[MitchBaker3]

Today I was boiling some acid out of a car battery. It was a dark grey (almost black) colour. I wanted to try and distill it by boiling it over a camp stove. After about 10 minutes it turned to a froth. I poured it into a bottle and then it went all hard. It was almost like the fat off a barbecue. Does anyone have any idea what might have happened and how can I do it properly next time?

Thanks

[Borek]

No idea what may have happened, perhaps the acid was contaminated, or contained some gelling agent (but then, it should semi solid from the very beginning).

Please note this is way too dangerous for being discussed at CF. Boiling sulfuric acid is a disaster waiting to happen, if not done properly, in acid proof protective clothes and under fume hood.

[MitchBaker3]

Thanks for the reply. I was out in the open air and had glasses, gloves, long shirt etc. the acid did appear to have bits of stuff in it, so I believe it may have been contaminated. Thanks again

[Intanjir]

If you literally drained the acid from a car battery then you should expect 'contamination' with lead. Lots of metal oxides will gel when precipitated under the right conditions. Gels are simply very fine networks of solid scaffolding immersed in a liquid. It is a very common phenomena.

I do not recommend casually toying about with accumulative toxins. I also do not recommend treating sulfuric acid lightly either. Concentrated sulfuric is extremely damaging to tissue due to its pronounced ability to dehydrate. This is one of the most dangerous acids to handle. I strongly recommend against attempting to 'do it properly next time'. You are not equipped. Purification is in general not easy. You are trying to handle something which is thoroughly hazardous, being both instantly caustic and long term toxic... over a camp stove...

If you need sulfuric acid for some reason then purchase it. Either reagent grade from an online chemical store or a more technical grade at local automotive or hardware stores. I would recommend substituting a different acid instead if possible. Hydrochloric(muriatic) acid is similarly available and every little splattered drop of it won't cause nearly as much scarring.