Reclaiming foundry sand by gravity flow system

摘要

A method of reclaiming foundry sand by (a) providing a treatment tower having a plurality of heat conductive tubes extending across the interior of the treatment tower, the tubes being arranged in rows and staggered with respect to tubes in adjacent rows to create close spacing therebetween sufficient to permit the sand to flow continuously and non- turbulently along the contours of the exterior under the influence of gravity before dropping to the next adjacent tube to thereby again flow continuously and non-turbulently in successive sequence downwardly of the tower; (b) quiescently heating the interior tower space and tubes to a temperature in excess of 1300° F. and introducing sufficient air or oxygen to permit combustion of the resin binder; and (c) feeding particulated sand to the top of the tower and tubes whereby such sand controllably flows along and through such labyrinth of tube spacings with little or no dwell on each contacted tube and in a time period of 5- 15 seconds, said sand exiting from the bottom of said tower with said binder having been combusted to form a gas that is extracted from the top of the tower.