The Study On Crystallization Process Of Inorganic Crystals

Crystallization process is one of the most important operation units in chemical engineering process,as well as an essential component in the manufacture of chemical products.Effective control on crystallization process is critical to the fabrication of functional crystal materials with high purity and high quality,which influences the development of materials science and industrial application.In order to investigate the factors during crystal growth process,dig the nature of crystal growth and realize the controlled fabrication of inorganic crystal materials,the crystallization behaviors of cuprous oxide(Cu₂O) and potassium dihydrogen phosphate(KDP) crystals have been systematically studied in this thesis.Based on the chemical bonding theory of single crystal growth,the crystal growth routes have been reasonably designed to investigate the influences of various factors on the crystallization morphologies of final products.Starting from the self-oxidation-reduction synthesis strategy,the EDTANaa-assisted hydrothermal crystallization technique has been designed to obtain polymorphological Cu₂O microcrystals.The morphology and structure information of the as-grown crystals have been characterized by scanning electron mi roscope(SEM) and X-ray powder diffraction(XRD). From the chemical bonding viewpoint,the growth mechanisms of polyhedral morphology and branch growth behavior have been reasonably interpreted,which can further guide the theoretical research and industrial preparation of Cu₂O crystals.For the unique ferro-and piezo-electric properties,KDP crystals are highly desirable in optical devices.From the study of crystallization character of KDP,the ideal morphology has been simulated by using chemical bonding theory.The final products obtained from different supersaturation have been characterized by SEM and XRD.The variation in solution supersaturation can effectively change the growth mechanisms of different crystal faces.In the thesis,new methods for controlling crystallization process have been designed; several factors that influence the growth habit of inorganic crystals have been investigated; the growth mechanisms have been reasonably interpreted according to the crystal growth theory.The current work can guide the shape-controlled synthesis of inorganic crystals.