Industrial process of preparing magnesia of high purity

摘要

In an industrial process of preparing high-purity magnesia from an impure magnesium-containing starting material, wherein the starting material is dissolved in HCl and the resultant acidic solution is subjected to a multistep treatment for precipitating the impurities out of the solution, the precipitate is separated from the residual purified magnesium chloride solution, and the magnesium chloride is thermally decomposed to obtain magnesia, the purified magnesium chloride solution is first concentrated and sulfate ions are then added thereto to precipitate calcium ions from the concentrated solution as calcium sulfate.