Removal of iron from quartz sands: a study by column leaching using a complete factorial design

The aim of the work was to decrease the iron content of ferrous quartz sands by fixed-bed column leaching with recycling of the leaching solutions in order to attain a product suitable for industrial use. Dissolution of iron was achieved by treating the sands in an acid medium with a reducing agent (oxalic acid) to convert FeIII into FeII. The factors assumed to affect dissolution of iron, such as temperature, oxalic acid concentration, pH and flow-rate, were studied with a 24 full factorial design in order to assess the main effects and the interactions among the factors. Removal of 46.1% iron gives a product containing 0.0163% Fe2O3 which is fit for industrial applications.