The Rate of HF Formation During Addition of Alumina to NaF-AlF3 Melts

Karen S. Osen; Dian Mughni Fellicia; Christian Rosenkilde; Camilla Sommerseth; Ole Kjos

doi:10.1007/978-3-030-36408-3_91

The Rate of HF Formation During Addition of Alumina to NaF-AlF₃ Melts

Karen S. Osen^*, Dian Mughni Fellicia, Christian Rosenkilde, Camilla Sommerseth, Ole Kjos

^*Corresponding author for this work

Laboratory of Metallurgy and Manufacturing

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

A major contributor to HF gas evolution during aluminium electrolysis is the hydrolysis of alumina water. The objectives of this work were to investigate the kinetics of HF generation, and how water residence time in the atmosphere above the bath influences the HF formation. The HF concentration in the off-gas was measured during additions of alumina to a NaF-AlF₃ melt (r = 2.2). The alumina water release rate upon rapid heating was also measured separately when alumina was added to a hot empty quartz cell. In the melt experiments, the residence time of the alumina water was varied by changing the nitrogen gas flow rate through the experimental reactor. The HF formation occurred instantly and the rate determining step is the alumina water release rate. For the range in this study, there was no effect of residence time of the gas in the reaction chamber on the amount of HF formed.

Original language	English
Title of host publication	Light Metals 2020
Editors	Alan Tomsett
Publisher	Springer Science and Business Media Deutschland GmbH
Pages	672-679
Number of pages	8
ISBN (Print)	9783030364076
DOIs	https://doi.org/10.1007/978-3-030-36408-3_91
Publication status	Published - 2020
Event	Light Metals Symposium held at the 149th Annual Meeting and Exhibition, TMS 2020 - San Diego, United States Duration: 23 Feb 2020 → 27 Feb 2020

Publication series

Name	Minerals, Metals and Materials Series
ISSN (Print)	2367-1181
ISSN (Electronic)	2367-1696

Conference

Conference	Light Metals Symposium held at the 149th Annual Meeting and Exhibition, TMS 2020
Country/Territory	United States
City	San Diego
Period	23/02/20 → 27/02/20

Keywords

Alumina
HF formation
Kinetics

Access to Document

10.1007/978-3-030-36408-3_91

Cite this

@inproceedings{08e87d140e724407b35f4a4197f1a246,

title = "The Rate of HF Formation During Addition of Alumina to NaF-AlF3 Melts",

abstract = "A major contributor to HF gas evolution during aluminium electrolysis is the hydrolysis of alumina water. The objectives of this work were to investigate the kinetics of HF generation, and how water residence time in the atmosphere above the bath influences the HF formation. The HF concentration in the off-gas was measured during additions of alumina to a NaF-AlF3 melt (r = 2.2). The alumina water release rate upon rapid heating was also measured separately when alumina was added to a hot empty quartz cell. In the melt experiments, the residence time of the alumina water was varied by changing the nitrogen gas flow rate through the experimental reactor. The HF formation occurred instantly and the rate determining step is the alumina water release rate. For the range in this study, there was no effect of residence time of the gas in the reaction chamber on the amount of HF formed.",

keywords = "Alumina, HF formation, Kinetics",

author = "Osen, {Karen S.} and Fellicia, {Dian Mughni} and Christian Rosenkilde and Camilla Sommerseth and Ole Kjos",

note = "Publisher Copyright: {\textcopyright} 2020, The Minerals, Metals & Materials Society.; Light Metals Symposium held at the 149th Annual Meeting and Exhibition, TMS 2020 ; Conference date: 23-02-2020 Through 27-02-2020",

year = "2020",

doi = "10.1007/978-3-030-36408-3_91",

language = "English",

isbn = "9783030364076",

series = "Minerals, Metals and Materials Series",

publisher = "Springer Science and Business Media Deutschland GmbH",

pages = "672--679",

editor = "Alan Tomsett",

booktitle = "Light Metals 2020",

address = "Germany",

}

Osen, KS, Fellicia, DM, Rosenkilde, C, Sommerseth, C & Kjos, O 2020, The Rate of HF Formation During Addition of Alumina to NaF-AlF₃ Melts. in A Tomsett (ed.), Light Metals 2020. Minerals, Metals and Materials Series, Springer Science and Business Media Deutschland GmbH, pp. 672-679, Light Metals Symposium held at the 149th Annual Meeting and Exhibition, TMS 2020, San Diego, United States, 23/02/20. https://doi.org/10.1007/978-3-030-36408-3_91

The Rate of HF Formation During Addition of Alumina to NaF-AlF₃ Melts. / Osen, Karen S.; Fellicia, Dian Mughni; Rosenkilde, Christian et al.
Light Metals 2020. ed. / Alan Tomsett. Springer Science and Business Media Deutschland GmbH, 2020. p. 672-679 (Minerals, Metals and Materials Series).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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AU - Kjos, Ole

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AB - A major contributor to HF gas evolution during aluminium electrolysis is the hydrolysis of alumina water. The objectives of this work were to investigate the kinetics of HF generation, and how water residence time in the atmosphere above the bath influences the HF formation. The HF concentration in the off-gas was measured during additions of alumina to a NaF-AlF3 melt (r = 2.2). The alumina water release rate upon rapid heating was also measured separately when alumina was added to a hot empty quartz cell. In the melt experiments, the residence time of the alumina water was varied by changing the nitrogen gas flow rate through the experimental reactor. The HF formation occurred instantly and the rate determining step is the alumina water release rate. For the range in this study, there was no effect of residence time of the gas in the reaction chamber on the amount of HF formed.

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