What is the reason for significant depolarization after the aluminum electrolysis anode is installed in the cell?
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Over the past month, anode detachment has occurred in a certain workshop; the cause is unknown. The specific situation is as follows: 8 to 25 days after being placed in the anode tank, some of the anodes began to fall off; some broke off, some separated due to fractures beneath the ferrophosphorus, and some fell off as a result of horizontal cracks. Depolarization accounts for about 15%. The technical specifications for the electrolyzer are as follows: temperature of 935–955 degrees, molecular ratio of 2.35–2.55, electrolyte level of 19–21 centimeters, average aluminum level of 23 centimeters, pressure drop at the bottom of the furnace of 330 mV; the bottom of the furnace is clean, with no deposits or crusts present. The secondary startup tank began to show the above issues 2 months after startup. The age before startup was 730 days. Discussion is welcome.
The overall detachment is likely due to insufficient bonding strength between the claw tip and the anode, while the local detachment of the anode is mainly caused by oxidation.
The partial shedding of phosphorus-containing pig iron indicates a problem with its composition, as it cannot withstand high temperatures.
In the case of anode slagging and longitudinal cracks, anode quality issues should be considered