from the conferences organized by TANGER Ltd.
Refractory linings of metallurgical furnaces have two main purposes: to control the heat flow, and to contain high temperature liquids (metal and slag). Through a proper management of heat flows, a layer of slag called freeze lining crystallizes on the internal walls of the furnace thereby protecting the bricks from the very corrosive high temperature liquid slag. The thickness, stability and properties of this frozen slag are key parameters for the performance of a safe and stable process. In situ observations of the crystallization process during furnace operations are very difficult. To overcome this difficulty, the present work proposes a combination of heat flow monitoring, numerical modeling of heat transfer and the mineralogical characterization of the residual freeze lining after the furnace operation. The combination of these tools helps with the management of the process and the understanding of how to preserve the thermal balance of the furnace and the stability of the refractory lining. Within a pilot furnace freeze lining, physical and chemical properties change depending on the operation parameters. The thickness of the free lining is one of the most important process variables to follow-up. An inverse heat transfer issue is solved using the software FLUENT in a simplified 2-D axisymmetric geometry of the furnace. After completion of the pilot, the freeze lining of the furnace is analyzed and characterized. All the significant evolutions in the operating parameters (temperature variations, slag chemistry changes) are recorded within the oxide layers of the skull. Additionally to characterization, the crystallization paths that occurred during the process can be calculated using thermodynamic equilibrium computations. This work provides a multi-disciplinary approach to understand usually unobservable phenomena within the furnace, allowing an estimation of the thickness, and physical and chemical properties of the freeze lining inside furnace.
Keywords: Metallurgy, freeze-lining, thermodynamic, characterization, Qemscan© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.