Barium hydroxide (CAS 17194-00-2): storage and disposal
Barium hydroxide is held in school, college and university stores as octahydrate crystals and as a clear solution used in place of limewater. It is classified Danger for severe skin burns and eye damage, and it is harmful if swallowed or inhaled. Because the solution turns cloudy when it meets carbon dioxide, an old bottle may no longer be what its label says.
- CAS number
- 17194-00-2
- Form
- Solid
- Storage class
- Alkali
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Corrosive
Harmful or irritant
What to do this week
- Check the label is readable and write down the opened date if it is not already there.
- Check it is stored as alkali stock and apart from the items listed under "Do not store with".
- If you no longer need it, add it to your disposal list so it goes on the next collection.
Safe storage in a school or lab
Acids are the neighbour to avoid: acids and alkalis react with strong heat and spattering if they meet, so keep octahydrate tubs and solution bottles on a different level and tray. Because it is harmful if swallowed or inhaled, store it in a closed tub in the alkali cupboard and not on an open prep room shelf where a dusty spill can go unnoticed. Solution bottles used as a limewater substitute need a name, a date and the word barium on the label, since a clear bottle on a bench looks like ordinary limewater and is easily mistaken for it.
How to tell it has deteriorated
Fresh octahydrate is a white crystalline solid. A white crust over the crystals or a hard cake in the tub shows the stock has taken carbon dioxide from the air and formed barium carbonate. Clear solution that has gone milky has done the same, which is exactly the reaction it is used to show, so a cloudy bottle with a white deposit has been exposed and is no longer fresh. Stoppers can stick where the alkali has dried at the neck. Labels fade, and a bottle that looks like limewater but has no name on it should be recorded as unknown and left closed.
How it must be disposed of
By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a corrosive alkali laboratory pack with compatible chemicals.
Octahydrate tubs and solution bottles are packed with other alkalis in strong, sealed packaging, kept separate from acids, so list them clearly and say which are solid and which are solution. Barium hydroxide must not go into a sink, a drain, a general waste bin or a skip, and nobody should neutralise or treat the solution before collection. Because it is classified, hazardous waste paperwork applies. For a college or university store, record the form, container size, the date if known, and whether the solution is a limewater substitute, since a cloudy bottle with a deposit is described as it is found.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| Hazardous waste | Yes |
The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.
Do not store with
- AcidAcids and alkalis react with strong heat and spattering if they meet.
- OxidiserSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
Named chemicals to keep apart
- Acetic acidAcids and alkalis react with strong heat and spattering if they meet.
- Calcium hypochloriteSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Hydrochloric acidAcids and alkalis react with strong heat and spattering if they meet.
- Hydrogen peroxideSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Nitric acidAcids and alkalis react with strong heat and spattering if they meet.
- Potassium nitrateSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Potassium permanganateSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Sulfuric acidAcids and alkalis react with strong heat and spattering if they meet.
Common quantities we collect
Usually held as: octahydrate, limewater substitute.
Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.
Where it is commonly held
Hazard statements
- H302 Harmful if swallowed.
- H314 Causes severe skin burns and eye damage.
- H332 Harmful if inhaled.
Precautionary statements
- P234 Keep only in original packaging.
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P270 Do not eat, drink or smoke when using this product.
- P271 Use only outdoors or in a well-ventilated area.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P301+P317 IF SWALLOWED: Get medical help.
- P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
- P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P316 Get emergency medical help immediately.
- P317 Get medical help.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P363 Wash contaminated clothing before reuse.
- P390 Absorb spillage to prevent material damage.
- P405 Store locked up.
- P406 Store in corrosive resistant container with a resistant inner liner.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Our barium hydroxide solution is cloudy. Is it still usable?
A cloudy solution with a white deposit has reacted with carbon dioxide and is no longer fresh. Whether to keep it is a stock decision, but label it, keep it closed and record it for collection if it is surplus.
Can used barium hydroxide solution from a class test be discarded on site?
No. Used solution still contains barium compounds and must not go into a sink or drain or be treated first. Keep it in a closed, labelled bottle and hold it for specialist collection.
How should crystals and solution be recorded?
Record octahydrate tubs and solution separately, with container size and label details. The collector packs solid and liquid differently, and a solution used as a limewater substitute should be identified as barium hydroxide, not limewater.
