Pyrometallurgy: Roasting, Smelting, Refining & Electrowinning

Pyrometallurgy: Roasting, Smelting, Refining & Electrowinning

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calcium on heat plate exchanger (4 replies and 1 comment)

m
hulk
7 years ago
hulk 7 years ago

During gold elution, a calcium deposit is formed on the plate exchanger surfaces, we perform shutdowns to clean them, can we clean effectively without Disassemble the plates, which cleaner should i use and at which concentration and which depth?

David
7 years ago
David 7 years ago
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Hello Hulk,

5 or 10 percent HCl to remove and clean. Weaker if try to flush system. When running try to keep steady pH may not scale as much or use caustic soda for pH control. If possible use fresh water plus caustic soda plus CN for initial strip solution.

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m
hulk
7 years ago

thanks David!
1- i have H2SO4 in store ,is it possible to use it?
2-my initial solution is caustic soda
3-pH is between 10-12 should it be more steady?
thanks

Paul Morrow
7 years ago
Paul Morrow 7 years ago
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Mineral acids such as hydrochloric acid (HCl), sulfamic acid (NH2SO3H), nitric acid (HNO3), phosphoric acid (H3PO4) and sulfuric acid (H2SO4) have a good ability to dissolve scale. However, they can also corrode the stainless steel or copper if used improperly.

Sulfuric acid is a stronger acid than nitric acid = Best use a weaker acid.

Sulfuric will work, but longterm, nitric is better.

David
7 years ago
David 7 years ago
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Try the weak sulfuric acid, it should work. Be careful if metal Is not stainless. It will dissolve unless scale is gypsum. Keep pH steady as possible to whatever your procedure calls for.

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C
czambrano
7 years ago
czambrano 7 years ago
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I remember to complete with a final step of passivation in order to recover a protective film, but this was for boiler water in calenders, not sure if suitable for Hulk´s application.

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