Copper slags produced in vast quantities in smelting operations could be considered as secondary material sources instead of stockpiling them in landfills. This study investigates the recovery of valuable metals from copper slag and the valorisation of the leach residue as construction material in line with the principles of a circular economy. By taking into account that the environmental characterization of the as-received copper slag did not allow its disposal in landfills without prior treatment, chemical and biological leaching were tested for the recovery of metals. Pre-treatment with acids, namely HNO₃ and H₂SO₄, resulted in the extraction of several target metals and the production of an almost inert waste. Despite the clearly better oxidative conditions prevailing in the bioleaching reactors, chemical leaching resulted in the higher dissolution of Cu (71% vs. 51%), Co (70% vs. 36%), and Zn (65% vs. 44%). The acid consumption was much lower during the bioleaching experiments compared to the chemical leaching. The bioleach residue was suitable for its use as supplementary cementitious material, showing a better performance than the reference sample without causing any detrimental effects to the calcium aluminate cement (CAC) quality. The complete valorisation of copper slags is expected to improve the economics of the process, by avoiding landfill costs and producing saleable products with high added value.

中文翻译：

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铜渣化学和生物浸出对金属回收的有效性以及水泥生产中作为原料的浸出残渣的均值化

可以将在冶炼操作中大量生产的铜渣视为次要材料来源，而不是将其存储在垃圾填埋场中。本研究根据循环经济原理，研究了从铜渣中回收有价值的金属以及作为建筑材料的浸出残渣的增值方法。考虑到原样的铜渣的环境特征不允许未经事先处理就将其丢弃在垃圾填埋场，因此对化学和生物浸出进行了金属回收的测试。用酸（即HNO ₃和H ₂ SO _4）进行预处理导致提取了几种目标金属并产生了几乎惰性的废物。尽管生物浸提反应器中普遍存在明显更好的氧化条件，但化学浸提导致铜（71％比51％），钴（70％比36％）和锌（65％比44％）的溶解度更高。 。与化学浸出相比，生物浸出实验期间的酸消耗量要低得多。该生物沥滤残渣适合用作辅助水泥材料，显示出比参考样品更好的性能，而不会对铝酸钙水泥（CAC）的质量造成任何不利影响。通过避免垃圾填埋成本和生产具有高附加值的可销售产品，铜渣的全部增值有望改善该工艺的经济性。