Angry Beaker

[Dreamer]

I had to unfortunately learn the hard way to be VERY thorough looking for ferric metal before processing gold filled material. Everything was marked either 12 or 14k GF and I cut off any clasps. However, when I was done with my first Nitric wash, the solution went from green to brown. Took it off the heat overnight and the next morning rinsed everything well and pulled out anything magnetic. Yes, I fell victim to fleaBay so a couple of the pieces must have been fictitiously marked. The rest of the process went well except I have one angry beaker stained with Iron. Tried dilute nitric to no avail and tried a caustic bath with no result. Any Suggestion ?

 

[eaglekeeper]

I had to unfortunately learn the hard way to be VERY thorough looking for ferric metal before processing gold filled material. Everything was marked either 12 or 14k GF and I cut off any clasps. However, when I was done with my first Nitric wash, the solution went from green to brown. Took it off the heat overnight and the next morning rinsed everything well and pulled out anything magnetic. Yes, I fell victim to fleaBay so a couple of the pieces must have been fictitiously marked. The rest of the process went well except I have one angry beaker stained with Iron. Tried dilute nitric to no avail and tried a caustic bath with no result. Any Suggestion ?

Did you try hot hydrochloric?

 

[Dreamer]

Did you try hot hydrochloric?

I did not! I wanted to cut my losses and consult you pros. I will give it a boil and let you know. Thank you!

 

[ChopperGreg]

FYI…
Oxalic acid's main applications include cleaning or bleaching, especially for the removal of rust (iron complexing agent). Its utility in rust removal agents is due to its forming a stable, water-soluble salt with ferric iron

Oxalic acid - Wikipedia

Worth a shot.

 

[Dreamer]

FYI…
Oxalic acid's main applications include cleaning or bleaching, especially for the removal of rust (iron complexing agent). Its utility in rust removal agents is due to its forming a stable, water-soluble salt with ferric iron

Oxalic acid - Wikipedia

Worth a shot.

Thanks Chopper, I don't have much experience with Oxalic and it's interaction with other acids in my lab. Is it safe to treat it as a typical (Nitric, Hydrochloric, Sulfuric) acid in my waste stream? Will it compromise the cementation of PMs during waste treatment?

 

[Martijn]

HCl is good enough to dissolve iron or iron stains, so if you have it, don't buy things you don't need.

 

[Dreamer]

Doing it now.

 

[Shark]

Barkeeps Friend and a soft cloth or sponge. Add hot water and some mild elbow grease. Check the main ingredient in the stuff, might be surprised.

 

[ChopperGreg]

Thanks Chopper, I don't have much experience with Oxalic and it's interaction with other acids in my lab. Is it safe to treat it as a typical (Nitric, Hydrochloric, Sulfuric) acid in my waste stream? Will it compromise the cementation of PMs during waste treatment?

If it’s just iron, it probably safe enough to dry and dump. Calcium Oxalate is the cause of ~70% of all kidney stones, and most of those are just flushed down the toilet.

Oxalic acid, is a natural acid…that is to say that foods like rhubarb, spinach, carrots, cauliflower, broccoli, cabbage and others contain low levels of it. You still want to use lab safety gear but you’ve probably already dealt with an oxalate salt of one sort or another and not even known it. It’s used in bee keeping as a mite control and it’s also used to bleach wood.

Another possibility to chelate some iron salts, is citric acid. Ferric citrate is useful to plants, as a source of soluble iron. The ferric citrate is photo-reduced in the leaves to Iron (II), that is then transported into the plant cells.

EDIT: I looked up the MSDS of Barkeeper’s Friend, and it contains both oxalic acid and citric acid…
7.5-9.5% oxalic acid by weight.

 

[Dreamer]

Surprisingly, hot HCL cleaned it right away. I'll keep the Oxalic in my back pocket though. Thank you for your help! My beaker is much happier. Now back to those birds...lol!

 

[VK3NHL]

If it’s just iron, it probably safe enough to dry and dump. Calcium Oxalate is the cause of ~70% of all kidney stones, and most of those are just flushed down the toilet.

Oxalic acid, is a natural acid…that is to say that foods like rhubarb, spinach, carrots, cauliflower, broccoli, cabbage and others contain low levels of it. You still want to use lab safety gear but you’ve probably already dealt with an oxalate salt of one sort or another and not even known it. It’s used in bee keeping as a mite control and it’s also used to bleach wood.

Another possibility to chelate some iron salts, is citric acid. Ferric citrate is useful to plants, as a source of soluble iron. The ferric citrate is photo-reduced in the leaves to Iron (II), that is then transported into the plant cells.

EDIT: I looked up the MSDS of Barkeeper’s Friend, and it contains both oxalic acid and citric acid…
7.5-9.5% oxalic acid by weight.

That’s interesting,
Here in Australia ‘Barkeepers Friend’ contains NO Oxalic only Citric Acid.
Cheers
Tony

 

[Darkthirty]

If it’s just iron, it probably safe enough to dry and dump. Calcium Oxalate is the cause of ~70% of all kidney stones, and most of those are just flushed down the toilet.

Oxalic acid, is a natural acid…that is to say that foods like rhubarb, spinach, carrots, cauliflower, broccoli, cabbage and others contain low levels of it. You still want to use lab safety gear but you’ve probably already dealt with an oxalate salt of one sort or another and not even known it. It’s used in bee keeping as a mite control and it’s also used to bleach wood.

Another possibility to chelate some iron salts, is citric acid. Ferric citrate is useful to plants, as a source of soluble iron. The ferric citrate is photo-reduced in the leaves to Iron (II), that is then transported into the plant cells.

EDIT: I looked up the MSDS of Barkeeper’s Friend, and it contains both oxalic acid and citric acid…
7.5-9.5% oxalic acid by weight.

Iron Out Rust Stain Remover is 5-10% oxalic acid.