BIOLEACHING OF GALENA CONCENTRATES FROM BOGOR USING IRON- AND SULFUR-OXIDIZING MIXOTROPHIC BACTERIA WITH ADDITION OF FeCl3 AND NaCl

• Main Author: AMADEA PUTRI (NIM : 12513014), EDINA
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/21869
• Institution: Institut Teknologi Bandung

In general, the recovery of lead from galena via a pyrometallurgical route has environmental problems because of SO2 generation. Recovering lead from galena via hydrometallurgical route is using several organic and inorganic acids for lead dissolution. Currently, the recovery of lead has been studied by several investigators using bioleaching technology. This process is more efficient, simple, and environmentally friendly compared with conventional process. Unfortunately, undissolved lead sulfate is generated as the final product of bioleaching, thus requiring further process to leach lead from the lead sulfate. Hence, the present study investigated the bioleaching of galena concentrates from Bogor using mixotrophic bacteria (herein Citrobacter youngae strain SKC-4 and Alicyclobacillus ferrooxydans) with the addition of FeCl3 and NaCl. <br /> <br /> <br /> <br /> A series of bioleaching experiments were carried out to study the influence of NaCl, FeCl3, molasses as source of organic substrate, types of bacteria, pulp density, and bioleaching methods on the extraction efficiency of lead, Eh-pH, and bioleaching selectivity to copper and zinc. Bioleaching experiments were conducted on rotary shaker at room temperature for 7 days. Concentrations of lead, copper, and zinc in the solution were measured by atomic absorption spectroscopy (AAS). The bioleaching solid residues were analyzed by X-ray diffraction (XRD) and Fourier transfrom infrared spectroscopy (FTIR). <br /> <br /> <br /> <br /> Experimental results showed that the highest lead extraction from galena concentrates on semi-direct bioleaching using Citrobacter youngae was 13%, which was obtained at 5% pulp density, 5 g/L FeCl3, 50 g/L NaCl, and 20 g/L molasses. The lead extraction on semi-direct bioleaching using Alicyclobacillus ferrooxydans decreased over a period of 7 days, which reached the level of 3.17% at 2% pulp density, leaching time of 7 days, 5 g/L FeCl3, 50 g/L NaCl, and 20 g/L molasses. In addition, the highest extraction levels of lead on direct bioleaching for Alicyclobacillus ferrooxydans and Citrobacter youngae were 25.05% and 23.51%, respectively, which were achieved at 2% pulp density, 5 g/L FeCl3, 50 g/L NaCl and 20 g/L molasses. <br />