Moulding mixture for producing casting moulds for metalworking

The invention relates to a moulding mixture for producing casting moulds for metalworking, a process for producing casting moulds, casting moulds obtained by the process and also their use. To produce the casting moulds, a refractory mould raw material and a binder based on water glass are used. A proportion of a particulate metal oxide selected from the group consisting of silicon dioxide, aluminium oxide, titanium oxide and zinc oxide is added to the binder. Particular preference is given to using synthetic amorphous silicon dioxide as metal oxide.