Abstract:

With the development of metal smelting and other industries, a large amount of arsenic sulfide slag that is difficult to handle is accumulated, causing serious harm to resources, the environment and human health. The stabilization/solidification technology represents a highly efficient method for fixing arsenic with promising applications. However, the high reagent consumption and cost, along with limited efficacy in treating complex and highly concentrated arsenic slag, have hindered the progress of this technology. In this study, low-cost and highly active steel slag and carbide slag were employed instead of chemical stabilizers to create an advanced oxidation/stabilization system through acid-activated steel slag, iron ions, and H₂O₂, then it was solidified with cement. The aforementioned processes were characterized by using XRD, FTIR, XPS techniques and so on. It is demonstrated that the low-valence arsenic compounds, sulfur compounds, and organic substances are effectively oxidized to form stable high-valence calcium iron salts while maintaining structural stability after solidification. Following process optimization steps involving 0.2 g steel slag, 0.5 g H₂O₂, 0.3 g carbide slag, and 1.0 g cement for stepwise synergistic stabilization/solidification treatment of 1.0 g arsenic sulfide slag, the compressive strength of the solidified body is 5.7 MPa, and the arsenic leaching concentration is only 0.66 mg·L^-1,^{which is far lower than the safe landfill standard of 1.2 mg·L-1.}

Key words: arsenic sulfide slag, steel slag, advanced oxidation, stabilization, solidification

摘要：

随着金属冶炼等工业的发展，难以处理的硫化砷渣大量堆存，对资源环境和人体健康造成严重危害。稳定化/固化技术是一种应用前景广阔的高效固砷技术，但是药剂消耗大、成本高、对复杂高浓度砷渣处理效果差等问题一直限制着该技术的发展。以低成本、高活性的钢渣和电石渣代替化学稳定剂，利用酸改性钢渣、铁离子和H₂O₂形成高级氧化/稳定化体系，随后在水泥作用下固化。通过XRD、FTIR、XPS等对上述过程进行表征，结果显示低价态砷、硫和有机物质被高效氧化成稳定的高价态钙铁盐，最终形成的固化体结构较为稳定。工艺优化后，1.0 g硫化砷渣在0.2 g钢渣、0.5 g H₂O₂、0.3 g电石渣和1.0 g水泥的分步协同稳定化/固化处理后，固化体抗压强度为5.7 MPa，砷浸出浓度仅为0.66 mg·L^-1，远低于1.2 mg·L^-1的安全填埋标准。

关键词: 硫化砷渣, 钢渣, 高级氧化, 稳定化, 固化