Speciation of nickel in Canadian subbituminous and bituminous feed coals, and their ash by-products
Bibliographic record
Abstract
The nickel species in the feed coals and ash by-products from seven Canadian power plants (including one with a fluidized bed combuster) burning local subbituminous and bituminous coals with sulfur contents ranging from 0.22 to 3.6% have been examined using nickel XANES spectroscopy. XANES spectroscopy of Ni in coal and coal derived ash is complicated by a poor signal : noise ratio due to fluorescence of the much more abundant iron in the coal. Nevertheless, it has proved possible to show that the Ni environment in coals varies from largely oxidic species to mixtures of Ni-containing oxide and sulfide species. The nickel in one oxidized coal appears to be present as nickel sulfate. Nickel in all bottom and fly ash samples examined appears also to be present largely in oxygen anion environments. With the exception of one fly ash sample, for which the Ni exhibited spectral features similar to those for Ni(2+) in spinel or oxide phases, the nickel in the bottom and fly ash samples appears to exist largely as Ni(2+) in environments similar to those reported for Ni in silicate glasses. The data obtained indicate that the presence of potentially carcinogenic nickel sulfides in ash by-products from combustion of these coals is unlikely.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.000 | 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 teacher head, 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".