Di Palma L, Ferrantelli P
Dipartimento di Ingegneria Chimica, dei Materiali, delle Materie Prime, Metallurgia, Università di Roma La Sapienza, Italy.
J Hazard Mater. 2005 Jun 30;122(1-2):85-90. doi: 10.1016/j.jhazmat.2005.03.010.
A series of 24h batch tests of copper extraction from a sandy soil were performed by washing the soil with aqueous solution of ethylenediaminetetraacetic acid, EDTA. EDTA versus copper molar ratio were in the range between 1 (equimolar tests) and 13.3. The tests were performed at three selected liquid/solid ratio, 5, 12.5 and 25. Results show that decreasing the pH of the washing solution an higher copper extraction yield was achieved: an almost complete copper extraction was achieved after 23 h of mixing at a L/S = 5, and after 5 h of mixing at an L/S = 12.5. The mechanism of copper extraction was found to involve two sequential processes: the former dissolution of metal salts, that lead to an initial high concentration of both copper and some competitive cations (essentially Ca(2+)), and the following EDTA exchange reaction between calcium and copper complexes, which corresponded an increase of pH in the washing solution. A negligible extraction of Fe(3+) was also observed at the investigated operative conditions.
通过用乙二胺四乙酸（EDTA）水溶液洗涤砂土，进行了一系列为期24小时的从砂土中提取铜的批次试验。EDTA与铜的摩尔比在1（等摩尔试验）至13.3之间。试验在三种选定的液固比5、12.5和25下进行。结果表明，降低洗涤溶液的pH值可实现更高的铜提取率：在液固比为5时混合23小时后，以及在液固比为12.5时混合5小时后，几乎可实现完全铜提取。发现铜提取机制涉及两个连续过程：前者是金属盐的溶解，导致铜和一些竞争性阳离子（主要是Ca(2+)）的初始高浓度，以及随后钙和铜络合物之间的EDTA交换反应，这对应于洗涤溶液中pH值的增加。在所研究的操作条件下，还观察到Fe(3+)的提取量可忽略不计。
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