The application of an alternating magnetic field to a fluidized bed of ferromagnetic particles leads to intensive magnetic stirring and strongly improves mass transfer. Liquid/solid mass transfer was studied with respect to the applied frequency and liquid flow rate. In the system investigated, magnetic stirring resulted in up to 4-fold increased mass transfer rates as compared to the same particles operated in a common fluidized bed without the influence of a magnetic field. The mass transfer rates showed a dependence on the square root of the rotational Reynolds number. (C) 2004 Elsevier B.V. All rights reserved.