Advances in Pyrometallurgy: Developing Low Carbon Pathways: Biocarbon and Alternative Reduction Methods
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
Monday 8:30 AM
March 20, 2023
Room: 29B
Location: SDCC
Session Chair: Dean Gregurek, RHI Magnesita; Camille Fleuriault, Eramet Norway
8:30 AM Invited
Ferroalloy Production without Use of Fossil Carbon - Some Alternatives: Eli Ringdalen1; 1SINTEF
To reach the goal of fossil free ferroalloy production within 2050, several alternative materials and processes are investigated. Fast transition requires that the more mature technologies are implemented first. In parallel technologies with lower TRL level must be further developed. Substituting fossil carbon with biocarbon seems to be among the first to be implemented. How differences in key properties for these to reductants may affect operation of Mn-alloy and Si/FeSi furnaces will be discussed.Pretreatment and prereduction by sustainable energy sources are another way for reducing fossil CO2 emission. Pretreatment of Mn-ores with CO-rich off-gases and with thermal solar heated air have been investigated and tested in pilot in the PreMa project. The effect of different temperatures and gas atmospheres have been studied. Effect on CO2 emissions on integrated pretreatment unit and furnaces are evaluated by comparing various scenarios in a HSC Sim model adapted for this purpose.
9:00 AM Invited
The Path to Zero Carbon Dioxide Emissions in Silicon Production: Gudrun Saevarsdottir1; Thordur Magnusson2; Halvor Kvande3; 1Reykjavik University; 2Normi; 3Previously NTNU
The global community has set a path towards carbon neutrality by 2050. Almost one fourth of global emissions is attributed to direct emissions from industrial processes. Therefore, a zero-carbon alternative must be developed for each process, including the production of silicon. The silicon industry is exploring ways to efficiently capture CO2 from the flue gases from the submerged arc furnaces for silicon production, for example by increasing the CO2 concentration. Replacing fossil reducing agents with biofuel is a carbon neutral alternative, while recycling waste streams from aluminium production as a reducing agent for silicon is a more recent development. Also, electrochemical methods have been explored in laboratory scale. This paper gives a review of the efforts to date, from industry and academia, to decarbonise the production of silicon. The development of the largest part of the carbon footprint, arising from the production of the electrical energy used, is also discussed.
9:30 AM Invited
Towards Bio-Carbon Substitutes in the Manufacture of Electrodes and Refractories for the Metallurgical Industries: A Science and Technology Review: Jesse White1; Natalia Skorodumova1; Björn Glaser1; 1KTH Royal Institute of Technology
The unique structural versatility, chemical and thermophysical properties of carbon make it essentially irreplaceable for non-reductant uses in many high-temperature metallurgical processes. At present, bio-carbon substitutes are not technically feasible for large-scale use in electrode and refractory materials that are vital consumables in the steel, aluminum, and non-ferrous metal industries. Carbon electrodes of all types (including Söderberg, prebaked, and anodes/cathodes for Al), as well as carbon lining pastes are all similar in that they are comprised of a granular carbon aggregate and a carbon-based binder. Similarly, refractories such as MgO-C utilize both natural (mined) graphite and carbon-based binders.Replacement of fossil materials with equivalent bio-carbon substitutes has the potential to dramatically reduce the carbon footprints of these products. However, there are still considerable materials engineering challenges that must be surmounted. The properties of bio-carbon materials and technological obstacles are explored, including catalytic graphitization and development of bio-pitch materials.
10:00 AM Break
10:20 AM
A Pilot Trial Investigation of Using Hydrochar Derived from Biomass Residues for EAF Process: Chuan Wang1; Yu-Chiao Lu2; Liviu Brabie1; Guangwei Wang3; 1Swerim AB; 2KTH Royal Institute of Technology; 3University of Science and Technology Beijing
Biocarbon will play an important role to achieve a carbon neutral and sustainable steel industry. In this study, three hydrochars (one type of biocoal produced via the hydrothermal carbonization process) derived from green waste, rice husk and orange peel were tested in a 10-ton test-bed EAF. These hydrochars were added to EAF (electric arc furnace) via injection and top-charge as carburizer to substitute anthracite. In general, the slag formed is good for the desulphrization process, and a better carbon yield can be achieved with hydrochar top charging. P and S level in metal could be controlled at an acceptable level. Perspectives of using hydrochar for EAF steelmaking is also presented.
10:40 AM
Biocarbon Materials in Metallurgical Processes – Investigation of Critical Properties: Nicholas Smith-Hanssen1; Goril Jahrsengene1; Eli Ringdalen1; 1SINTEF
The silicon, ferroalloy and aluminum industries in Norway have traditionally relied on fossil carbons for their respective process. However, in efforts to reduce their fossil CO2-emissions the switch to biocarbon has already begun and targets of 25 to 40 % biocarbon by 2030 have been set by various producers in Norway. To achieve this transformation a better understanding of the effects of physical properties of the carbon on the process must be obtained so that the transformation can occur with minimal process interruptions. For the silicon, ferrosilicon, and ferromanganese industries the effects of biocarbon reductants are the primary interest whereas for the aluminum industry use of biocarbon to replace packing coke used in anode baking is desired. In this work, an overview over relevant biocarbon properties and methods to characterize these are presented together with an evaluation of how these properties may affect the different processes when introducing biocarbon.
11:00 AM
Characterizing Bio-carbon for Metallurgical Processes Using Micro X-ray Computed Tomography with High Temperature Experiments: Stein Rørvik1; Nicholas Smith-Hanssen1; Sethulakshmy Jayakumari1; Liang Wang1; 1Sintef Industry
An important path to the goal of reducing the metal producing industries' CO2 footprint is to replace fossil carbon sources with bio-based carbon sources for the electrodes and reductant agents. Since the structure of bio-carbon is substantially different from fossil carbon, characterizing the bio-carbon structure and examining its behavior during the relevant processes are important. Focusing on the silicon and ferroalloy industries in Norway, micro X-ray computed tomography (µCT) has been used to analyse and compare single grains of bio-carbon before and after various experimental procedures. These procedures consist of high-temperature treatment under different conditions for CO/CO2 and SiO gas reactivity test, K-impregnation and CH4-based carbon deposition. This paper shows examples on results from µCT measurements before and after the experiments, and describes briefly the data processing methods applied. The relevance to the experiments and industrial applications is also discussed.