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Title: Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue

Abstract

Thorium (IV) content in industrial residue produced from rare earth elements production industry is one of the challenges to Malaysian environment. Separation of thorium from the lanthanide concentrate (LC) and Water Leach Purification (WLP) residue from rare earth elements production plant is described. Both materials have been tested by sulphuric acid and alkaline digestions. Th concentrations in LC and WLP were determined to be 1289.7 ± 129 and 1952.9±17.6 ppm respectively. The results of separation show that the recovery of Th separation from rare earth in LC after concentrated sulphuric acid dissolution and reduction of acidity to precipitate Th was found 1.76-1.20% whereas Th recovery from WLP was less than 4% after concentrated acids and alkali digestion processes. Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine Th concentrations in aqueous phase during separation stages. This study indicated that thorium maybe exists in refractory and insoluble form which is difficult to separate by these processes and stays in WLP residue as naturally occurring radioactive material (NORM)

Authors:
; ;  [1]
  1. Nuclear Science Programme, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)
Publication Date:
OSTI Identifier:
22308341
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1614; Journal Issue: 1; Conference: 2014 UKM FST postgraduate colloquium, Selangor (Malaysia), 9-11 Apr 2014; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; ICP MASS SPECTROSCOPY; LEACHING; MATERIALS RECOVERY; RADIOACTIVE MATERIALS; RARE EARTHS; SULFURIC ACID; THORIUM; WATER

Citation Formats

AL-Areqi, Wadeeah M., Majid, Amran Ab., and Sarmani, Sukiman. Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue. United States: N. p., 2014. Web. doi:10.1063/1.4895244.
AL-Areqi, Wadeeah M., Majid, Amran Ab., & Sarmani, Sukiman. Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue. United States. doi:10.1063/1.4895244.
AL-Areqi, Wadeeah M., Majid, Amran Ab., and Sarmani, Sukiman. Wed . "Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue". United States. doi:10.1063/1.4895244.
@article{osti_22308341,
title = {Separation of thorium (IV) from lanthanide concentrate (LC) and water leach purification (WLP) residue},
author = {AL-Areqi, Wadeeah M. and Majid, Amran Ab. and Sarmani, Sukiman},
abstractNote = {Thorium (IV) content in industrial residue produced from rare earth elements production industry is one of the challenges to Malaysian environment. Separation of thorium from the lanthanide concentrate (LC) and Water Leach Purification (WLP) residue from rare earth elements production plant is described. Both materials have been tested by sulphuric acid and alkaline digestions. Th concentrations in LC and WLP were determined to be 1289.7 ± 129 and 1952.9±17.6 ppm respectively. The results of separation show that the recovery of Th separation from rare earth in LC after concentrated sulphuric acid dissolution and reduction of acidity to precipitate Th was found 1.76-1.20% whereas Th recovery from WLP was less than 4% after concentrated acids and alkali digestion processes. Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) was used to determine Th concentrations in aqueous phase during separation stages. This study indicated that thorium maybe exists in refractory and insoluble form which is difficult to separate by these processes and stays in WLP residue as naturally occurring radioactive material (NORM)},
doi = {10.1063/1.4895244},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1614,
place = {United States},
year = {Wed Sep 03 00:00:00 EDT 2014},
month = {Wed Sep 03 00:00:00 EDT 2014}
}
  • Lynas Advanced Materials Plant (LAMP) has been licensed to produce the rare earths elements since early 2013 in Malaysia. LAMP processes lanthanide concentrate (LC) to extract rare earth elements and subsequently produce large volumes of water leach purification (WLP) residue containing naturally occurring radioactive material (NORM). This residue has been rising up the environmental issue because it was suspected to accumulate thorium with significant activity concentration and has been classified as radioactive residue. The aim of this study is to determine Th-232, U-238 and rare earth elements in lanthanide concentrate (LC) and water leach purification (WLP) residue collected from LAMPmore » and to evaluate the potential radiological impacts of the WLP residue on the environment. Instrumental Neutron Activation Analysis and γ-spectrometry were used for determination of Th, U and rare earth elements concentrations. The results of this study found that the concentration of Th in LC was 1289.7 ± 129 ppm (5274.9 ± 527.6Bq/kg) whereas the Th and U concentrations in WLP were determined to be 1952.9±17.6 ppm (7987.4 ± 71.9 Bq/kg) and 17.2 ± 2.4 ppm respectively. The concentrations of Th and U in LC and WLP samples determined by γ- spectrometry were 1156 ppm (4728 ± 22 Bq/kg) and 18.8 ppm and 1763.2 ppm (7211.4 Bq/kg) and 29.97 ppm respectively. This study showed that thorium concentrations were higher in WLP compare to LC. This study also indicate that WLP residue has high radioactivity of {sup 232}Th compared to Malaysian soil natural background (63 - 110 Bq/kg) and come under preview of Act 304 and regulations. In LC, the Ce and Nd concentrations determined by INAA were 13.2 ± 0.6% and 4.7 ± 0.1% respectively whereas the concentrations of La, Ce, Nd and Sm in WLP were 0.36 ± 0.04%, 1.6%, 0.22% and 0.06% respectively. This result showed that some amount of rare earth had not been extracted and remained in the WLP and may be considered to be reextracted.« less
  • Thorium-229 can be used to produce {sup 213}Bi. Researchers in phase 1 human trials are investigating the use of antibodies labeled with {sup 213}Bi for selectively destroying leukemia cells. Other types of cancer may potentially be treated using similar approaches. Crude {sup 229}Th was liberated from Rachig rings by sonication in 7.5 M HNO{sub 3} followed by filtration. Contaminants included significant levels of uranium, a number of other metals, and radiolytic by-products of di-(2-butyl) phosphoric acid extractant (which was used i the original separation of {sup 233}U from thorium). Thorium was selectively retained on Reillex HPQ anion-exchange resin from 7.5more » M HNO{sub 3} at 65%, where U(VI), Ac(III), Fe(III), Al(III), Ra(II), and Pb(II) were eluted. Thorium and uranium isotherms on Reillex HPQ are reported. The thorium was then easily eluted form the bed with 0.1 M HNO{sub 3}. To overcome mass transfer limitations of the resin, the separation was conducted at 65 C. The resin stood up well to use over several campaigns. Other researchers have reported that HPQ has excellent radiological and chemical stability. The eluted thorium was further purified by hydroxide precipitation from the organic contaminants. This process yielded 65 mCi of {sup 229}Th.« less
  • A rapid and accurate means of separating thorium and uranium was developed. Experiments have shown that the adsorption of thonium as a negatively- charged nitrate complex on strongly-basic anion exchangers from solutions containing aliphatic alcohols and nitric acid is very high compared with its adsorption from pure nitric acid solutions devoid of any organic solvent. After determining the distribution coefficients of thorium and uraninm in nitric acid solutions containing aliphatic alcohols it was possible to develop a method for the separation of thorium from uranium by means of anion exchange. (auth)