Hydrolysis of Ferric Sulfate in the Presence of Zinc Sulfate at 200 °C: Precipitation Kinetics and Product Characterization
Bibliographic record
Abstract
The hydrolysis of ferric sulfate was studied in a batch reactor at 200 °C with the initial Fe(III) concentration ranging from 0.10 to 0.80 M in the presence/absence of zinc sulfate (1.2 M ZnSO 4 ) with 3 h retention time. Regardless of the presence or not of ZnSO 4, the hydrolytic precipitation kinetics at 200 °C was determined to be first-order with respect to Fe(III), and expressed by the following rate equation, r hyd = k hyd ( C Fe(III) − C Fe(III),eq ), where the apparent kinetic constant, k hyd, was determined to be 10 -2 min -1 . Two reaction stoichiometries were established: one leading to the formation of kinetically favored basic ferric sulfate at C Fe(III),initial ≥ 0.4 M in the absence of ZnSO 4 or at C Fe(III),initial ≥ 0.7 M in the presence of ZnSO 4, while the other led to the production of hematite. The hydrothermally produced hematite material possessed very high specific surface area (50−80 m 2 /g) and contained around 1% S (as SO 4 via chemisorption), 0.2% Zn (when ZnSO 4 was present), and about 4.5% H 2 O/OH. After excluding the SO 4 and Zn content, the following stoichiometric formula for hematite was determined: Fe 2 O 3 - x (OH) 2 x · y H 2 O where x = 0.08 and y = 0.29.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 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".