factorial design with the levels: 3, 4, and 5 mm for the underflow orifice diameter, and 12, 21, and 30 mm for the length of the vortex finder, respectivelly. The cylinders, the impermeable cone and other accessories of hydrocyclones HC11 and HF11 were built of brass. The porous cone of hydrocyclone HF11 was built of sinterized bronze particles ...