226Ra dynamic lixiviation from phosphogypsum samples by an automatic flow-through system with integrated renewable solid-phase extraction.
The release of226Ra from phosphogypsum (PG) was evaluated by developing a novel tool for fully automated226Ra lixiviation from PG integrating extraction/pre-concentration using a renewable sorbent format. Eight leached fractions (30mL each one) and a residual fraction were analyzed allowing the evaluation of dynamic lixiviation of226Ra. An automatic system allows this approach coupling a homemade cell with a226Ra extraction/pre-concentration method, which is carried out combining two procedures: Ra adsorption on MnO2and its posterior co-precipitation with BaSO4. Detection was carried out with a low-background proportional counter, obtaining a minimum detectable activity of 7Bqkg-1. Method was validated by analysis of a PG reference material (MatControl CSN-CIEMAT 2008), comparing the content found in fractions (sum of leached fractions + residual fraction) to the reference value. PG samples from Huelva (Spain) were studied.226Ra average activity concentration of the sum of leached fractions with artificial rainwater at pH 5.4±0.2 was 105±3Bqkg-1d.w. representing a226Ra lixiviation of 37%; while at pH 2.0±0.2, it was 168±3Bqkg-1d.w., which represents a 50%. Also, static lixiviation, maintaining the same experimental conditions, was carried out indicating that, for both considered pH, the226Ra release from PG is up to 50% higher in a dynamic leaching that in a static one, may have both environmental and reutilization implications.
Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, 07122 Palma de Mallorca, Spain; Sciware Systems, S.L., R&D department, 07193 Bunyola, Spain.
Melisa Rodas
MR
Ceballos
Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, 07122 Palma de Mallorca, Spain.
Antoni
A
Borràs
Dpto. Física Aplicada II, Universidad de Sevilla, ETSA, Avda. Reina Mercedes s/n, 41012 Seville, Spain.
Rafael
R
García-Tenorio
Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, 07122 Palma de Mallorca, Spain.
Rogelio
R
Rodríguez
Environmental Analytical Chemistry Laboratory (LQA(2)), University of the Balearic Islands, 07122 Palma de Mallorca, Spain.
José Manuel
JM
Estela
Environmental Analytical Chemistry Laboratory (LQA(2)), University of the Balearic Islands, 07122 Palma de Mallorca, Spain.
Víctor
V
Cerdà
Environmental Radioactivity Laboratory (LaboRA), University of the Balearic Islands, 07122 Palma de Mallorca, Spain. Electronic address: laura.ferrer@uib.es.
Laura
L
Ferrer
D001331:Automation; D002133:Calcium Sulfate / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry*; D011883:Radium / Q000032:analysis / Q000302:isolation & purification*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction / Q000379:methods*
C077769:phosphogypsum; D010758:Phosphorus; C000615152:Radium-226; D011883:Radium; D002133:Calcium Sulfate
(226)Ra; Automatic flow system; Dynamic lixiviation; Phosphogypsum