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

Author(s): Lelis MDF, Goncalves CM, Fabris JD, Mussel WN, Serrano WAP

Source: JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY 15 (6): 884-889 NOV-DEC 2004

Document Type: Article

Language: English

Abstract: Two magnetic samples, collected at 5 m and 52 m from the top of a weathering mantle developing on peridotite, from the Cerro Matoso (7degrees54' 31" N 75degrees33' 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 Mossbauer 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. Mossbauer analysis revealed that NaOH selectively removed silicates and chromite from samples, whereas CBD dissolved hematite, goethite, and partially oxidized non-stoichiometric magnetite.

Author Keywords: Mossbauer spectroscopy; magnetization; NaOH-treatment; CBD-treatment; iron oxide; spinel

KeyWords Plus: BICARBONATE-DITHIONITE EXTRACTION; FINE-GRAINED MAGNETITE; IRON-OXIDES; MAGHEMITE; SOILS; DISSOLUTION; HEMATITE

Addresses: Lelis MDF (reprint author), Univ Fed Minas Gerais, Dept Quim, ICEx, Campus Pampulha, Belo Horizonte, MG BR-31270901 Brazil
Univ Fed Minas Gerais, Dept Quim, ICEx, Belo Horizonte, MG BR-31270901 Brazil
UPTC, Dept Fis, Tunja, Boyaca Colombia

E-mail Addresses: mfflelis@cce.ufes.br, jdfabris@ufmg.br

Publisher: SOC BRASILEIRA QUIMICA, CAIXA POSTAL 26037, 05599-970 SAO PAULO, BRAZIL

Subject Category: CHEMISTRY, MULTIDISCIPLINARY

IDS Number: 886CR