Advances in Pyrometallurgy: Developing Low Carbon Pathways: Hydrogen
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee
Program Organizers: Camille Fleuriault, Eramet Norway; Joalet Steenkamp, XPS Glencore; Dean Gregurek, RHI Magnesita; Jesse White, Kanthal AB; Quinn Reynolds, Mintek; Phillip Mackey, P.J. Mackey Technology, Inc.; Susanna Hockaday, Curtin University, WASM
Tuesday 8:00 AM
March 21, 2023
Room: 29B
Location: SDCC
Session Chair: Quinn Reynolds, MINTEK; Jesse White, Kanthal AB
8:00 AM Invited
Hydrogen, a Promising Carbon Substitute in Metallurgy?: Juergen Antrekowitsch1; 1University of Leoben
Minimization of CO2-emissions has become one of the main topics in our daily life. Especially industry as one of the biggest emitters has to contribute essentially to a global CO2-reduction. When focusing the metal production sector, one of the most promising solutions seems to be the utilization of hydrogen. Similar to carbon hydrogen can act as both, reducing agent and energy source. However, this looks easy only on the first glance. Various aspects such as efficient production, storage, transport, requirement for new processes concepts or a more difficult off-gas treatment underline that such a change will also be a future challenge. The paper gives an overview of hydrogen-production processes with some details about the ongoing development of methane pyrolysis as effective way to generate hydrogen in huge volumes. Furthermore, it discusses where hydrogen can be used efficiently in metallurgical processes and in which areas alternatives have to be developed.
8:30 AM Invited
Use of H2 in Mn-ferroalloy Production: Merete Tangstad1; Trygve Schanche1; Faan Du Preez2; 1Norwegian University of Science and Technology; 2North West University
The use of H2 as a reductant in the iron and steel industry is obvious choices. For pyrometallurgical processes like e.g. Mn and Si, H2 can not be the only solution, as the stability of the oxides of these elements are higher than Fe. H2 can however be used in the Mn-process together with other low CO2 emission mitigations like the use of electrolysis or the use of biocarbon or the use of biocarbon. In the Mn-ferroalloy process H2 can be used to reduce higher manganese oxides to MnO, and the last part of the reduction to metallic Mn can be done with biocarbon or with electrolysis. The reduction of higher manganese oxides to MnO has been investigated with pure H2 or with CO/H2 mixtures, and it is shown that the use of H2 will give a higher prereduction rate compared to the traditional CO gas.
9:00 AM Invited
Development of Fossil Free Technologies for the Metallurgical Industry – Swerim Pilot and Industrial Experiences: Guozhu Ye1; Ida Heintz1; Elsayed Mousa1; 1Swerim
The metal industry alone contributes about 8% CO2 emission globally. For a sustainable and carbon neutral metal industry, use of H2 and biocarbon for substitution of fossil carbon is essential. SWERIM has in the recent years made great efforts to support the metal industry for a smoothly C-neutral transition. This paper will highlight the projects using biocarbon and H2 different metallurgical processes including installation of a H2-electrolyser which could be connected to various pilot test facilities in Swerim including an EAF, a DC furnace and a Universal Converter of 6-10 tons in scale. The Swerim H2-electrolyser has a capacity to produce 100 Nm3 of H2/h. Our unique gas processing equipment for separation of CO2, production of H2 in combination with our demo facilities enable us to develop high TRL demonstration of different CCUS opportunities for steel and metal industry. Using H2 in metallurgical applications will also be discussed
9:30 AM Break
9:50 AM
Investigation of High-H2 Reducing Gas Delivery through Shaft-level Tuyeres with Computational Fluid Dynamics: Tyamo Okosun1; Samuel Nielson1; Orlando Ugarte1; Chenn Zhou1; 1Purdue University Northwest
As both a significant contributor to the steelmaking process and the largest single source of CO2 emissions in integrate steelmaking, the blast furnace is a critical area of focus for decarbonization efforts. Generally, the replacement of coke with injected fuels such as natural gas or syngas has been a key pathway for reducing emissions. These injectants provide higher concentrations of H2 reducing gas, decreasing reliance on CO reactions, but delivery rates are limited by their endothermic impacts on flame and reducing gas temperature. One potential method of circumventing these limitations is the use of shaft-level tuyeres for high rates of hot reducing gas delivery, in a similar fashion to the direct-reduced ironmaking process. In this paper, the impacts of such a system are investigated with Computational Fluid Dynamics to predict the reaction rates, coke replacement ratios, and carbon emissions of the blast furnace process under the proposed operating scheme.
10:10 AM
Hydrogen Plasma Reduction of Iron Oxides: Dierk Raabe1; Hauke Springer1; Isnaldi Souza Filho1; Yan Ma1; 1Max-Planck Institute
We present a study about the reduction of hematite ores by hydrogen plasma. The transformation kinetics and chemical composition are studied over several intermediate states. We find that the reduction kinetics depends on the balance between the input mass and arc power. For an optimized input mass-arc power ratio, reduction is obtained within 15 min exposure to the hydrogen plasma. Micro- and nanoscale chemical and microstructure analysis show that the gangue elements partition to the slag oxides, revealed by energy dispersive spectroscopy and atom probe tomography. Si-enrichment was observed in the interdendritic fayalite domains, at the wüstite/iron hetero-interfaces and in the oxide particles inside iron. With proceeding reduction, however, such elements are gradually removed from the samples so that the final iron product is nearly free of gangue-related impurities.
10:30 AM
Hydrogen Plasma Reduction of Metal Oxides: Halvor Dalaker1; Even Hovig1; 1Sintef
Hydrogen is a candidate to replace carbon in metal production, as it can reduce some metal ores (e.g. iron ore); FeOx + XH2(g) = Fe + XH2O(g) . However, many oxides cannot be converted to metals using molecular hydrogen. Higher order manganese oxides can, for example, be reduced to MnO, but not metallic Mn. For other oxides, like those of chromium, metallisation is possible, but extent of reaction limited. The use of hydrogen plasma can improve hydrogen reduction for all these classes of oxides: The kinetics and efficiency of iron oxide reduction can be improved significantly; the theoretical limit of metallisation of chromium can be increased, and complete conversion of manganese oxide past MnO to metallic Mn becomes thermodynamically favourable: MnO + 2H = Mn + H2O(g)Here we present lab scale experiments demonstrating the production of iron, chromium and manganese from reactions between hydrogen plasma and metal oxides.
10:50 AM
Hydrogen-based Direct Reduction of Iron Oxides: Dierk Raabe1; Hauke Springer1; Yan Ma1; Isnaldi Souza Filho1; 1Max-Planck Institute
The lecture presents some recent progress in understanding the key mechanisms of hydrogen-based direct reduction. The kinetics of the solid state reduction reactions strongly depend on mass transport kinetics, nucleation during the multiple phase transformations, the oxide’s chemistry and microstructure, and on plasticity, damage and fracture associated with the phase transformation and mass transport phenomena occurring during reduction. Understanding these effects is key to produce hydrogen-based green steel and design corresponding direct reduction shaft or fluidized bed reactors, enabling massive CO2 reductions