The Parkes process is a pyrometallurgical industrial method for removing silver from lead during bullion production, patented by Alexander Parkes in 1850. It exploits the fact that zinc does not mix with molten lead but dissolves silver at roughly 3,000 times the concentration lead does, so introducing zinc to lead containing silver impurities draws the silver into a separate zinc layer that is skimmed off and then heated to vaporize the zinc, leaving nearly pure silver behind.
Facts
SignificanceUses zinc, which is immiscible with lead while silver is far more soluble in zinc, to extract silver from lead 1 FAQs
Does the Parkes process remove anything besides silver from lead?
It also draws out gold; the zinc compounds form a crust that is removed.
Yes. Grace's Guide describes the method as adding zinc to lead and melting the two together. When the mixture is stirred, the molten zinc forms compounds with any silver and gold present in the lead. These zinc compounds are lighter than the lead, so on cooling they form a crust that can be removed easily. The same source says the process was used at Sims' works at Llanelly.
Connections
In Field
Source Parkes process, Wikipedia
Invented By
Source Wikipedia: Alexander Parkes
Sources
1. Parkes process, Wikipedia
Article body, patent statement
The process was patented by Alexander Parkes in 1850.
Article body, process principle
The process takes advantage of two liquid-state properties of zinc. The first is that zinc is immiscible with lead, and the other is that silver is 3000 times more soluble in zinc than it is in lead.
In Field: Metallurgical Engineering, Categories
Metallurgical processes
In Group: Non-Ferrous Extraction and Refining, Introduction
The Parkes process is a pyrometallurgical industrial process for removing silver from lead during the production of bullion.
View the SourceWikipedia: Alexander Parkes
Invented By: Alexander Parkes, Article bodyQuote, Invented By: Alexander Parkes, Article body
with his brother Henry Parkes). In 1850, he developed and patented the Parkes process for economically desilvering lead,
Reader Challenges (0)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.