The effect of oxygen lancing into a furnace alloy tap-hole : a computational case study for an open-bath furnace

The opening of a furnace tap-hole with an oxygen lance is a complex phenomenon that is not well understood in a quantitative way. By means of a case study, the effect of lancing on flow in and around the tap-hole area at the hot face and potential chemical wear of the refractory material are studied with multiphase fluid flow and thermochemistry models. By decoupling the modelling work into two separate sections, it is possible to obtain more quantitative results on the effect of lancing into process material such as alloy.https://link.springer.com/journal/118372023-10-31hj2023Materials Science and Metallurgical Engineerin

Comparison of 2D and 3D computational multiphase fluid flow models of oygen lancing of pyrometallurgical furnace tap-holes

Furnace tap-holes vary in design depending on the type of furnace and process involved, but share one common trait: the tap-hole must be opened and closed periodically. In general tap-holes are plugged with refractory clay after tapping, thereby stopping the flow of molten material. Once a furnace is ready to be tapped, drilling and/or lancing with oxygen are typically used to remove tap-hole clay from the tap-hole. Lancing with oxygen is an energy-intensive, mostly-manual process, which affects the performance and longevity of the tap-hole refractory material as well as the processes inside the furnace. Computational modeling offers an opportunity to gain insight into the possible effects of oxygen lancing on various aspects of furnace operation.http://link.springer.com/article/10.1007/s11837-016-1873-62017-06-30hb2016Materials Science and Metallurgical Engineerin

Multiphase flow modelling of lancing of furnace tap-holes : validation of multiphase flow simulated in OpenFOAM®

Pyrometallurgical furnaces are tapped through tap-holes that are opened with drills and oxygen lances. The lance is often used on its own or as the last step of opening the tap-hole. Interaction of oxygen with molten material inside the tap-hole can occur, and is a phenomenon that is not well understood. As part of a study that focuses on the effect of lancing on flow inside and around the furnace tap-hole, a cold-model validation was done. The validation study focuses on validating the MULTIPHASEINTERFOAM multiphase flow solver in OpenFOAM® for the problem involved. The sensitivity of the model to different materials properties (viscosity and density in particular) is presented with both cold models and the results from flow simulations in OpenFOAM®.This paper was first presented at the Furnace Tapping 2018 Conference, 15–16 October 2018, Nombolo Mdhluli Conference Centre, Kruger National Park, South Africa.http://www.saimm.co.za/journal-papersam2020Materials Science and Metallurgical Engineerin

A Review of Ferroalloy Tapping Models

Tapping is an important furnace operation in the ferroalloy industry and poses a number of complex and coupled challenges of both practical and economical importance. Owing to the hazardous high-temperature conditions surrounding the tap hole, the application of various modeling techniques allows for development and acquisition of both scientific and engineering knowledge of the process through physical or numerical proxies. In this review, earlier work on modeling of ferroalloy tapping is summarized and main principles of the tapping process and multiphase interaction of slag and metal are discussed and summarized. The main focus is on drainage of slag and alloys, but some attention will also be given to metal loss, metal overflow and health, safety and environment. Our review shows that although considerable progress has been made in computational capability over the last decades, However, it is clear that research and development in the field of ferroalloy furnace tapping remains at a relatively nascent stage. The most progress up to date has happened in the area of so called reduced-order models. Such models are robust and simple, and may be easily fitted to process data from a particular operation in order to develop tailored solutions. Such models are more easily combined with software and instruments, ultimately enabling improved automation, process control and ultimately improved tapping consistency

Electric arc length-voltage and conductivity characteristics in a pilot-scale AC electric arc furnace

Abstract The heat transfer processes and the molten metal bath kinetics of the electric arc furnace are governed by the changes in the arc length and voltage. Thus, information on the electric arc behavior with respect to the voltage is important for accurate computation of the furnace processes and adjustment of the industrial furnace parameters. In this work, the length-voltage characteristics of electric arcs have been studied in a pilot-scale AC electric arc furnace with image analysis, electrical data from the furnace, and slag composition. The arc length was determined with image analysis and the relation between the arc length and voltage from test data. The relation between arc length and voltage was found to be non-linear and dependent on the slag composition. The voltage gradients of the arcs were evaluated as a function of arc length and sum of anode and cathode voltage drops resulting in a reciprocal relation. Furthermore, the electrical conductivity of the arc plasma with respect to arc length was estimated