Preparation of active magnesium oxide with caustic calcined magnesia by ammonia circulation method

•A process using light calcined powder to prepare high purity MH was described.•The process was a convenient and efficient route to control the morphology of MH.•Synthesized in one step in the absence of surfactant and hydrothermal treatment.•Shape-controlled active MgO was synthesized from MH.•The crystal growth mechanism of MgO precursors were simulated by materials studio.

Magnesium oxide (MgO) with different morphology were prepared by calcining precursors (magnesium hydroxide MH). The precursors were synthesized from industry lightly calcined powder (MgO content of 80–93%) by ammonia circulation method. The structures of MH and MgO were characterized by scanning electron microscope and laser particle size analyzer. The crystal growth mechanism of MgO precursors were simulated by materials studio. The experimental results showed that the MgO had the same morphology with their precursors. The adsorption of SO42− can significantly increase the particle size of precursors, and its D50 reached 2.05 μm. After adsorping Cl−, the exposure proportion of planes (0 0 1) and (1 0 1) was reduced, and the morphology of MH more easily grow to be uniform bulk crystal. The activity of MgO (CAA) produced with MgCl2 was 15″85 by the citric acid method, which was higher than other MgO produced with Mg(NO3)2 and MgSO4.

Graphical abstractSEM micrographs of MgO prepared from different Mg salt.Figure optionsDownload full-size imageDownload as PowerPoint slide