The boundary conditions for an axial diffusion model are overviewed and modified concerning the pulp layer in a column flotation cell. It is confirmed by the transfer function representation that the four general boundary conditions for an axial diffusion model correspond to the particular cases of Wehner and Wilhelm's, which considers not only the reaction section itself but also its fore and after ones.
Various mathematical models for the pulp layer in a column flotation cell have been proposed and the most popular one of them is an axial diffusion with first order reaction model of one stage. However, they can't estimate the behaviors of non-adhesive particles at the pulp level.
In this paper, the authors, therefore, represented the transportation of non-adhesive particles in the pulp layer of a column flotation cell by the two-stage axial diffusion with first order reaction model. The Wehner and Wilhelm's as well as Danckwerts' boundary conditions have been partly modified and then applied to the feed point, the pulp level and the tailing point of the column flotation. The proposed models with their appropriate boundary conditions make it possible to estimate the behaviors of non-adhesive particles at the pulp level.
