Abstract: Chlorine gas is directly introduced, without the necessity of adding water with the gas, into a paper pulp slurry (i.e. comminuted cellulosic fibrous material) having a consistency of between about 6-15 percent. The gas is added to the inlet of a fluidizing mixer at the point where the slurry enters the fluidizing mixer, and is intimately mixed with the pulp by the mixer. The flow of the chlorine gas is in a flow controlled pathway, which is split into at least two flows so as to increase the total gas volume added to the pulp stock and obtain enhanced mixing. Each of the split flows is introduced to the inlet of a fluidizing mixer. The split flow addition of chlorine gas into two or more mixer inlets also may be practiced for low consistency pulp (e.g. pulp having a consistency of between about 1-5 percent).