FIELD: chemistry.
SUBSTANCE: invention relates to magnesium oxide for annealing separator, suitable for production of anisotropic electrical steel plate with excellent magnetic and insulating properties. Proposed magnesium oxide for annealing separator has sulphur content from 0.1 to 0.5 wt. % and degree of aggregation RBlaine/RBET from 3.0 to 5.5, where RBlaine is particle size, calculated from Blaine specific surface area, and R BET is particle size calculated from BET specific surface area. Magnesium oxide contains from 0.04 to 0.15 wt. % of boron and has content of chlorine of not more than 0.05 wt. %.
EFFECT: disclosed magnesium oxide for an annealing separator provides formation of a forsterite film, having excellent characteristics with respect to the degree of formation of the forsterite film, the appearance of the film, film adhesion and removal of unreacted magnesium oxide from the acid on the surface of the sheet steel.
4 cl, 1 tbl, 5 ex
