Patent ID: 8813829
Filing Date: 2014-08-26
Classification: B22C,B22D

Abstract:
1. A method for producing a mold comprising the steps of: producing a mold with a spherical molding sand (A) having a sphericity of 0.95 or more, a binder (II) comprising an acid-hardening resin and a hardening agent (II), pouring metal into the obtained mold; disintegrating and reclaiming the mold to obtain reclaimed molding sand; mixing the reclaimed molding sand, a binder (I) comprising an acid-hardening resin and a hardening agent (I) to obtain kneaded sand; and forming the kneaded sand into a second mold, wherein the reclaimed molding sand comprises 60% by weight or more of Al both of the hardening agents (I) and (II) comprise an organic sulfonic acid, and, in the hardening agents, a content of sulfuric acid is 2% by weight to 5% by weight and a content of phosphoric acid is not more than 5% by weight, wherein an ignition loss of the reclaimed molding sand is not more than 0.5% by weight; and an elution amount of elemental aluminum per 1 g of the reclaimed molding sand is not more than 50 μg in accordance with the following method of measurement: