STUDY OF MAGNESIUM BIOLEACHING FROM SLAG OF FERRONICKEL SMELTING UTILIZING BACTERIUM Citobacter youngae STRAIN SKC-4

• Main Author: PARDOMUAN BUTARBUTAR (NIM : 12513025), PETRUS
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29930
• Institution: Institut Teknologi Bandung

Ferronickel slag is an industrial by-product from ferronickel smelting and processing. The <br /> <br /> amount of slag produced by ferronickel industry accounts for more than 50% of the total ore <br /> <br /> used. Ferronickel slag produced by PT Antam Pomalaa contains about 16.9% of magnesium <br /> <br /> which can be extracted by leaching. Slag leaching studies have been conducted using sulfuric <br /> <br /> acid and hydrochloric acid. In this study, the leaching of slag was carried out by utilizing the <br /> <br /> activity of sulfur-oxidizing bacteria, namely Citrobacter youngae strain SKC-4 which can <br /> <br /> produce sulfuric acid and extracellular polymeric substances (EPS). The slags used are the <br /> <br /> ferronickel slag from Southeast Sulawesi produced by PT Antam Pomalaa. <br /> <br /> A series of experiments began with grinding ferronickel slag samples up to 75 &#956;m and <br /> <br /> sampling to take the representative of the samples. The leaching experiments were carried out <br /> <br /> with direct vs. semi-direct bioleaching methods, variation of sulfur addition, size fraction of <br /> <br /> slag, and solid/liquid (S/L) ratio. Leaching experiments with the variation of sulfur addition <br /> <br /> were performed at 5% (w/v), 10% (w/v), and 15% (w/v) sulfur addition. Experiments with <br /> <br /> variation in the size fraction were performed on slags at 75 µm, 75-105 µm, dan 105-150 µm. <br /> <br /> Leaching experiments with variation of the solid/liquid (S/L) ratio were performed at 5% <br /> <br /> (w/v), 10% (w/v), dan 15% (w/v). Slag leaching experiments were performed in 250 mL <br /> <br /> Erlenmeyer flasks with shaking an orbital shaker at 180 rpm. <br /> <br /> Direct bioleaching method led to Mg extraction level of 45.86%, while the semi-direct <br /> <br /> bioleaching method brought about Mg extraction level of 26.41%. The best extraction level <br /> <br /> of Mg on the sulfur addition variation was obtained in leaching at 15 g/L sulfur addition. The <br /> <br /> highest extraction level of Mg on the S/L ratio variation was 33.04% at 5% (w/v) S/L ratio <br /> <br /> without sulfur adition. The leaching with the variation of the slag particle size yielded the <br /> <br /> highest Mg extraction level of 55.62% at the FeNi slag size of 75-105 µm. <br />