Reduction of HF Emissions from the TRIMET Aluminum Smelter (Optimizing Dry Scrubber Operations and Its Impact on Process Operations)

Iffert, Martin; Kuenkel, Markus; Skyllas‐Kazacos, Maria; Welch, B. J.

doi:10.1007/978-3-319-48156-2_143

Cited by 4 publications

(1 citation statement)

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“…6 and 13. Studies were performed at TRIMET's Essen smelter employing an injector-type dry scrubber; for the interested reader, full details of the gas treatment centre (GTC) system is provided by Iffert et al 14 One of the models of particular relevance to the current work is that of the excess AlF 3 levels of the cell (XsAlF 3 ). It is reasonable to assume that bath fluoride levels should correlate with the surface area of the feed alumina as one of the predictors: the higher the surface area, the greater its ability to capture fluoride and return this to the pots, thereby increasing the XsAlF 3 levels.…”

Section: The Impact Of Alumina Pore Size On Fluoride Balances In An Omentioning

confidence: 99%

The Pivotal Role of Alumina Pore Structure in HF Capture and Fluoride Return in Aluminum Reduction

McIntosh

Agbenyegah

Hyland

et al. 2016

JOM

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Fluoride emissions during primary aluminum production are mitigated by dry scrubbing on alumina which, as the metal feedstock, also returns fluoride to the pots. This ensures stable pot operation and maintains process efficiency but requires careful optimization of alumina for both fluoride capture and solubility. The Brunauer-Emmett-Teller (BET) surface area of 70-80 m 2 g À1 is currently accepted. However, this does not account for pore accessibility. We demonstrate using industry-sourced data that pores <3.5 nm are not correlated with fluoride return. Reconstructing alumina pore size distributions (PSDs) following hydrogen fluoride (HF) adsorption shows surface area is not lost by pore diameter shrinkage, but by blocking the internal porosity. However, this alone cannot explain this 3.5 nm threshold. We show this is a consequence of surface diffusion-based inhibition with surface chemistry probably playing an integral role. We advocate new surface area estimates for alumina which account for pore accessibility by explicitly ignoring <3.5 nm pores.

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Section: The Impact Of Alumina Pore Size On Fluoride Balances In An Omentioning

confidence: 99%