comparison of copper scavenging capacity between two different red mud types铜的比较两种不同的红泥类型之间的清除能力.pdf

Materials 2012, 5, 1708-1721; doi:10.3390/ma5091708 OPEN ACCESS materials ISSN 1996-1944 /journal/materials Article Comparison of Copper Scavenging Capacity between Two Different Red Mud Types Yingqun Ma 1,3, Chunhua Si 1 and Chuxia Lin 2,* 1 Centre for Ecological and Environmental Technologies, South China Agricultural University, Guangzhou 510642, China; E-Mails: myoungking@163.com (Y.M.); siqisxnd@ (C.S.) 2 Australian Centre for Sustainable Catchments, University of Southern Queensland, Toowoomba QLD 4350, Australia 3 Chinese Research Academy of Environmental Sciences, Beijing 100012, China * Author to whom correspondence should be addressed; E-Mail: Chuxia.Lin@.au; Tel.: +61-7-463-124-29; Fax: +61-7-463-155-81. Received: 27 July 2012; in revised form: 28 August 2012 / Accepted: 3 September 2012 / Published: 24 September 2012 Abstract: A batch experiment was conducted to compare the Cu scavenging capacity between two different red mud types: the first one was a highly basic red mud derived from a combined sintering and Bayer process, and the second one was a seawater-neutralized red mud derived from the Bayer process. The first red mud contained substantial amounts of CaCO3, which, in combination with the high OH− activity, favored the immobilization of water-borne Cu through massive formation of atacamite. In comparison, the seawater-neutralized red mud had a lower pH and was dominated by boehmite, which was likely to play a significant role in Cu adsorption. Overall, it appears that Cu was more tightly retai