Formation Mechanism of Ferronickel Alloy Due to the Reaction Between Iron and Nickeliferous Pyrrhotite at 850–900 °C

Abstract

A thermal upgradingThermal upgradingprocess by which nickelNickelvalue can be concentrated in a ferronickel alloyFerronickel alloyis a possible alternative to treat Sudbury pyrrhotitePyrrhotite(Po) tailings with nickelNickelcontent of 0.5--1.5 wt%. The basis of this process is precipitationPrecipitationof Ni from Po at high temperatureTemperatureonce Fe/S ratio in the ironIron-deficient Po is shifted towards stoichiometric or near stoichiometric FeS (troilite) either by the addition of ironIronand/or the removalRemovalof sulfurSulfur. For the ironIronaddition route, the reaction between elemental ironIronand nickeliferous pyrrhotiteNickeliferous pyrrhotiteto produce ferronickel alloyFerronickel alloyand Ni-depleted ironIronsulfideSulfidephase plays a critical rule. In this paper, the formation mechanism of ferronickel alloyFerronickel alloywas investigated using the diffusion couple technique to better understand the nickel diffusionNickel diffusionbehavior in the ironIronand sulfideSulfidephases.