Special epsilon-HNIW crystals and preparation method thereof

The invention discloses special epsilon-HNIW crystals and a preparation method thereof. The HNIW content of the crystals is larger than or equal to 99.5%, the epsilon-HNIW content is larger than or equal to 95.0%, and the density of the crystals is larger than or equal to 2.033 g/cm ; observed from the appearance, no sharp edges exist, no cracks exist in crystal surfaces, and no wrapped substances exist between the crystals; the ratio of the short axis to the long axis of the crystals is larger than or equal to 0.75, and the ratio of the area to the perimeter of projection is larger than or equal to 0.80; the weight of the crystals with granularity of 150-300 microns accounts for 50-80% of the total weight. In the preparation method, no crystal species needs to be added; by adjusting the adding speed and the stirring speed of anti-solvent, the aim of controlling the morphology and granularity distribution of the crystals is achieved. The crystals have the advantages of being easy to operate, small in anti-solvent consumption, mild in reaction condition, safe, reliable, green, efficient, easy to industrialize and the like.