Analysis and experiment of sintering and densification of magnesia particles

•Reducing particle size intensifies heat transfer, sintering, and densification.•High-density MgO particles of 0–6 mm in primary sizes can be produced at 1300–1600 °C for less than 10 min.•The MgO grain growth is controllable by optimizing sintering temperature and time.•Processing small particles is effective in reducing energy consumption and carbon emission.