Recovery of Uranium from Philippine Wet Phosphoric Acid Using D2EHPA-TOPO Solvent Extraction
Botvinnik L. Palattao*, Jennyvi D. Ramirez, Estrellita U. Tabora,
Editha A. Marcelo, Edmundo P. Vargas, Socorro P. Intoy,
Reymar R. Diwa, and Rolando Y. Reyes
Philippine Nuclear Research Institute - Department of Science and Technology
Quezon City, Manila 1101 Philippines
Recovery of uranium from Philippine wet phosphoric acid was studied using a synergistic mixture of 0.5 M D2EHPA - 0.125 M TOPO diluted in kerosene. Results from characterization of materials in phosphate processing revealed the presence of valuable elements such as uranium and rare earths in both raw materials and fertilizer products. Variation of operating parameters on extraction such as P2O5 content and optical density was found to be inversely proportional with the extraction efficiency. The reaction was found to establish rapid equilibrium and is exothermic in nature. Distribution coefficient for the extraction of uranium from 27% P2O5 phosphoric acid was determined to be at 10.71 at about 25°C. Analysis of the equilibrium data and McCabe-Thiele plot based on batch testing indicates a 92.59% recovery rate could be achieved in three-ideal extraction stages at an aqueous to organic phase volume ratio of 4:1.
Key words: D2EHPA-TOPO, Philippines, phosphate fertilizer, phosphoric acid, uranium extraction
Phosphate rocks contain a wide variety of useful elements apart from phosphorus used in making fertilizers. Among these elements that are of value contained in the mineral are uranium, thorium, radium, and rare earths elements (REE) (Preston et al. 1996; Kouraim et al. 2014; Emsbo et al. 2015; Ramos et al. 2016). In the wet processing of phosphate rock, the mineral is broken down by sulfuric acid, which then produces two intermediate products, namely phosphoric acid and phosphogypsum precipitate. During this process, trace elements like REE and naturally occurring radionuclides uranium, thorium, and radium contained in mineral distributes into these intermediate products. Majority of the uranium and thorium content in the rocks are reported to redistribute itself into the acid phase (Hodge & Popovici 1994; Rutherford et al. 1994; Singh et al. 2009; Haneklaus et al. 2017) while most of the rare earths, and along with radium, precipitates with the phosphogypsum (USEPA 1992; Sahu et al. 2014; Kulczycka et al. 2015). The phosphoric acid is then further converted into fertilizers and, in the process, transfers all valuable elements into the product that is then consequently lost during land application. These valuable elements, if left in fertilizers, are considered as heavy metal contaminants and may pose negative environmental impacts. However, if recovered from phosphoric acid prior to fertilizer production, it presents a huge opportunity to utilizing these strategic metals in technological applications and/or marketable way. Recovery of these valuable elements thus, is not only a means of maximizing the mineral potential but also a means of environmental stewardship. . . . . . read more
BELTRAMI D, COTE G, MOKHTARIH, COURTAUD B, MOYER BA, CHAGNES A. 2014. Recovery of uranium from wet phosphoric acid by solvent extraction processes. Journal of American Chemical Society 114(24): 12002-23.
BELTZ K, FRANKENFELD K, LEHMANN R, ZINTL I. 1983. US Patent No. US4383978 A. USA: United States Patent. Retrieved from https://www.google.com/patents/US4383978 on 20 Sep 2017.
BROOK BW, ALONZO A, MENELEY DA, MISAK J, BLEES T, VAN ERP JB. 2014. Why nuclear energy is sustainable and has to be part of the energy mix. In: Sustainable Materials and Technologies. Retrieved from https://doi.org/10.1016/j.susmat.2014.11.001.
CRUZ PS. 1997. Aquaculture feed and fertilizer resource atlas of the Philippines. Retrieved from http://www.fao.org/3/a-w6928e.HTM on 2016.
DILLARD EF, FRAZIER AW, WOODIS TC. 1982. Precipitated impurities in 18-46-0 fertilizers prepared from wet-process phosphoric acid. Journal of Agricultural Food Chemistry 30: 382-388.
DARTIGUELONGUE A, CHAGNES A, PROVOST E, FURST W, COTE G. 2015. Modelling of uranium (VI) extraction by D2EHPA/TOPO from phosphoric acid within a wide range of concentrations. Hydrometallurgy, doi:10.1016/j.hydromet.2015.11.007.
EMSBO P, MCLAUGHLIN PI, BREIT GN, DU BRAY EA, KOENIG AE. 2014. Rare earth elements in sedimentary phosphate deposits: Solution to the global REE crisis? Gondwana Research 27(2015): 776-85. Retrieved from doi:10.1016/j.gr.2014.10.008.
GUPTA C, SINGH H. 2003. Uranium resource processing: secondary resources. Germany: Springer. p. 309-345.
HANEKLAUS N, REYES RY, LIM WG, TABORA EU, PALATTAO BL, PETRACHE C, VARGAS EP, KUNITOMI K, OHASHI H, SAKABA N, SATO H, GOTO M, YAN X, NISHIHARA T, TULSIDASH, REITSMA F, TARJAN S, SATHRUGNAN K, JACIMOVIC R, AL KHALEDI N, BIRKY BK, SCHNUG E. 2015. Energy neutral phosphate fertilizer production using high temperature reactors - a Philippine case study. Philippine Journal of Science 44(1): 69-79.
