PURPOSE: To prevent the intrusion of Zr into molten steel for a non-directional electrical steel plate and to reduce the iron loss of the electrical steel plate of product by coating a specific refractory material on the surface of the ZrO2 brick used in the slag zone in a ladle to be used for treating the molten steel.

CONSTITUTION: A zirconia brick having high refractoriness is used in the zone of the molten slag in a ladle for treating molten steel for a non-directional electrical steel plate contg. <4% Si. The brick is further coated thereon with a magnesium-chromium (MgO-Cr2O3) refractory material or MgO refractories. The entry of Zr into the molten steel from the zirconia brick is prevented and the formation and deposition of ZrN in the molten steel is prevented. The increase in iron loss as an electrical steel sheet on account of a retardation in the grain growth of a recrystal by ZrN in the stage of finish annealing is prevented when the molten steel is cold-rolled to the electrical steel sheet.