Advances in Pyrometallurgy: Furnace Containment: Refractories
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee, TMS: Process Technology and Modeling Committee, TMS: Materials Characterization Committee, TMS: Industrial Advisory Committee
Program Organizers: Gerardo Alvear Flores, CaEng Associates; Camille Fleuriault, Eramet Norway; Dean Gregurek, RHI Magnesita; Quinn Reynolds, Mintek; Hugo Joubert, Tenova Pyromet; Stuart Nicol, Glencore Technology; Phillip Mackey, P.J. Mackey Technology, Inc.; Jesse White, Kanthal AB; Isabelle Nolet, Hatch
Tuesday 8:00 AM
March 5, 2024
Room: Celebration 5
Location: Hyatt
Session Chair: Dean Gregurek, RHI Magnesita; Stuart Nicol, Glencore Technology
8:00 AM Introductory Comments
8:05 AM
Characterization of a Nickel Flash Smelter Refractory Material – The Effect of Thermal Gradient: Juho Lehmusto1; Saara Söyrinki2; Juha Lagerbom2; Tuomas Jokiaho2; Zaiqing Que2; Jorma Määttä3; Leena Hupa1; Elina Huttunen-Saarivirta2; Mari Lindgren4; 1Abo Akademi University; 2VTT Technical Research Centre of Finland Ltd; 3University of Turku; 4Metso
Magnesia-chromite (MgCr2O4) spinel-based refractories are applied in copper and nickel flash smelting furnaces, where the refractories experience high temperatures but also thermal gradients due to the cooling of the walls. In the gas space, the refractories are subjected to an aggressive environment with high SO2 concentrations. Furthermore, the increased use of recycled material streams has introduced new reactive impurities, such as halides, to the process. Therefore, the interactions between the refractories and gaseous species as well as the related reaction mechanisms need to be understood. This study presents a comparison between ac-received and spent refractories from a nickel flash smelting furnace to identify the reactive species and shed more light on their reaction mechanisms. The thermal gradient over the refractory is expected to affect the microstructure and diffusion of elements within the structure. Therefore, special attention was paid to the role of the temperature gradient in the abovementioned interactions.
8:25 AM Cancelled
Anchorage Force and High Temperature Stability of Refractory Fiber Modules: Dong Yue1; Jiulin Tang2; Bo Liu1; Liangying Wen1; 1Chongqing University; 2Dongfang Boiler Co. Ltd, Dongfang Electric Group
The stability of the refractory fibre module anchorage structure has a significant impact on the service life and operational efficiency of forge heating furnace. In this paper, the force balance of the stable and non-detachable interaction of refractory fibre modules with different anchorage structures and its correlation with the preset force F0 provided by anchorage welding are established by analyzing the force characteristics of the anchorage structure of refractory fibre modules. The stability and oxidation resistance of refractory fibre modules, metal structural components and pre-installed welding materials in anchorage structures are investigated through high-temperature heating experiments. Based on practical applications, an effective installation and a layout mode are proposed to reduce high-temperature shrinkage gaps between refractory fiber modules and the position distribution of anchoring metal structural components in refractory fiber anchorage structures are optimized to adjust anchorage welding schemes.
8:45 AM
Important Microstructural Features of Refractory Bricks and Their Relation With the Degradation Mechanisms: Annelies Malfliet1; 1KU Leuven
Refractory bricks are typically characterized by their chemical composition and their physical, mechanical and thermal properties. These properties are linked to the microstructure of the refractory, i.e. the type, composition and amount of phases present and their distribution. The microstructure is related to the used raw materials and the refractory production process. We will give an overview of important microstructural features of refractories and how they play a role in the behavior and degradation of the refractory lining. Especially the influence on the refractory corrosion and infiltration behavior will be discussed.
