Production of Ferroboron from Wastes by SHS-metallurgy and influence of Ligatures on the Structure/Properties of Cast Iron

Abstract

Waste, generated during the industrial process negatively affects the environment, but at the same time it is a valuable raw material and can be used to produce new marketable products. The study of the effectiveness of Self-propagating High temperature Synthesis (SHS) methods, which are characterized by the simplicity of the necessary equipment, the purity of the final product and the high processing speed, is under the wide scientific and practical interest to solve the set problem. The work describes technological aspects of production of ferro boron by the method of SHS - metallurgy from iron-containing wastes of rolled production for alloying of cast iron and results of effect of alloying element on degree of boron assimilation with liquid cast iron. Features of Fe-B system combustion have been investigated and the main parameters to control the phase composition of synthesis products have been experimentally established. Effect of overloads on patterns of cast ligatures formation and mechanisms of structure formation of SHS products was studied. It has been shown that an increase in the content of hematite Fe2O3 in iron-containing waste leads to an increase in the content of phase FeB and accordingly, the amount of boron in the ligature. Boron content in ligature is within 3-14%, and phase composition of obtained ligatures consists of Fe2B and FeB phases. Depending on the initial composition of the wastes, the yield of the end product reaches 91 - 94%, and the extraction of boron is 70 - 88%. Combustion processes of high exothermic mixtures allow obtaining a wide range of boron-containing ligatures from industrial wastes. In view of the relatively low melting point of the obtained SHS-ligature, the positive dynamics of boron absorption by liquid iron is established. According to the obtained data, the degree of absorption of the ligature by alloying gray cast iron at 1450 ° C is 80 - 85%. When combined with the treatment of liquid cast iron with magnesium, followed by alloying with the developed ligature, boron losses are reduced by 5-7%. At that uniform distribution of boron micro-additives in volume of treated liquid metal is provided.