Synthesis Of Spherical Magnesia With Ammonia And Application Research

This thesis researchs the process of synthesis of spherical sagnesia with high purity and good monodisperse using the experimental materials (ammonia and magnesium sulfate) which has low prices.This paperuses the static gas-liquid reaction synthesis way, which uses the ammonia from 25% ammonia water and magnesium sulfate solution to execute the gas-liquid reaction to synthesize the flower spherical magnesium hydroxide particles. Then dealing with the flower spherical magnesium hydroxide particles used the NaOH solution, which would obtain spherical magnesium hydroxide with smooth surface and higher purity. At last, calcining the spherical magnesium hydroxide which would disintegrate to generate spherical magnesium oxide particles with smooth surface.When doing the experiments, by researching the factors of various experiment parameters on the structure and morphologyin the flower roundness magnesium hydroxide grains.By some tests to characterize the products, and considering the crystal growth theories.magnesium hydroxide crystal structure to explore its growth pattern of crystals. While it explored the factors of calcination temperature for citrate values to the spherical magnesium powder, and researched the effect that spherical magnesium oxide was applied into the experiment that phenol wastewater was degradated by ozone.The results show that only magnesium sulfate is conducive to synthesize the spherical magnesium hydroxide particles with complete structure by different magnesium salts. At the room temperiture, when the magnesium sulfate concentration is 0.5mol/L, ammonia magnesium ratio is 13:1, the reaction time is 24h, the experiment would obtain the flower spherical magnesium hydroxide precursor particles with complete structure and good monodisperse. Adding the spherical magnesium hydroxide precursor into 30℃ 0.2mol/L NaOH solution with stirring for 2h, then washing and filter.After repeatedly treated this four times it would got the spherical magnesium hydroxideproduct with higher purity and smooth surface. Spherical magnesium hydroxide was calcined at 600℃ for 2h,it could be obtained spherical magnesium oxide with structural integrity. After spherical magnesium oxide was added into phenol wastewater solution and then bubbling the ozone to oxidate phenol, it found that adding spherical magnesium the experiment had a higher degradation rate than adding other additives. while magnesium oxide also have other advantages, for examples, it could be recycled, reduce costs, have some economic benefits.