Three main types of issues arise with anodes during the electrolytic refining of antimony:

(1) Anode passivation: The formation of a dense oxide or salt film (such as Sb₂O₃ or SbOCl) on the surface increases electrical resistance and hinders dissolution, leading to higher cell voltage and reduced current efficiency. Contributing factors include excessive current density, insufficient free F⁻ concentration (which should be ≥20 g/L), high levels of impurities (lead, iron), and low operating temperatures. Severe cases require mechanical or chemical activation treatments.

(2) Non-uniform dissolution: Casting defects or uneven inter-electrode spacing cause significant variations in current distribution, resulting in "serrated" or "nodular" anode residues. This reduces anode utilization and produces rough, loose cathode deposits, thereby compromising the product's density and purity.

(3) Anode slime detachment: Insoluble impurities such as arsenic, copper, gold, and silver accumulate to form anode slime. If this layer becomes excessively thick with poor adhesion, it may detach and contaminate the electrolyte; the resulting impurity entrapment lowers the antimony grade of the cathode. Regular skimming or filtration, along with control of the anode composition, is required to manage this issue.

These three types of issues are often interrelated; ensuring stable operation in the electrolytic refining of antimony requires comprehensive control over factors such as anode material, current density, electrolyte composition, and operating temperature.