Characteristic of Core Manufacturing Process with Use of Sand, Bonded by Ecological Friendly Nonorganic Binders A. Fedoryszyn aa, *, J. Dańko b, R. Dańko b, M. Asłanowicz b, *, T. Fulko, A. Ościłowski a AGH University of Science and Technology, Faculty of Foundry Engineering, Reymonta 23 str., 30059 Kraków, Poland