Preparation method of ultrapure magnesium oxide powder

Abstract

The invention discloses a preparation method of ultrapure magnesium oxide powder. The preparation method comprises the following steps of A. dissolving magnesium sulfate heptahydrate in pure water to prepare a magnesium sulfate solution and filtering to remove mechanical impurities and insoluble impurities; B. adding oxalic acid with continuously stirring, ageing repeatedly and carrying out suction filtration to remove calcium impurity; C. dropwise adding hydrogen peroxide into the solution with calcium removed with continuously stirring; D. adding a sodium hydroxide aqueous solution with continuously stirring; standing for stratification after reaction is completed, extracting a supernatant liquid, and removing impurities by a multi-stage precipitation and multi-stage filtration under a normal pressure; and E. putting the filtered clear liquid into a polytetrafluoroethylene reaction kettle, dropwise adding ammonium hydroxide with continuously stirring to obtain a pure magnesium hydroxide turbid liquid, separating a turbid liquid product through centrifugation, washing, filtering, drying, sintering for at least 5 h, and thus ultrapure magnesium oxide powder with a purity of 99.999% can be obtained.

Description

technical field [0001] The invention belongs to the category of inorganic materials in the category of new materials, and specifically relates to a preparation method of ultrapure magnesium oxide powder. Background technique [0002] In China, high-purity magnesium oxide generally refers to W （MgO） ≥98% (weight percent) products, so most of them are used in silicon steel sheet coating, high-temperature insulating materials, advanced ceramics, etc. MgO protective layer plating as the key part of plasma display PDP device is a bottleneck on the plasma display production line. High-purity magnesium oxide (MgO) is widely used in many fields such as electronic components and advanced ceramic materials, especially in the new generation of plasma flat panel display (PDP), its performance directly affects the working characteristics and life of PDP. At present, the purity of MgO mass-produced in China is usually below 99.9%, and the content of impurities such as iron, silicon, cal...

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Problems solved by technology

At present, the existing high-purity MgO preparation methods include vacuum volatilization method, solvent evaporation method, inert gas evaporation method, liquid phase precipitation method, sol-gel method, alkoxide decomposition method and vapor phase deposition method, etc., and the product purity is usually 98%. -- Between 99.9%, although the organic magnesium salt decomposition method can obtain ultra-pure magnesium oxide, but the economic and technical competitiveness is not strong

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