AP moving slower than expected

[Jwdds]

I started with a 10g bar .999,9 pure and trying to dissolve it in AP. Using muriatic acid and 12% peroxide. Have it heated to 155. Been adding peroxide in 15 ml bumps. I’m almost 4 hours in yet the bar still looks in tact.

Is AP bot as good for bullion compared to Aqua Regia. Should I raise or lower temp? Im considering sodium metabisuphite to precipitate out what I do have then starting over with aqua regia.

Any advice would be appreciated!

On a side note I did search for ap temp but didn’t find anything concrete.

 

[Yggdrasil]

How big is your bar?

HCl/Peroxide are not good for solid metal. Only for foils and powders.
For solid metal it is recommended to melt it and make shots by pouring it into cold water.
The shots can then be dissolved in AR.

 

[Yggdrasil]

I started with a bar .999,9 pure and trying to dissolve it in AP. Using muriatic acid and 12% peroxide. Have it heated to 155. Been adding peroxide in 15 ml bumps. I’m almost 4 hours in yet the bar still looks in tact.

Is AP bot as good for bullion compared to Aqua Regia. Should I raise or lower temp? Im considering sodium metabisuphite to precipitate out what I do have then starting over with aqua regia.

Any advice would be appreciated!

On a side note I did search for ap temp but didn’t find anything concrete.

AP is usually used for Copper Chloride leach.
You are talking about the real AP

 

[Jwdds]

It is 10 grams. I think that’s the issue.

 

[Yggdrasil]

It is 10 grams. I think that’s the issue.

Too big for AP, you need to either make shots or roll it thin and cut it in thin strips.
Or go straight to AR.

 

[Jwdds]

Can I add nitric acid to existing solution or start from scratch? Btw thank you for your help

 

[Yggdrasil]

Should be ok, but gently in small increments. The Peroxide will make the Nitric last longer by recycling the NOx.
When the reactions slow down add a bit more and if no reaction add a bit HCl. Still no reaction heat more. When all stop you are done and should have minimal or no unused Nitric in solution.

 

[Jwdds]

Do you have a recommendation for temp?

 

[Yggdrasil]

Not especially. But if it is uncovered it is recommended not to boil it, since when the bubbles burst they fling their liquid around and it can be thrown out of the vessel. But as close to boiling as you feel confident. If it is properly covered one can boil it.

 

[Martijn]

Maybe i am missing something, but why are you dissolving a 4 nines fine bar???

 

[kurtak]

Maybe i am missing something, but why are you dissolving a 4 nines fine bar???

Good question

Kurt

 

[FrugalRefiner]

Look at his other thread. He's trying to make a specialized plating solution to create dental products.

Dave

 

[kurtak]

Look at his other thread. He's trying to make a specialized plating solution to create dental products.

Dave

Ah - OK - makes more sense now

Interesting - but it (plating solutions) is not really my thing as I normally take plating off (to recover the gold) not put plating on - so can't help much

Thank for the heads up Dave

Kurt