SEM, EDS and vibrational spectroscopic study of the sulphate mineral rostite AlSO₄(OH,F)·5(H₂O)

Ray L Frost; Ricardo Scholz; Rosa Malena Fernandes Lima; Andrés López

doi:10.1016/j.saa.2015.06.123

SEM, EDS and vibrational spectroscopic study of the sulphate mineral rostite AlSO₄(OH,F)·5(H₂O)

Spectrochim Acta A Mol Biomol Spectrosc. 2015 Dec 5:151:616-20. doi: 10.1016/j.saa.2015.06.123. Epub 2015 Jul 2.

Authors

Ray L Frost¹, Ricardo Scholz², Rosa Malena Fernandes Lima³, Andrés López⁴

Affiliations

¹ School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia. Electronic address: r.frost@qut.edu.au.
² Geology Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35,400-00, Brazil.
³ Mining Engineering Department, School of Mines, Federal University of Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35,400-00, Brazil.
⁴ School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.

PMID: 26163784
DOI: 10.1016/j.saa.2015.06.123

Abstract

We have studied the mineral rostite, a sulphate mineral of aluminium of formula AlSO4(OH,F)·5(H2O). The mineral is formed in mine dumps and wastes. Chemical analysis proves the presence of Al, F and S. A single intense band is observed at 991 cm(-1) and is assigned to the Raman active SO4(2-) ν1 symmetric stretching vibration. Low intensity Raman bands observed at 1070, 1083, 1131 and 1145 cm(-1) are assigned to the SO4(2-) ν3 antisymmetric stretching vibration. Multiple Raman and infrared bands in the OH stretching region are assigned to the stretching vibrations of water. The higher wavenumber band at ∼3400 cm(-1) may be due to the hydroxyl stretching vibrational mode. These multiple bands prove that water is involved in different molecular environments with different hydrogen bond strengths. Vibrational spectroscopy enhances our knowledge of the molecular structure of rostite.

Keywords: EDX; Hydroxyl; Infrared; Raman spectroscopy; Rostite; SEM; Sulphate.

Publication types

Research Support, Non-U.S. Gov't