The paper examines the possibility of using diatomite from the Ilyinsky deposit as aheat-insulating backfill for open heads of Al alloy castings. The technology was tested while casting a blade at UralCvetLit LLC (Kamensk-Uralsky). In order to optimize the casting head size, a computer simulation of cooling of the casting was carried out using the Elmer software package for different options of the production process. The simulation showed the possibility of a significant decrease in sizes of the casting head in case when diatomite was used. The economic evaluation showed the effectiveness of the proposed technology.