Malaysian Journal of Analytical Sciences Vol
21 No 6 (2017): 1250 - 1256
DOI:
10.17576/mjas-2017-2106-06
SOLVENT
EXTRACTION OF THORIUM FROM RARE EARTH ELEMENTS IN MONAZITE THORIUM CONCENTRATE
(Pengekstrakan Pelarut Torium daripada Unsur Nadir Bumi dalam Pekatan Torium Monazit)
Wadeeah M. Al-Areqi*, Che
Nor Aniza Che Zainul Bahri, Amran Ab. Majid, Sukiman Sarmani
Nuclear Science Programme, School of Applied Physics,
Faculty of Science and Technology,
Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor,
Malaysia
*Corresponding author: walareqi@yahoo.com
Received: 6
April 2017; Accepted: 20 August 2017
Abstract
Solvent extraction is a
powerful separation technique in the
preparation of nuclear grade thorium. In this study, monazite
thorium concentrates produced from Malaysian monazite were used. Thorium was
extracted from an aqueous nitric acid medium
with TBP (30%) in kerosene and Aliquat-336 (10%) in kerosene, respectively. Constant experimental conditions were used for the extraction in terms of the molarity of nitric acid,
concentration of extractants in kerosene, organic/aqueous
volumetric ratio, mixing time, and contact time
between phases. The stripping process was
carried out with distilled water. The determination of thorium and rare earth elements (REEs) in the monazite thorium concentrates
and aqueous solutions were performed by using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of thorium in the thorium concentrate samples were in the range of 11.58 – 83.56%. Three stages of
extraction and three stages of stripping were carried out for the extraction of thorium from the REEs in the nitrate solution.
The results of the study showed that the thorium extraction efficiency was in the range of 60.96 – 99.75% using TBP (30%) in kerosene and Aliquat-336 (10%) in
kerosene. Thorium was stripped from the loaded TBP (30%) in
kerosene and Aliquat-336 (10%) in kerosene at an average stripping percentage of 89.04% and 75.75%, respectively. The
stripped aqueous solutions were analysed, and it was shown that the thorium content was in the range of 29.49 – 91.28%. This study
indicated that both extractants can be successfully used to recover thorium from REEs, but in order to increase the purification of thorium, the extraction and stripping process cycle should be
increased.
Keywords: thorium,
rare earth elements, solvent extraction, monazite thorium concentrate
Abstrak
Pengekstrakan pelarut adalah teknik pengasingan yang kuat digunakan untuk
mengasingkan torium bergred nuklear. Dalam kajian ini, pekatan torium monazit
yang dihasilkan daripada monazit Malaysia telah digunakan. Torium diekstrak
daripada medium akues asid nitrik dengan TBP (30%) dalam kerosin dan
Aliquat-336 (10%) dalam kerosin. Kondisi eksperimen digunakan iaitu molariti
asid nitrik, kepekatan pengekstrak dalam kerosin, nisbah isipadu organik/akues,
masa percampuran dan masa sentuhan antara fasa dikekalkan. Proses pelucutan
dilakukan menggunakan air suling. Torium dan unsur nadir bumi (REEs) dalam
pekatan torium monazit dan larutan akues ditentukan menggunakan spektrometri
jisim plasma gandingan teraruh (ICP-MS). Kepekatan torium dalam sampel pekatan
torium ditentukan adalah dalam julat 11.58 – 83.56%. Tiga peringkat
pengekstrakan dan pelucutan dilakukan untuk mendapatkan torium dari REEs dalam
larutan nitrat. Hasil kajian menunjukkan kecekapan pengekstrakan torium adalah
dalam julat 60.96 – 99.75% menggunakan TBP (30%) dalam kerosin dan Aliquat-336
(10%) dalam kerosin. Torium telah dilucutkan daripada muatan TBP (30%) dalam
kerosin dan Aliquat-336 (10%) dalam kerosin dengan purata peratus pelucutan
masing – masing adalah 89.04% dan 75.75%. Larutan akues yang dilucutkan telah
dianalisis dan menunjukkan bahawa kandungan torium adalah dalam julat 29.49 –
91.28%. Kajian ini menunjukkan bahawa kedua – dua pengekstrak boleh digunakan
dengan berkesan untuk mendapatkan torium daripada REEs tetapi untuk
meningkatkan kemurnian torium, pengekstrakan dan kitaran proses pelucutan harus
dipertingkatkan.
Kata kunci: torium, unsur nadir bumi, pengekstrakan
pelarut, pekatan torium monazit
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