Palm kernel shell, as a hydrocarbon material, has the potential to act as a reducing agent in carbothermic ilmenite reduction to obtain iron (Fe) and rutile (TiO2). This study investigates fresh oil palm shells as a reducing agent without going through carbonization. Pre-carbothermic chemical activation of fresh palm shells and ilmenite calcination was carried out to increase the surface area and fixed carbon. Increasing the ilmenite porosity is a strategy applied to trap the tar fraction of the biomass so that it increases the contact zone and reduction occurs at a relatively lower temperature. The results showed that fresh oil palm shells had a reduced activity in forming Fe at a temperature of 1000°C and a tendency to form pseudobrookite (Fe2TiO5) at 1100°C. Meanwhile, activated fresh palm shells already have reduced activity towards forming Fe, accompanied by forming Fe2TiO5 at a temperature of 1000°C. At a temperature of 1200°C, both types of reducing agents lead to the formation of Fe. The Fe content and degree of metallization increased with each increase in temperature, both with fresh and activated palm oil shells. The degree of metallization of Fe reached 98.9% at a reduction temperature of 1200°C with the ratio of adding fresh palm kernel shells 2 times the stoichiometry for 120 minutes. The increase in the ratio accompanied by an increase in temperature significantly affects the increase in the content and degree of metallization. The increase in the ratio of reducing agents more than 1 time with a holding time of 60 minutes did not have a significant effect, as indicated by the presence of ilmenite (FeTiO3) at a temperature of 1000°C.
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This study aims to investigate thermodynamic simulation analysis and the influence of temperature and NH3 addition during the reduction of synthetic saprolitic nickel laterite. HSC Chemistry 9.1.5® thermodynamic simulation software is used to predict the phases present, equilibrium composition, and reaction spontaneity. The synthesis of feed material involves ball milling and calcination at 1200oC then reduced at temperatures of 800, 900 and 1000oC with ammonia addition variety of 35, 40, and 45%. Predominance diagram analysis showed that a reducing atmosphere with oxygen partial pressure of 10-18 atm or lower is required for phase transformation. Equilibrium composition diagram analysis revealed maximum nickel recovery at low temperature, but peak Fe recovery at ammonia addition of 35%. Furthermore, ammonia decomposition occurred at 200oC. Reaction spontaneity analysis revealed Ammonia operates directly in reduction at temperatures lower than 600°C while indirect reduction of oxides was spontaneous starting at 900oC. X-ray diffraction analysis revealed that reduction of fayalite, forsterite, and enstatite occurred at 900oC with peak nickel and iron recovery at 1000oC with optical microscope analysis predicted the presence of a metallic phase.
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