Commercially procured magnesium aluminate (MgAl₂O₄) spinel powder with average particle size of 300 nm and irregular morphology were spray and freeze granulated. The granules were characterized for the texture, strength, granule size and its distribution. In order to evaluate the flowability of granules, rheological parameters, such as Carr index and Hausner ratio were measured. The granules were further subjected to quasi-static compaction under loading, unloading conditions and compaction curves were constructed. Compaction coefficients thus obtained were correlated with granulation conditions and other parameters including green densities. Compacted green samples were also subjected to flexural strength measurements following ASTM standards and fractographs were observed under FESEM. A Carr index of 13.7 and Hausner ratio of 1.16 were obtained for freeze dried granules indicating the superiority in flow behavior as compared to its spray granulated counterpart, thereby showing a better compaction behavior: compaction coefficient of 5.9 in combination with higher true and predicted green density values and lower granule strength of 1.22 MPa. The green samples exhibited a flexural strength of 11 and 12.5 MPa and compressive strength of 2.44 and 1.22 MPa for spray and freeze granulated sample, respectively. The above observations were also complemented by the fractographs.

商业采购的铝酸镁 (MgAl ₂ O ₄) 将平均粒径为 300 nm 且形态不规则的尖晶石粉末喷雾并冷冻造粒。对颗粒的质地、强度、颗粒大小及其分布进行表征。为了评估颗粒的流动性，测量了流变参数，例如卡尔指数和豪斯纳比。颗粒在加载、卸载条件下进一步进行准静态压实，并构建了压实曲线。由此获得的压实系数与造粒条件和其他参数（包括生坯密度）相关。还按照 ASTM 标准对压实的生坯样品进行了弯曲强度测量，并在 FESEM 下观察了断口图。卡尔指数为 13.7，豪斯纳比率为 1。获得了 16 个冷冻干燥颗粒，表明与其喷雾造粒对应物相比在流动行为方面具有优越性，从而显示出更好的压实行为：5.9 的压实系数与更高的真实和预测的生坯密度值和 1.22 MPa 的较低颗粒强度相结合。对于喷雾和冷冻造粒样品，生坯样品的弯曲强度分别为 11 和 12.5 MPa，压缩强度分别为 2.44 和 1.22 MPa。上述观察结果也得到了断层图的补充。对于喷雾和冷冻造粒样品，生坯样品的弯曲强度分别为 11 和 12.5 MPa，压缩强度分别为 2.44 和 1.22 MPa。上述观察结果也得到了断层图的补充。对于喷雾和冷冻造粒样品，生坯样品的弯曲强度分别为 11 和 12.5 MPa，压缩强度分别为 2.44 和 1.22 MPa。上述观察结果也得到了断层图的补充。