Abstract: A method and apparatus for combusting black liquor generated by semi-chemical and other pulping processes, using a draft airflow furnace such as a rotating kiln, and a lower end mixing nozzle for black liquor and combustion air. A combustion agent is added to the black liquor to support ignition and permit a closely controllable combustion plume or flame adjacent the nozzle. Resulting combustion is complete and well below government environmental air emission standards. Chemical recovery is efficient, clean, and free from products of incomplete combustion.