Effectiveness of selective chemical treatments on concentrating magnetic minerals of samples from a nickel-ore peridotite mantle

Journal of the Brazilian Chemical Society

Maria De Fátima F. Lelis²  Cláudia M. Gonçalves²  José D. Fabris²  Wagner N. Mussel²  William A. Pacheco Serrano¹ 

[1] ,Universidade Federal de Minas Gerais Departamento de Química Belo Horizonte MG ,Brazil

关键词: Mössbauer spectroscopy;    magnetization;    NaOH-treatment;    CBD-treatment;    iron oxide;    spinel;   

DOI  :  10.1590/S0103-50532004000600015

来源: SciELO

【 摘 要 】

Two magnetic samples, collected at 5 m and 52 m from the top of a weathering mantle developing on peridotite, from the Cerro Matoso (7° 54' 31" N 75° 33' 23" W) mining area for nickel, Department of Cordoba, Colombia, were submitted to magnetic separation with a hand magnet in the laboratory. The so concentrated samples were found to contain intimately associated magnetic and non-magnetic minerals. The magnetic phases were further concentrated by selective chemical treatments with 5 mol L-1 NaOH to remove silicates, and with a mixture citrate - bicarbonate - dithionite, to remove non-magnetic iron oxides. Powder X-ray diffractometry, RT Mössbauer spectroscopy, saturation magnetization measurements, scanning electron microscopy, energy dispersive spectroscopy and optical microscopy analyses were used to give a mineralogical description of the magnetic phases. The chemical treatments were effective on concentrating iron oxides so to improve the mineralogical analysis of this nickel ore. Mössbauer analysis revealed that NaOH selectively removed silicates and chromite from samples, whereas CBD dissolved hematite, goethite, and partially oxidized non-stoichiometric magnetite.

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