First results of scale-up of the updated pyrometallurgical-hydrometallurgical Pedersen Process within the HORIZON2020 project ENSUREAL and examples for industrial concept
Bibliographic record
Abstract
The HORIZON2020 project "ENSUREAL" is developing a modernized version of the Pedersen process for production of alumina. The process counters challenges in raw material availability, energy availability, CO2 emissions and sustainability. European universities, institutes, technology partners, metal producers, fertilizers and plant suppliers cooperate to consider newest technologies, research results and current boundary conditions like climate change discussions. After calculations, simulations lab tests and pilot tests now all data are evaluated for upscaling to the investigated case, a capacity of 500 kt industrial grade alumina. The flowsheet and the industrial scale plant will be shown as a first complete process concept, consisting of four main sections: Pretreatment, pyrometallurgical melting, hydrometallurgical steps and calcination. The pretreatment contains mixing, milling and pelletizing of bauxite or bauxite residual, limestone, coke and gray mud reverts. In the pyrometallurgical section the pellets are dried, pre-reduced and preheated by a rotary kiln. The hot pellets are afterwards hot transferred to a large SAF to produce a Ca-Al-slag and to separate iron. The Ca-AL-slag is cooled down slowly. This is important to enable the formation of leachable crystal phases and the formation of phases that make the slag self-disintegrating. The modern SAF enables to use renewable enerygy, to integrate energy management and heat recovery. The hydrometallurgical part contains as first step the leaching of the Ca-Al-slag using a recycled Na2CO3 solution, forming solid gray mud (CaCO3) and dissolved NaAlO2. Afterwards the NaAlO2 solution is treated with CO2. As a result dissolved Na2CO3 and solid Al(OH)3 are generated. While the Na2CO3 solution is returned to leaching step the generated Al(OH)3 is finally transferred to the calcination step. The updated Pedersen process requires a long well cooperating process line, gives flexibility in usage of a wide range of raw materials and renewable energy and a contribution to reduce CO2 emissions.
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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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.003 |
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".