The effects of Li 2O doping on the interaction between α-Fe 2O 3 and basic nickel carbonate were investigated using DTA, TG, DTG and X-ray diffraction techniques. The results obtained showed that ferric oxide underwent solid-solid interaction with pure NiO at temperatures starting from 800°C, yielding well-crystallized NiFe 2O 4 (trevorite). The amount of ferrite produced increased when the roasting temperature of the mixed solids was increased. However, the completion of this reaction required prolonged heating at elevated temperatures, ⩾ 1100°C, owing to the formation of the NiFe 2O 4 phase which covered the surfaces of the grains of each oxide thus hindering the diffusion of Ni 2+ and Fe 3+ ions. Doping with Li 2O (although effecting the transformation of some Ni 2+ ions into Ni 3+ ions (not contributing in the ferrite formation)) enhanced the solid-solid interaction between the mixed oxides to an extent proportional to the amount of Li 2O added. The promotion effect of lithium oxide was attributed to an effective increase in the mobility of the various reacting ions. The activation energy of formation (Δ E) of nickel ferrite was determined for pure and lithium-doped mixed solids. This was achieved by following up the change in the height of some diffraction lines, or key lines of the NiFe 2O 4 phase (with d spacings at 2.95 and 1.605 Å) as a function of roasting temperature. The computed values of Δ E were 26, 19 and 16 kcal mol −1 for pure solids and those doped with 3 and 5 mol% Li 2O, respectively.