Hydrothermal synthesis of calcium sulfate whisker from flue gas desulfurization gypsum

doi:10.1016/j.cjche.2016.04.024

Abstract

Abstract: Plenty of flue gas desulfurization (FGD) gypsum generated from coal-fired power plants for sulfur dioxide sequestration caused many environmental issues. Preparing calcium sulfate whisker (CSW) from FGD gypsum by hydrothermal synthesis is considered to be a promising approach to solve this troublesome problem and utilize calcium sulfate in a high-value-added way. The effects of particle size of FGD gypsum, slurry concentration, and additives on CSW were investigated in this work. The results indicated that fine particle size of FGD gypsum and moderately high slurry concentration were beneficial for crystal nucleation and growth. Three additives of magnesium chloride, citric acid, and sodium dodecyl benzene sulfonate (SDBS) were employed in this study. It was found that mean length and aspect ratio of CSW were both decreased by the usage of magnesium chloride, while a small quantity of citric acid or SDBS could improve the CSW morphology. When multi-additives of citric acid-SDBS were employed, the mean length and aspect ratio increased more than 20%. Moreover, surface morphology of CSW went better, and the particle size and crystal shape became more uniform.

Key words: Calcium sulfate whisker, Hydrothermal, Synthesis, Environment

摘要： Plenty of flue gas desulfurization (FGD) gypsum generated from coal-fired power plants for sulfur dioxide sequestration caused many environmental issues. Preparing calcium sulfate whisker (CSW) from FGD gypsum by hydrothermal synthesis is considered to be a promising approach to solve this troublesome problem and utilize calcium sulfate in a high-value-added way. The effects of particle size of FGD gypsum, slurry concentration, and additives on CSW were investigated in this work. The results indicated that fine particle size of FGD gypsum and moderately high slurry concentration were beneficial for crystal nucleation and growth. Three additives of magnesium chloride, citric acid, and sodium dodecyl benzene sulfonate (SDBS) were employed in this study. It was found that mean length and aspect ratio of CSW were both decreased by the usage of magnesium chloride, while a small quantity of citric acid or SDBS could improve the CSW morphology. When multi-additives of citric acid-SDBS were employed, the mean length and aspect ratio increased more than 20%. Moreover, surface morphology of CSW went better, and the particle size and crystal shape became more uniform.

关键词: Calcium sulfate whisker, Hydrothermal, Synthesis, Environment

Chengjun Liu, Qing Zhao, Yeguang Wang, Peiyang Shi, Maofa Jiang. Hydrothermal synthesis of calcium sulfate whisker from flue gas desulfurization gypsum[J]. Chin.J.Chem.Eng., 2016, 24(11): 1552-1560.

Chengjun Liu, Qing Zhao, Yeguang Wang, Peiyang Shi, Maofa Jiang. Hydrothermal synthesis of calcium sulfate whisker from flue gas desulfurization gypsum[J]. Chinese Journal of Chemical Engineering, 2016, 24(11): 1552-1560.

