Tang Yuanyuan, Lu Xiuqing, Shih Kaimin
Department of Materials Science and Engineering, South University of Science and Technology of China, 1088 Xueyuan Blvd, Nan Shan, Shenzhen, Guangdong, China; Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
Chemosphere. 2014 Dec;117:575-81. doi: 10.1016/j.chemosphere.2014.08.065. Epub 2014 Oct 7.
The feasibility of recycling copper-bearing industrial sludge as a part of ceramic raw materials was evaluated through thermal interaction of sludge with aluminum-rich precursors. To observe copper incorporation mechanism, mixtures of copper-bearing sludge with alumina polymorphs (γ-Al2O3 and α-Al2O3) were fired between 750 and 1250°C. Different copper-hosting phases were identified by X-ray diffraction, and CuAl2O4 was found to be the predominant phase throughout the reactions. The experimental results indicate different CuAl2O4 initiating temperatures for two alumina materials, and the optimal temperature for CuAl2O4 formation is around 1100°C. To monitor the stabilization effect, prolonged leaching tests were carried out to leach sintered products for up to 20d. The results clearly demonstrate a substantial decrease in copper leachability for products with higher CuAl2O4 content formed from both alumina precursors despite their different sintering behavior. Meanwhile, the leachability of aluminum was much lower than that of copper, and it decreased by more than fourfold through the formation of CuAl2O4 spinel in γ-Al2O3 system. This study clearly indicates spinel formation as the most crucial metal stabilization mechanism when sintering multiphase copper-bearing industrial sludge with aluminum-rich ceramic raw materials, and suggests a promising and reliable technique for reusing industrial sludge.
通过含铜污泥与富铝前驱体的热相互作用，评估了将含铜工业污泥作为陶瓷原料一部分进行回收利用的可行性。为了观察铜的掺入机制，将含铜污泥与氧化铝多晶型物（γ -Al2O3和α -Al2O3）的混合物在750至1250°C之间进行焙烧。通过X射线衍射确定了不同的含铜相，发现CuAl2O4是整个反应过程中的主要相。实验结果表明两种氧化铝材料形成CuAl2O4的起始温度不同，且CuAl2O4形成的最佳温度约为1100°C。为了监测稳定化效果，进行了长达20天的延长浸出试验以浸出烧结产物。结果清楚地表明，由两种氧化铝前驱体制备的、具有较高CuAl2O4含量的产物，其铜的浸出率大幅下降，尽管它们的烧结行为不同。同时，铝的浸出率远低于铜，并且在γ -Al2O3体系中通过形成CuAl2O4尖晶石，铝的浸出率下降了四倍多。这项研究清楚地表明，当用富铝陶瓷原料烧结多相含铜工业污泥时，尖晶石的形成是最关键的金属稳定化机制，并提出了一种有前景且可靠的工业污泥再利用技术。
