title: Effect of ferrous sulfate and nitrohumic acid neutralization on the leaching of metals from a combined bauxite residue.
abstract: Bauxite residue neutralization is intended to open opportunities for revegetation and reuse of the residue. Ferrous sulfate (FS) and nitrohumic acid (NA) were two kinds of materials studied for pH reduction of the residue from 10.6 to 8.3 and 8.1, respectively. The effects of FS and NA on the leaching of metals from a combined bauxite residue were investigated by using sequential and multiple extraction procedures. Neutralization with FS and NA restricted the leaching of Al, V, and Pb from the residue but promoted the leaching of Fe, Cu, Mn, and Ni, consistent with the changes in the potentially mobile fractions. With the exceptions of Pb and Ni, leaching of metals increased during a 10-day extraction period. However, the maximum leaching of Al, V, Pb, Fe, Cu, Mn, and Ni from neutralized bauxite residue were 0.46 mg/L, 59.3, 12.9, 167, 95.3, 15.5, and 14.5 μg/L, respectively, which were under the corresponding limits in the National Standard (GB/T 14848-93). Although it is necessary to consider the continued leaching of metals during neutralization, both maximum and accumulation leaching concentrations of metals from a combined bauxite residue were too low to pose a potential environmental risk.
authors.affiliation: College of Water Science, Beijing Normal University, Beijing, 100875, People's Republic of China.|State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ren
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
authors.forename: Jidong
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
authors.forename: Xiaolian
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Water Science, Beijing Normal University, Beijing, 100875, People's Republic of China.|State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China.
authors.forename: Fasheng
authors.initials: F
authors.lastname: Li
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, People's Republic of China. duping@craes.org.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Du
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D005296:Ferrous Compounds; D006812:Humic Substances; D008670:Metals / Q000737:chemistry; D019216:Metals, Heavy / Q000737:chemistry
chemical_list: D005296:Ferrous Compounds; D006812:Humic Substances; D008670:Metals; D019216:Metals, Heavy; C054525:nitrohumic acid; C020748:ferrous sulfate; D000537:Aluminum Oxide
keywords: Bauxite residue; Ferrous sulfate; Leaching properties; Multiple extraction procedure; Nitrohumic acid