Hydrocyclone classification of particles in the micron range

In nanotechnology, classification in the micron and submicron range is of growing interest. Usually, hydrocyclones do not reach these low cut sizes. This study presents a special batch processing technique using a 20 mm hydrocyclone for classification in the micron range. This hydrocyclone was equipped with a special underflow box that stored the coarse particles. The overflow was recirculated to the hydrocyclone entrance. A set of experiments was conducted using this batch hydrocyclone technology. Quartz with particle size <20 μm and a SiC/Si residue with size <10 μm was fed to the hydrocyclone, which operated in a closed circuit for 120 min. The results showed that the hydrocyclone preferably separates the particles that are >1 μm in the first 60 min. Later, the particles in the submicron range were increasingly discharged in the underflow. A simulation for the classification in a batch hydrocyclone with a closed circuit and underflow box is presented.