investigated the bioleaching
processes in a rotating drum bioreactor, and found that the total
concentration of iron in the rotating drum bioreactor was 2.3 times
higher than that in the conventional stirred tank at solids concentration
of 50%w/w. Though the rotating drum bioreactor shows excellent
capacity for the treatment of slurry with high solids concentration, its
gas–liquid mass transfer performance is not satisfactory for the lack of an efficient gas-sparger