Influencing factors on PFC (perfluorocarbon) emission were investigated in Chinese smelters. The formation mechanism of non-anode effect related PFC emissions (short as NAE-PFC) from aluminum reduction cells were discussed. Anodic overvoltage has an obvious influence on NAE-PFC formation, CF4 will emit when anodic overvoltage is higher than 2.55 volts, C2F6 will be generated when anodic overvoltage surpasses 2.68 volts. Alumina concentration in bath with anodic current density also has a clear influence on NAE-PFC formation. Alumina fluctuates in large cells from the metal-tapping-end to the flue-end. Alumina always distributes unevenly in the bath because of bath flow driven by magnetic fields, which will also cause NAE-PFC formation. NAE-PFC will emit when there is not enough alumina under certain anode’s bottom. The limit alumina concentration is 75% of normal level which is 2.0–3.5% in Chinese smelters. Cells will generate NAE-PFC when any anode’s current density is higher than 1.5 times of normal level which is 0.72–0.80A/cm2 in Chinese smelters.
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- Investigation on Formation Mechanism of Non-Anode Effect Related PFC Emissions from Aluminum Reduction Cells
- Springer International Publishing
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