Efficient utilization of nickel rich Chromite Ore Processing Tailings by carbothermic smelting

Chromite ore processing tailing, a solid waste generated during the processing of chromite ore, is difficult to recover due to its ultra-fine size. The tailings generated from the process contains valuable chromite and iron-bearing minerals, loss of which is a matter of concern for the ferrochrome industry worldwide. Tailings generated from the processing plant is mainly dumped, causing space and environmental concerns. Researchers worldwide have carried out a rigorous study on the recovery of chromite from tailings, considering the low quantity of Cr_(T) and Fe_(T) in the ore. These processes are partially successful due to the further assimilation of waste in the form of tailings. In the present study, the tailings generated from a chromite ore beneficiary plant in India were investigated through a pyro-metallurgical route. The initial characterization confirmed the presence of nickel (0.5–0.9% Ni) in the ore, which led to the interest in smelting the ore to obtain nickel in the metal. The smelting behaviour of the tailings is studied under the submerged arc furnace and blast furnace condition, under varying basicity. A cost economic analysis of the process is evaluated to understand the feasibility of the real-time operation. The present investigation has revealed that the smelting of such tailings could result in a metal product with 79.23% Fe_(T), 12.94% chromium and 1.11% nickel with a recovery >94%. The produced slag is enriched with a higher quantity of amorphous phase with a glassy phase >89%. The suggested process is a cleaner and sustainable approach towards valorisation of such mining waste and realization through the concept of the circular economy. It is concluded that the carbothermal smelting of tailings generated during enrichment can be valorized through submerged arc furnace route at optimum basicity of 1 by promoting the concept of zero discharge.