Numerical computation of fluid flow in different nonferrous metallurgical reactors

Heat, mass and fluid flow phenomena in metallurgical reactor systems such as smelting cyclones or electrolytic cells are complex and intricately linked through the governing equations of fluid flow, chemical reaction kinetics and chemical thermodynamics. The challenges for the representation of flow phenomena in such reactors as well as the transfers of these concepts to non-specialist modelers (e.g. plant operators and management personnel) can be met through scientific flow visualization techniques. In the first example the fluid flow of the gas phase and of concentrate particles in a smelting cyclone for copper production are calculated three dimensionally. The effect of design parameters (length and diameter of reactor, concentrate feeding tangentially or from the top, ..) and operating conditions are investigated. Single particle traces show, how to increase particle retention time before the particles reach the liquid film flowing down the cyclone wall. Cyclone separators are widely used in the metallurgical and chemical industry for collection of large quantities of dust. Most of the empirical models, which today are applied for the design, are lacking in being valid in the high temperature region. Therefore the numerical prediction of the collection efficiency of dust particles is done. The particle behavior close to the wall is considered by applying a particle restitution model, which calculates individual particle restitution coefficients as functions of impact velocity and impact angle. The effect of design parameters and operating are studied. Moreover, the fluid flow inside a copper refining electrolysis cell is modeled. The simulation is based on density variations in the boundary layer at the electrode surface. Density and thickness of the boundary layer are compared to measurements in a parametric study. The actual inhibitor concentration in the cell is calculated, too. Moreover, a two-phase flow approach is developed to simulate the behavior of anode slime particles during electrolysis. The computations show the disadvantages of the common used principle of transverse flow. Different arrangements for the electrolyte in- and outlet are suggested to optimize the electrolyte flow. (author)