Moulding and core sand and method for producing it

摘要

The invention relates to moulding and core sand coated with binder. According to the invention the sand core is coated with alkali silicate salt, which in crystallised form contains a stable quantity of water of crystallisation. According to one embodiment of the invention the alkali silicate salt used as binder is ortho, meta or other alkali silicate. The alkali silicate salt used as binder is sodium metasilicate with 5 or 9 water of crystallisation molecule (Na2SiO3 . 5H2O or Na2SiO3 . 9H2O). The invention also relates to a method for producing the sand