ACID BIOGENERATION BY UTILIZING ALICYCLOBACILLUS FEROOXIDANS BACTERIA AND ITS USE FOR BIOLEACHING OF NICKEL LATERITE ORES FROM POMALAA

• Main Author: ALFI ARINANDA (NIM : 12509023), MUHAMMAD
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23189
• Institution: Institut Teknologi Bandung

Bioleaching is a leaching process by the assistance of microorganisms that generated acids through their metabolism process. The investigations of nickel bioleaching from laterite and sulphide ore by utilizing bacteria have been conducted with various conditions to obtain sufficient nickel recovery. The previous investigations that have been carried out are mostly implementing direct bioleaching, in which acid biogeneration and leaching of ores being done in the same reactor, thus, the condition for obtaining high nickel extraction is hard to controll. In term of the type of bacteria used, the previous researches mostly utilized heterotrophic or chemolithotrophic bacterias. This research studies organic acid biogeneration process by the assistance of mixotrof bacteria of and the effectiveness of Pomalaa nickel laterite leaching using organic acid that have been produced by the Alicyclobacillus ferooxidans bacteria. <br /> <br /> <br /> <br /> Series of organic acid biogeneration experimental works have been performed at various organic substrate’s sources, addition of elemental sulfur, and addition of Fe nutrient to obtain the best condition that give a highest bacterial growth of Alicyclobacillus ferooxidans and generated organic acid concentration. Furthermore, series of leaching experimental works also were carried out at various particle size distribution, solid percentage, and addition of 2 M commercial citric acid to evaluate the effectiveness of the use of acid solution from the biogeneration process for the leaching of Pomalaa nickel laterite ores. <br /> <br /> <br /> <br /> The investigation results showed that after 16 days of incubation, the highest bacterial growth of Alicyclobacillus ferooxidansand organic acid concentration was obtained from the acid biogeneration test using leachate as organic substrate’s source, at 2,5% (w/v) of elemental sulfur and 10% (v/v) of Fe nutrient, in which the final result of bacterial growth was 3.100.000 cell/mL and generated organic acid concetration was 7,457 ppm (0.04 M). The highest nickel extraction percentage of 10,49% was obtained from the leaching test at temperature 95°C, for 480 menit, stirring speed 200 rpm, particel size distribution of -100+200 mesh, and solid percentage of 5% for saprolite ore, while the highest nickel extraction percentage for limonite ore of 8,05% was obtained from the leaching test at temperature 95°C, duration of 480 menit, stirring speed 200 rpm, particel size distribution of -100+200 mesh, and solid percentage of 5%. The mixing of 2 M commercial citric acid with a ratio of 1:1 (v/v) with acid solution the biogeneration process increases the percentage of nickel extraction to 82.94% and and 45.29%, respectively for saprolite and limonite ores.