Malaysian Journal of Analytical Sciences Vol 18 No 1 (2014): 221 - 225

 

 

 

DIGESTION STUDY OF WATER LEACH PURIFICATION (WLP) RESIDUE FOR POSSIBILITY OF THORIUM EXTRACTION

 

(Kajian Penghadaman Residu Pemurnian Larut Resap Air (WLP) Untuk Kebarangkalian Pengekstrakan Torium)

 

Wadeeah M. AL-Areqi*, Amran Ab. Majid, Sukiman Sarmani

 

Nuclear Science Programme, School of Chemical Sciences & Food Technology,

Faculty of Science and Technology,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

*Corresponding author: walareqi@yahoo.com

 

 

Abstract

Water leach purification (WLP) is the main residue being produced by Lynas Advanced Materials Plant (LAMP). During rare earths elements extraction process, thorium is removed completely to WLP. The objective of this study was to extract thorium from WLP in order to reduce the level of radioactivity and to store Th for future nuclear fuel. Alkali and concentrated acids process was used to recover the Th from WLP. The concentration of Th and U in WLP was determined by Instrumental Neutron Activation Analysis (INAA) and found to be 1952.9 ± 17.6 mg/kg and 17.2 ± 2.4 mg/kg respectively. Digestion process of WLP via sodium hydroxide, concentrated nitric and sulphuric acids using different time and temperature has been tested. The Th concentrations in liquid phrase were determined by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS). In both processes less than 5% recovery of Th has been achieved. This study showed that very low Th recovery was achieved due to thorium was probably converted into refractory and insoluble form through the calcination stage of LAMP processing. Therefore different techniques should be used to recover the thorium.

 

Keywords: thorium, digestion, WLP, Th recovery

 

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