Mixing, Mass Transfer, and Numerical Models

We want to eliminate dissolved impurities to another phase: slag, gas, solid, or a molten metal that has limited solubility in the main metal. The various phases may be in the form of droplets, bubbles, particles, or walls. The contact areas with metal should be large. The aim in reactor design and operation is to achieve relatively high velocities and small dimensions. Relations for mass transfer are also included since the behaviour of systems with molten metals may be different from that usually treated in chemical engineering. In the field of turbulence the Prandtl eddy length is important for describing removal to walls. Hydrogen in aluminium and the pick-up of hydrogen in aluminium from water vapour is studied in some detail, measured, and modelled. It is taken into account that hydrogen gas is two-atomic. The approach concerning aluminium may be applied to a range of metals.