the method and apparatus for reclaiming substantially pure sand from a heat treating furnace ; wherein a casting with sand core and / or sand mold , comprising sand bound by a combustible binder , attached thereto is introduced into the heat treating furnace ; or , wherein portions of sand core and / or sand mold that are not attached to a casting are introduced into the heat treating furnace . wherein , the reclaiming within the furnace is carried out , in part , by a fluidizer that promotes binder combustion by one or more process of agitating , heating , and oxygenating . wherein , the characteristics of the reclaimed sand are selectively controlled by controlling the dwell time of the sand within the heat treating furnace .