High-purity magnesia refers to sintered magnesia with a content of more than 99% (China often refers to magnesia with a content of more than 98% as high-purity magnesia) and a bulk density greater than 3.4g/cm3. The production methods of high-purity magnesia all use magnesium-containing compounds as raw materials. Some use light magnesia as raw material to obtain high-purity magnesia through electric melting or re-burning (re-burning), and some use magnesium chloride to spray thermal decomposition and calcined to produce high-purity magnesium. sand.