Question

Which of the following statements are correct in connection with the extraction of silver ?

• A. Silver is obtained as a by-product in the extraction of copper, lead and zinc.
• B. Silver is obtained from the anode slime formed in the electrolytic refining of copper and zinc
• C. Zinc is used to extract silver by solvent extraction from molten lead in Parke's process.
• D. Pattinsons process is used for desilverization of lead

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A Silver is obtained as a by-product in the extraction of copper, lead and zinc.
B Silver is obtained from the anode slime formed in the electrolytic refining of copper and zinc
C Zinc is used to extract silver by solvent extraction from molten lead in Parke's process.
D Pattinsons process is used for desilverization of lead

The parke's process is used for the desilverization of argentiferous lead (PbS + 0.01 to 1 % Ag) is based on distribution principle.

The principle follows as Molten zinc and molten lead form a two phase system.

Silver is more soluble in molten zinc than the molten lead.

The Zn - Ag alloy is lighter than Pb and freezes fast.

The floating solidified Zn - Ag alloy can be easily removed from molten Pb. From Zn - Ag alloy, zinc is separated by distillation.

Pattinson's Process is the method which is usually adopted for desilverising lead, and is so effectual that silver, if present in the lead to the extent of only two or three ounces to the ton, may be profitably extracted. The process depends on the fact that when argentiferous lead is melted and allowed to cool the portions that solidify first are not so rich in silver as the still liquid portion.