Sulfuric color after long shelf storage

oldgeek · Jan 31, 2020

Greetings, its been a while since I did any recovery/refining. I put it all on a shelf in the shed for about 8 years or so due to lack of a decent place to work. I did a bit of board selling a few years back when I had a very good supply of free IT equipment. All that is left in my gold collection is some cherry picked stuff and some gold chloride that I never dropped the gold from. I also have some chemicals leftover that I am currently moving around in the shed to ensure they are still safely stored. Which brings me to my question, I have some pint bottles of concentrated sulfuric that have all turned black. Several of them were used in a stripping cell, and I expect them to be dark, but at least one of the bottles was unopened and it was also black.

Is my sulfuric still ok to use in something like poor mans AR? What happened to it, I remember it being very clear.
Thanks!

FrugalRefiner · Jan 31, 2020

Was your sulfuric just pure sulfuric, or was it one of the drain cleaners? If a drain cleaner, what brand? It might help others give a good answer.

Dave

oldgeek · Jan 31, 2020

It is unbranded, sold as sulfuric on feebay.

g_axelsson · Jan 31, 2020

I have had rubber seals in chemical containers go bad over time and discolor acids. Check the lid so it isn't on it's way to break.

My sulfuric acid was bought at least 20 years ago and it looks pristine.

Göran

Geo · Feb 1, 2020

If it is in a poly bottle, the sulfuric acid reacts with the poly over time and breaks it down to carbon. The bottles do not hold up indefinitely. I've had poly bottles from Duda that turns black in a year.

oldgeek · Feb 1, 2020

Geo said:
If it is in a poly bottle, the sulfuric acid reacts with the poly over time and breaks it down to carbon. The bottles do not hold up indefinitely. I've had poly bottles from Duda that turns black in a year.

Mine also came from Duda. I have not had a chance to check the bottles over, but this is likely what is going on. I guess I need to be extra careful since the bottles are likely very fragile. They are still in their original ziplock bags so they should be good until I can find a suitable container.
Thanks for the information.