Jarosite process is one of the most widely used methods in removing Fe, but in which the nucleation mechanism of ammonium jarosite has not been reported. Solubilities of the ammonium jarosite crystals under different Fe-2(SO4)(3) and (NH4)(2)SO4 concentrations and under different temperatures were measured, and the experiments of induction periods were systematically investigated in different temperatures (348 k, 358 k and 368 k) and H2SO4 concentrations (9 g/L, 10.8 g/L and 12.6 g/L) by reaction crystallization process based on the thermodynamic equilibrium data. According to the model of classical nucleation theory, the interfacial tension and the surface entropy factors in different conditions were calculated as 1.21 mJ/m(2), 1.85 mJ/m(2), 1.71 mJ/m(2) and 1.51, 1.27, 1.17. The SEM photographs of (H3O, NH4) Fe-3(SO4)(2)(OH)(6) approved that the ammonium jarosite crystals were clearly grown by the two-dimensional nucleation mechanism and/or the spiral growth mechanism. But the growth mechanism of (H3O, NH4)Fe-3(SO4)(2)(OH)(6) had been determined to be the continuous growth by the surface entropy factor. (C) 2017 Published by Elsevier B.V.

中文翻译：

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黄钾铁矾在硫酸溶液中的热力学及成核机理

黄钾铁矾法是目前应用最广泛的除铁方法之一，但其中铵黄钾铁矾的成核机理尚未见报道。测定了不同 Fe-2(SO4)(3) 和 (NH4)(2)SO4 浓度和不同温度下铵黄钾铁矾晶体的溶解度，并系统研究了不同温度（348 k, 358 k 和 368 k) 和 H2SO4 浓度（9 g/L、10.8 g/L 和 12.6 g/L）通过基于热力学平衡数据的反应结晶过程。根据经典成核理论模型，计算出不同条件下的界面张力和表面熵因子分别为1.21 mJ/m(2)、1.85 mJ/m(2)、1.71 mJ/m(2)和1.51、1.27 , 1.17. (H3O, NH4) Fe-3(SO4)(2)(OH)(6) 证实铵黄钾铁矾晶体是通过二维成核机制和/或螺旋生长机制明显生长的。但(H3O, NH4)Fe-3(SO4)(2)(OH)(6)的生长机理已被表面熵因子确定为连续生长。(C) 2017 年 Elsevier BV 出版