Advances in Pyrometallurgy: Furnace Containment: Furnace Design and Operations
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
Monday 8:30 AM
March 4, 2024
Room: Celebration 5
Location: Hyatt
Session Chair: Phillip Mackey, P J Mackey Technology; Jesse White, Kanthal
8:30 AM Introductory Comments
8:35 AM Keynote
Considerations for Robust Containment of Operating Furnaces: Lloyd Nelson1; Isabelle Nolet2; 1PYRO ONE (Pty Ltd); 2Hatch
Successful furnace containment of different commodities depends strongly on the specific pyrometallurgical process and its operating conditions. This informs diligent selection of a holistic furnace design, compatible with the specific mode of furnace operation adopted. For reliable and sustainable operation at design limits, this further requires appropriate monitoring, control, operating and furnace maintenance practices. Critical aspects of these requirements will be explored with reference to different furnace operating regimes and process intensities.
9:05 AM Keynote
Sustainability in the Production of Refractory Products - Ensuring an Optimal Circular Economy: Thomas Prietl1; Thomas Drnek1; 1RHI Magnesita GmbH
In addition to the major industrial CO2 emitters, such as the steel and cement industries, the production of mainly basic refractory raw materials also contributes to CO2 emissions. Like other industries, RHI Magnesita aims to produce towards net zero by 2050. In order to achieve this strategic company target, several initiatives have been launched. One of the main pillars to achieve the net zero target is the establishment of a circular economy with regard to used refractory materials. RHI Magnesita is already a technology leader in this field and constantly strives to improve the yield and the quality of the processed secondary raw materials with new technologies. This allows us to save primary raw materials, to reduce CO2 emissions and to do so without any loss of performance of the finished refractory product used by the customer. This paper describes RHI Magnesita's approach as well as case studies from practice.
9:35 AM Keynote
Designing Smelting Furnaces to Meet Process Requirements: Allan MacRae1; 1Macrae Technologies, Inc.
Pyrometallurgical furnaces are not conventional structures that fall directly under a single design code. Engineering companies attempt to apply appropriate safety factors for stresses and temperatures to vessel shells, refractory, and cooling elements. The furnace components must be designed to function together to avoid plastic deformation, erosion, corrosion, and fracture. Thermal cycling, intense heat loads, and required design loads are not typically found in design handbooks or codes. The loads can vary significantly as the refractory lining wears. Historical analysis of vessel performance under similar operating conditions and processes are key for developing design loads and limits for heat, stress, corrosion, and movement.Advancements made in furnace design over the past several decades are highlighted.
10:05 AM Break
10:20 AM Invited
The Importance of Understanding Mechanisms in Open-bath (DC) Processes Related to Furnace Containment: Harmen Oterdoom1; Markus Reuter2; Johan Zietsman3; 1Butter Bridge / OTI-LS; 2Curtin University; 3University of Pretoria - Ex Mente
The paper starts with a discussion on “furnace containment systems”. Recently, there have been several experiences with DC furnaces for continuous processing of particulate feed, some of which have experienced containment challenges. The Kazakh high-carbon ferrochrome DC operation is used to investigate what process mechanisms could take place in such a furnace. Several scenarios have been simulated with a dynamic multi-zone model to see how and especially how rapidly deviations in feed composition, quantity, or charging location can affect the operation. Of interest also are how fast these deviations could be detected and especially what data could be monitored to recognise them. This paper contributes to understanding fundamental mechanisms inside DC furnaces, which are becoming even more important due to an increased interest in open-bath furnaces for smelting DRI. A better understanding of process mechanisms can support in de-risking new equipment and processes, ensuring a safer operation, also for green steel production
10:40 AM
The Optimisation of ISASMELT™ Furnace Linings and Cooling Elements to Achieve Low Annualised Costs: Stuart Nicol1; Ben Hogg1; 1Glencore Technology
Traditionally, furnace linings have been optimised to achieve the longest campaign, or time between lining replacement. These linings have used mechanical engineering solutions, such as water-cooled elements, to contain the aggressive molten materials inside the furnace. In recent years it has become apparent that these mechanical engineering solutions results in high cost relining. ISASMELT™ technology has been optimised using metallurgical engineering solutions, a vastly different philosophy. The ISASMELT™ furnace lining system has been optimised through the use of simple and low cost lining materials, but using metallurgical controls to manage the lining system. These metallurgical controls enable freeze linings to form on the refractory lining of a furnace, without the need of cooling systems. This approach has resulted in low cost relining and long furnace campaigns. This paper will review the ISASMELT™ approach to furnace lining, element and binding optimisation and the results in real world operations.
11:00 AM
Freeport-McMoRan Miami - Waste Heat Boiler Availability Improvements: Avi Nanda1; Kurt Westerlund2; Bradley Fox1; 1Freeport-Mcmoran; 2Kamwest Oy
Freeport-McMoRan Inc. (FCX) uses ISASMELTTM TSL technology for the primary smelting of copper concentrates at the Miami smelter. The furnace was installed in 1992 with a capture system designed to cool and contain molten splash, dust, and gases generated from smelting reactions. The capture system is comprised of water radiant roof and wall panels, some of which generate steam. “Waste heat boiler” is often used to refer to the primary furnace’s off-gas handling system because of the useful steam it generates. The waste heat boiler system must be available to operate the primary smelting furnace. Issues related to a waste heat boiler often make up a significant portion of a smelter’s downtime. Thus, effectively maintaining and operating the waste heat boiler is critical to a smelter’s overall effectiveness. The Miami smelter’s boiler maintenance, and operational improvements to date will be reviewed in this paper.
11:20 AM
Composite Copper-graphite Cooler for PGM Furnace Sidewall: Hugo Joubert1; Gerrit de Villiers1; Pfariso Mbedzi2; John Davis2; 1Tenova Pyromet; 2Sibanye-Stillwater
The corrosion of copper cooling elements in the sidewall of platinum group metal (PGM) furnaces is unique in its severity and nature. ‘Chloride-accelerated sulphidation’ has been identified as the most likely corrosion mechanism and is prominent in the zone directly adjacent to the slag-concentrate interface. Tenova Pyromet developed a new composite copper-graphite cooler for implementation in one of Sibanye-Stillwater’s circular PGM furnaces at their Marikana smelter complex. The cooler design is unique as, in addition to the hot face, the sides, bottom and top of the cooler are completely covered with graphite, preventing contact between the copper cooler and the sulphur- and chlorine-bearing species thought responsible for the corrosion. The design of the cooler and test work performed to evaluate its effectiveness are discussed. The coolers have been in operation since August 2022. The implementation and performance of the coolers to date are discussed.