ACID BIOGENERATION BY UTILIZING ALICYCLOBACILLUS FEROOXIDANS AND ITS USE
FOR BIOLEACHING OF NICKEL LATERITE ORES
Muhammad Alfi Arinanda1, Mohammad Zaki Mubarok2, Siti Khodijah Chaerun3
1
EMERALD Erasmus Mundus Master in Georesources Engineering, Université de Liège
Place du 20 Août 7, 4000 Liège - Belgium
2, 3
Department of Metallurgical Engineering, Institut Teknologi Bandung
Jl. Ganesha 10, Bandung, Jawa Barat – Indonesia
1muhammadalfi.arinanda@student.ulg.ac.be
2zaki@mining.itb.ac.id
3skchaerun@metallurgy.itb.ac.id
ABSTRACT
Bioleaching is a leaching process by the assistance of microorganisms that generated acids through their
metabolism process. The previous investigations that have been carried out are mostly implementing direct
bioleaching, in which acid biogeneration and ore leaching being done in the same reactor, thus, the
condition for obtaining high nickel extraction is hard to control. This research studies organic acid biogeneration process by assistance of mixotrophic bacteria and the effectiveness of nickel laterite leaching
using organic acid that have been produced by the Alicyclobacillus ferooxidans. Series of organic acid biogeneration experimental works have been performed at various organic substrate sources, addition of
elemental sulfur, and 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 were also carried out with addition of commercial citric acid to evaluate the
effectiveness of the use of acid solution from the bio-generation process for the leaching of Pomalaa nickel
laterite ores.
The investigation results showed that after 16 days of incubation, the highest bacterial growth of
Alicyclobacillus ferooxidans and 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 3.1 million cell/mL and generated organic acid
concentration was 0.04 M. The highest nickel extraction percentage was obtained from the leaching test at
temperature 95°C, for 480 minutes, and solid percentage of 5%, which is 10.49% for saprolite ore and
8.05% for limonite ore. The mixing of 2 M commercial citric acid with ratio of 1:1 (v/v) increases the
percentage of nickel extraction to 82.94% and 45.29%, respectively for saprolite and limonite ores.
Figure 1 – Profile of nickel extraction percentage of saprolite ore leaching with 5% solid percentage,
particle size of -100+200 mesh, and addition of commercial citric acid
KEYWORDS
Biogeneration, Alicyclobacillus ferooxidans, Nickel, Leaching, Extraction