Reduction Roasting of Nickeli-ferrous Ore: Experimental Study and Simulation of the Process in Multiple Hearth Furnace

摘要

Extraction of nickel from the lateritic nickeliferrous ore involves energy intensive reduction process followed by leaching and electrowinning techniques. The overall economy of the process depends on efficient and selective reduction of nickel for fuel economy and leaching efficiency. A comprehensive study of the process is done, starting from single pellet reduction with hydrogen, reduction under packed bed condition, to the final simulation of the process in Multiple Hearth Furnace. Single pellet and packed bed reduction study is done to experimentally determine the kinetic parameters for both iron and nickel oxides. The macrostructure of the reducing pellet is then computationally simulated by using the two layer model to get a better insight of the reaction mechanism and visualization of the process. Based on the experimental results, a complex oxide reduction mechanism is proposed which gave better match for nickel reduction. Multiple Hearth Furnace (MHF) is commonly used for this type of reduction roasting process due to its efficiency in treating slowly reacting systems requiring good control of the process parameters. This type of modelling study will help in optimizing the process parameters, scaleup of the furnace and finally for the process control during its operation.