PURPOSE: To obtain sprue and riser type products for casting with which the deterioration at the time of recycling of molding sand is suppressed and which produce castings having stable quality by compounding an org. binder with a granular material consisting essentially of refractories and molding the mixture.
CONSTITUTION: Aluminate shale and aluminum bydroxide are compounded at specific ratios. The compd. is pulverized and mixed for a prescribed time under addition of water thereto in a ball mill and the mixture is palletized to specific particle sizes by a spray direr. High aluminous powder is mixed with these pellets at a specific ratio and the pellets are burnt for a specific time at a specific temp. in a rotary kiln. The burnt matter is put into an agitating machine where the massive matter is disintegrated and thereafter, the high aluminous powder is removed and spherical mullite ceramics particles are obtd. These particles are adjusted by sieving to specific particle sizes. A novolak type phenol resin charged into the resultant granular material and the mixture is kneaded by a mixer. A hexamethylene tetramine is charged in the form of an aq. soln. thereto. Further, a calcium stearate is added to the mixture and the mixture is kneaded. The resulted resin coated sand is compression molded under heating.
MATSUBARA MAKOTO
YASUKAWA SHOGO
Next Patent: DEVICE FOR RECONDITIONING MOLDING SAND