Vliv přídavku slévárenských odprašků na vlastnosti bentonitových formovacích směsí a kvalitu povrchu odlitků

Abstract

The objective of this master thesis is to assess the effect of foundry dust additives on the properties of bentonite moulding mixtures and on the surface quality of castings produced using moulds made from these mixtures. The dust samples from 7 foundries were characterized through laboratory tests to determine their moisture content, loss on ignition, granulometry, chemical composition, pH and electrical conductivity of the infusion, the proportion of active bentonite, and the content of lustrous carbon produced by pyrolysis. The dust additives were incorporated into a selected bentonite moulding mixture in amounts ranging from 0 to 12 %. For each moulding mixture, the moisture content, compactability, compressive strength, split strength, shear strength, strength in the water condensation zone, permeability, and bulk density were determined. Test castings were subsequently produced using selected modified moulding mixtures, and their surface quality was evaluated. The experimental methods used are described in a separate chapter. The theoretical part provides basic information on bentonite moulding mixtures, on additives for moulding mixtures, on foundry waste materials, and on foundry defects related to moulding mixtures.