Reduction of phosphogypsum for <scp> SO <sub>2</sub> </scp> production: Insights into the release characteristics of <scp> SO <sub>2</sub> </scp> following the solid–solid reaction of <scp>CaS</scp> and <scp> CaSO <sub>4</sub> </scp> under different atmospheres
Bibliographic record
Abstract
Abstract Phosphogypsum (PG) severely pollutes the environment and is difficult to recycle. PG is primarily composed of CaSO 4 · 2H 2 O. In this study, the characteristics of SO 2 released from the solid–solid reaction between calcium sulphide (CaS) and CaSO 4 were thoroughly investigated using thermodynamic calculations. Experiments were performed by tuning the molar ratio of CaS to CaSO 4 , reaction atmosphere (S, CH 4 , N 2 , and air), and the heating rate. As shown by the phase diagram, high reaction temperatures favour CaO stability, and the corresponding maximum SO 2 equilibrium partial pressure increases. The total SO 2 production significantly increased with increasing molar ratio and slightly increased when the ratio exceeded 1:3. The SO 2 productions were ranked from highest to lowest as follows: S, CH 4 , N 2 , CO, and air. The total SO 2 production decreased with increasing heating rate. For the reaction between CaS and CaSO 4 , a higher molar ratio of CaS to CaSO 4 no less than 1:3, both S and CH 4 reductive atmospheres, and a lower heating rate (2°C/min) favour the total SO 2 emission.
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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 | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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".