Study on the Preparation and Morphology Mechanism of Micron-Sized Hexagonal Flake Basic Zinc Chloride (Zn-5(OH)(8)Cl-2 center dot H2O) by Ammonia Precipitation Method

The chemical formula of basic zinc chloride is Zn-5(OH)(8)Cl-2 center dot H2O (denoted as ZHC). It is a new type of zinc source additive, widely used in the feed industry. In this article, micron-sized hexagonal flake ZHC with a diameter of 10-60 mu m is directly prepared by ammonia precipitation method using ZnCl2 as raw material. The products are characterized and analyzed by X-ray diffraction, scanning electron microscopy, and laser particle size analyzer. The effects of reaction temperature, ammonia flow rate, aging time, and reactant concentration on the product morphology are studied. Under the optimum reaction conditions, the ZnCl2 concentration is 2.0 mol L-1, NH3 flow rate is 300 mL min(-1), the reaction time is 1 h, the reaction temperature is 80 degrees C, and the aging time is 5 h. Lastly, the yield reaches 49.06%. The growth habit of ZHC is theoretically analyzed by the Morphology program. The calculation results are in good agreement with the experimental results. The change of (003) crystal plane exposure caused by temperature is an important reason for the non-ideality of macroscopic morphology.