Mechanical and chemical behavior of MgO-C bricks under near-service conditions

MOLINÉ MARCOS N.; GASS, SEBASTIÁN E.; TOMBA MARTINEZ, ANALÍA G.; GALLIANO, PABLO G.; GUTIÉRREZ-CAMPOS, DELIA

Fráncfort del Meno ("Frankfurt am Main")

Congreso; UNITECR 2023 (18th Unified International Technical Conference on Refractories ); 2023

The German Refractory Association

In spite of the long use of MgO-C bricks in the steelmaking industry, there are still issues, regarding the influence of compositional variables on the behavior of this kind of refractories, that have to be better understood. For instance, the effect of graphite content or the addition of antioxidants has been extensively studied and well established; but less is known about the interactions between those components. With the aim of contributing to clearing up these relationships, different non-commercial MgO-C materials were tested under near-service conditions. The bricks were formulated with 83-85 wt% of magnesia (fused/sinter: 70/30), with various contents of graphite (8 and 12 wt.%) and types of binder (phenolic resin or soft binder). The addition of 2 wt.% of a metallic additive was also considered as a variable. A comprehensive characterization of bricks was performed by using several techniques (XRD, XRF, ICP-OES, DTA/TGA, density, porosity and permeability measurements, mercury intrusion porosimetry, and SEM/EDS). Compressive tests between RT and 1400°C (Ar atmosphere) were performed to study the mechanical behavior. The chemical response of bricks to the attack of a typical steelmaking ladle slag at 1600°C was determined by static and dynamic tests (cup and dipping tests), and the oxidation resistance was evaluated by thermal treatments at 1000°C using gaseous atmospheres with different oxygen contents.