Gallium Recovery from Bayer Liquor Using a Chelating Resin
Bibliographic record
Abstract
This paper investigates the recovery of gallium from the aluminate solution of Bayer process (Bayer liquors), using a synthetic chelating resin.Gallium is extensively used in modern electronics and strategic energy technologies [1,2].Today, almost 95% of the global gallium production is used in semiconductor applications, although new uses for the metal in high-tech alloys and energy technologies are constantly being discovered.The strategic importance of gallium in low-carbon technologies makes it critical to the global economy.For the Europe economy, it is considered a highly important raw material of high supply-risk and therefore, it is included in the EU list of Critical Raw Material (CRM), since 2011.The minerals of gallium are rare and of no significant economic importance to serve as primary sources of the element or its compounds.They are present usually in trace amounts in the aluminum, zinc and iron ores.Generally, gallium is produced as by-product of these ores processing or from other secondary resources, like as fly ash and electronic waste.It is estimated that about 90% of the primary gallium worldwide is produced from the aluminate solution obtained in Bayer process used for the production of alumina from bauxite [3].The gallium content in Bayer liquor is low (about 200 ppm), making ion-exchange the most efficient method to be industrially applied for its recovery [4].In this work, the recovery of gallium from the Bayer liquor was studied, using a commercial chelating resin based on the amidoxime functional group, the Puromet MTS9701 (Purolite Ltd., UK).The resin's capacity and selectivity and the kinetics of gallium recovery were experimentally investigated, while an attempt to understand the process mechanism and the factors affecting the process efficiency was also made.The process equilibrium was investigated according to Langmuir and Freudlich isotherms, while its kinetics was analyzed using the pseudo first-and second-order empirical models.Moreover, the regeneration process of resin was investigated with acidic and basic solutions and its performance in sequential cycles' operation was evaluated.According to the experimental results, the Freudlich isotherm and the pseudo second-order kinetic model were proved more accurate to describe the equilibrium and kinetics, respectively, of gallium loading on the chelating resin used.The ratio of resin to solution was the most important factor of process efficiency.Equilibrium was reached after 5 h, when more than 75% of gallium was selectively extracted from the Bayer liquor, using a resin to solution ratio equal to 50 g/L.The maximum extraction of gallium was about 80%, after 24 h.The used resin was proved to be highly selective for gallium, which was thought to be bound on the nitrogen atom of amidoxime group.The in-depth understanding of the binding mechanism between amidoxime and gallium could result in designing a more efficient process for the recovery of gallium from Bayer liquors.
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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".