The effects of impurities such as Si, F, K and Na on the crystallization process of calcium sulfate in wet-process phosphoric acid were investigated. The results showed that two types of alkali metals had different effects on the crystallization of calcium sulfate. The addition of K was beneficial for the growth and agglomeration of the crystals, and the increase of Na content inhibited the agglomeration of calcium sulfate. The particle size was barely affected by the amount of silica except the irregular shape, and the addition of H2SiF6 can lead to the diversion of the particles. K2SiF6 had a synergistic effect on the particles to improve the growth of calcium sulfate crystals.
Xu LI Ganyu ZHU Xiaokang GONG Shaopeng LI Bingbing LIU Huiquan LI
. Effects of Si/F/K/Na impurities on the crystallization of calcium sulfate[J]. The Chinese Journal of Process Engineering, 2018
, 18(4)
: 815
-820
.
DOI: 10.12034/j.issn.1009-606X.217389
[1] 刘代俊, 钟本和, 张允湘. 磷矿的铁铝杂质物相及其在磷酸中分解速率的实验研究 [J]. 化肥工业, 1998, 25(5): 27-33.
Liu D J, Zhong B H, and Zhang Y X. Phases of Iron and Aluminum Impurities in Phosphate Rock and Experimental Study of their Decomposition Rate in Phosphoric Acid [J]. Chem. Fertilizer Ind., 1998, 25(5): 27-33.
[2] 吴佩芝. 湿法磷酸 [M]. 北京: 化学工业出版社, 1987 , 40-81 .
[3] Rashad M M, Mahmoud M H H, Ibrahim I A, et al. Crystallization of Calcium Sulfate Dihydrate under Simulated Conditions of Phosphoric Acid Production in the Presence of Aluminum and Magnesium ions [J]. J. Cryst. Growth, 2004, 267: 372.
[4] Hasson D, Addai-Mensah J, Metcalfe J. Filterability of Gypsum Crystallized in Phosphoric Acid Solution in the Presence of Ionic Impurities [J]. Ind. Eng. Chem. Res. 1990, 29, 867.
[5] 吴佩芝. 湿法磷酸生产中硫酸钙的结晶过程 [J] . 磷肥与氮肥, 1993, 4: 16 -21.
[6] 王良士, 龙志奇, 于瀛等. 湿法磷酸生产过程中控制硫酸钙结晶的研究 [J]. 化工矿物与加工, 2008, 4: 1-4.
Wang L S, Long Z Q, Yu Y, et al. Study on the Crystallization of Calcium Sulfate during the Course of Phosphoric Acid Production by Wet-process [J]. IM&P, 2008, 4: 1-4.
[7] Amin A B, and Larson M A . Crystallization of Calcium Sulfate from Phophoric Acid [J]. I&EC Process Design. and Dev., 1968, 7(1): 133-137.
[8] 高晓清, 钟本和, 李军. 磷酸中的Al3+、SO42-和NH4+对二水硫酸钙结晶习性的影响 [J]. 成都科技大学学报, 1993, 70: 34-39.
[9] Jiang G M, Fu H L, Savino K, et al. Nonlattice Cation-SO42- Ion Pairs in Calcium Sulfate Hemihydrate Nucleation [J]. Cryst. Growth Des., 2013, 13: 5128?5134.
[10] Li J, Wang J, Zhang Y. Effects of the Impurities on the Habit of Gypsum in Wet-process Phosphoric Acid [J]. Ind. Eng. Chem. Res., 1997, 36 : 2657.
[11] Gao X, Huo W, Zhong Y, et al. Effects of Magnesium and Ferric Ions on Crystallization of Calcium Sulfate Dihydrate under the Simulated Conditions of Wet Flue-gas Desulfurization [J]. Chem. Res. Chin. Univ., 2008, 24, 688.
[12] Budz J, Jones A G and Mullin J W. Effect of Selected Impurities on the Continuous Precipitation of Calcium Sulphate (Gypsum) [J]. J. Chem. Tech. Biotechnol., 1986, 36: 153-161.
[13] Sarig S and Mullin J W. Effect of Trace Impurities on Calcium Sulphate Precipitation [J]. J. Chem. Tech. Biotechnol., 1982, 32: 525-531.
[14] Rabizadeh T, Stawski T M, Morgan D J, et al. The Effects of Inorganic Additives on the Nucleation and Growth Kinetics of Calcium Sulfate Dihydrate Crystals [J]. Cryst. Growth Des., 2017, 17, 582?589.
[15] Feldmann T and Demopoulos G P. Influence of Impurities on Crystallization Kinetics of Calcium Sulfate Dihydrate and Hemihydrate in Strong HCl-CaCl2 Solutions [J]. Ind. Eng. Chem. Res., 2013, 52, 6540?6549.
