Electrochemistry Evaporation of muratic acid

[drtyTshrt]

Is the 37% strong enough for the cell or is it being evaporated to concentrated strength? I am not understanding the consensus from what I have been reading.

 

[FrugalRefiner]

drty,

I'm not sure I understand your post. Your title mentions muriatic acid, but then you ask about using it in a cell.

Muriatic acid (hydrochloric acid - HCl) at 37% will actually become less concentrated if evaporated. It reaches its azeotrope (the point at which the HCl and the water vaporize at the same rate, so further evaporation will not concentrate it any further) at a bit over 20%. If you evaporate your concentrated HCl, the HCl will vaporize faster than the water until it approaches 20%.

But if you're talking about a gold stripping cell, they use concentrated sulfuric acid (H₂SO₄), not muriatic. Sulfuric acid can be concentrated by evaporation to about 98%. Concentrated sulfuric acid is required in the stripping cell as less concentrated acid will attack base metals more agressively.

I don't know if that answers your question. If not, let us know a little more about what you're trying to do.

Dave

 

[drtyTshrt]

Thank You. I was just confused. You cleared it up for me.
I also got my printer friendly version of Hoke yesterday. Thank you for this as well your time to do this for the forum is greatfully appreciated. My print guy did not even charge me. Win Win.

 

[drtyTshrt]

A 15 GALLON drum of 39% sulpuric acid is $90.00 at my chemical supply house.

 

[FrugalRefiner]

I'm glad to hear the book worked out for you. It was a labor of love to be able to give a little back to the forum.

That's a lot of sulfuric acid. Once it's evaporated down, you'll still have well over 5 gallons. Remember that hot sulfuric acid is one of the most destructive acids to organic material like our bodies. If I were going to do it, I would take my time and work on small batches at a time. Full face shield, PVC full length apron, long gloves. Once you've reached the concentration you want, cover your container but leave it right where it is until it cools back down to room temperature. Then transfer it to another container and start another batch.

Safety first, especially with sulfuric!

Dave

 

[drtyTshrt]

I am not near ready to try anything. I am still reading and learning from the forum. Thanks for you knowledge as well as everyone else in here.

 

[jimdoc]

A 15 GALLON drum of 39% sulpuric acid is $90.00 at my chemical supply house.

You are better off with a gallon of Rooto (98%) from a hardware store for about $20.

Jim

 

[drtyTshrt]

You are better off with a gallon of Rooto (98%) from a hardware store for about $20.

Jim[/quote]

I can not find Rooto. Is it drain cleaner or did I read somewhere it was in the garden section. I have only looked at Lowes and Home Depot though.

 

[FrugalRefiner]

Rooto is a drain cleaner. I don't believe either Lowes or Home Depot carry the Rooto brand. Ace Hardware does. Not all stores have it in stock, but I believe most of them can order it for you. If you don't have an Ace nearby, try to find a small, local hardware store if you have any left where you live. They can probably order it for you. The little stores are much more accomodating on special requests like this. Lowes and Home Depot don't need your little purchase of a gallon of drain cleaner, but a small independent store would love to make a few dollars.

If that doesn't work you can try an auto supply store like NAPA. They carry dilute acid for batteries. You would still have to evaporate it to increase the concentration, but they have it in smaller quantities at reasonable prices.

Dave

 

[necromancer]

i got this at home depot, 93%

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=35&t=17669