Sodium Hydroxide (NaOH), Caustic Soda, Granule Cleanup

[Billy Joe Davis]

I am a System Engineer for a facility. We have an old Sodium hydroxide dissolver tank, ~200 gallons, and associated equipment. At some point the system was shut down and not properly cleaned up. The tank contains white powder, which based on its past use I believe to be Sodium hydroxide. The tank and piping are constructed of Stainless Steel and visually appear to have no outward degradation. However, many of the piping components such valves, pumps and flanges have failed. The sealing materials within these components have deteriorated and allowed leaks. As this leakage takes place the liquid the small amount of liquid evaporates and crystals are being formed.

We no longer have use for the system and I would like to D&D the entire system. How can I remove the granules from the tank safely? I cannot dissolve them in the tank because of the leaks that would occur. I thought of vacuuming out the tank, but I am not sure what type of vacuum system would filter the exhaust properly so the sodium hydroxide would not be blown out into the surrounding area.

Anyone have any experience with this type of situation?

Thanks in advance.

 

[zeusfaber]

I'd take the time to find out what the powder really is.

Exposed to the air for any time, sodium hydroxide tends to deliquesce and then absorb atmospheric CO2 - turning itself into a collection of less objectionable materials.

Once you know what you're actually dealing with, you'll have a better idea of what options you've got.

A.

 

[3DDave]

Adding water creates an exothermic reaction and is discouraged. If it was in solution then adding CO2 would allow the formation of a bicarbonate. I'd say the first step is to determine where it will be disposed of, because until you have a destination you shouldn't do anything that will make that worse.

COSHA recommends shoveling or sweeping. I expect that is to prevent airborne clouds of NsOH, which would be a problem for people in the area.

https://www.ccohs.ca/oshanswers/chemicals/chem_profiles/sodium_hydroxide.html

It might be worthwhile to contact a local university chemistry department for an on-site visit to get a better answer. The professors might bring some students interested in managing industrial chemistry to see what care should be taken in their future careers.

 

[mk3223]

Suggest to consult the company, such as ONYX Industrial, who is specialized in the chemical cleaning service, to provide a recommendation for you.