  It has been clarified that bulk superconductivity in
Fe$_{1+y}$Te$_{0.6}$Se$_{0.4}$ can be induced by annealing in an appropriate
atmosphere to remove the harmful effects of excess iron. In order to clarify
the details of the annealing process, we studied the changes in the physical
properties and reaction products of Fe$_{1+y}$Te$_{0.6}$Se$_{0.4}$ annealed in
pnictogen (P, As, Sb) atmospheres. Crystals annealed in a pnictogen atmosphere
show bulk superconductivity and the values of $T_{c}$ and $J_{c}$ are about
$14~$K and 2-4 $\times 10{^5}~$A/cm$^2$ ($2~$K, self-field), respectively. It
is also found that the reaction rate increases with the increase in the
saturated vapor pressure of the pnictogen. Unexpectedly, the reaction products
of Fe$_{1+y}$Te$_{0.6}$Se$_{0.4}$ after annealing in a P atmosphere mainly
consist of FeTe$_2$. In addition, the amount of P required to obtain the
optimal $T_{c}$ is much smaller than the amount of excess iron, which is
similar to the case of oxygen annealing. P, oxygen, and to some extent As could
serve as catalysts to form FeTe$_2$ to remove excess iron.
