The influence of SrO (0·0-5·0 wt%) on partial substitution of alpha alumina (corundum) in ceramic composition (95 Al 2 O 3 -5B 2 O 3 ) have been studied by co-precipitated process and their phase composition, microstructure, microchemistry and microwave dielectric properties were studied. Phase composition was revealed by XRD, while microstructure and microchemistry were investigated by electron-probe microanalysis (EPMA). The dielectric properties by means of dielectric constant (ε r ), quality factor ( Q× f ) and temperature coefficient of resonant frequency (τ f ) were measured in the microwave frequency region using a network analyser by the resonance method. The addition of B 2 O 3 and SrO significantly reduced the sintering temperature of alumina ceramic bodies to 1600 • C with optimum density (∼ 4 g/cm 3 ) as compared with pure alumina powders recycled from Al dross (3·55 g/cm 3 sintered at 1700 • C).The sintered ceramic bodies show different ranges for the dielectric properties. Dielectric constant exists between 24 and 29, quality factor ( Q × f ) is ranging between 15,236 and 22,020 GHz with a slight increase than those recorded with commercial alumina (10,000 -20,000 GHz) and temperature coefficient of resonant frequency (τ f ) in the -69 to -83 ppm/ • C range. The addition of SrO up to 5 wt% leads to a maximum (ε r ) value (29) due to relatively higher ionic polarizability of Sr 2+ than that of the Al 3+ and B 3+ ions. On the other hand, changing chemical and phase composition with the formation of platelets of Sr-hexaluminate phase (SrAl 12 O 19 ) results in maximizing value of ( Q × f ) up to 22,020 GHz at ≈ 8 GHz and large negative charge of (τ f ) to -83 ppm/ • C.