OPTIMIZATION OF SULFIDE COPPER ORE BIOLEACHING PROCESS FROM WETAR ISLAND USING SKC-BROTH MODIFICATION MEDIUM

• Main Author: Hafidavi Fahrezy, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/40145
• Institution: Institut Teknologi Bandung

Owing to its unique characteristics such as excellent heat and electrical conductivity, corrosion resistant, and is readily formed, copper (Cu) has been widely used in various fields. Therefore, it is obvious that the demand for metallic Cu in the future gradually increases. However, currently, world Cu production is still dominated by the pyrometallurgical process (approximately 80%), in which produces pollutants, such as particulates and SO2 gases, so that it is eco-unfriendly as well as high cost. In parallel, the hydrometallurgical process requires a significant volume of leaching agents which leads to high operational cost. Therefore, with the aim to seek for an alternative method for Cu extraction, an environmentally friendly extraction method with a relatively efficient cost, biohydrometallurgical/bioleaching was investigated in this study. However, in the process, it is necessary to know the operating factors that affect the performance of the microorganisms used. Optimization processes of Cu bioleaching at room temperature was carried out to investigate the factors affected the microbial process: the ratio of bacteria, pulp density, and inoculum concentration in modified SKC-Broth modified medium to optimize Cu extraction. A series of experiments began with the preparation of Cu sulfide ore samples originated from Wetar Island to obtain a particle size of -200 # (±75?m). The ore samples were withdrawn for the purposes of sample characterization and bioleaching experiments. Sample characterization was performed using XRD and XRF. Prior to the bioleaching experiment, a bacterial growth curve was constructed to determine the optimum time for bacterial growth that used for bioleaching experiments: Alicyclobacillus ferrooxydans (A), Bacillus aryabhattai SKC-5 (B) and Citrobacter freundii (BS-5). Then, bioleaching experiments were carried out with variations in the ratio of bacteria to obtain the most optimum ratio of bacteria which resulted in the highest Cu extraction for 10 days of leaching. Finally, bioleaching experiments were conducted using the most optimum bacterial ratio at several variations, including pulp density (5%, 10%, and 15%) and inoculum concentration (5%, 10%, and 15%). Samples were withdrawn periodically for further analysis. According to XRD analysis, it was shown that Cu in the ore was in the form of covellite (CuS) and chalcopyrite (CuFeS2) minerals which required acid and oxidizers for the dissolution process. The highest Cu extraction was 98,19% obtained under the condition of 5%-pulp density, 5%-inoculum with a mixed culture of Bacillus aryabhattai SKC-5 (B bacteria) and Citrobacter freundii (BS-5 bacteria) with a ratio of 1:2. Thus, bioleaching of Cu sulfide ores is highly potential to be applied as an alternative low-cost and environmentally friendly method in field scale with further optimization process.