Life Cycle Assessment Comparison of Two Refractory Brick Product Systems for Ladle Lining in Secondary Steelmaking

Francesco Boenzi,Joaquín Ordieres-Meré,Raffaello Iavagnilio

doi:10.3390/su11051295

Abstract

This paper aims to compare the environmental performance of two types of refractory bricks for the internal lining of ladles in secondary steelmaking, where the dissolved inclusions coming from the refractory material require fine control to obtain the target steel quality. In this context, magnesia-carbon-based refractories are largely utilized, thanks to the adequate durability of the ladle lining in terms of number of heats before re-lining, but the utilization of organic binders in the mixture (pitch, resins) arises ecological and human health concerns. Concurrently, research efforts in refractory material science look at improving the quality of steel by reducing the content of dissolved carbon due to the release from the bricks, thus focusing on different refractory materials and specifically on alumina-based materials. The European Commission funded the research project “LeanStory”, aiming to promote such new lines of refractories through the cooperation between industrial partners and scholars where different recipes are considered. In the present paper, two representative systems of the refractory types considered, magnesia-carbon and magnesia-alumina, are compared with a preliminary Life Cycle Assessment (LCA). Suppliers and transports for the two product systems have been taken into account, referring to one tonne of refractory material as the functional unit for comparison. Preliminary impact results (adopting the ReCiPe Midpoint–Hierarchist perspective methodology for calculating the impact indicators) show that the new solution performs largely better almost for each indicator. Further investigations are required in order to assess the ecological performance of the two systems, considering the effective consumption of bricks for the production of steel.

Highlights

Refractory materials have high melting points and maintain their structural properties at very high temperatures
As regards the localization of processes or of utility providers comprised in the ecoinvent® 3.4 database, the general rules adopted are the following: if the dataset exists as a version with a specific national localization, this version is used; if the process is localized in Europe, the “RER” or “ESuustraoinpaebilwityi2th01o9u, 1t0S, xwFiOtzRePrElaERndR”EVvIEeWrsion of the dataset is used, if it exists (“RER” stands for E7uorfo2p2e according to the database documentation); if the process is localized outside Europe or if the “RdEesRc”ridpatitoanseotfdtoheespnrootcesxsisets, cthoemnptrhiese“dRionWth”e(RdepsticotfetdhperWodourlcdt)sdyasteamsetaorer tihlleus“tGraLtOed”,idthattahseet aaredoupsteedd. references of their Life Cycle Inventories (LCIs)
A new calculation of the “ReCiPe Midpoint (H)” impact indicators is performed for this product system, assuming that in the recipe specified in Table 1 the component fused magnesia could be entirely substituted by DBM97, that’s to say by high purity magnesia, as described in [24]

Summary

Introduction

Refractory materials have high melting points and maintain their structural properties at very high temperatures They are required in ferrous and non-ferrous industries, where furnaces or kilns are used. The different conditions in each steel plant, where none remain the same, require multiple processing routes during secondary metallurgy to obtain the expected steel grades (including primary melting, stirring, vacuum or vacuum-oxygen decarburization degassing (VD/VOD)), ladle furnaces and chemical heating facilities are always of crucial importance. In this context, the steel ladle furnace can be considered

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