Characterization of Interactions of Biosurfactant-Producing Bacteria with Pyrite Minerals as An Alternative to Depressant Reagents in The Bioflotation Process Of Copper Sulfide Minerals That Are More Environmentally Friendly Tri Wahyuningsih1,a), Siti Khodijah Chaerun2,3,b), and Edy Sanwani2,c)
1 Metallurgical Engineering, Mining Engineering Department, Mineral Technology Faculty, UPN "Veteran" Yogyakarta, Jl. SWK 104 (Lingkar Utara) Condongcatur Yogyakarta 55283 Indonesia 2 Metallurgy Engineering, FTTM, Bandung Institute of Technology (ITB), Bandung 40132, Indonesia 3 Laboratory of Geomicrobiology, Biomining & Biocorrosion, Research Center for Bioscience and Biotechnology, Bandung Institute of Technology (ITB), Jln. Ganesha 10, Bandung 40132, Indonesia a)Corresponding author: tri.wahyuningsih[at]upnyk.ac.id b)skchaerun[at]metallurgy.itb.ac.id c)esanwani[at]mining.itb.ac.id;
Abstract: Several studies have been conducted on the benefits of bacteria to replace chemical reagents in the bioflotation process of copper sulfide minerals. Most of the processing of copper sulfide minerals is carried out by flotation by adding reagents. Flotation is one of the mineral processing processes to separate valuable minerals and their impurities, by utilizing different mineral surface properties. In copper sulfide minerals there is a high sulfur content of pyrite impurities (FeS2) which must be separated or depressed (become more hydrophilic) to be separated with valuable minerals, while valuable minerals will remain hydrophobic (prefer air). However, not all bacteria can survive at high sulfur concentrations. In this research characterization of the interaction of biosurfactant-producing bacteria that can survive in environments with high sulfur content (Citrobacter youngae strain SKC-4) with pyrite minerals. The effect of bacterial and pyrite interactions is observed by analyzing the composition of mineral surface elements and the morphological changes of the sample with SEM-EDS (Scanning Electron Microscope - Energy Dispersive Spectrometer) showing the interaction of bacteria that is able to stick and make mineral particles into complex aggregates and from the EDS results show that in the presence of bacteria are able to change the components of the initial mineral elements, this is dominated by the element components Fe, S, and a little content of element C which is the main element of microbial activity. Sampling for functional group testing (FT-IR Spectroscopy) was carried out on days 0,7,14, and 30 when bacteria interacted with minerals, showing a peak of C = O carbonyl bonds and carboxylic acid formation on the 7th day. The contact angle value of interaction culture with pyrite minerals results in a decrease on the 7th day, this causes the pyrite minerals to become more hydrophilic. From the results of the interaction characterization, the Citrobacter youngae strain SKC-4 has the potential as an alternative to a depressant reagent in a more environmentally friendly copper sulfide mineral bioflotation process.