The physical and chemical changes of the components in the preparation process of the dissolution and precipitation system polyethylene catalyst used in the slurry process were studied. The dissolution process of the system was explored. For the first time

dynamic light scattering was used to dynamically track the dissolving liquid. Combined with characterization methods such as scanning electron microscopy and liquid nuclear magnetism

it was proven that magnesium chloride-ethanol (MgCl2-EtOH) microcrystals were formed during the dissolution process. The precipitation process of the catalyst was also analyzed

finding that there was a two-phase structure in the catalyst that is the crystalline phase dominated by magnesium chloride and the amorphous phase dominated by titanium alkoxide (Ti(OC2H5)nCl4-n ). This study deepens the understanding of the catalyst and lays the foundation for its further optimization and the development of new catalyst systems.