Hebei Messi Biology Co., Ltd. stated that magnesium oxide can be used as flame retardant in chemical fiber and plastic industry, high temperature dehydrating agent in silicon steel sheet production, high-grade ceramic materials, binder and additive of chemical raw materials of electronic industry materials; magnetic device materials of high frequency magnetic rod antenna in wireless electronic industry, insulating material filler and various carriers; electrical insulating materials, manufacturing crucibles, furnace insulation, conduits, electrode rods, electronic sheets, glass cover plates, etc. At present, with the rapid development of electronic equipment, various touch screen products have sprung up, and a new industry is about to rise. The research of a new generation of cover glass is in full swing. Magnesium oxide, as the main product of cover glass, has been widely valued and studied.
Magnesium oxide is odorless, tasteless, insoluble in water and ethanol, with a melting point of 2852℃ and a boiling point of 3600℃. Magnesium oxide has high fire-resistant insulation properties. It can be transformed into crystals after high temperature burning above 1000℃, and it becomes dead burnt magnesium oxide or sintered magnesium oxide when it rises to above 1500℃. Magnesium oxide is an alkaline oxide with the common properties of alkaline oxides. When exposed to the air, it easily absorbs water and carbon dioxide and gradually becomes basic magnesium carbonate. It is soluble in acid and ammonium salts but difficult to dissolve in water. Its solution is alkaline and insoluble in ethanol.
The magnesium oxide used in cover glass needs to be in a spherical shape and its specific surface area should be less than 10m2/g. However, the specific surface area of magnesium oxide prepared by the existing technology (soda ash method, caustic soda method) is relatively large, which is a great problem for the production of high-purity magnesium oxide for cover glass.
The invention discloses a production process of magnesium oxide, comprising: preparing a magnesium chloride solution, purifying the magnesium chloride solution and then adding it into a reactor, then adding a crystal form control agent, and ultrasonicating; obtaining a mixed material; passing ethanol atomized material into the mixed material of the reactor through a carrier gas; continuously passing ammonia into the mixed material of the reactor under stirring conditions until the precipitation is stable, stopping the passing of ammonia, filtering, washing, and obtaining magnesium hydroxide; adding magnesium hydroxide into a ball mill, adding stainless steel grinding balls at the same time, passing liquid nitrogen into the ball mill, immersing the magnesium hydroxide and the stainless steel grinding balls in the liquid nitrogen, ball milling, collecting the ball-milled magnesium hydroxide, calcining at high temperature, grinding and crushing, and obtaining magnesium oxide; through the production process of magnesium oxide provided by the invention, magnesium oxide with a purity of more than 99%, a bulk density of more than 1 g/cm3, a whiteness of more than 98, and a specific surface area of less than 10 m2/g can be prepared, and the magnesium oxide meets the use requirements of cover glass.