HANEKLAUS N, SUN Y, BOL R, LOTTERMOSER B, SCHNUG E. 2017. To extract, or not to extract uranium from phosphate rock, that is the question. Environmental Science and Technology 51: 753-754. Retrieved from http://pubs.acs.org/doi/pdfplus/10.1021/acs.est.6b05506.
HODGE CA, POPOVICI N. ed. 1994. Pollution control in fertilizer production. ed. NY: Marcel Dekker Incorporated. p. 237-250.
HURST FJ, CROUSE DJ, BROWN KB. 1972. Recovery of uranium from wet phosphoric acid. Industrial and Engineering Chemistry Process Design and Development 11(1): 122-128.
IAEA. 1987. IAEA-TECDOC-533. Recovery of uranium from phosphoric acid. Vienna, Austria: International Atomic Energy Agency. Retrieved from http://www-pub.iaea.org/MTCD/publications/PDF/te_0533.pdf on 11 Feb 2016.
IAEA. 1992. Analytical techniques in uranium exploration and ore processing (Technical Report Series 341). Vienna, Austria: International Atomic Energy Agency. p. 65-72. Retrieved from http://www-pub.iaea.org/MTCD/Publications/PDF/trs341_web.pdf on 15 Sep 2017.
KHLEIFIA N, HANNACHI A, ABBES N. 2013. Studies of uranium recovery from Tunisian wet process phosphoric acid. International Journal of Innovation and Applied Studies 3(4): 1066-71.
KOURAIM MN, FAWZY MM, HELALY OS. 2014. Leaching of lanthanides from phosphogypsum waste using nonyl phenol ethoxylate associated with HNO3 and HCl. International Journal of Sciences: Basic and Applied Research 16(2): 31-44.
KULCZYCKA J, KOWALSKI Z, SMOL M, WIRTH H. 2015. Evaluation of the recovery of Rare Earth Elements (REE) from phosphogypsum waste – case study of the WIZÓW Chemical Plant (Poland). Journal of Cleaner Production. Retrieved from doi: 10.1016/j.jclepro.2015.11.039.
ÖZAYTEKIN H, UYANÖZ R. 2012. Trace and Rare Earth Element (REE) status of ÇarsambaFan soils in the ancient Konya lake region, Turkey. African Journal of Agricultural Research 7(7): 1110-17.
PETRACHE C, MARCELO EA, SANTOS JR G. 1987. Notes on the extraction of uranium from phosphoric acid. Philippine Technology Journal 12(4): 95-99.
PRESTON JS, COLE PM, CRAIG WM, FEATHER AM. 1996. The recovery of rare earth oxides from a phosphoric acid by-product. Part 1: Leaching of rare earth values and recovery of a mixed rare earth oxide by solvent extraction. Hydrometallurgy 41: 1-19.
RAMOS SJ, DINALI GS, DE CARVALHO TS, CHAVES LC, SIQUEIRA LC, GUILHERME LRG. 2016. Rare earth elements in raw materials and products of the phosphate fertilizer industry in South America: Content, signature, and crystalline phases. Journal of Geochemical Exploration 168: 177-186.
ROTHBAUM HP, MCGAVESTON DA, WALL T, JOHNSTON AE. 1979. Uranium accumulation in soils from long-continued applications of superphosphate. European Journal of Soil Science 30: 147-153.
RUTHERFORD PM, DUDAS MJ, SAMEK RA. 1994. Environmental impacts of phosphogypsum. Science of the Total Environment 149(1-2): 1-38.
SAHU SK, AJMAL PY, BHANGARE RC, TIWARI M, PANDIT GG. 2014. Natural radioactivity assessment of a phosphate fertilizer plant area. Journal of Radiation Research and Applied Sciences 7(1): 123-128. Retrieved from https://doi.org/10.1016/j.jrras.2014.01.001.
STAS J, OTHMAN I, ABBAS M, SHLEWIT H. 2010. Uranium extraction from Syrian phosphate: A case study. Journal of Economics and Environmental Geology 1(2): 30-34.
SINGH SK, DHAMI PS, TRIPATHI SC, DAKSHINAMOORTY A. 2009. Studies on the recovery of uranium from phosphoric acid medium using synergistic mixture of (2-ethyl hexyl) phosphonic acid, mono(2-ethylh hexyl ester (PC**A) and tri-n-butyl phosphate (TBP). Hydrometallurgy 95: 170-174.
[STC] Scientific and Technical Committee Euratom. 2003. The energy challenge of the 21st century: The role of nuclear energy. Belgium: European Communities. p. 2-9. Retrieved from http://cordis.europa.eu/pub/fp6/docs/euratom_challenge_21stcentury.pdf on 20 Dec 2017.
[USEPA] United States Environmental Protection Agency. 1992. Potential uses of phosphogypsum and associated risks. Retrieved from https://www.epa.gov/sites/production/files/2015-07/documents/0000055v.pdf on 9 Sept 2017.
[WNA] World Nuclear Association. 2016. Supply of uranium. Retrieved from http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources/supply-of-uranium.aspx on 20 Dec 2016.