Waste foundry sand (WFS) from the brass and bronze casting and molding process include various potentially toxic elements (PTEs), such as copper, zinc, tin, and lead. Hence, the utilization of WFS in construction and geotechnical applications evokes environmental concerns due to the rain-induced leaching of PTEs into the groundwater system. The present study investigated the extractive decontamination of WFS using mineral acids, e.g., HCl, H2SO4, or HNO3. Favorable extraction efficiency was achieved with HCl as compared to the other mineral acids, which was further enhanced at high temperatures and increased acid concentrations. The thermodynamic analysis indicated that ≥ 4 mol L-1 of HCl and ≤ 100 °C temperature ensured maximum extraction of PTEs due to the endothermic interactions between the HCl and PTEs. The HCl-treated WFS needed to be rinsed with water to restrict the after treatment elution of PTEs. The hazardous environmental impact of acid-treated WFS was evaluated following the standard leaching test and comparison with legislative recommendations for PTEs, which showed the water-assisted leaching rate of all the PTEs are within the regulatory limits.

中文翻译：

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酸诱导的黄铜铸造厂产生的废绿砂去污的热力学研究。

黄铜和青铜铸造和成型过程中产生的废铸造砂（WFS）包括各种潜在有毒元素（PTE），例如铜，锌，锡和铅。因此，由于雨水引起的PTE渗入地下水系统，在建筑和岩土工程中使用WFS引起了环境问题。本研究调查了使用无机酸（例如HCl，H2SO4或HNO3）对WFS的萃取净化作用。与其他无机酸相比，使用HCl可获得良好的萃取效率，在高温和更高的酸浓度下进一步提高了萃取效率。热力学分析表明，由于HCl和PTE之间的吸热相互作用，≥4 mol L-1的HCl和≤100°C的温度可确保最大程度地提取PTE。HCl处理的WFS需要用水冲洗以限制PTE的后处理洗脱。通过标准浸出试验并与PTE的立法建议进行比较，评估了酸处理的WFS的有害环境影响，该结果表明所有PTE的水辅助浸出率均在法规范围内。