Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong Special Administrative Region.
Department of Applied Physics and Applied Mathematics, Henry Krumb School of Mines, Columbia University, New York, NY 10027, USA.
Waste Manag. 2014 Jun;34(6):1085-91. doi: 10.1016/j.wasman.2013.07.001. Epub 2013 Jul 30.
A promising strategy for effectively incorporating metal-containing waste materials into a variety of ceramic products was devised in this study. Elemental analysis confirmed that copper was the predominant metal component in the collected electroplating sludge, and aluminum was the predominant constituent of waterworks sludge collected in Hong Kong. The use of waterworks sludge as an aluminum-rich precursor material to facilitate copper stabilization under thermal conditions provides a promising waste-to-resource strategy. When sintering the mixture of copper sludge and the 900 °C calcined waterworks sludge, the CuAl2O4 spinel phase was first detected at 650 °C and became the predominant product phase at temperatures higher than 850 °C. Quantification of the XRD pattern using the Rietveld refinement method revealed that the weight of the CuAl2O4 spinel phase reached over 50% at 850 °C. The strong signals of the CuAl2O4 phase continued until the temperature reached 1150 °C, and further sintering initiated the generation of the other copper-hosting phases (CuAlO2, Cu2O, and CuO). The copper stabilization effect was evaluated by the copper leachability of the CuAl2O4 and CuO via the prolonged leaching experiments at a pH value of 4.9. The leaching results showed that the CuAl2O4 phase was superior to the CuAlO2 and CuO phases for immobilizing hazardous copper over longer leaching periods. The findings clearly indicate that spinel formation is the most crucial metal stabilization mechanism when sintering multiphase copper sludge with aluminum-rich waterworks sludge, and suggest a promising and reliable technique for reusing both types of sludge waste for ceramic materials.
本研究提出了一种将含金属废料有效纳入各种陶瓷产品的有前景的策略。元素分析证实，收集的电镀污泥中主要金属成分为铜，而香港收集的水厂污泥中主要成分为铝。利用水厂污泥作为富含铝的前体材料，在热条件下促进铜的稳定化，提供了一种有前景的废物转化为资源的策略。当烧结铜污泥和 900°C 煅烧水厂污泥的混合物时，首先在 650°C 检测到 CuAl2O4尖晶石相，并且在高于 850°C 的温度下成为主要的产物相。使用 Rietveld 精修方法对 XRD 图谱进行定量分析表明，在 850°C 时 CuAl2O4尖晶石相的重量超过 50%。CuAl2O4相的强信号一直持续到温度达到 1150°C，进一步的烧结引发了其他含铜相（CuAlO2、Cu2O 和 CuO）的生成。通过在 pH 值为 4.9 的长时间浸出实验评估了 CuAl2O4和 CuO 的铜浸出率来评估铜的稳定化效果。浸出结果表明，在较长的浸出时间内，CuAl2O4相在固定危险铜方面优于 CuAlO2和 CuO 相。研究结果清楚地表明，在多相铜污泥与富含铝的水厂污泥烧结时，尖晶石形成是最重要的金属稳定化机制，并为将这两种污泥废物再用于陶瓷材料提供了一种有前途且可靠的技术。
