  We use numerical simulations to examine two-dimensional particle mixtures
that strongly phase separate in equilibrium. When the system is externally
driven in the presence of quenched disorder, plastic flow occurs in the form of
meandering and strongly mixing channels. In some cases this can produce a fast
and complete mixing of previously segregated particle species, as well as an
enhancement of transverse diffusion even in the absence of thermal
fluctuations. We map the mixing phase diagram as a function of external driving
and quenched disorder parameters.
