If the anode, hearth or aluminum solution is in a poor state, the aluminum solution will suffer from a big fluctuation, thereby leading to the change of electrode distance at some positions. Finally, the cell voltage will fluctuate accordingly, and this is called voltage fluctuation.
According to the on-site inspection result, different measures should be applied to solve this problem, and prevention is of great importance before anything happens.
1. For a newly installed electrode including temporarily changed used electrode, the current distribution test is necessary. Based on the result, height modification should be carried out. Moreover, the operator needs to lift the anode, and check if there is any carbon residue, broken pieces or other things. If the answer is yes, please remove them.
2. If the hearth is in a bad condition, the electrode distance could be enlarged to solve this problem.
3. If the voltage fluctuation is not over 0.2V, the computer program will automatically raise the anode, keep it steady for some time, and then drop the anode to recover the voltage. If it doesn’t work, the computer will automatically print the information, and then the operator is asked to handle it.
4. For the voltage fluctuation which is less than 0.5V, the workers should lift the anode manually until the fluctuation disappears. Then, detect the current distribution, and fix the abnormal anode. But, for one cell during one shift, only one anode is supplied. After this, the anode is lowered slightly every 30 minutes. If voltage fluctuation doesn’t occur in the following 8 hours, the voltage could be set to the normal value. If the voltage rises to 5V and the fluctuation is still out of control, please inform the production director and other relevant managers.
The above are temporary solutions that can’t eliminate the root cause. To completely get rid of voltage fluctuation, the operator must well control the production specifications to regulate the hearth and reduce the horizontal current component of the aluminum solution.