FIELD: aluminum production. SUBSTANCE: piercing cryolite-silica crust at a heat is performed on a local region with length constituting 0.08-0.65 crust length on longitudinal side of electrolyzer and width not exceeding 0.02-0.10 width of wall-anode space. Pierced are at least two sites on each longitudinal side of electrolyzer in cyclic manner in cross-diagonal sequence. Summary number of daily piercings ranges from 14 to 144. Piercing member in its longitudinal-vertical cross-section perpendicular to wall-anode distance constitutes isosceles trapezium. There are also guides attached pivoting-wise to piercing member on the length of sides of trapezium on the side of its large base. EFFECT: increased reliability of process. 5 cl, 2 dwg, 2 tbl
