<p>Traditional antimony salt purification methods require 100–500 times the theoretical amount of zinc powder for three stages of purification to meet the requirements. The purification efficiency is suboptimal. To address this issue, a one-step antimony salt purification method under an Ar atmosphere was investigated. The study revealed that one-step antimony salt purification proceeds through three primary stages: formation of Cu and Cu₂Sb substrates, deposition of Co and Cd, and redissolution of the precipitates. First, as the zinc powder dissolves, Cu²⁺ and SbO⁺ are reduced on the exposed zinc surface to form Cu and Cu₂Sb substrates. Second, these substrates form microgalvanic cells with zinc powder and act as positive electrodes, on which Co and Cd further accumulate and eventually evolve into aggregates. Finally, as the reaction progresses, the dissolution of Zn powder increases the system potential, promoting system oxidation. The increase in oxidation facilitates the redissolution of Cd by enabling its reaction with H⁺. Under optimal conditions, purification requirements can be met using zinc powder with an amount of 4.73 times the theoretical molar amount. Thus, the proposed approach can reduce zinc powder consumption while ensuring the effective removal of Co, Cd, and Cu.</p>