Abstract: The present invention relates to a molding process using a silicate binder substantially based upon an alkali silicate having a higher molecular ratio of silica to alkali. More particularly, it relates to improvements in a molding process, wherein the mold and core are cured by gassing with exceedingly diluted CO.sub.2 and the CO.sub.2 gas consumption for the curing of the molds is reduced to between about 1/2 - 1/20 compared with that of the conventional CO.sub.2 curing process. The resulting molds and cores exhibit an excellent collapsibility after casting, develop no harmful gas in curing and casting procedures, and the used waste sands do not cause any serious soil or water pollution problems.