Assessing the Applicability of Gravity Separation for Recycling of Non‐Metal Fraction from Waste Printed Circuit Boards
Bibliographic record
Abstract
Abstract Printed circuit boards (PCB) are one of the most studied electronic waste streams due to the presence of high‐value metals. The rejects from waste PCB recycling, also known as a non‐metal fraction (NMF), are usually sent to landfill. This work explores the applicability of gravity separation, widely used in the mineral processing industry, to separate organic and inorganic components in the NMF. The float‐sink test is conducted to understand the gravity separation performance, and the results show that a 47% yield at 86% organic content with 70% combustible recovery can be obtained using dense media separation. The washability behavior of NMF is assessed using different washability indices standard in the coal industry; and the material is classified as difficult‐to‐clean. The float‐sink products show the concentration of organic stream in −1.8 g cm−3 range, fiberglass in +2.0–2.5 g cm−3 range, and metals in +2.5 g cm−3 range. The recovery of these components will facilitate the concept of the circular economy and promote sustainability.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".