STUDY OF BIOLEACHING BEHAVIOUR OF COMPLEX COPPER SULFIDE ORE FROM WETAR ISLAND USING Alicyclobacillus ferrooxydans AND Citrobacter sp. IN FE BROTH MEDIUM WITH ADDITION OF NaCl, PYRITE, AND SULFUR

• Main Author: SUGANDA RULIE (NIM : 12514040), VICTOR
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31476
• Institution: Institut Teknologi Bandung

Nowadays, copper resources are not only derived from primary sulfide ores, which are well known for their high grade and easy recovery techniques, but also include complex minerals, which require further study. One of the technically and economically possible and interesting methods is bioleaching, which utilizes microorganisms to produce leaching agents. In an attempt to increase leaching efficiency, the present study dealt with the utilization of two mixotrophic bacteria namely Alicyclobacillus ferrooxydans and Citrobacter sp. strain SKC-4 for the bioleaching of the complex copper sulfide ore, Tuff Breccia type, which was collected from PT Batutua Tembaga Raya, Wetar Island, Southwest Maluku. <br /> <br /> The experiments were carried out with several steps. The first step was the ore preparation through comminution, sieving and sampling. Subsequently, the sample taken was characterized using X-ray diffraction (XRD) and X-ray fluorescence (XRF). Bacterial growth of Alicyclobacillus ferrooxydans and Citrobacter sp. SKC-4 was determined spectrophotometrically by measuring optical density (OD) of bacterial cell suspension over 7 days of incubation. The varied bioleaching parameters included pulp density, NaCl concentration, elemental sulfur to ore ratio, and pyrite to ore ratio to investigate their effects on copper extraction. The leaching experiments were conducted on gyratory shaker at 180 rpm and 25oC. <br /> <br /> Characterization of ore indicated that the ore used was a complex sulfide ore with SiO2, FeS2, and CuO as the dominant minerals with copper content of 2.5% wt%. For bacterial cell number measurement for 7 days of incubation, the maximum bacterial growth of Alicyclobacillus ferrooxydans and Citrobacter sp. SKC-4 was reached after 2 days of incubation before entering stationary phase. Furthermore, the highest extraction level of copper achieved for pyrite to ore ratio (1:1) and sulfur to ore ratio (1:1) was 88.7% and 79.37%, respectively, at 7 days for bioleaching parameters of 30 g/L NaCl and 10% (w/w) pulp density. Based on the pH and solution potential (E), it can be seen from the Pourbaix diagram that the solution contained Cu2+ and Fe3+.