Efficient recovery of iron and chromium from laterite residue by non-molten metallization reduction

Abstract

Laterite residues are good iron-bearing resources to decrease the external dependence on iron ores in China. At present, laterite residues are deposited in the land or transported to deep sea, which causes serious resource waste and environmental pollution. In order to utilize laterite residues efficiently and ease shortages of iron ores, non-molten metallization reduction was proposed to treat laterite residue. The thermodynamic and equilibrium analysis were studied to analyze the transformation mechanism and predict the optimal condition of the technology. The optimal conditions for non-molten metallization reduction are as follows: anthracite dosage is 30%, roasting time is 60 min and roasting temperature is 1200 °C. In the experimental results, the content of iron and chromium in the final concentrate is 88.64% and 1.45%, respectively. The reduction, migration and aggregation of calcines were researched to study the phase transformations and microstructural evolutions of the roasting process.