Hebei Messi Biology Co., Ltd. has demonstrated a method for preparing a silicon steel-grade magnesium oxide coating specially used for oriented silicon steel sheets, including the following process steps: selecting natural aphanitic magnesite to produce light-burned magnesium oxide powder; Magnesium oxide digestion, acid-base neutralization and decalcification, react at a temperature of 15-30°C for 5-15 minutes to generate magnesium hydroxide, then wash with water, filter, and dry at a temperature of 1100±50°C for a period of time Calcined for 2.0±0.5 hours, high-purity magnesium oxide can be obtained; processed into the required micron-sized particle size segment by jet milling.
In order to improve the reactivity between magnesia and silicon dioxide, magnesia must be active, and nano-magnesia has the greatest reactivity. Therefore, nano-technology is used to introduce nano-magnesia particles into magnesia for silicon steel coating, which improves the Reactivity of magnesium oxide on silicon steel. In order to improve the packing density between the magnesium oxide particles on the surface of the silicon steel sheet, the structure of the magnesium oxide material used for silicon steel coating must tend to be approximately spherical, because the sphere has the advantage of the most compact packing, and the magnesium oxide particles can tend to be the most compact after being coated on the surface of the silicon steel sheet accumulation.
After the magnesium oxide acts on the silicon steel sheet, it must be dried and curled into a coil shape for secondary high-temperature annealing. Before entering the high-temperature annealing stage, the magnesium hydroxide generated by the magnesium oxide during the beating process must be gradually driven off during the annealing and heating process. In the implementation of this process, the coated magnesia layer must have good air permeability, even if the water molecules in the magnesia can escape in the gap between the tightly rolled steel coils, so as to avoid the water vapor Affect the quality of the magnesium orthosilicate film produced. Therefore, as magnesia for high temperature annealing, a single nano-sized magnesia material cannot be used, but the magnesia should be an aggregate of magnesia with various particle sizes, that is, it should have various particle sizes. The magnesium oxide materials each occupy a certain distribution ratio.
The magnesium oxide for silicon steel coating produced by Hebei Messi Biology Co., Ltd. has the characteristics of high chemical purity, low impurity ions, good suspension, low hydration rate, good coating and adhesion; its physical properties are far superior to those of the same kind The product is a good annealing separator for the production of oriented silicon steel sheets; and the production process is simple and the production cost is greatly reduced.