# Can You evaporate battery acid too long?



## dbrick81 (May 10, 2008)

Can You evaporate* battery acid too long? I was concentrating battery acid by evaporating* it down and kind of left it for probably 45min to 1 hour to long (no more water just heavy white fumes coming of). It was a batch of 1000ml of 35% acid that should have cooked down to 350ml but when I came back to it was down to just under 300ml with lots of white fumes coming out of it! Did I destroy any of the acid or just boiled it away?

Thanks,

Dave

*Noxx edit


----------



## Irons (May 10, 2008)

The white fumes were SO3. Nasty stuff.

This is a good reminder to not leave boiling reagents unattended.

The Sulfuric is fine, just be careful when adding it to water. Don't add water to the acid. It will react violently and splatter you with very concentrated Sulfuric Acid.

The problem is that now everything in the room you boiled the Sulfuric in is coated with a thin film of concentrated sulfuric acid. It won't evaporate, just corrode everything it touches.

It might be a good idea to spray down the area with a solution of baking soda.

You were lucky you weren't killed by the fumes.


----------



## dbrick81 (May 10, 2008)

Well, Thank God I was at less smart (I use this term loosely  ) enough to do this out doors away from people, but that’s also why I forgot about it for an hour! I was busy inside dissolving a test batch of gold in HCL and Clorox. But anyways I know that’s no excuse.

Thanks,

Again


----------



## Irons (May 10, 2008)

At least someone is listening.

I had visions of your kitchen slowly flaking away and falling on the floor. 8) 

I shouldn't lecture too much. I've stepped on my crank a few times too.


----------



## Harold_V (May 10, 2008)

Irons said:


> I shouldn't lecture too much. I've stepped on my crank a few times too.



Ahh! But you should! :wink: 

You are amongst the voices of wisdom on the forum, and serve to keep fresh the safety precautions that may not be evident to some readers. 

Very good comments, Irons.

Harold


----------



## Irons (May 10, 2008)

Harold_V said:


> Irons said:
> 
> 
> > I shouldn't lecture too much. I've stepped on my crank a few times too.
> ...



Thank you Harold.

I am but a grasshopper before your experience.


----------



## evolx10 (Jul 30, 2008)

yea its not so good done indoors w/o proper vents. 

For no apparent reason and with little to no knowledge i did the same thing when i was a kid, but it happened to be indoors in an unventilated -sealed room. I became acclimated to the cloud, and if a friend hadn't shown up, and almost get knocked to the floor from the cloud i would of been in it way longer. Coughed blood for a few days afterwards.. 

live and learn- hopefully :lol: :twisted:


----------



## NuggetHuntingFool (Jul 30, 2008)

> Very good comments, Irons.



Irons is The Man. His attention to safety is something we should all strive to emulate in every endeavor. Not to mention his knowledge of chemistry as well as recovery techniques.


----------



## solar seeker (Aug 1, 2010)

That acid is likely 98% if it was boiled that long. :shock: It will pull water out of the air if it's not sealed properly causing it to lose it's high concentration.
I'd watch out because concentrated sulfuric acid gets quite hot when it mixes with water which means if it spills you need to use a lot of cold water to wash it off otherwise it'll heat up enough to burn skin if only small amounts of water are used to clean it with baking soda is good too but it also heats when it reacts with an acid of that strength.


----------



## goldsilverpro (Aug 1, 2010)

I'm about ready to bounce anyone who uses the word "boiling" - it sends the wrong message. Please use "evaporation", which is generally done at a temperature below boiling. I can't ever recall having to "boil" anything. It's stupid - it's dangerous in some cases and, if the solution contains PMs, you can easily experience losses.


----------



## Harold_V (Aug 2, 2010)

goldsilverpro said:


> I'm about ready to bounce anyone who uses the word "boiling" - it sends the wrong message. Please use "evaporation", which is generally done at a temperature below boiling.


I agree. I've been calling readers on that one, too. It's tough enough learning to do the right thing in refining without constantly using improper terms, reinforcing something that is nothing short of stupid. 



> I can't ever recall having to "boil" anything. It's stupid - it's dangerous in some cases and, if the solution contains PMs, you can easily experience losses.


Well, I can, and it is a very important part of processing polishing wastes, assuming you don't want cracked beakers. I used to boil the solids, after incineration and screening, in HCl. That is a very important step in the process, assuming you have any desire to filter the resulting values at some point, before precipitation. 

If you didn't keep the material well suspended, it overheats at the bottom, creating a hard layer akin to concrete. If you managed to disturb the layer once over-heated, you can expect to lose the beaker to cracking. It was for that reason that my objective was to boil the material, in the hopes that it kept the bottom constantly clear of a hard deposit. So, yes, boiling does have a place in refining, but when dealing with solutions of value, it is generally a mistake. 

Harold


----------



## goldsilverpro (Aug 2, 2010)

goldsilverpro said:


> I'm about ready to bounce anyone who uses the word "boiling" - it sends the wrong message. Please use "evaporation", which is generally done at a temperature below boiling. I can't ever recall having to "boil" anything. It's stupid - it's dangerous in some cases and, if the solution contains PMs, you can easily experience losses.



I probably spoke a little too strongly on this boiling issue. However, the title of this thread involves "boiling" battery acid, which could be very dangerous. I guess that's what caused my tirade. In this case, the boiling point slowly increases as the water is eliminated and can go as high as about 550F when the H2SO4 becomes quite concentrated. Boiling always creates small drops of solution to be thrown out of the container and, no matter the concentration, you don't want any of this on you. It can create nasty burns. Let's use the term "evaporated", please.

Unfortunately, when eliminating nitric from AR by evaporation, the term "boiling down" has been commonly used. If you do "boil" the solution, you will surely experience gold losses. Here again, let's all try to adapt to the word, "evaporate", instead.

Anyone with some experience knows that they don't boil these particular solutions. My concern is that noobies will take this "boil" thing literally and someone will get hurt or, at the least, will lose values.


----------



## Barren Realms 007 (Aug 2, 2010)

When sulfuric is on your skin one of the reasons it is so desructive is because it is pulling the moisutre out of your skin.


----------



## rewalston (Aug 2, 2010)

Barren, you are quite right in your "burn" description. Years ago (don't have that many fingers or toes to count hehe) I remember reading some place that the reason acids of any kind burn is that it isn't a burn akin to holding lit match but more of a dehydration. The same thing happens if you get MEK on your skin. What happens with MEK is that it is actually dehydrating the fat cells within the skin. 

Rusty



Barren Realms 007 said:


> When sulfuric is on your skin one of the reasons it is so desructive is because it is pulling the moisutre out of your skin.


----------

