Preventing the incorporation of impurities in Li‐Zn ferrite grains during sintering is essential for production of ceramics withreproduciblemagnetic and electrical properties. Li‐Zn ferrites of composition Li0.3Zn0.4Mn0.05Fe2.25O4were prepared with Bi2O3and borosilicate sintering additives. The distribution of impurity ions in the sintered ferrites was investigated using transmission electron microscopy (TEM) coupled with energy dispersive spectroscopy (EDS). Ceramics prepared with Bi2O3contained Si, Ca, and S impurities, located at grain boundaries and triple point regions. The low viscosity and good wetting properties of the Bi2O3and to a lesser extent the borosilicate liquid phase allowed impurities to be selectively removed from the growing ferrite phase during sintering, thus improving sample resistivit