EXTRACTION OF IRON FROM RED MUD USING PALM KERNEL SHELL CHARCOAL AND COAL REDUCTANT AT TEMPERATURES 1350 °C – 1450 °C

• Main Author: Dharma Hendrawan, Rizqi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64782
• Institution: Institut Teknologi Bandung

The Bayer process is used to convert bauxite ore into alumina, which produces waste in the form of bauxite residue. If the residue is not managed properly, it can harm the surrounding environment. Bauxite residue, which has a high iron content (> 30%), has a potential to be used as raw material for iron-steel making by reducing the iron oxide contained therein. Indonesia has the most significant palm oil production globally, which produces a by-product in the form of palm kernel shell that can be processed as palm kernel shell charcoal (PKSC). Therefore, it is necessary to treat the waste of bauxite residue and oil palm shells to reduce environmental problem and increase the use value of the two components. This research utilizes palm shell charcoal as a reducing agent in reducing iron oxide from bauxite residue to produce iron metal. A series of experiments has been performed which started with preparation of red mud, PKSC, and coal. The initial characterization of red mud was carried out using X-Ray Fluorescence (XRF). At the same time, PKSC was tested for proximate, and coal was tested for proximate, the ultimate test, and ash content. The red mud sample was then shaped into 2 grams of briquettes and was covered by a 5 grams of reductant bed with varying proportions of PKSC and coal. Red mud briquettes that have been covered by reducing agents were reduced at a temperature of 1000-1450 °C for 120 minutes by the isothermal-temperature gradient method using a muffle furnace. The reduction products in the form of ferrous metal and slag were weighed, and the dimensions were measured. An optical microscope, SEM-EDS, and ImageJ software were used to analyze the reduction products. The results showed that the optimum yield of ferrous metal was 81.99%, with an iron content of 94.63%, which occurred at the final isothermal temperature of 1450 °C with 100% PKSC in the reducing agent. At the final isothermal temperature of 1450 °C, the metallic products were in the form of iron granule with an average yield of above 70%, while at the final isothermal temperature of 1350 °C and 1400 °C, the metallic products were in the form of a fines with iron metal recovery below 60%. Increasing the proportion of PKSC as a reducing agent increased the recovery of ferrous metal even though the iron content in it was decreased. At the final isothermal temperature of 1450 °C with 0% PKSC in the reducing agent, the levels of Fe, S, and P were obtained at 95.51%; 0.25%; and 0.35%, while in 100% PKSC, the Fe, S, and P levels were 94.63%; 0.34%; and 0.22%.