The electrical conductivity of alkali molten carbonates coexisting with gamma-LiAlO2 powders have been measured by ac impedance method. The temperature and composition dependence of the electrical conductivity are investigated. The effects of the solid phase upon the ionic species are discussed. The electrical conductivity varies with the liquid content and drastically increases at ca. 30 vol.%. The Arrhenius plot shows an increase of the electrical conductivity with increasing temperature. A significant value of the electrical conductivity below the salt melting point is observed. This indicates the existence of a non-frozen phase assuming conduction within the system. The activation energy increases with a decrease of apparent average thickness of the liquid layer. The influence of the solid system is conspicuous in Na2CO3 mixtures rather than in K2CO3 or Li2CO3 one. This shows that the order of magnitude of perturbations by the solid phase depends also on the cationic species associated within the system. (C) 2007 Elsevier Ltd. All rights reserved.