Fundamental aspects of sintering of chromites concentrates

Abstract

Brazilian chromite ores need to be crushed to a size below 1 mm to allow concentrations that decrease the content of gangues. The concentrate particle size distributions therefore are not favourable for sintering. The chromite concentrates are mainly composed of chromite grains and gangues of magnesium silicates. Because of its refractoriness and low rate of dissolution in gangue, the chromite minerals participation in liquid phase formation during the sintering process is low, and the gangue also shows a solidus temperature of ∼1400°C. This paper attempts to analyse these fundamental aspects by characterising chromites, with estimates of the liquidus temperatures of chromite grains and gangue. To improve permeability, fines of lump ore (not concentrate) were added to the charging sintering mixture, and some slag forming agent was also added to facilitate the liquid phase formation. With these changes, the results of the industrial runs demonstrated improved sintering yields.