Clay materials useful as binding agents in green sandcasting and other molding processes are discussed, as well as methods of preparing such clay materials. The clay materials may be chemically treated. For example, a natural clay may be combined with one or more reducing agents, such that an amount of iron present as ferric iron (Fe.sup.3+) in the natural clay is at least partially reduced to ferrous iron (Fe.sup.2+) in the chemically-treated clay. The chemically-treated clay may exhibit greater water absorption, binding properties, and/or sintering properties as compared to an untreated, natural clay.

Clay materials useful as binding agents in green sandcasting and other molding processes are discussed, as well as methods of preparing such clay materials. The clay materials may be chemically treated. For example, a natural clay may be combined with one or more reducing agents, such that an amount of iron present as ferric iron (Fe.sup.3+) in the natural clay is at least partially reduced to ferrous iron (Fe.sup.2+) in the chemically-treated clay. The chemically-treated clay may exhibit greater water absorption, binding properties, and/or sintering properties as compared to an untreated, natural clay.