Patent ID: 7281570

Claim:
A method for producing a core sand or molding sand for casting purposes comprising the steps of: (a) providing an additive having an organic component and an inorganic mineral component, the organic component containing over 50 wt.-% carbon and less than 30 wt.-% oxygen, the additive having a water content of less than 10 wt.-% and emitting a gas amount in a temperature range of 250° C. to 800° C. of less than 500 ml/g; (b) coarsely grinding or pelletizing additive grains of the additive so that more than 50 wt.-% of the additive grains have a grain size of at least approximately 0.05 mm; and (c) subsequently mixing a granular mineral molding material with molding material grains having an average grain size less than 0.50 mm with the additive grains to form a finished mixture comprising over 90 wt.-% of the molding material and a residual amount comprising the additive and if necessary binding agents.