Influence of the hardener type on the sulfur diffusion from moulding sand to the casting surface

The article is discussing authors examinations concerning the influence of the sulphur diffusion from moulding sand on reduction the efficiency of modifier elements in the process of making the nodular cast iron. In case of magnesium decrease of its content is observe, as a result of forming the magnesium sulphide. In consequence the participation of magnesium is falling below the concentration essential to create a spheroid graphite. The source of sulphur in no-bake sand with resin modified by furfuryl alcohol is a hardener, on the basis of sulphonic acids and sulphuric acid. Described examinations relate to no-bake sands made on the warp of fresh quartz sand.