Abstract
Chemical resistance of commercial refractory raw materials against Cu slag is critical to consider them as candidates for the production of refractories used in Cu metallurgy. In this study, we show the comparative results for the corrosion resistance of four commercial refractory raw materials—magnesia chromite co-clinkers FMC 45 and FMC 57, PAK, and fused spinel SP AM 70—against aggressive, low-melting PbO-rich Cu slag (Z1) determined by hot-stage microscopy (up to 1450 °C) and pellet test (1100 and 1400 °C). Samples were characterized after the pellet test by XRD, SEM/EDS, and examination of their physicochemical properties to explore the corrosion reactions and then assess comparatively their chemical resistance. Since many works have focused on corrosion resistance of refractory products, the individual refractory raw materials have not been investigated so far. In this work, we show that magnesia chromite co-clinker FMC 45 exhibits the most beneficial properties considering its application in the production of refractories for the Cu industry. Forsterite (Mg2SiO4) and güggenite (Cu2MgO3) solid solutions constitute corrosion products in FMC 45, and its mixture with slag shows moderate dimensional stability at high temperatures. On the other hand, the fused spinel SP AM 70 is the least resistant to PbO-rich Cu slag (Z1); it starts to sinter at 970 °C, followed by a fast 8%-shrinkage caused by the formation of güggenite solid solution in significant amounts.
Highlights
The experiment consisted of three main stages: the chemical and structural characterization of four refractory raw materials and Cu slag, preparation of the samples for corrosion tests, and corrosion tests of mixtures by hot-stage microscopy (HSM) and pellet test (PT)
Cr2 O3 content was under half that amount at 25%; other oxides were present in lower amounts, such as Fe2 O3 at 15% and Al2 O3 at 6%, while the range of the other oxides was below 1%
The oxides existed in the slag in the form of four main phases—Pb2 SiO4, Fe3 O4, Fe2 SiO4, and Cu2 O—which are aggressive towards refractory material as they possess low melting points: Pb2 SiO4 at 747 ◦ C [7] Fe2 SiO4 at 1220 ◦ C [72], and Cu2 O at 1230 ◦ C [73]
Summary
The lifetime of refractory lining is one of the most critical factors during high-temperature processes. The repairs of the lining are both time-consuming and expensive, so high-quality refractories are desired and consistently developed. Refractory materials used in the Cu industry are not exposed to extremely high temperatures. They have to resist major thermal shocks. They are subjected to chemical interactions with the surrounding environment, mechanical wear due to the movement of the stove charge, induced mechanical stresses in the linings, and hot erosion [1]. Refractory linings should withstand the influence of Cu, Cu matte, Cu slag, and SO2.
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