Magnesium oxide particles and method for producing same

The magnesium oxide particles of the present invention comprise spherical bodies having open pores, each of which is obtained by partially welding a plurality of burnt magnesium oxide particles to each other. The average particle diameter (D2) of the spheroids is 10 [mu] m or more and 200 [mu] m or less, and the circularity of a projected image is 0.7 or more. It is preferable that the void fraction in the spheroid is 10-50% (inclusive) as determined by image analysis. It is also preferable that the ratio D2/D1 of the average particle diameter D2 of the spheroids to the BET specific surface area-converted particle diameter D1 of the spheroids is 3-10 (inclusive). 本发明的氧化镁颗粒由复数个僵烧氧化镁颗粒彼此部分熔接而成的具有开气孔的球状体构成。上述球状体的平均粒径(D2)为10μm以上200μm以下，投影图像的圆形度为0.7以上。基于图像分析的上述球状体内的空隙率优选为10％以上50％以下。上述球状体的平均粒径D2相对于上述球状体的BET比表面积换算粒径D1之比D2/D1也优选为3以上10以下。