Gas Phase Distribution in a Mixer with a Mechanical High-Speed Mixer – Case Study

Abstract

The mechanical mixing process is a common operation in the technological processes of many industries, also in the mineral processing. The separation of valuable mineral from gangue in the flotation chamber results in electrical power consumption of 1-10 kW/m 3 and depending on the type of flotation machine. Air is introduced into the flotation chamber and the bubbles are dispersed using a rotor- stator system, which simultaneously mixes the suspension with air bubbles. Flotation efficiency depends on tank shape, rotor and stator design, as well as operating conditions such as rotor speed, aeration rate, and suspension properties. Striving to reduce energy consumption while maintaining high process efficiency, optimizing the shape of the stator-rotor system is crucial. This system determines the distribution of bubble in flotation chamber and the occurrence of elementary flotation acts. The article presents experimental results from measurements of the velocity field of the water and air-water systems in a laboratory flotation chamber under various hydrodynamic conditions by using the digital image anemometry (PIV) technique and numerical simulations (CFD).The obtained dates were used to check the distribution of the gas phase in the flotation chamber and to assess the energy consumption of the rotor.