ABSTRACT
Green sand molding processes are used worldwide in the manufacture of castings. Usually green sands are made up of silica sand, bentonite clay, water and additives. The use of sodium bentonite is widespread for its superior qualities as binders. Clays are composed of clay minerals based on hydrated aluminum silicates that commonly reach a certain level of plasticity when moistened. What differentiates one clay from another is the type of structure and the substitutions that can occur within this structure; of aluminum by magnesium or iron, and of silicon by aluminum or iron. In any case, kaolin is an important industrial mineral in the various world markets including applications in covering and loading paper, ceramics, paints, plastics, rubbers, glass fibers and many other uses. The mixtures present the moisture content that varied the water / clay ratio from 0.1 to 0.3 for sand agglomerated with 10% kaolin. For each compactability, permeability and resistance to compression test in green, 3 specimens were prepared according to ABNT with different sand / clay / water ratio. As an enrichment of the work, the permeable properties of the silica sand used in the tests were evaluated. It is concluded that kaolin, without additives, from the city of Tijucas do Sul (PR), presents acceptable mechanical resistance to compression for its use in foundry, however, the permeability was not satisfactory in any composition. Compactability was acceptable only when moisture caused the sand to swell, and at this point, there was also maximum mechanical resistance to compression.
Keywords
Clays; Kaolin; Foundry; Sand to green; Refractory Materials
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