Particle size, density, and shape are the most sensitive factors in entrainment. However, the particle size is still the most critical one; the more fineness of particles, the more entrainment. Nevertheless, the simultaneous presence of fines and ultrafine particles will make a problem in the separation degree. There are also other factors such as flotation operating conditions and froth properties. There are many methods to reduce the entrainment, however, the enlargement of the particle size of gangue minerals is the most successful factor by the selective aggregation of hydrophilic gangue minerals.

I recommend the following papers that will be more beneficial for you.

Article Entrainment of Gangue Minerals in Froth Flotation: Mechanism...

https://www.sciencedirect.com/science/article/abs/pii/S0892687514003045?via%3Dihub