Nitrate-exchanged sodalite Na8Al6Si6O24(NO3)(2) and mixed sodium magnesium silicate with sodalite-like structure Na8Mg3Si9O24(NO3)(2) were obtained by reaction of Mg or Al salts with silica or glass in molten NaNO3 fluxes in the range of temperatures 673-823 K, in the presence of Na3VO4 as mineralizer.