Resumo

MAPHUTHA, M.P.; RAMAILI, M.; SITEFANE, M.B.  e  GOSO, X.C.. The effect of magnesia and alumina crucible wear on the smelting characteristics of titaniferous magnetite. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.7, pp.649-655. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2017/v117n7a6.

Test work was conducted to investigate the effect of magnesia and alumina crucible wear in laboratory-scale smelting tests on titaniferous magnetite (titanomagnetite) in terms of iron and vanadium recoveries as well as slag properties. The study was motivated by the desire to develop capacity to provide technical support to the minerals industry in the establishment and continuous optimization of industrial processes for the efficient extraction of Fe, V, and Ti from titanomagnetite. The tests were conducted using the smelting recipe used by Evraz Highveld Steel and Vanadium Corporation (EHSV); that is, the same titanomagnetite feed material and a dolomite flux to achieve a typical CaO:MgO ratio of 16:14 in the slag. The results of the test work demonstrated that chemical attack by the titania-bearing slag on the magnesia and alumina crucibles is inevitable. The crucible wear was more pronounced with magnesia crucibles than with alumina crucibles. The Fe and V recoveries to alloy in alumina crucibles were higher than those obtained in magnesia crucibles. However, the recoveries in both cases were comparable to the EHSV data. The phase chemical compositions of the best slags, in terms of Fe and V recoveries to alloy, from each crucible type were significantly different. In a magnesia crucible, the slag was composed mainly of perovskite (CaTiO₃), forsterite (Mg₂SiO₄), and monticellite (CaMgSiO₄). However, the phase chemical composition of the slag produced using an alumina crucible was similar to that of the typical EHSV titanomagnetite, comprising pseudobrookite solid solution (MgTi₂O₅-Al₂TiO₅), spinel [(Mg)(Al,Ti)₂O₄], and perovskite. The results have shown that both magnesia and alumina crucibles can be used to conduct laboratory-scale test work using the reviewed slag chemical composition. In addition, the more readily available alumina crucibles are better than magnesia crucibles in terms of Fe and V recoveries as well as the slag phase chemistry.

Palavras-chave : smelting; titaniferous magnetite; crucible wear; slag characteristics.

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