View Full Version : rinsing sulfuric acid barrels

08/19/2010, 07:12 PM
Ok I was going to get some plastic 55 gallon propylene glycol barrels but after talking to the supplier found out they also had nitrite and some kind of fluoro chemicals. Instead I was able to get some barrels that were used for holding 50% sulfuric acid and was told they will rinse very clean and shouldnt leave anything harmful. So should a few good rinses with water be enough? Would dumping in some baking soda be good, bad or useless?

08/20/2010, 06:15 AM
Sulfuric acid barrels would be about ideal. Worst case you'd be adding a very small amount of sulfate. Any dissolved metals should be pretty easily flushed since the acid would have solubalized them pretty well. Rinse well with water. Some baking soda wouldn't hurt. If you are using this for tank make up water, a quick pH check would make sure there is no residual acid.

08/20/2010, 08:08 AM
Depending on how much residue of sulfuric acid is in the barrel it can be a dangerous explosive situation adding water to acid when rinsing. One MSDS sheet recommeds covering the liquid acid with lime to netralize first. Water should not be added to sulfuric acid. Instead acid should be added to water in small amounts to prevent the explosive release of heat and oxygen which forms when water and the acid are mixed together. Sulfuric acid should not be mixed with bleach as this will release toxic gases. 50% Sulfuric acid has the same disposal recommendations as at 98% concentration per the MSDS sheets I have read.

Disposal recommendations state that any liquid sulfuric acid is to be absorbed using dry earth, sand or other inert dry clay type material and then placed in a loosely covered plastic bag for proper disposal. The fumes are highly toxic and proper respiration equipment should be used. After that allowing the container to air outside would be advisable to reduce the dangerous fumes from possibly becoming explosive. At that point, if there is no liquid acid present and the fumes are gone, I would cautiously assume that the barrel would be safe to fill with water adding enough baking soda to to neutralize any acid remnants. Some of the MSDS sheets I have read state that sulfuric acid container disposal needs to follow special procedure and equipment which are more involved and expensive.

Please be advised that I am not a chemist and am simply passing on information I have read in MSDS sheets provided below. I do not want to be responsible for any possible explosive problems that may occur following what I have stated above.

Its too bad Randy is on vacation as I would definitely let him handle any recommendations here.

Sulfuric Acid MSDS sheet:



From the above MSDS sheet:

Accidental Release Measures
Ventilate area of leak or spill. Wear appropriate personal protective equipment as specified in Section 8. Isolate hazard area. Keep unnecessary and unprotected personnel from entering. Contain and recover liquid when possible. Neutralize with alkaline material (soda ash, lime), then absorb with an inert material (e. g., vermiculite, dry sand, earth), and place in a chemical waste container. Do not use combustible materials, such as saw dust. Do not flush to sewer! US Regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities. The toll free number for the US Coast Guard National Response Center is (800) 424-8802.

J. T. Baker NEUTRASORB® acid neutralizers are recommended for spills of this product.


7. Handling and Storage
Store in a cool, dry, ventilated storage area with acid resistant floors and good drainage. Protect from physical damage. Keep out of direct sunlight and away from heat, water, and incompatible materials. Do not wash out container and use it for other purposes. When diluting, always add the acid to water; never add water to the acid. When opening metal containers, use non-sparking tools because of the possibility of hydrogen gas being present. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product.


FWIW, the Handling and storage recommendations sums up how I feel about using these containers. "Do not wash out container and use it for other purposes." :(

08/20/2010, 02:52 PM
It was rinsed once already I was just wondering if its something that is likely to leave a residue on the plastic or if it will readily disolve into the water and easily rinse out.

08/20/2010, 03:03 PM
Adding a solution of baking soda should neutralize any residual acid in the container. Other than that, all you can do is heavily rinse the containers. Judging by the fact that the owner was using these to store a 50% solution of H2SO4, I would assume the barrel's material (polypropylene?) to be inert to the acid.

08/20/2010, 03:07 PM
Take a 1/4 cup of Sodium Hydroxide (NaOH) and swish it around in the barrel. Rinse at least 10 times and your good to go. The NaOH can be found at the hardware or big box store in the plumbing section (look for 100% lye).

I have used this when regenerating DI resin and after rinsing multiple times I have had no affects on livestock.

FWIW, I gave up trying to find clean or actually cleaning barrels and went the Brute way. If you could find a food processing plant nearby that handles liquids that would be the ticket!


08/20/2010, 04:56 PM
I agree that sulfuric acid isn't much of a problem. You could clean them with a bit of lye or perhaps some baking soda, and rinse well. I'd likely just rinse them a bit.

08/20/2010, 06:20 PM
Semi Hijack. Candy factories have tons of food grade barrels that they constantly have to get rid of. I get my 55gal barrels for $5 up here. Look for a big candy maker.

08/20/2010, 07:16 PM
It was rinsed once already I was just wondering if its something that is likely to leave a residue on the plastic or if it will readily disolve into the water and easily rinse out.

IF it has already been rinised then it should be ok. I would add some baking soda or soda ash in water and rinse that to remove any remanants which should not be much, since the acid will dissolve in water readily.

08/20/2010, 07:47 PM
Plastic is funny stuff. I have four 55 gallon plastic drums that are used for water storage for yet another hobby. They originally held syrup for everybody's favorite carbonated cola beverage. After 12 years if intermittent use they STILL smell like coke!


08/20/2010, 08:17 PM
Mine still smells like Pepsi and many of our local club members use them without any problems. We have pulled over 60 barrels from the local Pepsi dealer over the last couple of years alone. They usually cost around $10.00 per 55 gal barrel.

08/20/2010, 08:43 PM
There shouldn't be a problem adding water to a container that had 50% sulfuric in it (the other 50% was water btw). The add acid to water thing only applies to concentrated forms or otherwise high concentrations of mineral acids. I'd add water, add baking soda, rinse and repeat until no more fizzing occurs. Big bags of baking soda are available at your local box store. These barrels should end up nice and clean.

08/20/2010, 08:50 PM

You have clarified what my first impression of 50% acid. Muriatic acid is around 30% and I have added water to it per directions without problems. The MSDS sheets can be funny, it seems many are identical for all the different concentrations of chemcals regardless. Thanks. :)

08/20/2010, 11:58 PM
Plastic is funny stuff....They originally held syrup for everybody's favorite carbonated cola beverage. After 12 years if intermittent use they STILL smell like coke!

Mine still smells like Pepsi and many of our local club members use them without any problems.

Tim/HighlandReefer -

Funny you guys should mention that point. When I was in college I took some pickle buckets home from work and used those for aquarium duties. The smell slowly dissipated over time. Ten years later those same buckets hold bicarbonate, MagFlake & Epsom salt and every time I open those buckets I get a blast from the past with the strong smell of pickles...:D