Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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PROCESSING OF THE GOLD ORE FROM KEDONDONG AREA, SOUTH LAMPUNG USING GRAVITY CONCENTRATION METHOD
No full textKedondong gold ores seem promising to be processed. Referring to its mineralogy characters, the ores can be treated by gravity concentration method that include Knelson concentrator, shaking table, jig and sluice box as well. Processing the gold sample coded A from Kedondong, South Lampung by Knelson concentrator increased the Au grade from 21.87 to 399.76 g/t. Its recovery was 91.57 %. The silver grade also improved from 287.83 to 3,427.12 g/t performing recovery of 49.65 %. Re-processing Knelson concentrator concentrates using shaking table enlarged the Au and silver grades to 1,199.28 and 5,430.80 g/t respectively. Both Au and Ag recoveries were around 89.84% and 47.45% respectively. Another sample, coded B, provided grade 165.80 g/t Au (from 8.93 g/t) and 3,275.05 g/t Ag (from 172.73 g/t) when processed by Knelson concentrator. A shaking table process for such a B-Knelson concentrate yielded the Au and Ag grades to 710,05 and 13.800,80 g/t respectively and also improved the Au and Ag recoveries to 85.56 and 85.17%. Concentrate Sample A has satisfied the requirement for final processing using smelting method, however, Sample B still needs more shaking table process in order to get satisfied condition for smelting process, namely the grade of gold >1,000 g/t
EFFECT OF COMBUSTIBLE CONTENT IN COAL ASH REFUSE ON THE EFFICIENCY OF THERMAL OIL HEATER SYSTEM
No full textThis paper provides an analysis on the effect of combustible content in coal ash refuse the efficiency towards combustion and heat thermal oil heater system in a coal furnace that had been studied. The study investigated the discrepancy of the actual performance of the heater compared to that as stated in the design specification. The study assumed that coal type and operational problem were the cause of deviation. Both affect combustion efficiency and the amount of reactive materials within coal ash refuse. Combustible content within the coal ash refuse was the used as the source data. Using indirect method, the amount of losses can be determined from the amount of combustibles in the coal ash refuse. The work involved measuring the temperature of oil and flue gas, analyzing the ash content and calculating the losses based on two sets of operational data. System efficiency and heat exchanger rating were calculated by reducing the amount of total losses from the full design capacity. If the reactive composition within the coal ash in combustible content, the amount of coal consumption is higher in order to attain the heat desired capacity for heating. Such a contition is caused by decreasing the energy capacity and reducing the furnace effectivenes
THE EFFECT OF KCN ON GOLD ADSORPTION FROM HCl SOLUTION BY SYNTHESIZED MAGNETIC ACTIVATED CARBON COMPOSITE FROM IRON SAND
No full textThe composites of magnetic activated carbon has been successfully synthesized by utilizing the available materi- als abundant in the country such as iron sand, and other chemicals which are easily procured in local markets at low prices. The phase identifi cation using X-ray diffraction technique showed that the magnetic part is Fe3O4 with crystallite size about 30 nm. The effectiveness of gold absorption from chloride solution by activated carbon magnetic composites are close to 100% and showed very dependent on pH. An addition of KCN in to the gold chloride solution can reduce effectiveness of activated carbon to adsorb gold by up to 20%. These might be caused by the formation of Au(CN)2-, in the solution, which could change the mechanism of adsorption of gold by the activated carbon. Based on these experimental results, by using chloride it is possible to recover valuable minerals from the ore processing of mining, which are economically,as well as environment friendly and safe