of heavy metals in FT had been well controlled.
浮选矿渣 (FT) 是水热硫化浮选工艺的主要副产物。FT (FT1 和 FT2) 是通过处理两种不同的中性化污泥 (NS) (NS1 和 NS2) 得到的。本文定量评估了 FT 与 NS 中重金属 (Zn、Cd、Cu、Pb 和 As) 的环境风险。FT 中重金属的总浓度和浸出率 (R2) 均明显低于 NS，表明水热硫化浮选工艺能有效抑制重金属的迁移性和浸出性。FT 的 BCR 三步连续浸出程序证实，所有金属均转化为比 NS 中更稳定的形态（残渣和可氧化形态）。潜在生态风险指数表明，重金属造成的总体风险分别从 NS1 和 NS2 中的 6627.59 和 7229.67（严重风险）显著降低至 FT1 和 FT2 中的 80.26 和 76.27（低风险）。根据风险评估准则，除 Zn（低风险）外，FT 中的重金属对自然环境均不构成显著风险。总的来说，FT 中重金属的风险已得到很好的控制。
