Dissolution of Calcareous Phosphate Rock from Gafsa (Tunisia) Using Dilute Phosphoric Acid Solution


In the present study, porous structure of raw and calcined phosphate ore particles was examined. The specific surface area and the pore volume were determined by nitrogen adsorption. Raw particles and calcined ores were leached using dilute phosphoric acid solution (4% P2O5). In all cases, the ESEM (Environmental Scanning Electron Microscopy) observations show that the grain of phosphate holds its shape ovoidale. The sample heated at 780?C presented the lowest specific surface area 0.6 m2/g at each reaction time, and the unreacted phases were analysed using XRD, FT-IR, Nitrogen adsorption and ESEM observations. The selective leaching curves were evaluated in order to test the validity of kinetics models. A mathematical model in the following form was applied. The dissolution of the two samples (raw and calcined phosphate) has been observed to take place in two steps: the first being fast and the second being slow.

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Lefires, H. , Medini, H. , Megriche, A. and Mgaidi, A. (2014) Dissolution of Calcareous Phosphate Rock from Gafsa (Tunisia) Using Dilute Phosphoric Acid Solution. International Journal of Nonferrous Metallurgy, 3, 1-7. doi: 10.4236/ijnm.2014.31001.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] [1] J. B. Sardisco, D. E. Holcomb and E. K. Drechsel, “Phosphoric Acid and Additional Products from Phosphate Ore,” US Patent, Vol. 4, No. 479, 1984, p. 923.
[2] T. Gunduz and B. Gumgum, “The Enrichment of LowGrade Mazidagi Phosphates by Calcination and Extraction Methods,” Separation Science and Technology, Vol. 22, No. 6, 1987, pp. 1645-1648.
[3] S. I. Abu-Eishah, I. S. El-Jallad, M. Muthaker, M. Touqan and W. Sadeddin, “Beneficiation of Calcareous Phosphate Rocks Using Dilute Acetic Acid Solutions: Optimisation of Operating Conditions for Ruseifa (Jordan) Phosphate,” International Journal of Mineral Processing, Vol. 31, No. 1-2, 1991, pp. 115-126.
[4] E. D. Economou, T. C. Vaimakis and E. M. Papmichael, “The Kinetics of Dissolution of the Carbonate Minerals Phosphate Ore Using Dilute Acetic Acid Solutions, the Case of PH Range from 3.96 to 6.40,” Journal of Colloid and Interface Science, Vol. 245, No. 1, 2002, pp. 133-141.
[5] M. Ashraf, Z. I. Zafar and T. M. Ansari, “Selective Leaching Kinetics and Upgrading of Low-Grade Calcareous Phosphate Rock in Succinic Acid,” Hydrometallurgy, Vol. 80, No. 4, 2005, pp. 286-292.
[6] H. Sengul, A. K. Ozer and M. S. Gulaboglu, “Benefication of Mardin-Mazidagi (Turkey) Calcareous Phosphate Rock Using Dilute Acetic Acid Solutions,” International Journal of Mineral Processing, Vol. 30, 2006, pp. 113-125.
[7] Z. I. Zafar and M. Ashraf, “Selective Leaching Kinetics of Calcareous Phosphate Rock in Lactic Acid,” The Canadian Journal of Chemical Engineering, Vol. 131, No. 1-3, 2007, pp. 41-48.
[8] E. M. E. Ouradi, “Etude de la Calcination du Phosphate Clair de Youssoufia (Maroc),” Afrique science Vol. 4, No. 2, 2008, pp. 199-211.
[9] F. Ben Brahim, A. Mgaidi and M. El Maaoui, “Exploration of Mesoporous Structure of Tunisian Raw and Acid-Leached Phosphate Ore Particles,” The Canadian Journal of Chemical Engineering, Vol. 75, No. 4, 1997, pp. 759-764.
[10] A. Mgaidi, F. Ben Brahim, D. Oulahna, A. Nzihou and M. El Maaoui, “Chemical and Structural Changes of Raw Phosphate during Heat Treatment,” High temperature Materails and Processes, Vol. 23, No. 3, 2004, p. 183.
[11] F. B. Brahim, “Dissolution des Phosphates Naturels dans l’Acide Phosphorique Dilué,” Ph.D. Thesis, Faculty of Science of Tunis, University El Manar, Tunisia, 1999.
[12] P. Blazy and E.-A. Jdid, “Calcination du Phosphate Sédimentaire à Gangues Carbonatée en Four Rotatif d’Akashat (Irak) et en Four Eclair (flash),” Comptes Rendus de l’Académie des Sciences, Vol. 325, No. 10, 1997, pp. 761-764.
[13] M. Gharabaghi, M. Noaparast and M. Irannajad, “Selective Leaching Kinetics of Low-Grade Calcareous Phosphate Ore in Acetic Acid,” Hydrometallurgy, Vol. 95, No. 3-4, 2008, pp. 341-345
[14] E. O. Hoffmann, W. E. Cate, M. E. Demin and K. L. Elmore, “Rates of Solution of Calcium Phosphates Inn Phosphoric Acid Solutions,” Journal of Agricultural and Food Chemistry, Vol. 5, No. 4, 1957, pp. 266-275.
[15] A. Yartasi, M. Kocakerim, S. Yapici and C. Ozmetin, “Dissolution Kinetics of Phosphate Ore in SO2-Saturated Water,” Industrial & Engineering Chemistry Research, Vol. 33, No. 9, 1994, pp. 2220-2225.
[16] Y. Abali, S. Colak, A. Yartazi, “Dissolution Kinetics of Phosphate Rock with Cl2 Gas in Water,” Hydrometallurgy, Vol. 46, No. 1-2, 1997, pp. 13-25.
[17] A. Brassens, “Mise en Evidence de Deux Types D’eau et de Deux Localisations des Ions CO32dans la Matière Phosphatée d’un Phosphate Sedimentaire Marocain,” Comptes Rendus de l’Académie des Sciences, 1975, p. 280.
[18] C. Szilas, C. B. Koch, M. M. Msolla and O. K. Broggard, “The Reactivity of Tanzanian Minjingu Phosphate Rock Can Be Assessed from the Chemical and Mineralogical Composition,” Geoderma1, Vol. 47, No. 3-4, 2008, pp. 172-177. http://dx.doi.org/10.1016/j.geoderma.2008.08.009

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