Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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STUDY ON COMBUSTION CHARACTERISTICS OF COAL-BIOMASS FOR CO-FIRING SYSTEM AS A FEEDSTOCK OF COAL GASIFICATION PROCESS
No full textBiomass co-firing is recognised as a crucial technology to aid in the use of fossil fuels, particularly due to its relative ease of implementation. Many studies of the combustion processes associated with co-firing have been conducted elsewhere. This paper discusses the combustion characteristics of coal and torrefied biomasses. Combustion profiles can be used to study certain combustion properties of fuels and fuel blends. The biomass fuels utilized in this study include twig, trunk and weed as the wastes from tea plantation. The results of this work provide data concerning the combustion processes of co-firing determined by simultaneous thermal analysis (STA) methods. Simultaneous thermogravimetric & differential scanning calorimetry/differential thermal analysis (STA, TGA-DSC/DTA) measures both the heat flow (DSC) and the weight changes (TG) in a material as a function of temperature or time in a controlled atmosphere. The results indicate that the mixture of coal and torrefied trunk in the weight ratio of coal-trunk of 25:75 shows the best combustion performance compared to other compositions of coal – torrefied biomass
REMOVAL OF METALLIC IMPURITIES FROM QUARTZ SAND USING OXALIC ACID
No full textQuartz sand of Mojosari deposit from Rembang, Central Java has been beneficiated using oxalic acid to en- hance its purity, especially that is associated with the removal of iron oxide impurities. The removal of metallic impurities has been studied under experimental conditions to optimize the process parameters such as oxalate concentration (0.1-0.5M), leaching temperature (25-50°C) and pH of solution (1-5). The optimum leaching pro- cess removed iron from originally 1.44% to reach a level of 0.243% (82% removal of iron) with the SiO2 content increases from 95.50 up to 97.77%. The obtained beneficiated quartz sand matches the required Fe level for glass insulating fibers industry, which is less than 0.3%. The best result was yielded under experimental condi- tion using oxalic acid at concentration of 0.3M, pH 1, temperature of 40°C for 4 hours of leaching process. The experimental results of this study have opened up a practically significant and technically viable approach for the production of quartz sand suitable for glass insulating fiber industry
THE FINANCIAL FEASIBILITY ANALYSIS FOR CONSTRUCTION PLAN OF FERRO-NICKEL (Fe-Ni) SMELTER PLANT AT SOUTH KONAWE REGENCY, SOUTH EAST SULAWESI
No full textThe objective of the study is to comprehend the feasibility for construction plan of smelter plant to process the nickel laterite into ferro-nickel (Fe-Ni). PT. Macika Mineral Industries (PT. MMI), located at Lolowua village South Konawe, Southeast Sulawesi will implement such a plan Law No. 4 of 2009 on Mineral and Coal Mining obliges the mining investors to process the minerals into semi-finished or finished products in the domestic country before selling them abroad. The raw materials for PT. MMI smelter plant will be supplied by PT. Macika Mada Madana (PT. MMM) as one of PT. MMI group members PT. MMI is the holder of Production Operation Mining Permit that covers an area of 705 Ha and is located in Watudemba village, Palangga District and Keono Village, South Palangga District, South Konawe Regency. The mining area of PT. MMI is located 7 km from the PT. MMM planed plant. The total Ni reserve owned by PT. MMM is 18,930,700 tons. Of 18,930,700 ton reserves; 4,390,645 tons belongs to the measured one performing the average grade of nickel and iron around 1.97 and 23.14% respectively while around 14,540,055 tons that contain the average grade of nickel and iron about 1.92 and 23.14% respectively goes to the inferred reserve. PT. MMI requires 960,000 tons per year of Ni raw material it means that PT. MMM can supply the processing plant up to 20 years. Net present value (NPV), internal rate of return (IRR), return on investment (ROI), payback period (PBP), benefit cost ratio (B / CR), and breakeven point (BEP) are the criteria for evaluating the financial need of PT. MMI. The results showed that the NPV was about US 754 per ton for the production of 50,504 tons. The analysis showed that the construction of ferro-nickel (Fe-Ni) plant by PT. MMI was financially acceptable to be. However, using several variable measurements in analyzing the sensitivity of the business, namely by the selling price of ferro-nickel is assumed to be reduced by 5% and production cost is increased by 5%, the plan is not sensitive to decreasing selling price and increasing production cost
EXTRACTION OF RARE EARTH METALS FROM MONAZITE MINERAL USING ACID METHOD
No full textThere are two types of REE-bearing mineral in Indonesia, namely monazite and xenotime. Those minerals have not been further processed to obtain pure REEs or to obtain its oxides. The objective of this study is to study the performances of the REE extracted from monazite in acid method. The results show that the highest REE-extraction (28.41%) is achieved when the comparison between of sulfuric acid and water (v/v) is 1:2 with leaching temperature 220°C and leaching time 150 minutes. The process employed hydrogen peroxide as an oxidizer. Pregnant solution was then precipitated using sodium hydroxide and then was calcined at 900°C for 3 hours to produce RE-oxide. Characteristic of the RE-oxide contains such elements of Ce, Gd, Y, Nd, La, Dy and Sm within 29.10, 1.54, 1.53, 11.53, 14.02, 0.489 and 1.85%, respectively