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 content of adhesive water and content of hydrated water, corresponding to quadrangular region formed by following points a-d as vertices on graph, which shows ratio between content of adhesive water and content of hydrated water: a: content of adhesive water: 0.25 wt. %, content of hydrated water: 0.1 wt. %; b: content of adhesive water: 0.60 wt. %, content of hydrated water: 0.1 wt. %; c: content of adhesive water: 0.40 wt. %, content of hydrated water: 6.0 wt. %; d: content of adhesion water: 0.20 wt. %, content of hydrated water: 6.0 wt. %. 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 dwg, 1 tbl, 7 ex
