  We report the discovery of 24 spectroscopic binary companions to giant stars.
We fully constrain the orbital solution for 6 of these systems. We cannot
unambiguously derive the orbital elements for the remaining stars because the
phase coverage is incomplete. Of these stars, 6 present radial velocity trends
that are compatible with long-period brown dwarf companions.The orbital
solutions of the 24 binary systems indicate that these giant binary systems
have a wide range in orbital periods, eccentricities, and companion masses. For
the binaries with restricted orbital solutions, we find a range of orbital
periods of between $\sim$ 97-1600 days and eccentricities of between $\sim$
0.1-0.4. In addition, we studied the metallicity distribution of single and
binary giant stars. We computed the metallicity of a total of 395 evolved
stars, 59 of wich are in binary systems. We find a flat distribution for these
binary stars and therefore conclude that stellar binary systems, and
potentially brown dwarfs, have a different formation mechanism than
planets.This result is confirmed by recent works showing that extrasolar
planets orbiting giants are more frequent around metal-rich stars. Finally, we
investigate the eccentricity as a function of the orbital period. We analyzed a
total of 130 spectroscopic binaries, including those presented here and systems
from the literature. We find that most of the binary stars with periods
$\lesssim$ 30 days have circular orbits, while at longer orbital periods we
observe a wide spread in their eccentricities.
