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Abstract

A carbohydrate is added to sand, which has been used to make foundry moulds or cores, and which has been bonded using an alkaline resol phenol-formaldehyde resin, prior to reclamation of the sand by a thermal reclamation. The thermal reclamation may be done in other equipment, for example, a rotary thermal reclamation unit, but is preferably done in a fluidized bed reclamation unit. The carbohydrate is preferably water soluble and is added to the used sand as an aqueous solution. The carbohydrate may be for example a monosaccharide, such as glucose, mannose, galactose or fructose, or a disaccharide such as sucrose, maltose or lactose. The carbohydrate may also be a carbohydrate derivative such as a polyhydric alcohol (e.g., ethylene glycol, glycerol, pentaerythritol, xylitol, mannitol or sorbitol), a sugar acid (e.g., gluconic acid), or a polysaccharide derivative (e.g., a starch hydrolysate, i.e., a glucose syrup or a dextrin). The amount of carbohydrate used in the reclamation process is usually of the order of 0.25% to 5.0% by weight based on the weight of used sand.

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First Claim