Vibrational spectroscopy study of hydrothermally produced scorodite (FeAsO4•2H2O), ferric arsenate sub-hydrate (FAsH; FeAsO4•0.75H2O) and basic ferric arsenate sulfate (BFAS; Fe[(AsO4)1-x(SO4)x(OH)x]•wH2O)
Vibrational spectroscopy study of hydrothermally produced scorodite (FeAsO4•2H2O), ferric arsenate sub-hydrate (FAsH; FeAsO4•0.75H2O) and basic ferric arsenate sulfate (BFAS; Fe[(AsO4)1-x(SO4)x(OH)x]•wH2O)
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DOI：
10.1002/jrs.2419
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发表时间：
2010-02-01
影响因子：
2.5
通讯作者：
Demopoulos, G. P.
中科院分区：
文献类型：
--
作者：
Gomez, M. A.;Assaaoudi, H.;Demopoulos, G. P.
用拉曼光谱和红外光谱研究了由Fe(III)-AsO(4)(3-)-SO42-溶液水热沉淀法(175-225℃)合成的三种晶态砷酸铁相：(1)蝎子石；FeAsO4中心点2H(2)O；(2)亚水合砷酸铁[FASH；FeAsO4中心点0.75H(2)O]和(3)碱式砷酸铁硫酸盐(BFAS；Fe[(AsO4)(1-x)(SO4)(X)(OH)(X)]WH(2)O)。这些高温Fe(III)-AsO43--SO42-相的光谱性质尚未得到广泛研究，尽管它们对贵金属(金和铜)砷硫化物矿石的湿法工业加工具有重要意义。研究发现，蝎子石、FASH和BFAS都有明显的砷酸根、硫酸盐和羟基振动。在蝎子石和FASH中，砷酸盐内模式的分布是不同的，其中因子效应在晶体体系中更为明显。对于结晶学上未知的BFAS相，振动光谱被用来监测在这一相中发生的硫酸砷盐固溶行为，在该相中，砷酸盐和硫酸盐在晶体结构中的分子对称性从理想的T-d降低到扭曲的T-d或C-2/C-2v对称。利用新收集的纯相振动数据，利用衰减全反射红外光谱(ATR-IR)研究了某金矿加压氧化产生的工业废渣中砷的性质，发现砷以BFAS的形式存在。版权所有(C)2009 John Wiley&Sons，Ltd.
Three crystalline ferric arsenate phases: (1) scorodite; FeAsO4 center dot 2H(2)O,(2) ferric arsenate sub-hydrate [FAsH; FeAsO4 center dot 0.75H(2)O) and (3) basic ferric arsenate sulfate (BFAS; Fe[(AsO4)(1-x)(SO4)(x)(OH)(x)]center dot wH(2)O) synthesized by hydrothermal precipitation (175-225 degrees C) from Fe(III)-ASO(4)(3-)-SO42- solutions have been investigated via Raman and infrared spectroscopies. The spectroscopic nature of these high-temperature Fe(III)- AsO43- -SO42- phases has not been extensively studied despite their importance to the hydrometallurgical industrial processing of precious metal (Au and Cu) arsenic sulfidic ores. It was found that scorodite, FAsH and BFAS all gave rise to very distinct arsenate, sulfate and hydroxyl vibrations. In scorodite and FAsH, the distribution of the internal arsenate modes was found to be distinct, with the factor effect being more predominant in the crystal system. For the crystallographically unknown BFAS phase, vibrational spectroscopy was used to monitor the arsenate sulfate solid solution behavior that occurs in this phase where the molecular symmetry of arsenate and sulfate in the crystal structure is reduced from an ideal T-d to a distorted T-d or C-2/C-2v symmetry. With the new collected vibrational data of the pure phases, the use of attenuated total reflectance infrared (ATR-IR) spectroscopy was finally extended to investigate the nature of the arsenate in an industrial residue generated by pressure oxidation of a gold ore, where it was found that the arsenate was present in the form of BFAS. Copyright (C) 2009 John Wiley & Sons, Ltd.