Gold extraction using novel ionic thiourea derivatives
Bibliographic record
Abstract
Cyanidation has been used worldwide for over a century as the primary method for gold extraction from ore. Unfortunately, accidents have occurred that released toxic cyanide and resulted in devastation of the environment and surrounding communities. For this reason, alternatives to cyanidation have been of great interest but have yet to be implemented owing to the high costs of materials and necessary changes to infrastructure, which make these alternatives economically unfeasible. Reported herein is the use of novel ionic thiourea derivatives for the extraction of gold without the use of cyanide. A series of six pyrrolidinium and imidazolium salts have been functionalized with a thiourea group and either the anion hexafluorophosphate ([PF6]-) or dodecyl sulfate ([DS]-). Gold(iii) extraction up to 90% was achieved from an aqueous solution with a methyl imidazolium-tagged [DS] salt. Extraction experiments using gold(i) showed a decrease in extraction efficiency, suggesting the oxidation state of the gold is important for complex formation. The extraction selectivity for gold(iii) and silver(i) over copper(ii), iron(ii) and zinc(ii) was demonstrated for all ionic thiourea derivatives.
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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) | 0.000 | 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".