A method includes measuring a water content and a magnetized matter content of molding sand discharged from green sand casting equipment; comparing the measured water content with a first control value, and if the water content exceeds the first control value, drying the molding sand until the water content becomes equal to or less than the first control value; comparing the measured magnetized matter content with a second control value, and if the magnetized matter content exceeds the second control value, magnetically separating the molding sand until the magnetized matter content becomes equal to or less than the second control value; thereafter, reclaiming the molding sand by dry mechanical reclamation until a loss-on-ignition becomes equal to or less than a third control value; and classifying the molding sand until a total clay content becomes equal to or less than a fourth control value.

A sand core making machine that includes a hopper having a hollow body with an inner surface delimiting a passageway for a material used in the manufacture of a sand core. The hopper includes a plurality of breaker assemblies with each breaker assembly having at least one string. The ends of a string are attached to corresponding attachment points of the inner surface of the hollow body, such that the strings are arranged in a flow passage of the material. At least two breaker assemblies are spaced apart such that the two breaker assemblies interact with each other to break lumps of the material supplied to the hopper when the hollow body is shaken.