TEMPERATURE VARIATION ON SULPHUR REMOVAL FROM LATERITE NICKEL LEACHING RESIDUE AND IRON EXTRACTION

• Main Author: Munawaroh, Mona
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/67947
• Institution: Institut Teknologi Bandung

Nickel production for electric vehicle batteries continues to increase by 30% every year. This increase is due to the large demand for electric vehicles as a solution to the issue of global warming due to fossil fuels. As the country with the most nickel production in 2021, Indonesia will operate 6 nickel refining plants with HPAL (high pressure acid leaching) technology. On the other hand, Indonesia is developing 1 nickel refining technology based on combination of hydrometallurgy – pyrometallurgy. New problems arise with the large number of hydrometallurgical-based nickel refining plants where the residual processing of will continue to accumulate and potentially pollute the environment. Acid leach residue has a high Fe content reaching 48% in the form of hematite and an S content of around 1.3%. On the other hand, demand growth in the iron and steel industry is greater than the availability of its raw materials, thus secondary sources for raw materials for the iron and steel industri is needed. The sulfur maximum value for iron and steel raw materials is 0.1% so that the sulfur content in leach residue must be set aside so that it’s still within permissible specifications for raw materials for the iron and steel industri. This research focuses on the removal of sulfur content in acid leach residue by roasting method at temperature 500 °C until 1100 °C. The roasted samples were characterized by X-ray Diffractometer (XRD) and X-Ray Fluorescence (XRF) to see the trend of removal sulfur content and changes in the composition of the roasted samples. The experiment was continued with reductive roasting on various temperature profiles for unroasted leach residue and roasted leach residue samples. The results of the reductive roasting experiment were analyzed using Scanning Electron Microscope–Energy Dispersive Spectroscopy (SEM-EDS) to see the formed phases. The composition of the reductive roasting phase of the roasted sample were then analyzed and compared with the reduced roasting phase of the unroasted samples. Sulfur content decreases with increasing roasting temperature, sulfur content reaches 0% at a roasting temperature of 1100 °C. The optimum reductive roasting temperature for unroasted leach residue sample was 1400 °C with 95.9% Fe content and 0.1% S in metal. The optimum reductive roasting temperature for 1100 °C roasted samples was 1200 °C with 94.6% Fe content and 0% S. Roasting treatment could decrease the optimum temperature for the reductive roasting process.