9:05 AM
Study on Slag Phase Erosion Behavior and Mechanism of Carbon Composite Brick in Hydrogen-rich Blast Furnace Hearth: Mingbo Song1; Kexin Jiao1; Cui Wang1; Chuan Wang1; 1University of Science and Technology Beijing
In this study, a damage investigation was carried out on a blast furnace using hydrogen-rich gas smelting. During the period, a green-white phase with a thickness of 150mm-200mm was found inside the carbon composite brick in the taphole area. The carbon bricks in this area were sampled, and XRD, chemical analysis, and SEM-EDS detection were carried out. The test results show that there are blast furnace slag erosion and harmful element Zn erosion in carbon composite bricks. The erosion of harmful elements caused the expansion and ring cracking of carbon composite bricks, resulting in further slag erosion, which eventually led to the macroscopic slag phase erosion in the taphole area.
9:25 AM Break
9:45 AM
A Modified Rotating Finger Test Aiming to Quantify Refractory Wear Based on Fundamental Equations Governing Refractory Dissolution and Erosion: Burhanuddin Burhanuddin1; Harald Harmuth1; 1Montanuniversitaet Leoben
Design of wear-resistant refractories necessitates an in-depth understanding and accurate quantification of the continuous wear. However, the experimental methods reported in the literature, are mostly phenomenological and unable to reveal the physicochemical background of continuous wear. Main goals of this work are scientific investigation of continuous refractory wear and acquisition of data for quantitative simulation of continuous wear to design wear-resistant refractories. A modified rotating-finger test (RFT) device was equipped with high-resolution laser to scan the sample surface for dimension measurement. Generally, refractory dissolution in molten-slag is controlled by diffusion through a boundary layer and diffusivity is the most important parameter to quantify dissolution. The data obtained from modified RFT studies were applied to accurately determine effective binary diffusivity using simulation method or mass transfer equation. Also, results of erosion studies were applied for inverse calculation of erosion parameters. Continuous wear of alumina in silicate slag will be exemplified here.
10:05 AM Invited
Slag Optimization with Respect to Steel Quality and Refractory Protection in a Steel Ladle Furnace: Elmira Moosavi1; Kianoosh Kaveh2; Mohammad Jahazi2; 1Ecole de technologie superieure; University of Toronto; 2Ecole de technologie superieure
Steel produced from an electric arc furnace is refined in the secondary steelmaking process such as the ladle metallurgical furnace, to remove harmful impurities such as sulfur. Slag optimization is fundamental to steelmaking, as poor slag practices reduce steel quality and refractory life, increasing production downtime and costs. There could be a trade-off between the slag desulfurization capacity and slag chemical neutrality in relation to the refractory lining. This work aims to optimize a ladle furnace slag to protect refractory lining and simultaneously maintain the slag’s desulfurization capacity, taking into account stringent steel quality requirements. A systematic thermodynamic evaluation is carried out to optimize slag basicity and viscosity as a function of process parameters in a dynamic industrial context, the details of which are discussed in the present work.
10:25 AM
Flexospheres Technology - Improved Flexibility and Corrosion Resistance of Fired Magnesia-chromite Bricks: Francesca Capo Tous1; Jürgen Schmidl1; Bernd Neubauer1; Dean Gregurek1; 1RHI Magnesita GmbH
Flexospheres is a recent product development successfully implemented in fired magnesia-chromite bricks. The technology focuses on the inhibition of the corrosion mechanism and a higher flexibility of the refractory product. The experimental investigation included chemical and physical analysis as well as dynamic corrosion wear experiments in a rotating high frequency induction furnace. According to the results, the technology does not only improve corrosion resistance but also contributes to the formation of a more flexible structure, which results in a better thermal shock stability. A field trial in the lower vessel of a RH degasser endorses the results observed in this investigation at laboratory scale revealing a clear performance increase. These extraordinary properties make the development suitable for special applications under aggressive conditions such as taphole areas, the tuyere area in copper furnaces or the RH degasser in the steel industry and guarantees a significant quality improvement of the magnesia-chromite product.
10:45 AM Concluding Comments