Permittivities of electric arc furnace dust/lignin mixtures as a function of temperature, frequency and gas composition
Bibliographic record
Abstract
• The permittivities of EAF dust/lignin mixtures during reduction reactions were studied. • The effect of reducing the gas atmosphere on permittivity changes was investigated. • The cavity perturbation method was utilized for permittivity measurements. • The results revealed that the permittivities the mixtures significantly affected by gas atmosphere. Increased electrification of pyrometallurgical processes and reduced greenhouse gas (GHG) emissions are important environmental targets both in Europe and around the world. Microwave heating is considered a potential new energy source that can use electricity from renewables and is consequently a more sustainable pyrometallurgical method. Studying the permittivities of the materials of interest under different conditions is a crucial step in understanding the behavior of these materials in microwave fields and designing microwave processes. The present work aims to investigate the permittivities of electric arc furnace (EAF) dust/lignin mixtures under various conditions. The effect of the reducing gas composition on the permittivity changes as a function of temperature and frequency was studied. Reduction did not occur within the EAF dust/lignin mixture in an air atmosphere. The changes in the permittivities of the mixture were associated with reactions in the range of 500 °C–600 °C and were related to the thermal decomposition of calcium carbonate into calcium oxide and carbon dioxide. In an argon (Ar) atmosphere, the EAF dust/lignin mixture permittivities exhibited two main peaks, one at approximately 600 °C and another at approximately 840 °C and these were due to the pyrolysis of lignin (biochar formation) and the reduction of both zinc oxide and zinc ferrite to metallic zinc and iron, respectively. In a hydrogen–argon (4 % H 2 –Ar) atmosphere, the EAF dust/lignin mixture permittivities displayed two peaks at approximately 600 °C and 715 °C that were attributed to the pyrolysis of the biochar and the reduction of both zinc oxide and zinc ferrite , respectively. In the hydrogen-containing atmosphere, the second peak occurred at a lower temperature. After the second peak in both the Ar and H 2 –Ar atmospheres, when the reduction reactions were completed, rapid decreases in the permittivities were observed. At this stage, the biochar was consumed, and the metals were produced, which resulted in a decrease in the permittivities.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".