A multiple feed for a rotary hearth calciner having a plurality of sets of rabbles arranged to engage with the materials in row form from the entrance portion of the hearth to the exit or discharge end thereof. The arrangement of the rabbles are such as to permit for the feed on to the hearth of the furnace materials of differing characteristics and to retain such differing materials in a separate state or row upon the hearth until the same are withdrawn from on to the hearth and directed to a suitable discharge or exit area. In certain instances, and where desired, the materials of one row may be caused to mix with the materials in the next adjacent row and to remain in such a mixture throughout the travel of the materials on the hearth.