References

[1] B.H. Guan, H.L. Fu, J. Yu, G.M. Jiang, B. Kong, Z.Wu, Direct transformation of calcium sulfite to α-calcium sulfate hemihydrate in a concentrated Ca-Mg-Mn chloride solution under atmospheric pressure, Fuel 90(1) (2011) 36-41.
[2] E. Álvarez-Ayuso, X. Querol, A. TomÁs, Environmental impact of a coal combustion-desulphurisation plant:Abatement capacity of desulphurisation process and environmental characterization of combustion by-products, Chemosphere 65(11) (2006) 2009-2017.
[3] P. Córdoba, Status of flue gas desulphurisation (FGD) systems fromcoal-fired power plants:Overview of the physic-chemical control processes of wet limestone FGDs, Fuel 144(2015) 274-286.
[4] G. Tzouvalas, G. Rantis, S. Tsimas, Alternative calcium-sulfate-bearing materials as cement retarders:Part Ⅱ:FGD gypsum, Cem. Concr. Res. 34(11) (2004) 2119-2125.
[5] C. Chandara, K.A.M. Azizli, Z.A. Ahmad, E. Sakai, Use of waste gypsumto replace natural gypsum as set retarders in Portland cement, Waste Manag. 29(5) (2009) 1675-1679.
[6] M. Miao, X. Feng, G.L.Wang, S.M. Cao,W. Shi, L.Y. Shi, Direct transformation of FGD gypsum to calcium sulfate hemihydrate whiskers:Preparation, simulations, and process analysis, Particuology 19(2) (2015) 53-59.
[7] T. Feldmann, G.P. Demopoulos, The crystal growth kinetics of alpha calcium sulfate hemihydrate in concentrated CaCl₂-HCl solutions, J. Cryst. Growth 351(1) (2012) 9-18.
[8] A. Papageorgiou, G. Tzouvalas, S. Tsimas, Use of inorganic setting retarders in cement industry, Cem. Concr. Comp. 27(2) (2005) 183-189.
[9] Z.C. Zhu, L. Xu, G.A. Chen, Y.L. Li, Optimization on tribological properties of aramid fibre and CaSO₄whisker reinforced non-metallic frictionmaterialwith analytic hierarchy process and preference ranking organization method for enrichment evaluations, Mater. Des. 31(1) (2010) 551-555.
[10] D. Freyer, W. Voigt, Crystallization and phase stability of CaSO₄ and CaSO₄-based salts, Monatsh. Chem. 134(5) (2003) 693-719.
[11] K.B. Luo, C.M. Li, L. Xiang, H.P. Li, P. Ning, Influence of temperature and solution composition on the formation of calcium sulfates, Particuology 8(3) (2010) 240-244.
[12] X. Wang, L.S. Yang, X.F. Zhu, J.K. Yang, Preparation of calcium sulfate whiskers from FGD gypsum via hydrothermal crystallization in the H₂SO₄-NaCl-H₂O system, Particuology 17(6) (2014) 42-48.
[13] L.S. Yang, X. Wang, X.F. Zhu, L.Z. Du, Preparation of calcium sulfate whisker by hydrothermal method from flue gas desulfurization (FGD) gypsum, Appl. Mech. Mater. 268-270(2013) 823-826.
[14] H. Cölfen, L.M. Qi, Y. Mastai, L. Börger, Formation of unusual 10-petal BaSO₄ structures in the presence of a polymeric additive, Cryst. Growth Des. 2(3) (2002) 191-196.
[15] C. Wang, Control the polymorphism and morphology of calcium carbonate precipitation from a calcium acetate and urea solution, Mater. Lett. 62(16) (2008) 2377-2380.
[16] C. Yang, X.F. Song, S.Y. Sun, Z. Sun, J.G. Yu, Effects of sodium dodecyl sulfate on the oriented growth of nesquehonite whiskers, Adv. Powder Technol. 24(3) (2003) 585-592.
[17] B.H. Guan, L.C. Yang, Z.B. Wu, Z.X. Shen, X.F. Ma, Q. Ye, Preparation of α-calcium sulfate hemihydrate from FGD gypsum in K, Mg-containing concentrated CaCl₂ solution under mild conditions, Fuel 88(7) (2009) 1286-1293.
[18] S.K. Hamdona, U.A.A. Hadad, Crystallization of calcium sulfate dihydrate in the presence of some metal ions, J. Cryst. Growth 299(1) (2007) 146-151.
[19] M.M. Rashad, M.H.H. Mahmoud, I.A. Ibrahim, E.A. Abdel-Aal, Crystallization of calcium sulfate dihydrate under simulated conditions of phosphoric acid production in the presence of aluminum and magnesium ions, J. Cryst. Growth 267(1-2) (2004) 372-379.
[20] L. Wang, J.H. Ma, Z.W. Guo, B.S. Dong, G.M. Wang, Study on the preparation and morphology of calcium sulfate whisker by hydrothermal synthesis method, Mater. Sci. Technol. 14(6) (2006) 626-629(In Chinese).
[21] N. Yang, H.N. Xiao, W.M. Guo, Additives-assisted hydrothermal synthesis of calcium sulfate whisker and its growth mechanism, J. Chin. Ceram. Soc. 42(2014) 539-544(In Chinese).
[22] J.H. Peng, J.D. Qu, L. Wu, J.X. Zhang, Effect of critic acid on crystalline habit and crystal morphology of dehydrate, J. Southeast Univ. (Nat. Sci. Ed.) 34(3) (2004) 356-360(In Chinese).
[23] M. Prisciandaro, A. Lancia, D. Musmarra, The retarding effect of citric acid on calcium sulfate nucleation kinetics, Ind. Eng. Chem. Res. 42(25) (2003) 6647-6652.
[24] X.L. Mao, X.F. Song, G.M. Lu, Y.X. Xu, Y.Z. Sun, J.G. Yu, Effect of additives on the morphology of calcium sulfate hemihydrate:Experimental and molecular dynamics simulation studies, Chem. Eng. J. 278(2015) 320-327.
[25] C.J. Liu, Q. Zhao, Y.G. Wang, P.Y. Shi, M.F. Jiang, Surface modification of calcium sulfate whisker prepared from flue gas desulfurization gypsum, Appl. Surf. Sci. 360(2016) 263-269.
[26] L.C. Yang, Z.B.Wu, B.H. Guan, H.L. Fu, Q.Q. Ye, Growth rate of a-calciumsulfate hemihydrate in K-Ca-Mg-Cl-H₂O systems at elevated temperature, J. Cryst. Growth 311(2009) 4518-4524.