Pretreatment of lead anode slime with low silver by vacuum distillation for concentrating silver

The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically. The volatilization rates and mass fractions of elements, influenced by distillation temperature, heat preservation time and material thickness, were investigated under laboratory conditions. The experimental results indicate that almost all of lead and bismuth can be separated from silver-contained multicomponent alloy at 1 223 K for 45 min when the chamber pressure maintains at 10-25 Pa. Silver can be easily enriched in the residue and its mass fraction increases from 3.6% to 27.8% when the distillation temperature is between 1 133 K and 1 373 K. Due to the forming ofintermetallic compounds Cu2Sb, Cul0Sb3 and Ag3Sb, the antimony could not be evaporated completely during the vacuum distillation. EDS analysis indicates that the condensate has a columnar crystal structure.

The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically.The volatilization rates and mass fractions of elements,influenced by distillation temperature,heat preservation time and material thickness,were investigated under laboratory conditions.The experimental results indicate that almost all of lead and bismuth can be separated from silver-contained multicomponent alloy at 1 223 K for 45 min when the chamber pressure maintains at 10-25 Pa.Silver can be easily enriched in the residue and its mass fraction increases from 3.6% to 27.8% when the distillation temperature is between 1 133 K and 1 373 K.Due to the forming of intermetallic compounds Cu2Sb,Cu10 Sb3 and Ag3 Sb,the antimony could not be evaporated completely during the vacuum distillation.EDS analysis indicates that the condensate has a columnar crystal structure.