APPROACHES TO THE PROCESSING OF JAMAICAN BAUXITE WITH HIGH GOETHITE CONTENT

摘要

Jamaican bauxite deposits can broadly be classified into two types, catchment and hillside, depending on their form and topographic setting. The major iron phase in catchment deposits is hematite, while in hillside deposits this is aluminous goethite. The difference in topographical setting between the catchment and hillside deposits has affected their degree of weathering, hence the degree by which the bauxite deposits have undergone secondary surficial alteration under the influence of ground water and humic acids. The dissolution and re-precipitation mechanism of surficial alteration has caused the original hematite and goethite in hillside bauxites to be transformed into aluminous goethite. Studies as well as plant experience have shown that aluminous goethite rich bauxites present several processing challenges especially under low temperature digestion conditions. This paper examines the major processing challenges and available approaches for their resolution. This is particularly important since the aluminous goethite rich bauxites become increasingly abundant in plant feeds as stocks of hematite rich deposits are getting depleted.