| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Aluminum Reduction Technology
|
| Presentation Title |
Lab Scale Experiments on Alumina Raft Formation |
| Author(s) |
Sindre Engzelius Gylver, Åste Hegglid Follo, Henrik Gudbrandsen, Asbjørn Solheim, Kristian Etienne Einarsrud |
| On-Site Speaker (Planned) |
Sindre Engzelius Gylver |
| Abstract Scope |
During feeding of alumina into a Hall-Héroult cell, rafts floating on the bath surface may be formed, hindering dissolution. In this study, rafts were created in a laboratory cell by adding secondary alumina in industrial bath, aiming to identify the effect of bath superheat and alumina temperature. Samples were withdrawn from the bath in a time interval between 30 and 300 seconds, showing that at a bath temperature of 970 °C, rafts will be formed within 30 seconds, and then slowly dissolve again with a rate of 0.8 g/min. Lowering the bath temperature resulted in higher mass gain and dissolution time, illustrating the effect heat transfer has on the dissolution process. Heating of alumina above 500 °C was found to change the structure significantly. The raft structure was analyzed using CT, showing average porosity of 7.7 % for both high and low bath temperature regimes, contributing strongly to raft buoyancy. |
| Proceedings Inclusion? |
Planned: Light Metals |