Moulding with natural sand

Some foundries use naturally bonded sand. This is sand which contains a natural percentage of clay. Only water needs to be added in order to activate the binding capacity. If needed, some additives may be mixed as well. The approximate composition of natural sand is given in Table 2.8. 

Natural sand, which is found ready-mixed in nature, does not have the same high demands for mixing equipment as synthetic sand. It is mainly used in small-sized non-ferrous (e.g. copper) foundries and is not used in foundries casting iron and steel. 

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