Radionuclides, trace elements, and radium residence in phosphogypsum of Jordan
- 238 Downloads
Voluminous stockpiles of phosphogypsum (PG) generated during the wet process production of phosphoric acid are stored at many sites around the world and pose problems for their safe storage, disposal, or utilization. A major concern is the elevated concentration of long-lived 226Ra (half-life = 1,600 years) inherited from the processed phosphate rock. Knowledge of the abundance and mode-of-occurrence of radium (Ra) in PG is critical for accurate prediction of Ra leachability and radon (Rn) emanation, and for prediction of radiation-exposure pathways to workers and to the public. The mean (±SD) of 226Ra concentrations in ten samples of Jordan PG is 601 ± 98 Bq/kg, which falls near the midrange of values reported for PG samples collected worldwide. Jordan PG generally shows no analytically significant enrichment (<10%) of 226Ra in the finer (<53 μm) grain size fraction. Phosphogypsum samples collected from two industrial sites with different sources of phosphate rock feedstock show consistent differences in concentration of 226Ra and rare earth elements, and also consistent trends of enrichment in these elements with increasing age of PG. Water-insoluble residues from Jordan PG constitute <10% of PG mass but contain 30–65% of the 226Ra. 226Ra correlates closely with Ba in the water-insoluble residues. Uniformly tiny (<10 μm) grains of barite (barium sulfate) observed with scanning electron microscopy have crystal morphologies that indicate their formation during the wet process. Barite is a well-documented and efficient scavenger of Ra from solution and is also very insoluble in water and mineral acids. Radium-bearing barite in PG influences the environmental mobility of radium and the radiation-exposure pathways near PG stockpiles.
KeywordsRadium Rare earth elements Phosphogypsum Barite Radiobarite Jordan
This research was conducted over 9 months in 2004–2005 while the second author, M.S. Al-Hwaiti, was a visiting Fulbright Scholar at the Colorado School of Mines, Golden, Colorado. We thank the personnel of the Aqaba Industrial Complex and the Indo-Jordan Chemical Company for site access and for support of field sampling. R. L. Driscoll of the US Geological Survey (USGS) performed X-ray diffraction analysis and fine-particle separations. H.A. Lowers of the USGS provided assistance with the operation of the scanning electron microscope. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US government.
- Abed, A. M. (1994). Shallow marine phosphorite-chert-palygorskite association, Upper Cretaceous Amman Formation, Jordan. In A. Iijima, A. M. Abed, & R. Garrison (Eds.), Siliceous, phosphatic and glauconitic sediments in the Tertiary and Mesozoic. Proceedings of the 29th international geology congress, part C (pp. 205–224). The Netherlands: VSP.Google Scholar
- Abed, A. M., & Abu-Murry, O. S. (1997). Rare earth element geochemistry of the Jordanian Upper Cretaceous Phosphorites. The Arab Gulf Journal Science Research, 15(1), 41–61.Google Scholar
- Abed, A. M., Rushdi, S., & Mustafa, A. (2008). Uranium and potentially toxic metals during the mining, beneficiation, and processing of phosphorite and their effects on ground water in Jordan. Mine Water Environment. doi:10.1007/s10230-008-0039-3.
- Abed, A. M., & Sadaqah, R. (1998). Role of Upper Cretaceous oyster buildups in the deposition and accumulation of high-grade phosphorites in central Jordan. Journal of Sediment Research, 68(5), 1009–1020.Google Scholar
- Abril, J. M., Garcia-Tenorio, R., Perianez, R., Enamorado, S. M., Andreu, L., & Delgado, A. (2009). Occupational dosimetric assessment (inhalation pathway) from the application of phosphogypsum in agriculture in southwest Spain. Journal of Environmental Radioactivity, 100, 29–34.CrossRefGoogle Scholar
- Adrianov, A. M., Rusin, N. F., Burtnenko, L. M., & Fedorenko, V. D. (1976). Influence of the main process parameters on the effectiveness of leaching of rare earth elements (RE) from phosphogypsum by sulfuric acid. Journal of Applied Chemistry, USSR, 49, 656–658.Google Scholar
- Al-Masri, M. S., Ali, A. I., Khietou, M., & Al-Hares, Z. (1999). Leaching of Ra-226 from Syrian phosphogypsum. In G. W. A. Newton (Ed.), Environmental radiochemical analysis (pp. 21–29). London: Royal Society of Chemistry.Google Scholar
- Berdanosova, D. G., Burlakova, E. V., Yasenkova, M. A., Ivanov, L. N., & Melikhov, I. V. (1989). Characteristics of transfer of europium ions from phosphoric acid solutions into the CaSO4 · 0.5H2O solid phase. Journal of Applied Chemistry USSR, 62, 211–216.Google Scholar
- Berish, C. W. (1990). Potential environmental hazards of phosphogypsum storage in central Florida. Proceedings of the third international symposium on phosphogypsum, Orlando, Florida, Florida Institute of Phosphate Research FIPR pub. no. 01-060-083, Vol. 2, pp. 1–29.Google Scholar
- Budahn, J. R., & Wandless, G. A. (2002). Instrumental neutron activation analysis by long count. In J. E. Taggert (Ed.), Analytical methods for chemical analysis of geologic and other materials, US Geological Survey. US Geological Survey open-file report 02-223, Chap. X, pp. X1–X13.Google Scholar
- Burnett, W. C., Chin, P., Deetae, S., & Panik, P. (1988). Release of radium and other decay-series isotopes from Florida phosphate rock. Final report, Florida Institute of Phosphate Research FIPR pub. 05-016-059.Google Scholar
- Burnett, W. C., Cowart, J. B., LaRock, P., & Hull, C. D. (1995). Microbiology and radiochemistry of phosphogypsum. Final report, Florida Institute of Phosphate Research FIPR pub. 05-035-115.Google Scholar
- Burnett, W. C., Schaefer, G., & Schultz, M. K. (1999). Fractionation of Ra-226 in Florida phosphogypsum. In G. W. A. Newton (Ed.), Environmental radiochemical analysis (pp. 1–20). London: Royal Society of Chemistry.Google Scholar
- Capetta, H., Pfeil, F., Schmidt-Kittler, N., & Martini, E. (1996). New biostratigraphic data on the marine Upper Cretaceous and Paleogene of Jordan. Jordan Phosphate Mining Company, Amman Jordan, Internal report.Google Scholar
- European Directive. (1996). Directive 96/29/Euratom-ionizing radiation. http://osha.europa.eu/en/legislation/directives/exposure-to-physical-hazards/osh-directives/73.
