  To study the nature of Bulge AGB stars and in particular their circumstellar
dust, we have analysed mid-infrared spectra obtained with the ISOCAM CVF
spectrometer in three Bulge fields. The ISOCAM 5-16.5 micron CVF spectra were
obtained as part of the ISOGAL infrared survey of the inner Galaxy. A
classification of the shape of the 10 micron dust feature was made for each
case. The spectra of the individual sources were modelled using a radiative
transfer model. Different combinations of amorphous silicates and
aluminium-oxide dust were used in the modelling. Spectra were obtained for 29
sources of which 26 are likely to be Bulge AGB stars. Our modelling shows that
the stars suffer mass loss rates in the range of 10^{-8} - 5 x 10^{-7} Msun /
yr, which is at the low end of the mass-loss rates experienced on the Thermally
Pulsing AGB. The luminosities range from 1,700 to 7,700 Lsun as expected for a
population of AGB stars with Minit of 1.5 - 2Msun. In agreement with the
condensation sequence scenario, we find that the dust content is dominated by
Al_2O_3 grains in this sample of low mass-loss rate stars.
