Method for making sand covered with bentonite, the sand, and a method for recycling molding sand for a mold using the sand covered by bentonite

摘要

Given green sand is obtained by a mixing operation that is carried out for a short period of time. Discarded sand is supplied as supplementary sand to a sand processing line, so that molding sand can be recycled. Green sand for a molding is used for facing sand or the pocket sand. Bentonite-covered sand is made by mixing reproduced sand, new sand, and discarded sand or any or all of them. The bentonite-covered sand is added to collected sand to supplement it. Also, the bentonite-covered sand is mixed with water, and used for facing sand or the pocket sand.