Carbothermic reduction roasting for processing of ferruginous chromite ore using conventional and microwave heating

The present study investigates the recovery of chromite from a low-grade ferruginous ore through the carbothermic magnetization route using conventional and microwave heating sources. The carbothermic magnetization of ore is studied in both a horizontal tube furnace and a microwave oven by varying different process variables. The main objective of the study is to enhance the magnetic susceptibility of iron bearing gangue minerals to enable the separation in a magnetic field. Alteration of crystalline structure and magnetic property of these minerals enables separation of low-grade ore by using magnetic separation. It is found that low-grade ferruginous chromite ore can be upgraded by reduction roasting, and 61.2% Cr2O3 was recovered with a chromium-to-iron ratio of 1.93 from a feed chromium-to-iron ratio of 1.01. The optimum result is achieved at a roasting temperature of 800 degrees C, with a roasting time of 60 min and a reductant dosage of 7.5%. Similarly, under microwave radiation, the chromium-to-iron ratio was upgraded to 1.81 with a recovery of 22%Cr2O3. The optimum result achieved under microwave radiation is at a microwave power of 900 W and exposure time of 7.5 min, with a reductant dosage of 10%. The findings of these two processing routes are discussed through characterization tools. (c) 2021 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

Automated summary

The study investigates the recovery of chromite from low-grade ferruginous ore using carbothermic magnetization route with conventional and microwave heating sources. Alteration of crystalline structure and magnetic property of gangue minerals enables the separation of low-grade ore through magnetic separation. The research achieved successful upgrading of the ore through optimal roasting conditions and under microwave radiation, with discussion of findings through characterization tools.