Patent ID: 6120284
Filing Date: 2000-09-19
Classification: B22C

Abstract:
A method of cleansing sand of resin binder, comprising:(a) providing a treatment tower having a top and a bottom and 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, the spacing being sufficient to permit the sand to flow continuously and non-turbulently along the contours of the tube exteriors 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 at least 1100-1300.degree. 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 of tubes whereby such sand controllably flows along and through said spacings of tubes with little or no dwell on each contacted tube, the sand traversing the height of the tower 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, wherein said sand flow hugs the tube exteriors 80% of the time when migrating from the top to the bottom of the tower.