Nizhniy Novgorod State Technical University (Nizhniy Novgorod, Russia):

I. O. Leushin, Dr. Eng., Professor, Department “Metallurgical Technologies and Equipment”, e-mail: igoleu@yandex.ru
A. Yu. Subbotin, Cand. Chem., Associate Professor, Department “Metallurgical Technologies and Equipment”, e-mail: an_s_temp@mail.ru

M. A. Geyko, Senior Teacher, Department “Metallurgical Technologies and Equipment”, e-mail: mices@bk.ru

Abstract. The technology of preparing of galvanized steel scrap for its use as charge material in cast iron melting in induction melting facilities is proposed. The technology consists of chemical drawing of zinc from steel base by reaction of steel scrap and hydrochloric acid aqueous solution at 15–25 °C during a set period of time. It is proposed to use hexamethylenetetramine (urotropin) in the amount 2.5 by weight as short stopping agent for steel base protecting from dissolving in acidic medium. Dependence between speed of zinc removing from steel base and initial density of hydrochloric acid, 9 % by weight (from one side) and the amount of the processed material (from other side) has been researched. A time slot optimal for processing steel scrap (15 minutes) has been identified for the given initial density of hydrochloric acid (9 % by weight). The quantity of commercial hydrochloric acid (70 litres) and hexamethylenetetramine (0.8 kg of dry substance) needed for processing one ton of galvanized steel scrap have been determined. Based on the research findings, the proposed technology of preparing galvanized steel scrap is recommended to be used in machine building plant foundries where in-house zinc coated steel scrap accounts for at least 1000 tons per year.

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