Silver Cyanidation Revision
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Transcript of Silver Cyanidation Revision
8/6/2019 Silver Cyanidation Revision
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SILVER CYANIDATION
2011-05-31 Metallurgical Engineering
RiantikaRafni
(333408
1636)
8/6/2019 Silver Cyanidation Revision
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OUTLINE
2011-05-31 Metallurgical Engineering
Prefac
e The Kinetic of DissolutionFactors Affecting The
Dissolution RateApplicationReferences
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Preface
What is leaching??
2011-05-31 Metallurgical Engineering
What is
cyanidation??
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Click icon to add picture The Kinetic of Dissolution Rat
Schematic representation of the dissolution of silver in cyanide solution
2011-05-31 Metallurgical Engineering
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Click icon to add pictureFactors Affecting The DissoluRate
Graphic of cyanide concentration
Effect of cyanide concentration
2011-05-31 Metallurgical Engineering
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Effect of Hydrogen Concentration
Diagram betweenconcetration and rate
of dissolution
2011-05-31 Metallurgical Engineering
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Effect of Temperat
Increasing the tempercause increase the ra
dissolution
2011-05-31 Metallurgical Engineering
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Click icon to add pictureEffect of OxygenConcentration
At low cyanidconcentration, the
dissolution dependsthe cyanide concen
while at high cyaconcentration th
depends only on thepressure
2011-05-31 Metallurgical Engineering
Rate of dissolution of silver at different
pressure and differentNaCN concentrations
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Effect of Foreign Io
1. Accelerating effect
e.g : lead, mercury, etc.
2. Retarding effect
e.g :
Ø. FeS : consumption of oxygen
solution
Ø. ZnS : formation of complex cya
Ø. S2- : formation of thiocyanate
2011-05-31 Metallurgical Engineering
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Application
Silver is by-product from goldleaching
at PT. Antam
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References
•
Habashi. 1980. Principles of ExtractMetallurgy vol.2. Science Publisher:
• Deitz G.A, Halpern J. 1953. ReactioSilver With Aqueous Solutions of Cy
and Oxygen.• http://extractivemetallurgy.blogspot
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T hank ’s f o r y o ur at t e nt i o n
2011-05-31 Metallurgical Engineering
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Revision
1. Why the rate decrease when the pH above 12?Because when the pH above 12, the pH is increapOH will be decrease. So the cyanide ion evaporate. The cyanide ion that evaporate in largcan decrease the recovery and the rate of dissolu
(Reference : Laporan Kerja Praktek PT. Antam)
2011-05-31 Metallurgical Engineering
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Revision
2.
[KOH] comes from? The reagant that usually used for cyanidation NaCN. If we use KCN for cyanidation, the reactioncyanidation become :
4 Ag + 8 KCN + O2 + 2 H2O 4 KAg(CN)2 + 4 KO
so from that reaction we know the KOH coKCN.
(Reference : Principle of Extractive Metallurgy by
2011-05-31 Metallurgical Engineering