Study on reactions of gaseous P2O5 with Ca3(PO4)2 and SiO2 during a rotary kiln process for phosphoric acid production

doi:10.1016/j.cjche.2017.11.016

摘要/Abstract

摘要： In a rotary kiln process for phosphoric acid production, the reaction between gaseous phosphorus pentoxide (P₂O₅) and phosphate ore and silica contained in feed balls (the so-called P₂O₅ "absorption") not only reduces phosphorous recovery but also generates a large amount of low melting-point side products. The products may give rise to formation of kiln ring, which interferes with kiln operation performance. In this study, the reactions of gaseous P₂O₅ with solid calcium phosphate (Ca₃(PO₄)₂), silica (SiO₂) and their mixture, respectively, were investigated via combined chemical analysis and various characterizations comprised of X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis and differential scanning calorimeter (TG&DSC), and scanning electron microscopy and energy dispersive spectrometer (SEM&EDS). Attentions were focused on apparent morphology, phase transformation and thermal stability of the products of the P₂O₅ "absorption" at different temperatures. The results show that the temperature significantly affected the "absorption". The reaction between pure Ca₃(PO₄)₂ and P₂O₅ occurred at 500℃. Calcium metaphosphate (Ca(PO₃)₂) was the primary product at the temperatures ≤ 900℃ with its melting point ≤ 900℃ while calcium pyrophosphate (Ca₂P₂O₇) was obtained over 1000℃, which has a melting point ≤ 1200℃. The "absorption" by pure SiO₂ started at 800℃ and the most significant reaction occurred at 1000℃ with formation of silicon pyrophosphate (SiP₂O₇) product of melting point ≤ 1000℃. Using mixed Ca₃(PO₄)₂ and SiO₂ as raw material, the "absorption" by Ca₃(PO₄)₂ was enhanced due to existence of silica. At 600-700℃, silica was inert to P₂O₅ and thus formed a porous structure in the raw material, which accelerated diffusion of gaseous P₂O₅ inside the mixture. At higher temperatures, the combined "absorption" by calcium phosphate and reaction between silicon dioxide and the "absorption" product calcium pyrophosphate, reinforced the "absorption" by the mixture. Besides, it was found that both Ca(PO₃)₂ and SiP₂O₇ were unstable at high temperatures and would decompose to Ca₂P₂O₇ and SiO₂, respectively, at over 1000℃ and 1100℃ with the release of gaseous P₂O₅ at the same time.

关键词: Kiln phosphoric acid, Kiln ring, Absorption, Calcium metaphosphate, Calcium pyrophosphate, Back reaction

Abstract: In a rotary kiln process for phosphoric acid production, the reaction between gaseous phosphorus pentoxide (P₂O₅) and phosphate ore and silica contained in feed balls (the so-called P₂O₅ "absorption") not only reduces phosphorous recovery but also generates a large amount of low melting-point side products. The products may give rise to formation of kiln ring, which interferes with kiln operation performance. In this study, the reactions of gaseous P₂O₅ with solid calcium phosphate (Ca₃(PO₄)₂), silica (SiO₂) and their mixture, respectively, were investigated via combined chemical analysis and various characterizations comprised of X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis and differential scanning calorimeter (TG&DSC), and scanning electron microscopy and energy dispersive spectrometer (SEM&EDS). Attentions were focused on apparent morphology, phase transformation and thermal stability of the products of the P₂O₅ "absorption" at different temperatures. The results show that the temperature significantly affected the "absorption". The reaction between pure Ca₃(PO₄)₂ and P₂O₅ occurred at 500℃. Calcium metaphosphate (Ca(PO₃)₂) was the primary product at the temperatures ≤ 900℃ with its melting point ≤ 900℃ while calcium pyrophosphate (Ca₂P₂O₇) was obtained over 1000℃, which has a melting point ≤ 1200℃. The "absorption" by pure SiO₂ started at 800℃ and the most significant reaction occurred at 1000℃ with formation of silicon pyrophosphate (SiP₂O₇) product of melting point ≤ 1000℃. Using mixed Ca₃(PO₄)₂ and SiO₂ as raw material, the "absorption" by Ca₃(PO₄)₂ was enhanced due to existence of silica. At 600-700℃, silica was inert to P₂O₅ and thus formed a porous structure in the raw material, which accelerated diffusion of gaseous P₂O₅ inside the mixture. At higher temperatures, the combined "absorption" by calcium phosphate and reaction between silicon dioxide and the "absorption" product calcium pyrophosphate, reinforced the "absorption" by the mixture. Besides, it was found that both Ca(PO₃)₂ and SiP₂O₇ were unstable at high temperatures and would decompose to Ca₂P₂O₇ and SiO₂, respectively, at over 1000℃ and 1100℃ with the release of gaseous P₂O₅ at the same time.

Key words: Kiln phosphoric acid, Kiln ring, Absorption, Calcium metaphosphate, Calcium pyrophosphate, Back reaction

Qiang Liu, Weizao Liu, Li Lü, Ruhu Li, Bin Liang, Hairong Yue, Shengwei Tang, Chun Li. Study on reactions of gaseous P₂O₅ with Ca₃(PO₄)₂ and SiO₂ during a rotary kiln process for phosphoric acid production[J]. Chinese Journal of Chemical Engineering, 2018, 26(4): 795-805.

参考文献

[1] L.C.C. Jr., Treatment of Phosphoric Acid Process, Apparatus and Product:US, US3649175 A[P], 1972.

[2] Chao Ma, Yuan-xin Wu, Fang Jin, et al., Current status and prospect of industrial phosphoric acid production, Chem. Eng. 41(6) (2013) 74-78.

