Speciation of Zn in Blast Furnace Sludge from Former Sedimentation Ponds Using Synchrotron X-ray Diffraction, Fluorescence, and Absorption Spectroscopy

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• 作者：Ruben Kretzschmar ; Tim Mansfeldt ; Petar N. Mandaliev ; Kurt Barmettler ; Matthew A. Marcus ; Andreas Voegelin
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：November 20, 2012
• 年：2012
• 卷：46
• 期：22
• 页码：12381-12390
• 全文大小：493K
• 年卷期：v.46,no.22(November 20, 2012)
• ISSN：1520-5851

文摘

Blast furnace sludge (BFS), an industrial waste generated in pig iron production, typically contains high contents of iron and various trace metals of environmental concern, including Zn, Pb, and Cd. The chemical speciation of these metals in BFS is largely unknown. Here, we used a combination of synchrotron X-ray diffraction, micro-X-ray fluorescence, and X-ray absorption spectroscopy at the Zn K-edge for solid-phase Zn speciation in 12 BFS samples collected on a former BFS sedimentation pond site. Additionally, one fresh BFS was analyzed for comparison. We identified five major types of Zn species in the BFS, which occurred in variable amounts: (1) Zn in the octahedral sheets of phyllosilicates, (2) Zn sulfide minerals (ZnS, sphalerite, or wurtzite), (3) Zn in a KZn鈥揻errocyanide phase (K₂Zn₃[Fe(CN)₆]₂路9H₂O), (4) hydrozincite (Zn₅(OH)₆(CO₃)₂), and (5) tetrahedrally coordinated adsorbed Zn. The minerals franklinite (ZnFe₂O₄) and smithsonite (ZnCO₃) were not detected, and zincite (ZnO) was detected only in traces. The contents of ZnS were positively correlated with the total S contents of the BFS. Similarly, the abundance of the KZn鈥揻errocyanide phase was closely correlated with the total CN contents, with the stoichiometry suggesting this as the main cyanide phase. This study provides the first quantitative Zn speciation in BFS deposits, which is of great relevance for environmental risk assessment, the development of new methods for recovering Zn and Fe from BFS, and potential applications of BFS as sorbent materials in wastewater treatment.