| 摘要 |
<p>Disclosed is a method for preparing ultrapure magnesia powder, which comprises the following steps: A. completely dissolving magnesium sulfate heptahydrate into purified water to formulate a magnesium sulfate solution, filtering off mechanical impurities and insolubles; B. adding oxalic acid while continuously stirring, and after reaction aging, removing calcium impurities by suction filtration; C. dripping hydrogen peroxide into the solution without calcium while continuously stirring; D. adding a water solution of sodium hydroxide while continuously stirring, and after complete reaction, then standing and stratification, extracting the supernatant and removing impurities therein by multistage precipitation and multistage filtration at normal pressure; E. adding the filtered clear liquid into a polytetrafluoroethylene reaction vessel, and dripping aqueous ammonia and continuously stirring, to give a pure magnesium hydroxide suspension; centrifuging the suspension product, washing, filtering, drying, calcining for at least 5 hours, to give 99.999% ultrapure magnesia powder.</p> |
