Concentrating sulfuric acid

[inonickname]

To concentrate sulfuric acid (say, around 40-50%, and no, not from car batteries) boiling chips are required (of something like porcelain). Is it acceptable to use old (clean) bits of broken plates, glasses (porcelain/ceramic) etc.? How finely should the chips be broken up (eg. 1cm squares, 5mm squares, 3mm) and how many chips should be used- perhaps enough to cover the solution?

 

If it's important, I'm experimenting with concentrating sulfuric acid from electrolysis of CuSO₄ solution (and at the same time, testing a sulfuric acid + nitrate salt method of making NC and electroplating).

[Lagrange]

If you want to boil excess water for a mixture of sulfuric acid and water, chips aren't need. the water will boil off event without chips (maybe not if your beaker/whatever u use have a microscopic PERFECT surface but else chips arent needed) Temperature of the boilling point of the solution can be use to determine with good precision the concentration of sulfuric acid. if you see thick fune stop the process and run away. then (after very dangerous situation) you will have reach near 98% acid concentration (plus or minus 1, i don't remember exactly).

 

using 5-6 chip should be already enough to ensure no overheating without work done (if they are of good size). The more chips surface, the smaller the bubble you get when boilling.

 

Be carefull, hot sulfuric acid is very nasty!

 

the CuSO4 route is difficult to carry for high yield, you should consider searching for drain cleaner like liquid fire and stuff like that.

Edited March 6, 2010 by Lagrange

[Swede]

Concentrating sulfuric by boiling is time honored and definitely works, but the temps are WAY high compared with most other liquids.

 

I'm thinking I'd do it out doors, using an appropriate container, and a propane-fired camping stove. Lab hot plates don't seem to have the necessary BTU. The great danger is if the container shatters and dumps 4 liters of HOT sulfuric all over the kitchen or lab. Yow!

[HazzWold]

Another danger involved in using a gas burner is if the vessel in which the acid is boiling fails, you have very hot sulfuric acid pouring over a container of pressurized flammable gas.

[Arthur]

Evaporating works to about 97% but it's a dangerous, messy process ending up with a highly acid vapour being driven off. Better if you can actually condense the vapour into a trap.

Yes, you need a lot of heat and you need a good quality boiling vessel.

 

Even better if you can buy drain cleaner.

 

Work out all the "what ifs" What if the flask breaks, what if the wind changes and the fumes blow indoors, or kill a neighbours roses.

 

PPE for handling boiling conc sulphuric is expensive. Boots, apron gloves and mask and a face mask will cost more than a few litres of acid. Your drain cleaner can be 98% sulphuric retail!

 

Boiling chips any size will help, but look for all the better alternatives to the whole process first. One chip will do for say half a litre, but you MUST add another chip if the temperature ever goes down in the boiling vessel. To re-use a boiling chip you MUST clean it and dry it completely (usually in a warm place for a few hours, or flame it dry) damp chips don't work.

[dagabu]

Please site your references, where on-line?

[TheEskimo]

And how cheap is "cheap"? Cheapest stuff I can find is sold at the Ace Hardware online store, and thats for $110 a gallon.

[Mumbles]

Look for Rooto drain cleaner. It's about $20-30 per gallon the last time I saw. It has some dyes, but it's never failed me for what I needed it for.

[TheEskimo]

Lawl. I've been reading that thing on the Ace website incorrectly. Derp, I feel dumb. It's 4 gallons to a pack for 103 dollars. Damn, now that doesn't sound like such a bad deal. I wonder if the shipping would be pricey, tho?

 

 

[Twotails]

I get it for about $21/gallon and change from Koopman's. he offerd to order a 4 pack for me(pay first) for like $80ish. not too bad, but a gallon lasts a while, and I can put up with the dyes(Not too dark, but still works fine).

[Mumbles]

If you boil it to concentrate to 98% (at like 92-94% as is), the dyes turn almost jet black.

[Twotails]

wow, the % I have now(90+ I guess?) is fine. I've heard you can clear it up with peroxide+ boiling? the dye's not that bad as to cause me worry(anything I need absolutly pure acids for, i'd pay $15/500ml(?) from cracker) although my NC is offcolored now >.<

[jimbo]

what percentage do you guys think sulphuric acid 1840 is, it says 1840g/litre, really heavy for the volume this stuff is,in australia its hard to get this strength, but I scored a bit from work and still have it.

[Mumbles]

Over 94%. Density is tricky when it gets to be almost pure.

 

http://www.amazingrust.com/experiments/how_to/Images/H2SO4_Density_Table.jpg

[Peret]

Or Try 'Sigma-Aldrich' Gillingham Dorset.

That is how I get it.

 

Sigma-Aldrich has a location in Dorset, but Gillingham is in a different county about 100 miles away.

 

I would have thought, you being in Florida, you would have used the St Louis location, since shipping concentrated acid across the Atlantic is a bit of a logistics problem.

[xtatic83]

Hello there !

