Microwave dewatering of deep-sea polymetallic nodules: Bench-scale and pilot-scale studies
Bibliographic record
Abstract
• Microwave dewatering of deep-sea nodules was demonstrated at bench (3.2 kW) and pilot (150 kW) scales. • Bench tests showed rapid drying and strong microwave absorption, classifying nodules as highly responsive (Class IV). • Pilot trials achieved 24 % mass loss at 397.3 kWh/t, demonstrating improved energy efficiency. • Scale-up showed faster drying and lower energy use, supporting continuous microwave processing design. Polymetallic nodules from the ocean floor are being considered as a significant potential resource for valuable metals such as manganese, nickel, copper, and cobalt. Various technologies are being investigated for the extraction of these metals, including hydrometallurgical, pyrometallurgical, and hybrid processes. In pyrometallurgical processing, a major challenge is the presence of water in various forms within the nodules, as its removal consumes a substantial amount of thermal energy. Consequently, more efficient and environmentally friendly dewatering techniques are being explored. One promising alternative is the use of electromagnetic radiation in the form of microwaves as a clean energy source. Microwave processing offers several potential advantages, including volumetric, selective, and rapid heating, and is in alignment with society’s future decarbonization directives. In the present study, bench-scale experiments were first conducted at a power level of 3.2 kW and a frequency of 2450 MHz to evaluate the microwave heating behaviour of nodules from the Clarion-Clipperton Zone. These experiments demonstrated that the nodules efficiently absorbed microwave energy, leading to rapid dewatering. Subsequently, pilot-scale studies were performed using a 150 kW microwave system operating at 915 MHz. The results confirmed that microwave dewatering is an effective pretreatment method for nodules prior to pyrometallurgical processing. Conclusions are drawn regarding the feasibility and applicability of microwave technology for the dewatering of polymetallic nodules and the potential advantages of further scale-up. The bench-scale tests achieved up to 31 % mass loss at an energy input of about 1067 kWh/t, while the pilot-scale trials removed up to 24 % moisture at about 397 kWh/t. These results demonstrate significant water removal with reduced energy demand compared to laboratory studies, highlighting the potential of microwave dewatering as a scalable pretreatment technology.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".