Nitric Acid

[FishinInTheDark]

Hello, you Helpful Expert Types! (Unabashed sucking up in hopes of getting help. )

I am in a discussion in another forum about impurities in pulverized limestone used as substrate. Someone has suggested that nitric acid could be used to remove any metal impurities from limestone. What say you about the safety and practicality of this?

Thank you in advance for the magnanimous gesture of educating a common bumbler like myself!

 

[Curtswearing]

I can't tell you how efficiently you would remove metals with nitric acid. If you had copper in the rock, it would dissolve instantly. However, for other metals, I don't know.

The safety issue is important IMO. This is some SERIOUS stuff. Inhalation of fumes will shred your mucous membranes, burn your skin, etc. You are going to need a respirator, safety goggles, a rubber smock, etc. I would highly encourage you to NOT got this route.

Interesting factoid, very small levels of nitric acid is formed naturally in our reef tanks but not at dangerous levels.

 

[MikeS]

Give them this one Conni...

why on earth would anyone want to go through the hassle and expense and potential danger of using nitric acid to remove metallic impurities from crushed limestone when there are so many reletively inexpensive calcium carbonate substrates available to the reefkeeper to start with?

Also...I don't think the nitric acid is going to strip metal impurities from limestone, quite the opposite. When you put some vinager or other acid on limestone, it fizzes, right? Is it the metal that's doing this? no...it's the calcite that's reacting to the acid. I'd imagine if you dumped the limestone in a strong acid like that, the calcite would be reduced, not the metal...

MikeS

 

[FishinInTheDark]

Mike, you're headed right down the same line of thoughts that I was: what's the point? But, since someone is coming up with questions, I felt I should try and find some answers (and NO! not because of who was doing the asking!). He said he has used nitric acid to quick-cure DIY live rock, which is why he has some on hand, which is why he came up with the idea to purify pulverized limestone. Anyway, I'm off to the other forum to remind him and others of the safety issues, and to bring up the reaction against the metallic element calcium.

Thanks to you both for clearing things up for me!