 

I have certain questions about boiling battery acid (like around 35% s. acid). Thing is I would really love to make it indoors - in the basement. It's kinda old style with a primitive ventilation system - old chimney - clean and not accidentally connected to any of my neighbours appartements (they're not going to pass out or sprayed with some weak yet harmful H2SO3 or H2SO4 - no worries). That's the deal, I got a hot plate with max 350 degress temp. so thats enough i guess. I can drop these SO2 and SO3 little bastards up the chimney (which is not quite the best way to get rid of them as the chimney is for burning wood and coal right? I really dont want to corrode any of the inner chimney parts, structure?) I would really enjoy capturing hot SO2 and SO3 fumes into some kind of solution. So ive been thinking:

1. Take fumes through condenser dropping the temp. real nice and either take it further through some kind of water filter to put it down completely or (maybe) just dropping the temp. of fumes will make them liquid.

2. Let the fumes eat some water on the way to turn into hot and misty vapor (as i read somewhere) then condense it and drop its temp. so (maybe) it'll turn to anything else then gas or vapor.

3. To get to the point: What's the best environment for SO3 and H2O getting together very smooth and quite fast?

 

And yes I know the risk, I'm taking nice and healthy precautions and I will experiment only on so small amount of any substances involved that the only thing i can kill or harm is mold or maybe some rats if theyre out there somewhere.

I just want to get rid of fumes without taking the reaction outdoors and maybe even catch some low very low yield H2SO3 on the way.

 

Please help

[Arthur]

If you are working indoors then the SOx fumes will eat at chimney liners and are best removed! If the glassware you are using is adequate the collect the fumes, bubble them through water (Dreschel bottle) then scrub then through something like limestone chips in a second bottle. This will absorb all gasses and then absorb/neutralise the acids in the fumes.

 

Possibly you could get some soft plastic pipe as an outlet from a cool fume point on your apparatus, just fill the pipe with limestone chips, a metre of inch bore pipe should hold enough chips to scrub enough fumes of corrosive acid vapours. Then send the fumes out into the atmosphere scrubbed. Get limestone chips that pass about 4 mesh or finer, hold them in the tube with a plug of cotton wool at each end.

 

Added: Make sure that there is NO chance that liquids from the fume scrubber can suck back into the rest of the apparatus.

Edited September 17, 2010 by Arthur

[xtatic83]

Accurate and fast as lighting feedback! Thank You, man, really appreciate it

 

I got the idea, so, tomorrow i'm taking day off to get on with my homework, gather materials, try to build some installation with what I got already and if some more questions come up I know where to go, thanks very much

 

Best regards

[xtatic83]

About that battery acid boiling again:Ok then, should the apparatus look something like this?

Is there something missing? Im really curious about and disturbed by the fact that these fumes are going to be hell hot, I wonder whats the good and cheap/easy to get material to withstand the heat and acid in them right after they come out the heatproof boiling vessel to the Drescher bottle and after that too. Thanks in advance for any advice.

 

 

[Arthur]

NO You are missing a lot of thought ans material from that sketch.

 

Think of it as a vacuum distillation at high temperature. You are going to need a round bottom flask to heat andd this will need to get to 350C or so, the vapour then needs to pass into a condenser and drip into a closed collecting flask -this may be cool. The vacuum delivery bend will have a gas outlet for the vac pump. you will not need the vac pump but will need to use the output scrubbers in this position.

SO boiling flask condenser receiver, then outlet pipe with scrubbers

[kiss]

Afew months ago i decided to boil some batt. acid outdoors. I used a pyrex dish and a hot plate. The pyrex dish i used was about 600ml. When this was full w/ Batt. acid, i placed my hotplate to 300f. Each batch took roughly 30min. to boil down to the point of where the solution that was left was about 1/5th of what i started with. Very thick fumes were present. At this point i decided that this was sulfuric acid. After a few boils i collected the remains and put them all together. The collection vessel was kept on the basement floor for about 8 days at room temp. The solution was very clear, with a slight tint of yellow. I put this vessel in a fridge, and 2 days latter their was some type of xtal formation on the bottom.

Any idea's what this xtal formation is?

The xtalls will not disolve at room temp. either.

The solution is VERY reactive with salt btw.

[superstring]

Boiling battery acid to concentrate it??? Why? Commercial CP H2SO4 is 66degree Baume. Really strong, not sure why anyone would want to try to make it stronger. Explain.

[Mumbles]

Battery acid runs around 30% or so. 93% (66 baume) is fine for most applications, but you have to make due with what you can get.

[danwine]

Does anyone know if I can concentrate sulfuric acid with electrolisis? i want to go beyond 100% into oleum. I have a job where a pvc drain line is filled with concrete. i want something that will pull the water back out of the concrete crystall. I have some 95% H2SO4,that is bubbling slowly in the drain right now.

I want to remove the water from the acid right in the drain line. I was going to try two lead(Pb) electrodes and DC current. I will solder the power source to the to the electrodes and use a fan to dilute/remove the H2 gas.

Anyone have any advice or experiance?

[SolarSeeker]

You can not concentrate sulfuric acid by electrolysis. You'd be better off replacing the drain itself as it would be cheaper considering the quantity of acid needed

BTW how on earth did concrete get in the drain in the first place? BTOW you should try muriatic acid instead of sulfuric acid since it's more effective at dissolving

stone as well as being $ 5.00 a gallon which is substantially cheaper (ACE hardware carries it).