- Federal Register. (1990, 10 April). Vol. 55, No. 69, pp. 13480–13481.Google Scholar
- Federal Register. (1991, 21 May). Vol. 56, p. 23398. http://www.nrc.gov/reading-rm/doc-collections/cfr/part020/part020-1301.html.
- Federal Register. (1992, 3 June). Vol. 57, No. 107, pp. 23305–23320.Google Scholar
- Fedorak, P. M., Westlake, D. W. S., Anders, C., Kratochvil, B., Motosky, N., Anderson, W. B., & Huck, P. M. (1986). Microbial release of 226Ra+2 from (Ba,Ra)SO4 sludges from uranium mine wastes. Appl. Environ. Microbiol. 52, 262–268.Google Scholar
- Grauch, R. I., Desborough, G. A., Meeker, G. P., Foster, A. L., Tysdal, R. G., & Herring, J. R. (2004). Petrogenesis and mineralogic residence in the Meade Peak Phosphatic Shale Member of the Permian Phosphoria Formation, southeast Idaho. In J. R. Hein, et al. (Eds.), Life cycle of the Phosphoria formation: from deposition to the post-mining environment. Handbook of exploration and environmental geochemistry (Vol. 8, pp. 189–226). Amsterdam: Elsevier.CrossRefGoogle Scholar
- Masri, A. (1992). The geology of the Ath-Thulaythuat area. Map sheet no. 3249 III. Bull. no. 23, Natural Resources Authority, Jordan.Google Scholar
- May, A., & Sweeney, J. W. (1984). Evaluation of radium and toxic element leaching characteristics of Florida phosphogypsum. In R. A. Kuntz (Ed.), The chemistry and technology of gypsum (pp. 140–159). Washington, DC: American Society of Testing Materials ASTM Spec. Tech. pub. no. 861.Google Scholar
- Michel, J. (1987). Radon transport mechanisms. In C. R. Cothern & J. E. Smith Jr. (Eds.), Environmental radon (pp. 86–92). New York: Plenum.Google Scholar
- Moisset, J. (1980). Radium removal from phosphogypsum. Proceedings of the international symposium on phosphogypsum, Lake Buena Vista, Florida, Florida Institute of Phosphate Research FIPR pub. no. 01-001-017, pp. 383–397.Google Scholar
- Moisset, J. (1988). Location of radium in phosphogypsum and improved process for removal of radium from phosphogypsum. Proceedings of the second international symposium on phosphogypsum, Miami, Florida, Florida Institute of Phosphate Research FIPR pub. no. 01-037-055, Vol. 1, pp. 303–317.Google Scholar
- Moisset, J. (1990). Complete removal of radium from phosphogypsum. Proceedings of the third international symposium on phosphogypsum, Orlando, Florida, Florida Institute of Phosphate Research FIPR pub. no. 01-060-083, Vol. 1, pp. 181–196.Google Scholar
- Quennell, A. M. (1951). The geology and mineral resources of Transjordan. Colonial Geology and Mineral Resources, 2, 85–115.Google Scholar
- Rashdan, M. (1988). The regional geology of the Aqaba-Wadi Arab area. Map sheets 3049 II. Geological Mapping Division, Natural Resources Authority.Google Scholar
- Roessler, C. E., Smith, C. A., & Bolch, W. E. (1979b). Management of low-level natural radioactivity wastes of phosphate mining and processing. Proceedings of the twelfth midyear topical symposium of the health physics society, Williamsburg, Virginia, pp. 182–195.Google Scholar
- Sadaqah, R. M., Abed, A. M., Grimm, K. A., & Pufahl, P. K. (2005). The geochemistry of rare earth elements (REE), yttrium (Y) and scandium (Sc) in some upper Cretaceous Jordanian phosphorites. Dirasat Pure Sciences, 32(1), 32–47.Google Scholar
- Smith, R. M., & Martell, A. E. (1976). Critical stability constants volume 4: Inorganic complexes. New York: Plenum.Google Scholar
- Sofremines. (1984). Ore reserve evaluation. Report no. II. Jordan Phosphate Mines Company, Amman, Jordan, 149 pp.Google Scholar
- US Geological Survey. (2008). Mineral commodity summaries: Phosphate rock. http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rocks/mcs-2008-phosp.pdf.