Effects of variation in water content, clay fractionudand sodium carbonate additions on the syntheticudmoulding properties of Igbokoda clay and silicaudsand

摘要

Loto, C.A. and Adebayo, H., 1990. Effects of variation in water content, clay fraction and sodiumudcarbonate additions on the synthetic moulding properties of Igbokoda clay and silica sand. Appl.udClay Sci., 5: 165-181.udIn this investigation, the Igbokoda pure silica sand is characterised and used as a base sand for theudIgbokoda clay- sand mixture in an attempt to develop an efficient synthetic moulding sand. The mechanicaludproperties of the clay-sand-water mixture were determined. The effect of additions ofNa2C03udto the moulding sand was examined with particular attention to its influence on mechanical propertiesudof the synthetic moulding sand. The fineness number, screen bulk fraction, total coarse fraction andudthe total fine fraction of Igbokoda silica sand were found to be within the range that could give goodudmouldable properties. The values obtained for the green compressive strength, the dry compressiveudstrength, the green and dry shear strengths, collapsibility and toughness indicate that Igbokoda clayudhas good values as a binder for synthetic moulding sand. In general, the addition of Na2C03 gives improved properties to the moulding sand though with a tendency towards impaired collapsibilityudvalues.