Research progress of magnesium oxide for silicon steel coating

With the increase of electrical steel production in China, the demand of silicon steel grade magnesium oxide is increasing, and the traditional process of preparing magnesium oxide from dolomite is unable to meet the market demand. China is a country rich in brine resources, therefore, it is becoming more and more important to study how to resourcefully and comprehensively utilize the salt lake resources. The silicon steel grade magnesium oxide is a kind of coating material for the preparation of oriented silicon steel, mainly used in the high temperature annealing treatment stage of oriented silicon steel, playing the role of isolator, insulating film, desulfurization, dephosphorization, etc. The methods, process flow, research progress and problems of preparing silicon steel grade magnesium oxide are reviewed, and the development direction of silicon steel grade magnesium oxide preparation technology is pointed out, and suggestions are made for the utilization of brine resources in China.

The article studied the preparation of silicon steel grade magnesium oxide by brine-ammonia method, discussed the factors affecting the settling performance and conversion rate of intermediate magnesium hydroxide, and determined the best process conditions for the preparation of magnesium hydroxide; through the study of calcination temperature and time of magnesium hydroxide, the calcination conditions were determined, and the produced magnesium oxide has small particle size, good dispersion performance and low hydration rate, which meets the requirements of silicon steel grade magnesium oxide.

The invention relates to a magnesium compound preparation method, specifically a special silicon steel grade magnesium oxide preparation method for oriented silicon steel sheet, to solve the existing silicon steel grade magnesium oxide preparation method of long process, the final product of low chemical purity and other defects, the use of salt brine soda method to produce silicon steel grade magnesium oxide, refined magnesium chloride solution and refined sodium carbonate solution at a temperature of 65-85 ℃, the time of 5-15min The reaction is carried out to produce alkaline magnesium carbonate, and then the magnesium oxide is calcined under the temperature of 1100±50℃ and time of 2.0±0.5h after maturation and filtration. The silicon steel grade magnesium oxide produced by this invention has the characteristics of high chemical purity, low impurity ions, small average particle size and high viscosity, good coating and adhesion; its physical properties are much better than similar products, the formed magnesium silicate insulation film layer is of good quality, is a good annealing isolator for the production of oriented silicon steel sheet; and the production process is simple and the cost is low.