Separating lead–antimony alloy by fractional crystallization using directional lifting process

• Fractional crystallization process was firstly used to separate Pb–Sb alloy.
• Crude lead (Pb > 83%) was gained in the bottom.
• Antimony was enriched on the top without converting into Sb2O3.

The conventional pyrometallurgical method for separating lead–antimony alloy produced from jamesonite has a lot of imperfections such as long-term process, tremendous energy cost and harm to the environment. Therefore, a new method to separate lead and antimony from lead–antimony alloy by fractional crystallization is investigated. The experimental results demonstrate that the lead content decreases with the increase of length to the metal column’s bottom. Lead content of the bottom can reach larger than 80% by weight after lifting. In the experimental speed range, the lifting speed has very small impact on the separation effect. After 4 times’ lifting, crude lead bullion (larger than 83% by weight) whose lead content is close to the eutectic point of lead–antimony binary system is gained in the bottom and the antimony can be used for further refining process without converting into Sb2O3. The separating efficiency of lead in the bottom has reached the theoretical level of fractional crystallization for lead–antimony alloy containing about 40% by weight antimony.