Solubility controls for molybdenum in neutral rock drainage
Bibliographic record
Abstract
Mineral controls on molybdate (MoO 4 2− ) solubility were studied to better understand the fate of molybdenum (Mo) in neutral rock drainage. Batch and column experiments lasting from 46–110 days predict that molybdate (MoO 4 2− ) mobility is limited by powellite (CaMoO 4 ) and wulfenite (PbMoO 4 ) precipitation under neutral pH conditions with aqueous Ca and Pb present. Batch experiments demonstrate that wulfenite forms almost instantaneously and effectively removes Pb from solution to concentrations below detection limits. Powellite formation is kinetically limited, but has the capacity to significantly reduce Mo concentrations in the presence of calcite. An initial inhibition of powellite formation is observed, likely due to a lack of available nucleation sites. After the nucleation phase, powellite formation from supersaturated conditions follows a second order rate expression with linear dependence on Ca 2+ and MoO 4 2− . A column experiment provides further evidence of rapid wulfenite formation and kinetically limited powellite formation. Both powellite and wulfenite have also been identified in molybdenum-bearing carbonate-rich waste rock sampled from barrel-sized field cell weathering experiments, providing direct evidence that these minerals affect Mo mobility under field conditions. In contrast to Pb and Ca, both Cu and Zn did not form distinct molybdate precipitates.
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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 | 0.001 |
| 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) | 0.001 | 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".