A patented method is introduced to you: heating magnesium metal to sublimate (the magnesium metal before the inlet of the sublimation tank can also be used in the normal production process of magnesium metal), then quickly mixing the sublimated magnesium metal with the air to be measured, paying attention to the oxygen content in the air, and obtaining nanometer magnesium oxide through a mixer. The morphology of this magnesium oxide tends to be acicular.
This is a Japanese patent. You can check it.