CHARACTERIZATION AND BENEFICIATION STUDIES OF CHARGE CHROME SLAG

Background: The slag generated at Indian charge chrome plants is assoc iated with various amounts of charge chrome values. It has been establ ished that charge chromes present in the slag are magnetic in nature. Hence, investigations have been carried out to recover these values lo st in the slag in order to enhance and improve the productivity of the charge chrome plant. Methods: A low-to medium-intensity magnetic sepa rator has been adopted in the process to recover the charge chrome val ues. The effects of different variables such as particle size, moistur e content and magnetic intensity have been studied. Large-scale magnet ic separation studies at a feed rate of 100-120 kg/h have also been ca rried out to confirm the bench-scale studies. Detailed mineralogical s tudies have been carried out by using different techniques. Results an d conclusion: Mineralogical studies reveal that the slag essentially c onsists of spinel, olivine, chromite, metallic phase and glassy matrix . The metallic phases are very fine grained and present within the spi nel grains. The textural pattern of the metallic phases indicated that complete recovery of chrome values from this slag is extremely diffic ult. The beneficiation study involving magnetic separation techniques indicated the possibility of recovering a product containing 57% Cr2O3 with a yield of 1.5% using 2-stage magnetic separation route. The pro duct obtained by this magnetic separation route can be reused in the c harge chrome furnace or blended with high-grade materials to improve t he economics of the plant.