Atmospheric Leaching of Enargite in the Presence of Carbon Based Catalyst
Bibliographic record
Abstract
Pyrometallurgy is not the most sustainable option for enargite concentrate treatment due to the environmental limitations on arsenic release. Therefore, developing an effective hydrometallurgical process is a promising solution for enargite treatment. Most hydrometallurgical processes proposed in literature have not reached commercial utilization because of common issues such as slow dissolution rate of the mineral, incomplete copper or precious metals recovery, sulfate generation, arsenic fixation problems, and high capital and operating costs. In this thesis, the atmospheric leaching of enargite in chloride media was investigated in the presence of activated carbon (AC) and AF 5, a novel carbon based catalyst. Both catalysts were found to be very effective in facilitating the enargite leaching process and improved the oxidation and copper recovery from 65% to 92% (AC) or 96% (AF 5) after 96 hours. The best leaching condition was found to be: ferric and cupric concentrations greater than 5 g/L, concentrate to catalyst mass ratio of 1:2, and a 90 °C working temperature or higher. The elemental sulfur product of the leach reaction did not coat the surface of the partially leached mineral particles. When AF 5 was used as the catalyst in the leaching process, it collected the generated elemental sulfur. The arsenic also precipitated in the form of scorodite, one of the most stable forms of arsenic, during the leaching in chloride media at temperatures higher than 80 °C. The catalytic properties of the carbon-base catalysts (CBC) was due to the oxidation via oxygen functional groups on their surfaces, which were detected by XPS analysis. The results showed that the chemical pre-treatment of CBC can be effective in increasing its catalytic effect on enargite leaching. The comparison between the chloride and sulfate media showed that the sulfate media has better copper and iron dissolution kinetics and promotes sulfur collection, whereas the remediation of arsenic in the form of scorodite can be superior in chloride media.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 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".