Studies on the transformation of calcium sulphate dihydrate to hemihydrate in the wet process phosphoric acid production

• Autorzy: Grzmil B. , Kuc B. , Żurek O. , Kubiak K.
• Języki publikacji: EN

Abstrakty

EN

The influence of the process temperature from 85°C to 95°C, the content of phosphates and sulphates in the wet process phosphoric acid (about 22-36 wt% P2O5 and about 2-9 wt% SO42-) and the addition of ?CaSO4ź0.5H2O crystallization nuclei (from 10% to 50% in relation to CaSO4ź2H2O) on the transformation of calcium sulphate dihydrate to hemihydrate has been determined. The wet process phosphoric acid and phosphogypsum from the industrial plant was utilized. They were produced by reacting sulphuric acid with phosphate rock (Tunisia) in the DH-process. The X-ray diffraction analysis was used to determine the phase composition and fractions of various forms of calcium sulphates in the samples and the degree of conversion of CaSO4ź2H2O to ?CaSO4ź0.5H2O and CaSO4. It was found that the transformation of CaSO4ź2H2O to ?CaSO4ź0.5H2O should be carried out in the presence of ?CaSO4ź0.5H2O crystallization nuclei as an additive (in the amount of 20% in relation to CaSO4ź2H2O), at temperatures 90š2°C, in the wet process phosphoric acid containing the sulphates and phosphates in the range of 4š1 wt% and 27š1 wt%, respectively.

Słowa kluczowe

EN

wet process phosphoric acid; phosphogypsum; transformation; calcium hemihydrate

PL

kwas fosforowy; fosfogips; transformacja; półhydrat wapnia

• Wydawca: West Pomeranian University of Technology. Publishing House
• Czasopismo: Polish Journal of Chemical Technology
• Rocznik: 2012
• Tom: Vol. 14, nr 2
• Strony: 80--87
• Opis fizyczny: Bibliogr. 23 poz., rys., tab.

Twórcy

autor

Grzmil B.

autor

Kuc B.

autor

Żurek O.

autor

Kubiak K.

• Institute of Chemical and Environment Engineering, West Pomeranian University of Technology, Szczecin, ul. Pułaskiego 10, 70-322 Szczecin, Poland,

Bibliografia

• 1. Heffer, P. & Prud’homme, M. (2009). Summary Report ‘Medium-Term Outlook for Global Fertilizer Demand, Supply and Trade: 2009–2013, Part 1- Global Economic Context and Agricultural Situation, 77th IFA Annual Conference, Shanghai, May 1–10.
• 2. Heffer, P. & Prud’homme, M. (2008). Outlook for World Fertilizer Demand, Supply, and Supply/Demand Balance. Turk J. Agric. For. 32(3), 159–164. TAR-0803-38.
• 3. Schlag, S. (2010). Wet-Process Phosphoric Acid, CEHReport.
• 4. Becker, P. (1989.) Phosphates and phosphoric acid (second ed.). Marcel Dekker, Inc., New York.
• 5. Integrated Pollution Prevention and Control Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers, European IPPC Bureau, Seville, August 2007, from http://eippcb.jrc.es/
• 6. Papadopoulosa, A.I. & Seferlis, P. (2009). Generic modelling, design and optimization of industrial phosphoric acid production processes. Chem. Eng. Process. 48(1), 493–506. DOI: 10.1016/j.cep.2008.06.011.
• 7. Abu-Eishah, S.I. & Abu-Jabal, N.M. (2001). Parametric study on the production of phosphoric acid by the dihydrate process. Chem. Eng. J. 81(1–3), 231–250. DOI: 10.1016/S1385- 8947(00)00166-2.
• 8. Agarwal, S.S. & Murugaperumal, S. (1998). HDH proces technology for phosphoric acid production. Phosph. Potass. 214, 38–42.
• 9. Singh, N.B. & Middendorf, B. (2007). Calcium sulphate hemihydrate hydration leading to gypsum crystalization. Prog. Cryst. Growth Charact. Mater. 53(1), 57–77. DOI: 10.1016/j. pcrysgrow.2007.01.002.
• 10. El Moussaouiti, M. Boistelle, R. Bouhaouss, A. & Klein, J.P. (1997). Crystalization of calcium sulphate hemihydrate in concentrated phosphoric acid solutions. Chem. Eng. J. 68(2–3), 123–130. DOI: 10.1016/S1385-8947(97)00116-2.
• 11. Prayon displays its phosphate technology and operations. (1991). Phosph. Potass. 174, 38–42.
• 12. Mitsui Toatsu Chemicals’MT-50 Hemihydrate-Dihydrate Phosphoric Acid Process. (1988). Phosph. Potass. 157, 29–31.
• 13. Phosphoric acid technology at large. (1999). Phosph. Potass. 221, 55–59.
• 14. Phosphoric acid technology at large –Part II. (1999). Phosph. Potass. 224, 19–25.
• 15. Dorozhkin, S.V. (1997). Fundamentals of Wet-Process phosphoric Acid production. 2. Kinetics and Mechanism of CaSO4 0.5H2O Surface Crystallization and Coating Formation. Ind. Eng. Chem. Res. 36(2), 467–473. DOI: 10.1021/ie960219f.
• 16. Xibing Li, Zilong Zhou, Guoyan Zhao, & Zhixiang Liu. (2008). Utilization of phosphogypsum for backfi lling, way to relieve its environmental impact. Gospodarka Surowcami Mineralnymi, 24(4/3), 226–232.
• 17. Altun, I.A. & Sert, Y. (2004). Utilization of weathered phosphogypsum as set retarder in Portland cement. Cem. Concr. Res. 34(4), 677–680. DOI: 10.1016/j.cemconres.2003.10.017.
• 18. Weiguo Shen, Mingkai Zhhou, & Qinglin Zhao. (2007). Study on lime-fl y ash-phosphogypsum binder. Constr. Buil. Mater. 21(7), 1480–1485. DOI: 10.1016/j.conbuildmat.2006.07.010.
• 19. Rusch, K.A. Guo, T. & Seals, R.K. (2002). Stabilization of phosphogypsum using class C fl y ash and lime: assessment of the potential for marine applications. J. Hazard. Mater. 93(2), 167–186. DOI: 10.1016/S0304-3894(02)00009-2.
• 20. Dang, L. Wie, H. Zhu, Z. & Wang, J. (2007). The infl uence of impurities on phosphoric acid hemihydrate crystallization. J. Cryst. Growth, 307(1), 104–111. DOI: 10.1016/j.jcrysgro.2007.05.041.
• 21. Thyes, T. (2003). Infl uence of the rock impurities on the phosphoric avid process, products and some downstream uses, IFA Technical Committee Meeting, Abu Dabi, October 2003.
• 22. Hamdona, S.K. & Al Hadad, U.A. (2007). Crystallization of calcium sulphate dihydrate in the presence of some metal ions, J. Cryst. Growth, 299(1), 146–151. DOI: 10.1016/j.jcrysgro.2006.11.139.
• 23. Rashad, M.M. Mahmoud, M.H.H. Ibrahim, I.A. & Abdel--Aal, E.A. (2004). Crystallization of calcium sulphate dihydrate under simulated conditions of phosphoric acid production in the presence of aluminum and magnesium ions. J. Cryst. Growth, 267(1–2), 372–379. DOI: 10.1016/j.jcrysgro.2004.03.060.