Method of making abrasive shards, shaped abrasive particles with an opening, or dish-shaped abrasive particles

A method comprising:

• providing a mold having a plurality of cavities, the plurality of cavities comprising polymeric surfaces;
• filling the plurality of cavities with a sol-gel, the sol-gel comprising particles that can be converted into alpha alumina in a liquid, the liquid comprising a volatile component;
• and
• removing at least a portion of the volatile component from the sol-gel while the sol-gel resides in the plurality of cavities and controlling the rheology of the sol-gel in the mold by selecting a viscosity of the sol-gel, a presence or absence of a mold release agent, and a drying rate to thereby form a plurality of precursor shaped abrasive particles having a type selected from the group consisting of a majority of abrasive shards, shaped abrasive particles with an opening, and dish-shaped abrasive particles.