Possible ecological advantages from use of carbonless magnesia refractory bricks in secondary steelmaking: a framework LCA perspective

Abstract

In the present paper, two types of magnesia-based refractory bricks for the wear lining of a steel ladle furnace are considered, with the aim of comparing their ecological performances. The adopted methodology is the Life Cycle Assessment (LCA) approach from cradle-to-gate of the two brick product systems, in accordance with the European and International Standard EN ISO 14044:2006, and the chosen methodology for the Life Cycle Impact Assessment (LCIA) is ReCiPe 2016, considering the midpoint impact categories and the hierarchist perspective. The conducted study is part of a European industrial research project aimed at investigating the possibility of cleanliness improvement of the steel produced in secondary steelmaking, by reducing the refractory contamination in the steel ladle furnace. The compared refractory bricks consist of a reference, currently used, MgO-C type and a more innovative "carbonless" one, containing magnesia and MA sintered spinel as principal components, on the basis of recipe data provided by the industrial partners of the project. The results attained so far in industrial practice are preliminary, because of the lack of a full-ladle lining experimentation, even though the application of the conceived innovative bricks in the upper part of the slag line of the ladle presents promising aspects. The results of the LCIA comparison between the two brick product systems highlight better performances for all the impact categories, except for "Human carcinogenic toxicity" and markedly for "Mineral resource scarcity." Besides these results, a general framework for shifting the ecological analysis to the steel production is provided. Calculations, referred to the production of one tonne of steel, are therefore performed, involving scenario assumptions not only regarding the refractory consumption but also the forecast operational features of the steel ladle with the "carbonless" lining. In this second set of results, it is clear how the principal contribution to almost all the impact categories is the electrical energy consumption of the ladle, while the contribution from the brick product systems remains important for the above-mentioned worsened impact categories, whose magnitude is strongly dependent on the refractory consumption.

Effects of clay and fireclay addition on the properties of magnesia–forsterite–spinel refractories synthesized at different firing temperatures

“…Refractory oxides are ceramics that can be employed for elevatedtemperature applications [1][2][3][4][5]. Magnesia with a melting point of 2800 °C is a member refractory materials that is broadly used for lining the industrial steel and metallurgical furnaces because of its properties like good slag resistance and superior refractoriness [6][7][8][9]. However, the high cost of production of pure magnesia is one of its shortcomings.…”

Refractory materials of metallurgical furnaces with the addition of silicon production waste

“…The obtained results of experiments conducted with the initial microsilica and its behavior in refractory mixtures indicate that the proposed fine composite material can be used in refractory products and introduced into technical standards. The wide variety of refractory materials is explained by the desire to exclude the interaction between the molten metal and the lining material [22]. In addition to mechanical and thermal destruction, metallization occurs, which is accompanied by exchange reactions between oxides and lining [23][24].…”