Studi Ekstraksi Bijih Thorit dengan Metode Digesti Asam dan Pemisahan Thorium dari Logam Tanah Jarang dengan Metode Oksidasi-Presipitasi Selektif

Moch Iqbal Nur Said, Mutia Anggraini, Mohammad Zaki Mubarok, Kurnia Setiawan Widana

DOI: http://dx.doi.org/10.17146/eksplorium.2017.38.2.3930

Sari


Abstrak

Thorium (Th) merupakan logam radioaktif yang dapat terbentuk bersama uranium dan logam tanah jarang (LTJ). Mineral-mineral yang mengandung unsur radioaktif diantaranya monasit ((Ce,La,Y,U/Th)PO4), thorianit ((Th,U)O2), dan thorit (ThSiO4). Daerah Mamuju, Sulawesi Barat diketahui mengandung mineral radioaktif, salah satunya adalah thorit. Untuk memisahkan LTJ dari unsur radioaktif dapat dilakukan dengan cara mengekstraksi thorium dari bijih thorit dengan metode digesti asam menggunakan asam sulfat (H2SO4), kemudian diikuti pelindian dalam air dan rekoveri thorium dalam bentuk thorium hidroksida dengan metode presipitasi kimia menggunakan ammonium hidroksida (NH4OH). Hasil percobaan menunjukkan bahwa kondisi optimum digesti asam yang memberikan persentase ekstraksi paling tinggi didapatkan pada rasio padat/cair 1:2 (g/mL) selama 60 menit dengan persentase ekstraksi Th, besi (Fe), dan LTJ masing-masing sebesar 82,47%, 80,08%, dan 83,31%. Persentase presipitasi Th tertinggi sebesar 95,47% diperoleh pada pH 4,5 dalam suhu ruangan (26±1°C). Pada temperatur yang lebih tinggi, (70°C), diperoleh persentase presipitasi thorium yang lebih rendah sebesar 83,69%. Pre-oksidasi dengan menggunakan larutan H2O2sebanyak dua kali stoikiometri selama 1,5 jam pada suhu kamar meningkatkan persentase presipitasi Fe dari 93,08% menjadi 99,93%.

 

Abstract

Thorium (Th) is a radioactive metal that can be formed along with uranumand rare earth metals (REM). Minerals contain radioactive elements are monazite ((Ce,La,Y,U/Th)PO4), thorianite ((Th,U)O2), and thorite (ThSiO4). Mamuju Area is containing radioactive minerals, thorite is one of them. To separate REM from radioactive elements can be conducted by exctracting thorium from thorite ore by acid digestion method using sulphuric acid (H2SO4), followed by leaching and thorium recovery in the form of thorium hydroxide by chemical precipitation using ammonium hydroxide (NH4OH). The experimental results showed that the optimum conditions of acid digestion that give the highest Th extraction percentage on solid to liquid ratio are obtained at 1:2 (g/mL) in 60 minutes with extraction percentages of Th, iron (Fe) and REM are 82.47%, 80.08%, and 83.31% respectively. The highest thorium precipitation percentage, as much as 95.47% , was obtained at pH 4.5 on room temperature (26 ± 1°C). At higher temperature (70°C), a lower percentage of thorium precipitation is obtained, as much as 83.69%. Pre-oxidation by using H2O2 solution with two times stoichiometry for 1.5 hours at room temperature is increasing Fe precipitation percentage from 93.08% to 99.93%.



Kata Kunci


thorium; thorit; digesti asam; ekstraksi; presipitasi

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Referensi


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