Partitioning and biodegradation of diethylenetriamine (DETA) and metal-DETA chelates, and their predicted behaviour in tailings management areas
Bibliographic record
Abstract
Pyrrhotite (Po) is an unwanted mineral with low economic value which dilutes valuable mineral streams and contributes significantly to SO2 emissions during smelting. The most effective pyrrhotite rejection method is by using chelating agents, such as diethylenetriamine (DETA), during flotation. DETA improves the concentrate grade; however, its use results in stable chelates between DETA and metal ions: nickel and copper. Once in the tailings management area, DETA-metal chelates cannot be removed by hydroxide precipitation. DETA mobilizes the metal ions through the treatment area and into the environment, which is detrimental to the local flora and fauna.To effectively assess the implications of DETA in a mine tailings management area, DETA must be reliably detectable. An analytical method for DETA detection method was developed using cation exchange chromatography with conductivity detection without the need for preconcentration or derivatization. The limits of detection and quantification were 0.002 and 0.005 mM, respectively, in deionized water samples. This method also proved effective to detect DETA chelated with metals such as nickel and copper. The behaviour of DETA was modeled in a theoretical tailings management area using experimental sorption data along with geochemical modelling using OLI Studio software to 1) predict the concentration of DETA, Cu-DETA, and Ni-DETA in final effluent and 2) ascertain if copper and nickel concentrations would be expected to exceed regulated limits. Operational parameters were investigated to ascertain their influence on the model outputs. In all cases, except the case for dry stacking the DETA containing tailings, the concentration of metal in the final effluent exceeded regulated limits. These results strongly indicate the necessity for a DETA mitigation strategy. This thesis investigates the potential of biodegradation of DETA and metal-DETA chelates using a mixed bacterial culture. Cation and anion ion chromatography results were used to track the DETA degradation progress by measuring DETA, ammonium, and succinate concentrations. The biomass generated by the degradation process was observed using microscopy, quantified using qPCR, and bacteria genera were identified using 16S rRNA sequencing. Evidence of complete DETA degradation in the presence of an external energy source, succinate, was demonstrated for unchelated DETA and for Ni-DETA. DETA was demonstrated to be a nitrogen source.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".