One of the main factors limiting the lining lifetime in pyrometallurgical smelters is continuous refractory oxides dissolution in the slag bath. The overall wear is accelerated when the slag infiltrates the porous brick and the dissolution thus occurs in a larger part of the lining. This work investigates the possibility of preventing deep infiltration by sealing off the pores with newly formed phases. Static finger tests at constant temperature (1200 °C) were performed in contact with a synthetic nonferrous PbO-SiO2-MgO slag showing the formation of forsterite (Mg2SiO4) throughout the refractory sample by the reaction between SiO2 (slag) and MgO (refractory). This phase grows with time, eventually sealing off the pores near the interface with the bath. The phase grows too slow to prevent full infiltration of the refractory but creates an equilibrium state in the sealed off part of the sample ceasing the chemical corrosion in that part of the sample.
In non-ferrous metallurgy the refractory life is application dependent, typically going from several months up to 2 years or more. Slag engineering is widely used to reduce the dissolution rate of a refractory lining by forming a solid protection layer at the slag-lining interface, thereby increasing the lining's lifetime. The non-ferrous slag in this paper is engineered to form a protective spinel layer. This phase, however, only forms near and at the slag-lining interface, while deeper inside the sample forsterite grains are detected, resulting in direct contact between the still unsaturated slag and the magnesia-chromite refractory phases. At this position the MgO dissolution increases with a factor 3-4 compared with the slag-refractory interface, attacking the bonding between grains and decreasing the brick's mechanical strength. As this happens deeper inside the sample, the spalling risk increases. Strategies to simultaneously reduce refractory dissolution and spalling are discussed.
Furnace relinings represent a major operating cost in pyrometallurgy. External cooling is, therefore, often used to reduce the chemical wear by limiting the slag infiltration depth, reducing the reaction kinetics and lowering the solubility of refractory components into the liquid slag. In this paper a new experimental setup is used to study the reaction between a synthetic PbO-SiO 2 based slag and a magnesia-chromite refractory under a temperature gradient. Forsterite (Mg 2 SiO 4 ) is formed throughout the sample, removing SiO 2 from the infiltrated liquid slag. The resulting change in slag composition causes the liquidus temperature and the viscosity of the liquid to decrease partially countering the effect of the applied temperature gradient and resulting in the complete infiltration of the sample. The extent to which external cooling prolongs the lifetime of an industrial furnace thus depends on the slag properties and how they are modified after reaction with the refractory.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.