Experimental results of a study of the effect of FeCl₃ impurity on the antisolvent crystallization of ammonium dihydrogen phosphate, involving processes of formation of 3D nuclei and growth of these nuclei, from its aqueous solutions saturated at 30 °C and containing different impurity concentrations c_i from in situ measurements of temperatures of saturated solutions and pure water as functions of feeding time t of antisolvent ethanol at predefined rates R_A are described and discussed. The processes of formation of 3D nuclei and growth of these nuclei are studied in terms of the maximum antisolvent content Δx_maxN and Δx_maxG, determined from intervals of temperature difference (T_s−T_w) = ΔT < 0 and ΔT > 0, respectively, obtained from measurements of temperature T_s and T_w of saturated solution, without and with impurity, and pure water. It is found that: 1) the processes of 3D nucleation in antisolvent crystallization from solutions containing impurities can be explained in the framework of theoretical expressions such as a Nývlt‐like relation and an approach based on 3D‐nucleation theory, and 2) adsorption of impurity particles accounts for the increase in the values of antisolvent contents Δx_maxN and Δx_maxG of solutions during 3D nucleation and growth of crystallites.

中文翻译：

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Fe（III）杂质对磷酸二氢铵水溶液反溶剂结晶的影响

研究FeCl ₃杂质对磷酸二氢铵反溶剂结晶的影响的实验结果，涉及3D核的形成过程和这些核的生长过程，这些过程由其在30°C饱和且含有不同杂质浓度c _i的水溶液形成描述并讨论了根据饱和溶液和纯水的温度的原位测量，以预定速度R _A注入抗溶剂乙醇的时间t的函数。形成三维核的和这些核生长的处理进行了研究，最大反溶剂含量Δ方面X _MAXN和Δ X _maxG分别由温差（T _s - T _w）= ΔT  <0和ΔT  > 0的间隔确定，分别是通过测量饱和溶液的温度T _s和T _w来获得的，该温度在无杂质和有杂质以及纯净水的情况下。发现：1）从含杂质的溶液中反溶剂结晶的3D成核过程可以在理论表达式的框架内进行解释，例如Nývlt关系和基于3D成核理论的方法，以及2）吸附杂质颗粒占在反溶剂含量的值的增加Δ X _MAXN和Δx在微晶3D成核和生长过程中的溶液的_maxG。