Influence of 25% Goethite on the Surface Chemistry of Hematite

Surface chemical techniques were used in an attempt to characterise two samples of hematite from the Iron Duke deposit in the Middleback Ranges of South Australia. The surface chemistry of the two naturally occurring samples was compared to a high purity, synthetic sample. The presence of 25% goethite affected the isoelectric point of the hematite, but the zero points of charge for all the samples examined in this study were identical. The differences between the values of isoelectric points and zero points of charge for these samples were deemed due to the presence of fine silica in the ore samples and the presence of unidentified amorphous material in the synthetic sample.