Abstract
The deoxidation of molten iron with aluminum was investigated by using an alumina crucible, the inner wall of which was partially covered with silica.
The deoxidation rate is analized on the basis of the kinetic theory with the following assumptions;(a) The deoxidation products (Al2O3) are nucleated homogeneously in the bulk of molten iron. Their agglomeration and growth are completed within about one minute after the aluminum addition.(b) Molten iron in the crucible follows the well?known flow pattern in the high frequency induction furnace.(c) The rising-out of the deoxidation products obeyed by the Stokes law takes place only in a thin layer close to the free surface of molten iron.(d) The deoxidation products are also separated through adsorption by the silica wall. This process is considered to take place through the bulk flow and the Brownian motion in a thin layer close to the side surface of molten iron.
These assumptions lead to the rate equation given as [%O]=[%O]°exp-kt/(1+βt/§) 2, which is quantitatively in good agreement with the experiments.
Here, t is the time after the completion of the agglomeration and growth, [%O] and [%O] the oxygen concentration at t=0 and t=t respectively, § the constant determined by the size distributions of the deoxidation products at t=0, β the constant associated with the Stokes law, and k represents the constant concerning to the adsorption process.
