Nickel recovery in ferronickel concentrate by green selective reduction of nickel laterite

Abstract

Nickel laterite is typically processed into ferronickel through a pyrometallurgical method involving high temperatures and the use of fossil fuels, such as coals or cokes. Unfortunately, this process releases emissions like CO2, SO2, and NOx into the environment. This study explores a sustainable approach for nickel laterite processing by investigating low-temperature selective reduction using various biomass reductants. The materials, including saprolitic nickel ore and biomass types (palm kernel shell charcoal or PSC, lamtoro wood charcoal, coconut shell charcoal, and rubber wood charcoal), undergo pelletization, selective reduction at 1150 °C, and wet magnetic separation. PSC biomass is superior to other biomass due to its 217.2 m2/g specific surface area value. Optimal conditions were achieved using 0.3 stoichiometric PSC, along with the addition of 10 wt% of sodium sulfate as an additive. This has led to a nickel mass fraction of 26.0 wt% and a recovery rate of 27.4 %.