A core forming device is equipped with a kneading tank in which raw materials of a core are kneaded, a raw material supply unit that supplies the raw materials to the kneading tank, a mold that accommodates a kneaded material including the raw materials kneaded in the kneading tank and that forms the core, a piston that injects the kneaded material into the mold, a position sensor that detects a position of the piston, and a control unit that controls a supply amount of the raw materials supplied to the kneading tank from the raw material supply unit. The control unit determines the supply amount of the raw materials based on a difference between the position of the piston upon completion of injection and a reference position of the piston.

In the disclosed solution sand to be cleaned is thermally cleaned by rotating the sand being cleaned in a large oven (1) by rotating the oven (1). Before cleaning, the sand may be pre-processed by crushing any lumps and cleaning the sand fraction by magnetic separation. Preprocessed sand to be cleaned and heat energy are fed (5) into the rotating oven. The oven (1) is set slightly inclined so that a second end of the oven (1) is lower than a first end. The inclination and rotating speed of the oven (1) as well as the feed amount of sand are adjusted, whereby the advancing speed of the sand may be adjusted, as well as the ratio of the sand being cleaned to the volume of the oven (1) kept as desired. The temperature of the oven (1) is monitored at the coldest area of the oven, which is substantially at the second end of the oven. The temperature of the oven (1) is adjusted by adjusting the amount of heat energy fed in. By means of temperature monitoring and knowing the advancing speed of the sand, it is also possible to determine the average temperature of the sand and adjust it as desired by adjusting the supplied heat energy. Finally, the cleaned sand is let run (12) from the second end of the oven (1).

In the disclosed solution sand to be cleaned is thermally cleaned by rotating the sand being cleaned in a large oven (1) by rotating the oven (1). Before cleaning, the sand may be pre-processed by crushing any lumps and cleaning the sand fraction by magnetic separation. Preprocessed sand to be cleaned and heat energy are fed (5) into the rotating oven. The oven (1) is set slightly inclined so that a second end of the oven (1) is lower than a first end. The inclination and rotating speed of the oven (1) as well as the feed amount of sand are adjusted, whereby the advancing speed of the sand may be adjusted, as well as the ratio of the sand being cleaned to the volume of the oven (1) kept as desired. The temperature of the oven (1) is monitored at the coldest area of the oven, which is substantially at the second end of the oven. The temperature of the oven (1) is adjusted by adjusting the amount of heat energy fed in. By means of temperature monitoring and knowing the advancing speed of the sand, it is also possible to determine the average temperature of the sand and adjust it as desired by adjusting the supplied heat energy. Finally, the cleaned sand is let run (12) from the second end of the oven (1).

A continuous mixing apparatus for a powder/granular material and a viscous liquid, with a mixing cylinder, a shaft member which is on a central axis of the mixing cylinder and rotates inside the mixing cylinder, and a plurality of mixing paddles disposed on a surface of the shaft member, wherein the mixing cylinder is with a powder/granular material feed port on one end portion, a mixed material discharge port on the other end portion, and a viscous liquid injection unit between the powder/granular material feed port and the mixed material discharge port, and the plurality of mixing paddles are disposed on the shaft member so as to form a spiral around the central axis, the plurality of mixing paddles being, in at least a portion between the viscous liquid injection unit and the mixed material discharge port, attached to provide first rows having an attachment angle of 5 to 60.

A continuous mixing apparatus for a powder/granular material and a viscous liquid, with a mixing cylinder, a shaft member which is on a central axis of the mixing cylinder and rotates inside the mixing cylinder, and a plurality of mixing paddles disposed on a surface of the shaft member, wherein the mixing cylinder is with a powder/granular material feed port on one end portion, a mixed material discharge port on the other end portion, and a viscous liquid injection unit between the powder/granular material feed port and the mixed material discharge port, and the plurality of mixing paddles are disposed on the shaft member so as to form a spiral around the central axis, the plurality of mixing paddles being, in at least a portion between the viscous liquid injection unit and the mixed material discharge port, attached to provide first rows having an attachment angle of 5 to 60.

Provided is a method of producing foamed sand (s) for forming a sand mold. The foamed sand (s) includes sand particles (p) and foam (f) adhering to surfaces of the sand particles (p). The foam (f) contains water glass (b), water (w), and a surfactant (c). According to the method, an aqueous surfactant solution (e) in which the surfactant (c) is dissolved is frothed to generate froth (d) from the aqueous surfactant solution (e). Then, the generated froth (d), the water glass (b), and the water (w) are kneaded with the sand constituted by the sand particles (p).

Provided is a method of producing foamed sand (s) for forming a sand mold. The foamed sand (s) includes sand particles (p) and foam (f) adhering to surfaces of the sand particles (p). The foam (f) contains water glass (b), water (w), and a surfactant (c). According to the method, an aqueous surfactant solution (e) in which the surfactant (c) is dissolved is frothed to generate froth (d) from the aqueous surfactant solution (e). Then, the generated froth (d), the water glass (b), and the water (w) are kneaded with the sand constituted by the sand particles (p).

A method of reusing core sand includes crushing a core used for casting into granules, the core includes water glass as a binder, and the water glass includes water-soluble water glass and water-insoluble water glass; heating the core; detaching the water glass from the core sand; and separating and collecting the core sand from a mixture of the water glass and the core sand.

A method of reusing core sand includes crushing a core used for casting into granules, the core includes water glass as a binder, and the water glass includes water-soluble water glass and water-insoluble water glass; heating the core; detaching the water glass from the core sand; and separating and collecting the core sand from a mixture of the water glass and the core sand.

A method for inorganic binder casting, comprising: selecting a Shape-Forming Material based on pre-determined manufacturing and shape characteristics, selecting a casting shape based on pre-determined design characteristics, and forming the Shape-Forming Material into a mold. The mold is coated with an inorganic binder solution at a pre-defined weight ratio and is dehydrated the Shape-Forming Material. The method further comprises pouring a hot liquid metal into the mold and allowing said hot liquid metal to cool to form a molded part. The Shape-Forming Material may be washed from said molded part with a solvent, the inorganic material and Shape-Forming Material reclaimed, reused, and the Shape-Forming Material reformed to a mold. The method further comprises recreating a liquid inorganic binder solution using the reclaimed inorganic material and recoating the Shape-Forming Material with the reclaimed inorganic binder solution.