[3] Yu-ping Zhu, Industrialization prospects of KPA, Phosphate Compd. Fertil. 23(5) (2008) 25-28.

[4] Yan-feng Li, Xi-zhu Bai, Guo-chao Sun, Technology development of CDK kilnprocess phosphoric acid, Phosphate Compd. Fertil. 26(2) (2011) 24-27.

[5] Yan-feng Li, Hui Hu, Chen Yu, et al., Industrial production experiments development of kiln-process phosphoric acid, Phosphate Compd. Fertil. 28(1) (2013) 25-29.

[6] S.V.D. Sluis, A.H.M. Schrijver, F.P.C. Baak, G.M.V. Rosmalen, Fluoride distribution coefficients in wet phosphoric acid processes, Ind. Eng. Chem. Res. 27(3) (2002) 527-536.

[7] T.A. Hendrickson, Production of Ortho Phosphoric Acid:US, US3341289[P], 1967.

[8] W.C. Saeman, Phosphorus Recovery Feed Control Method:US, US3558114[P], 1971.

[9] C.L. Levermore, R.E. Vivian, Manufacture of Phosphoric Acid:US, US2075212 A[P], 1937.

[10] W.C. Lapple, Production of phosphorus pentoxide from a phosphatic ore. US, US3241917[P],1996.

[11] W.C. Lapple, Recovery of phosphorus values and cement clinker from a phosphatic ore. US, US3235330[P],1966.

[12] J.A. Megy, R.A. Hard, Process for reducing phosphate ore. US, US4351809[P],1982.

[13] J.C. Barber, Production of Phosphorus and Phosphoric Acid:US, US 4656020 A[P], 1987.

[14] M.U. Jacob, L. Frederic, W.C. Park, et al., Reduction of phosphate ores by carbon part:Process variables for design of rotary kiln system, Metall. Trans. B 12(17B) (1986) 861-868.

[15] L. Frederic, R. Howard, M.U. Jacob, et al., Reduction of phosphate ores by carbon part Ⅱ:Rate limiting steps, Metall. Trans. B 17(1986) 869-877.

[16] Joseph A. Megy, 137 Casa Sueno Ct., Richland, WA(US) 99352, 2008. Phosphorous pentoxide producing methods:US, US7378070B2.

[17] Xian-guo Yin, Discussion on the current trial production of CDK kiln-method phosphoric acid technology in China, Phosphate Compd. Fertil. 22(1) (2007) 33-35.

[18] F. Leder, et al., New process for technical-grade phosphoric acid, Ind. Eng. Chem. Process Des. Dev. 24(3) (2002) 688-697.

[19] Vincent Ssuchell, Chemistry & Technology of Fertilizer, Reinhold Publishing Corp, New York, 1960346.

[20] A.E. Hokanson, D. Williams, C.S. Williams, Method of Forming Phosphoric Acid from Phosphate Ore:US, US20050002845 A1[P], 2005.

[21] D. Williams, C. Williams, A. Hokanson, Method of Producing Phosphoric Acid from Phosphate Ore, WO/2004/052938[P], 2004.

[22] D.B. Blake, J.A. Megy, S.A. Pachpor, et al., Phosphorous Pentoxide Producing Methods and Systems with Increased Agglomerate Compression Strength:, US20160090305[P], 2016.

[23] Shanxiang Jiang, Discussion on improving reduction rate of kiln phosphoric acid (continued), Phosphate Compd. Fertil. (2) (1995) 10-15.

[24] Shanxiang Jiang, Discussion on improving reduction rate of kiln phosphoric acid, Phosphate Compd. Fertil. (1) (1995) 13-17.

[25] K.D. Jacob, D.S. Reynolds, W.L. Hill, Reduction of tricalcium phosphate by carbon, Ind. Eng. Chem. 20(1) (2002) 1204-1210.

[26] J.A. Megy, Phosphorous Pentoxide Producing Methods:US, US7910080 B2[P], 2011.

[27] Honghui Yang, Chun Li, Bin Liang, et al., Thermodynamics of reactions for producing phosphoric acid by kiln method, Chem. React. Eng. Technol. 27(6) (2011) 543-549.

[28] Keli Jiang, Liyou Qiu, Bin Liang, et al., Solid reaction mechanism for the thermal reduction of fluorapatite by carbon, J. Chengdu Univ. Sci. Technol. 1(1995) 1-5.

[29] Xiao-feng Liang, Shi-yuan Yang, Guang-Fu Yin, Raman spectra analysis for calcium metaphosphate structure transformation in glass preparation process, Chin. J. Inorg. Chem. 26(8) (2010) 1404-1408.

[30] J. Zhang, Y. Yan, Q. Chu, et al., Solid phosphoric acid catalyst for propene oligomerization:Effect of silicon phosphate composition, Fuel Process. Technol. 135(2015) 2-5.

[31] Chengzhong Zhang, Jinglin You, Hui Chen, et al., Vibrational modes and in-situ high temperature Raman spectra of zircon, J. Chin. Ceram. Soc. 34(10) (2006) 1172-1176.

[32] Yu-hua Cao, Dong-xiang Wei, Lu-gen Huang, Study on composition and surface structure of silicon phosphate/boron phosphate by FT-IR, J. Catal. 4(1992) 285-290.

Study on reactions of gaseous P₂O₅ with Ca₃(PO₄)₂ and SiO₂ during a rotary kiln process for phosphoric acid production

Study on reactions of gaseous P₂O₅ with Ca₃(PO₄)₂ and SiO₂ during a rotary kiln process for phosphoric acid production

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