Recovery of thorium and rare earth element (REE) from different particle size of xenotime mineral
Abstract
Abstract
The present work describes the development of alkaline fusion process to recover thorium (Th) and rare earth elements (REE) from Malaysian xenotime. The steps investigated in the process to recover thorium and REE were: (i) milling of xenotime mineral with different speed, (ii) cracking process of xenotime mineral via alkaline fusion, (iii) washing process and (iv) leaching of mineral cake with hydrochloric acid (HCl). The influence of milling speed to particle size distribution and effect of particles size on recovery of thorium and REEs were investigated. Based on the results, the particle will be decrease from 220 µm to 17.12 µm as increasing the milling speed up to 300 rpm. However, not much reduction in the particle size upon milling at 400 rpm. The results revealed that the smallest particle size recover 77.02% of thorium, 68.08%, 58.95%, 53.69% and 51.67% of yttrium (Y), ytterbium (Yb), erbium (Er) and dysprosium (Dy), respectively. As compare to unmilling sample, the average Th and REE recovery were just in the range of 31.45% to 45.34%. The increase of surface area resulted in an increase of the Th and REE recovery by enhancing the reaction mineral surface area and HCl.
AbstraK
Kerja-kerja ini menerangkan perkembangan proses gabungan alkali untuk memulihkan torium (Th) dan unsur-unsur nadir bumi (REE) dari xenotime Malaysia. Langkah-langkah yang dikaji dalam proses untuk mendapatkan semula thorium dan REE adalah: (i) pengilangan mineral xenotim dengan kelajuan yang berbeza, (ii) proses retak mineral xenotim melalui gabungan alkali, (iii) proses pembersihan dan (iv) asid hidroklorik (HCl). Pengaruh kelajuan pengilangan kepada pengagihan saiz zarah dan kesan saiz zarah pada pemulihan torium dan REEs telah disiasat. Berdasarkan hasilnya, zarah akan berkurang dari 220 μm ke 17.12 μm sambil meningkatkan kelajuan penggilingan sehingga 300 rpm. Walau bagaimanapun, tidak banyak pengurangan saiz zarah pada penggilingan pada 400 rpm. Hasil kajian menunjukkan bahawa saiz zarah terkecil mengembalikan 77.02% torium, 68.08%, 58.95%, 53.69% dan 51.67% daripada yttrium (Y), ytterbium (Yb), erbium (Er) dan dysprosium (Dy). Seperti yang dibandingkan dengan sampel unmilling, purata pemulihan Th dan REE hanya dalam lingkungan 31.45% hingga 45.34%. Peningkatan kawasan permukaan mengakibatkan peningkatan pemulihan Th dan REE dengan meningkatkan kawasan permukaan mineral reaksi dan HCl.
