Foundry mould or core mfr. from granular and/or fibrous material - using silicate binder and surfactant to increase strength and facilitate disintegration after use

摘要

In the mfr. of a foundry mould or core from granular and/or fibrous material with sodium or potassium silicate as binder, a surfactant (I) is mixed with the material and mould or core is heated to 110-180 degrees C. (I) is pref. a tensile, silicone oil, silicone emulsion or siliconate and is used in an amount =0.1 wt.% of the total mixture. The amount of silicate binder is pref. 1-3 wt.%. Inclusion of (I) allows less silicate binder to be used without loss of strength. The resulting moulds or cores thus have improved refractoriness and are more easily disintegrated after use. The recovery of the used moulding sand is also improved. Tested after cooling. Compressive strengths of 500-600 N/cm2 were obtained, compared with 80-90 N/cm2 when no silicone emulsion was included.