Nizhny Novgorod State Technical University named after R. E. Alekseev, Nizhny Novgorod, Russia:
I. O. Leushin, Dr. Eng., Professor, Head of the Dept. of Metallurgical Technologies and Equipment, e-mail: igoleu@yandex.ru
O. S. Koshelev, Dr. Eng., Professor, Dept. of Machine-building Technological Complexes
L. I. Leushina, Cand. Eng., Associate Professor, Dept. of Metallurgical Technologies and Equipment
A. I. Markov, Post graduate Student, Dept. of Metallurgical Technologies and Equipment

Recently, there has been an active search and development of non-scarce and suitable for industrial use inorganic binders that can compete with synthetic resins in the composition of core mixtures in the production of castings, while ensuring comfortable working conditions for the personnel of foundries and reducing harmful emissions during the entire production process. To date, this goal has not yet been achieved and the search has not been completed, so research continues. The work, the results of which are presented by the authors of this article, is one of many ongoing in Russia in the mainstream of the designated topic. The authors decided to assign the role of the binder in the composition of the core mixture to the composition of inorganic salts, one of which is liquid glass - an aqueous solution of sodium or potassium silicates, and the other (others) are simultaneously hydrophilic and highly soluble in water salts of alkali or alkaline earth metals. The work focuses on the group of complex double salts, crystalline hydrates of sulfates of tri- and monovalent metals - the so-called alum, which have the required set of properties, and, in particular, on non-deficient potassium alum, which had previously proven itself well as a technological additive to the liquid glass core mixture. An environmentally friendly, easy-toimplement version of the technology has been proposed, experimentally verified and tested under the conditions of existing production, which provides the curing of the rod by the mechanism of dehydration of the rod mixture by a combination of heat exposure and the imposition of vacuum and the achievement of the required level of operational characteristics. Practical testing has confirmed the effectiveness of the application of the developed technology for the production of castings from iron and steel. Currently, work is underway to expand its application in foundries of Russian enterprises.

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