USING OF HIGH PHOSPHORUS GRAY IRON FOR THE STUB- ANODE CONNECTION IN THE ALUMINIUM REDUCTION CELLS

M. Ali, Mohamed; Nofal, Adel; Kandil, Amr; Agour, Mahmoud

doi:10.21608/jesaun.2011.129448

USING OF HIGH PHOSPHORUS GRAY IRON FOR THE STUB- ANODE CONNECTION IN THE ALUMINIUM REDUCTION CELLS

Document Type : Research Paper

Authors

¹ Al Azhar University, Faculty of Engineering, Qena, Egypt

² Central Metallurgical R&D Institute (CMRDI), P.O. Box 87 Helwan, Egypt

³ Al Azhar University, Faculty of Engineering, Cairo, Egypt

⁴ Aluminum Co. of Egypt (Egyptalum), Nagaa Hammadi, Egypt

10.21608/jesaun.2011.129448

Abstract

High phosphorus gray iron (HPGI) is used to secure the steel stub of an anode rod to a prebaked anode carbon block in the aluminium reduction cells. During this work, a detailed characterization for HPGI was done. The variation in the chemical composition of the HPGI collar, anodic voltage drop, and collar temperature over the 30 days anode life cycle were studied and compared with HPGI microstructure at different stages of the experiment. The carbon content in HPGI during anode life cycle was reduced from 3.73 to 3.38%. Significant changes in the HPGI microstructure were observed after 3 and 30 days from the anode changing. The collar temperature increases over the anode life cycle and reaches to 850°C in four weeks after anode changing. Different changes in the anodic voltage drop values at the stub- collar-anode connection during anode life cycle were recorded. Two bench- scale experimental set-ups were designed and implemented to simulate the operating conditions in the steel stub/ HPGI collar/ anode block connection and used to measure the electrical resistance and resistivity respectively. Comparison with steel electrical resistivity showed the greatest importance to modify the current HPGI or producing new alloys with excellent electrical and mechanical properties. The steel stub and HPGI thermal expansion were measured and studied. Considerable permanent expansion was observed for the HPGI collar after the completion of the heating-cooling cycle.

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