Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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BIOLEACHING OF LOW GRADE NICKEL ORE USING INDIGENOUS FUNGI
No full textIn this research, the biological leaching of nickel by indigenous fungi isolated from Indonesian limonite was studied to develop a feasible technique for microbial recovery of nickel from low grade nickel ore. XRD analyses indicated that goethite, alumina and quartz were major mineral composition of the ore. In the present study, isolated fungal strains having potential to solubilize nickel were characterized. that were identified as Aspergillus sp and Penicillium sp depending upon their colony morphology and microscopic studies. All microorganisms found were tested for organic acid production and leaching capabilities of nickel. Leaching experiments were performed in 250 ml Erlenmeyer flask at room temperature and 150 rpm agitation under aseptic conditions. It was observed that the Aspergillus sp substantially leached more nickel from limonite compared to the Penicillium sp. Nickel solubilization was related to pH decrease and organic acid excreted caused by growth of fungi in medium containing glucose as carbon source. The mechanisms of nickel extraction had been examined either directly or indirectly related to fungal activity. The presence of fungal cells seems to improve the leaching process. However, the use of higher pulp density resulted in a decrease of nickel solubilization. The maximum nickel recovery was 57% at 5% pulp density after 20 days of direct leaching by Aspergillus sp
CHARACTERISTICS OF SELECTED SUMATERAN TERTIARY COALS REGARDING THEIR PETRO- GRAPHIC ANALYSES
No full textType and rank variation of selected Sumateran (Ombilin and Bukit Asam) Tertiary coals were as- sessed by petrographic examination of 170 samples. The coals are dominated by vitrinite, common liptinite and rare inertinite and mineral matter. Vitrinite macerals are dominated by detrovitrinite and telovitrinite. Resinite, cutinite and suberinite are the dominant liptinite macerals in the coals. Inertinite macerals in the coals consist of semifusinite, sclerotinite and inertodetrinite. The higher vitrinite re- flectance of some coals is a result of the local and variable effects of igneous intrusions in both areas. Similarities in the type and rank characteristics in the coals reflect their geological setting, climatic influence and peat conditions
EFFECT OF DISPERSING AND STABILIZING ADDITIVES ON RHEOLOGICAL CHARACTERISTICS OF THE UPGRADED BROWN COAL WATER MIXTURE
No full textThe preparation of upgraded brown coal water mixture (UBCWM) by using an Indonesian upgraded coal that was produced by an upgraded brown coal (UBC) process in pilot scale, was carried out to obtain the effect of dispersing and stabilizing additives on rheological behaviour of the UBCWM. Three kinds of anionic dispersing additives, naphthalene sulfonate formaldehyde condensate (NSF), polymethacrylate (PMA) and polystyrene sulfonate (PSS) and three kinds of stabilizing additives, carboxyl methyl cellulose (CMC) an organic material a derivative of cellulose, rhansam gum (S-194) and gellan gum (S-60) some kinds of bio poly sacharide the trade mark of Dainippon Pharma- ceutical Co. Ltd. were used in this study. Results indicate that the addition of NSF 0.3 wt% together with S-194 0.01 wt% is effective in preparing UBCWM with good slurry ability and stability, based on its rheological characteristics (apparent viscosity at shear rate of 100 s-1 and yield stress at zero point of shear rate). Since the price of S-194 is expensive, the addition of CMC 0.01 wt% is also effective in preparing stable UBCWM
K/AR DATING OF BUKIT ASAM AND BUKIT KENDI INTRUSIONS RELATED TO AGE OF MATURITY AND INCREASING OF COAL QUALITY IN TANJUNG ENIM AREA, SOUTH-SUMATERA
No full textCoal bearing Muara Enim Formation is widely spread in Muara Enim, especially in Tanjung Enim District, South-Sumatera Province. Field observations display increasing maturity and quality towards Bukit Asam and Bukit Kendi intrusions. Potassium argons age analysis revealed that Bukit Asam is 0,9203 ± 0,26 million years in age and Bukit Kendi is 1,1472 ± 0,29 million years in age respectively, while Bukit Serilo displays negative age. These K/Ar ages result revealed that increasing maturity and quality of coal of the Bukit Asam and Bukit Kendi have taken place since 1,14 million years
GEOPHYSICAL PROSPECTING ON COAL DEPOSIT AT PARAMBAHAN AREA,WEST SUMATERA
No full textChanging coal mine method from open to underground mines needs preparing new data such as the type and the thickness of rocks as overburden on coal seam. Geophysical prospecting method is chosen to gather such the data. Based on 30 point measurements and compilated by regional geologi- cal data, it was assumed that the rocks at Parambahan area contained top soil, alternating beds of sand, silt and weathered clay, alternating beds of sand, silt and massive clay, coally clay and massive sand stone
