Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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THE ECONOMIC EVALUATION OF RESEARCH-BASED INDONESIAN COAL UTILIZATION
No full textEfforts of Indonesian Government in diversifying the available fuels from domestic coal in the forms of solid, liquid and gaseous fuels open the pissibility to overcome the depleted domestic oil reserves. Within the coming few years, Indonesia will be a net oil consumer after being the net oil importer in 2003. In the last forty years, Indonesian energy consumption was heavily depended on oil fuel. To meet the increase domestic energy demand, a large quantity of domestic coal reserves should be diversified into briquette, synthetic oil and gas as well as other non-fuel or chemical products. All these diversified products are expected to be economically competitive as well as environmental friendly using clean coal technology. This article is an evaluation on study results compilation of Indonesian coal utilization and diversification in the last 15 year
PETROGRAPHIC PROPERTIES OF PALAEOGENE SOUTHERN BANTEN COAL SEAMS WITH REGARD TO GEOLOGIC ASPECTS
No full textThe Palaeogene coal deposits occur in three coalfields in the Banten Province, which are distributed in Bayah, Cihideung and Cimandiri. The Bayah coals (Eocene Bayah Formation) mainly comprise vitrinite and subordinate inertinite and are of sub-bituminous A to high volatile bituminous A ranks (0.60-0.79%). The Cihideung coals (Eocene Bayah Formation) are of sub-bituminous A to medium volatile bituminous ranks (0.53-1.23%) and composed mainly of vitrinite. The Cimandiri coals (Oligocene Cijengkol Formation) are composed of variable proportions of vitrinite in the main and inertinite in very minor amounts. The rank of the coals is sub-bituminous A and high volatile bituminous A varying between 0.64% and 0.83% in vitrinite reflectance. Evaluation of these coals indicates that they tend to have similar coal petrographic properties and were formed in a littoral-neritic environment. Some of the coals, especially the Cihideung coals, show the highest vitrinite content and higher rank (0.99-1.23%), which is high A-medium volatile bituminous, due to an intrusive activity. Most of the coals have high contents of mineral matter (pyrite), mainly in the Bayah coals (2-13%), and this indicates that the coals were influenced by marine incursion during their deposition
GOLD RECOVERY OF REFRACTORY SULFIDE CONCENTRATES USING DIRECT CYANIDE LEACHING WITH NITRITE AS AN OXIDANT
No full textThe problem of refractory sulfide gold ore that has a gold recovery less than 50% when direct cyanidation applied, still exists until now. It needs oxidative pretreatment for cyanidation to be effective in gold recovery the objective of this study is figuring out the effect of sodium nitrite as an oxidizing reagent on cyanidation of refractory gold ore. Cyanide leaching of the concentrate was performed at 20%-w/w of solid (500 gram of refractory sulfide gold ore concentrate) in a 2.5-liter glass reactor with aeration and stirred at 250 rpm. Leach solutions were prepared using deionized-distilled water at the prescribed concentration of reagents. Recovery of gold increased gradually to its maximum value of 93.05% as the value of cyanide strength increased from 0.8 to 1.2% and the addition of sodium nitrite raise to 1.2 M. No improvement for further addition of nitrites. This introduction of new hydrometallurgical pre-treatment process has given more option for treating refractory ores
ALTERING FERROUS SULPHATE TO SYNTHETIC GOETHITE
No full textCatalyst is required in any reaction. Coal liquefaction is one of the processes to have need of it. The most common catalyst used in the process is ferrous based catalyst. It is very influenced by pyrhotite, which may be occurred from goethite while goethite can be composed of any iron sources. The research had the use of ferrous sulphate as the main iron source, which was reacted with caustic soda. Parameters on molar ratio of the FeSO4.7H2O/NaOH were 0.2 and 0.33, reaction time applied were 3.5; 6.5 and 17.15 hours, oxygen flow rates of 100; 200; 300; 400 and 500 cc/minute were also observed. The best result was achieved at 0.2 molar ratio of the FeSO4.7H2O/NaOH within 6.5 hours by oxidation process that was containing pure goethite, while 100 cc/minute of oxygen rate was enough for the process to be happened
