Extraction of silver from sulphide ore
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Argentite, which is a sulphide ore, is the chief source of silver. It is extracted by the process of leaching with a dilute solution of sodium cyanide. Silver dissolves and forms a complex, argentocyanide. It is further treated with scrap zinc, which displaces silver from the complex.
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The Extraction of Silver
Last updatedJun 6, 2019
Iron Production
Preparation and uses of Silver chloride and Silver nitrate
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Extraction of Silver by cyanide process and its uses
Silver also occurs both in combined state as well as in free state. The important ores of silver are: Argentite (Ag2S), Copper silver glance, Horn silver, Ruby silver. The silver ores are found along with gold ores in some parts of India.
Extraction
Silver is extracted from the ore-argentite (\(Ag_2S\)). The process of extraction of silver is called as cyanide process as sodium cyanide solution is used. The ore is crushed, concentrated and then treated with sodium cyanide solution. This reaction forms sodium argento cyanide \(Na [Ag(CN)_2]\).
\[ Ag_S + 4NaCN \rightleftharpoons 2Na [Ag(CN)_2] + Na_2S\]
The solution of sodium argento cyanide combines with zinc dust and forms sodium tetra cyanozicate and precipitated silver. This precipitated silver is called spongy silver.
\[ Zn + 2Na [ Ag (CN)_2] \rightarrow Na_2 [Zn(CN)_4] + 2Ag \]
The spongy silver is fused with potassium nitrate to obtain pure silver. Then the silver obtained is purified by electrolytic process.
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