Nizhny Tagil Technological Institute (branch) of the Ural Federal University named after the first President of Russia B. N. Yeltsin, Nizhny Tagil, Russia

A. P. Firstov, Cand. Eng., Associate Prof., Dept. of Metallurgical Technologies, e-mail: first55@mail.ru
O. I. Shevchenko, Dr. Eng., Associate Prof., Head of the Dept. of Metallurgical Technologies, e-mail: oleg.shevchenko@urfu.ru

Lignosulfonates have found application in foundries. They are a component of foundry glue for production of complex cores, are included in molding and core mixtures, and serve as additives in aqueous clay suspensions for active wetting of sand. In addition, lignosulfonates are binders, but due to their properties they provide insignificant strength to the cores and, according to the accepted classification, are weak binders. To increase the strength properties of manufactured cores, lignosulfonates are used with stronger binders. The use of lignosulfonates as an independent binder is possible when they are modified with sulfonols. In foundry production, sulfonols are used to obtain a uniform molding mixture with a high viscosity of the binder component in order to increase surface activity. To improve the wettability of the filler (as a flotation reagent), it is recommended to introduce various surfactants into the composition of molding and core mixtures. In foundry production, anionic sulfonols are usually used: DS-RAS, Petrov's Contact, black neutralized refined contact (KChNR) and neutralized black contact (NChK). The substances are low and moderately toxic and belong to hazard class 3 (the danger is posed by sulfonol dust, which can penetrate the respiratory system and come into contact with unprotected skin).

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