Development of an Improved Chemical Model for the Estimation of CaSO<sub>4</sub> Solubilities in the HCl−CaCl<sub>2</sub>−H<sub>2</sub>O System up to 100 °C
Bibliographic record
Abstract
A self-consistent chemical model based on a single set of model parameters for all three CaSO 4 modifications namely, dihydrate, hemihydrate, and anhydrite was developed and described in this work. The model was successfully tested for the estimation of CaSO 4 solubilities in concentrated (up to 20 m) mixed HCl−CaCl 2 −H 2 O systems up to 100 °C. The new model makes use of the OLI Systems software platform. Via regression of experimental solubility data, new Bromley−Zemaitis model parameters were determined for the Ca 2+ −SO 4 2- and Ca 2+ −HSO 4 - ion pairs. Moreover, for the first time, the new model incorporates data for hemihydrate modification (CaSO 4 · 1 / 2 H 2 O). After validation, the model was calibrated by determining new temperature-dependent parameters of the solubility product constants of the hemihydrate and anhydrite. With the aid of the newly developed model, the bell-shaped solubility curves for dihydrate and anhydrite, as a function of HCl concentration, were successfully explained, based on the bisulfate ion formation and ion-activity coefficient.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".