Modeling of fields in magnetic drum separators

Little analytical work has been done in evaluating the periodic magnetic fields and associated field gradients which determine small particle behavior in drum separator systems. One of the few investigations of recent times is that of W. F. Brown, Jr. [1] in which experimental data on field values are fitted to a Fourier series expressed in terms of the azimuthal angle about the drum axis. Here, a simpler Fourier series for linear periodic field arrays is adapted to the cylindrical geometry of drum separators, enabling for the first time, the construction of satisfactory equations of motion for small magnetic particles in such systems.