Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Recycling and Waste Management, Renova AB, Box 156, SE-401 22 Gothenburg, Sweden.
Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
J Environ Manage. 2019 Apr 15;236:68-74. doi: 10.1016/j.jenvman.2019.01.098. Epub 2019 Feb 1.
Worldwide, the number of contaminated sites is large, and remediation methods including recovery of metals have potential to be key aspects of a sustainable and circular economy. Soil washing, followed by chemical precipitation is a possible method for recovery of metals. The purpose of this study is to propose a complete recovery method, where Cu is efficiently leached from samples with contaminated bark ash and soil. Thereafter the Cu is precipitated as metal hydroxide. The results show that pH is the most important parameter that controls the leaching of Cu. The leaching process was independent of the liquid to solid ratio (L/S) for the soil, while the leaching increased with the L/S ratio for the bark ash. The shaking method used for leaching affected the results, as a low leaching efficiency was achieved with the turn-over-end technique used. The final Cu precipitation product from the bark ash contained ≥40 wt % Cu, whereas the corresponding soil precipitation product contained ≤15 wt % Cu. The conclusion is that the bark ash precipitation product is of interest for further refining within the metal industry. Due to inefficient leaching and washing, the soil and bark ash residues left after leaching are classified as hazardous waste.
在全球范围内，受污染场地的数量庞大，包括回收金属在内的修复方法可能成为可持续和循环经济的关键方面。土壤淋洗后进行化学沉淀是回收金属的一种可行方法。本研究旨在提出一种完整的回收方法，该方法可以有效地从含有污染树皮灰分和土壤的样品中浸出 Cu。然后，将 Cu 沉淀为金属氢氧化物。结果表明，pH 值是控制 Cu 浸出的最重要参数。土壤的浸出过程与液固比（L/S）无关，而树皮灰分的浸出则随 L/S 比的增加而增加。浸出过程中使用的搅拌方法会影响结果，因为采用翻转技术的浸出效率较低。来自树皮灰分的最终 Cu 沉淀产物含有≥40wt%的 Cu，而相应的土壤沉淀产物含有≤15wt%的 Cu。结论是，树皮灰分沉淀产物对于金属行业的进一步精炼具有重要意义。由于浸出和洗涤效率低下，浸出后剩余的土壤和树皮灰分残留物被归类为危险废物。
