The main challenge in the industrial production of low-ash polypropylene lies in achieving a high level of product quality consistency. This study discusses several key aspects involved in the industrial preparation of low-ash polypropylene

including the sources of ash

residual metal elements

and the implementation of an integrated process-cleanliness strategy. Based on a catalytic system employing MgCl₂/TiCl₄-type Ziegler–Natta catalyst as the primary catalyst

the effects of trace impurities in polypropylene feedstocks

triethylaluminum cocatalyst

external electron donors

polymerization process stability

additive cleanliness

and post-treatment operations on the ash content of polypropylene were systematically evaluated. The results show that residual Ti and Mg are primarily associated with the utilization efficiency of the primary catalyst

whereas Al residue is related to both the dosage of cocatalyst and the consumption of organoaluminum species by impurities in the reaction system. Abnormal levels of Ca

Fe

and other metallic elements are closely associated with additives and externally introduced contaminants.