Jurnal Puslitbang tekMira (Teknologi Mineral dan Batubara)
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PENINGKATAN MUTU BIJIH BAUKSIT TAYAN MENGGUNAKAN PEMISAH MAGNETIK
No full textSumberdaya bauksit yang ada di Tayan, Kalimantan Barat belum dimanfaatkan secara optimal dan perlu dilakukan peningkatan nilai tambah bauksit melalui proses pencucian dan pengolahan, sehingga perlu dilakukan pengkajian peningkatan mutu bijih bauksit. Percontoh bijih bauksit yang diambil dari daerah Tayan memiliki kadar SiO2 total 11,55%, Al2O3 43,64%, Fe2O3 9,63%. Proses peningkatan mutu (upgrading) bijih bauksit bertujuan untuk menaikkan kadar bauksit agar memenuhi persyaratan alumina di atas 51% Al2O3, maksimum 3% SiO2 dan maksimum 7 % Fe2O3 untuk bahan baku alumina. Tahapan proses scrubbing meliputi pemercontohan, scrubbing, pengayakan, pengeringan, penimbangan, penggerusan, pemisah magnetik dan analisis kimia. Parameter mutu yang digunakan untuk menilai keberhasilan adalah persen kumulatif ukuran butiran +2 mm (+10 mesh), perolehan Al2O3, kadar SiO2 total, Al2O3, dan Fe2O3. Uji coba proses pencucian-magnetik separator ini telah memberikan hasil yang baik ditinjau dari peningkatan kadar Al2O3 dan perolehan Al2O3. Kadar Al2O3hasil uji coba berkisar antara 57,29-59,78% dengan perolehan berkisar 69,67-85,58%. Bauksit tercuci-magnetik separator yang dihasilkan telah meningkatkan mutu bijih bauksit sebagai bahan baku pembuatan alumina melalui proses Bayer.
SYNTHESIS AND CHARACTERIZATION OF GAMMA ALUMINA AND ITS ADSORPTION CAPABILITY TEST FOR POMALAA MAGNESIUM LATERITE, SOUTHEAST SULAWESI
No full textBased on variations in calcination temperature, gamma alumina has successfully been made using a simple sol-gel method for Pomalaa magnesium-laterite adsorption from the South East of Sulawesi. The laterite leached by sulfuric acid was then precipitated by ammonia, to make the magnesium was separated from its main impurities (Si, Fe and Al). Temperature variations at 500, 650, 800 and 950 °C in gamma alumina making formed the gamma alumina phase while the alpha alumina phase was formed at 1100 °C. The higher calcination temperature the lower the specific surface area respectively from 196.385, 156.239, 105.725, 96.134 and 15.396 (m2/g). This results in decreasing the magnesium of the laterite 9.04, 8.70, 8.09, 6.39 and 0.29 (mg/L) respectively. The 800 °C-calcination gamma alumina has the highest volume of the pore, namely 0.3265 mL/g and the radius of 61.76 Å. The gamma alumina isotherm curve is type IV. The SEM-EDS test shows an aggregation spherical shape. Gamma alumina was detected to adsorb Mg laterite. The X-ray mapping of SEM-EDS test shows even distribution between gamma alumina, magnesium and nickel. The highest adsorption is retained by GA-800/3 sample, namely 81.31 %
PURIFICATION OF PREGNANT SOLUTION RESULTED FROM SPHALERITE CONCENTRATE EXTRACTION USING SULFATE ACID FOR ZINC OXYDE PRODUCTION
No full textPurification of pregnant solution from sphalerite concentrate extraction using sulfate acid to produce zinc oxide was meant to prepare zinc oxide production technology utilizing existing internal sphalerite mineral raw material. The pregnant solution used to produce zinc oxide contains 29.84% zinc (Zn), with the biggest impurities iron (Fe) 11.68%. In order to obtain high purity zinc oxide, the pregnant solution should be recovered. It was done through solvent extraction method, in two process steps: extraction and stripping. The extraction was applying ligan bis di2ethylhexyle phosphate acid (D2EHPA) in toluene solvent, through ligan concentrate variation, pH and comparison of aqueous volume with organic volume (VA:Vo) and its excess. Stripping was carried out using sulphate acid through variation of concentration, pH and Vo:VA. To obtain optimum recovery, thus extraction and stripping should be carried out in many steps. The extractions and the strippings were calculated using McCabe Thiele diagram. Furthermore, zinc oxide was resulted from deposition and calcination of pure pregnant solution at temperature 700°C. Purification results show that the best extraction occurred at concentration D2EHPA 1 M, pH 3 and Vo:Va 2:1, through 4 step processes obtained recovery 97.50% with distribution coefficient 77.9; while the best stripping was obtained at H2SO4 concentration 2 M, VO:VA 2:1 through 3 step processes which obtained stripping percent 98.22% with stripping coefficient 1.51. On the other hand, zinc oxide solution resulted from purification was obtained Zn 93.31% in the form of hexagonal crystals (wurtzite)
TAMBANG INKONVENSIONAL: PERAN MASYARAKAT DAN DAYA TARIK EKONOMI BAGI PENAMBANG
No full textMasih tingginya aktivitas pertambangan timah rakyat di Provinsi Kepulauan Bangka Belitung membuktikan bahwa timah merupakan komoditas penting dalam membentuk ekonomi masyarakat pedesaan. Tujuan penelitian ini adalah diperolehnya informasi tentang bagaimana masyarakat memainkan perannya dalam aktivitas pertambangan rakyat dan kontribusi ekonomi yang diperoleh sehingga aktivitas ini menjadi tumpuan ekonomi. Metodologi penelitian dilakukan melalui wawancara terhadap aparatur pemerintahan desa dan pelaku pertambangan untuk memetakan kelompok masyarakat yang beraktivitas di sektor ini, selanjutnya dilakukan wawancara mendalam terhadap kelompok masyarakat tersebut guna mendapatkan informasi tentang daya tarik ekonomi dari tambang rakyat ini. Dari hasil penelitian, diketahui bahwa aktivitas masyarakat dalam proses pertambangan rakyat terdiri dari pelimbang timah, pekerja tambang inkonvensional, penambang dengan menggunakan pompa air, pemilik tambang inkonvensional, pekerja lobi timah, dan pembeli timah. Aktivitas tersebut sangat berpengaruh terhadap kondisi ekonomi masyarakat penambang yang dikelompokkan ke dalam pelaku pertambangan berpenghasilan rendah yaitu pelimbang, pekerja tambang inkonvensional (TI), pekerja robin, berpenghasilan sedang yaitu pekerja lobi timah, berpenghasilan tinggi yaitu pemilik TI serta berpenghasilan sangat tinggi yaitu pembeli timah. Hasil penelitian ini diharapkan dapat dijadikan masukan bagi pemerintah daerah dalam merumuskan strategi pembangunan di Provinsi Kepulauan Bangka Belitung
ASH DEPOSIT CHARACTERISTICS OF BLENDED COAL IN COAL COMBUSTION PROCESS
No full textCoal combustion process often occurs the problems in the reactor which is caused by fouling and slagging. One of the procedures to reduce the risk of fouling and slagging by blending the coal of Pendopo, Palangkaraya, Muara Enim and Samarinda, with the ratio of 25:75, 50:50, and 75:25. The ash deposit tendency is known by analyzing the composition and ash fusion temperature of coal, determining the ash type and calculating of the fouling and slagging. The results showed that the Pendopo and Palangkaraya coal with a ratio of 25:75 and 50:50 were classified as lignite with fouling and the slagging index was classified as a high and medium tendency. While the other blended coal was classified as a low and low-medium tendency
