Calcium nitrate (CAS 10124-37-5): storage and disposal

The tetrahydrate usually arrives in a plastic or glass jar with a screw cap, and the cap is the weak point because the salt draws moisture from the air. Shelve it in the oxidiser section on non-combustible shelving, apart from flammable, organic and reducing stock. Paper labels, cardboard trays and wooden shelf liners are the combustible items most often found underneath it, and they should go. Keep the jar tightly closed after each use and dated on arrival. A part-used jar from a practical on thermal decomposition or solubility is better kept in its own labelled space than left on the open bench shelf.

Free-flowing white granules are what to expect. The salt takes up water readily, so look for granules that have fused into a cake, a damp film at the bottom of the jar and wet staining on the shelf under it. A cap that has corroded or stuck, and a label that has been attacked by seepage, show that liquid has escaped. Because it is an oxidiser, wet stock that has touched paper, wood or dust is a bigger concern than the same wet stock in a clean tub. Brown staining on a nearby cardboard tray may indicate contact between the oxidiser and combustible material. Do not disturb suspected contaminated stock. Record what is visible and arrange specialist assessment. Note the date of receipt if the jar is undated.

We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in an oxidising laboratory pack with compatible chemicals.

Leave as a closed jar in the oxidiser group and expect the collection team to keep it away from organic and combustible stock in the pack. It is normally classified as hazardous waste, with 16 05 06* as the usual entry in a lab pack and 16 05 07* where it is a discarded inorganic chemical outside one, though the producer classifies the waste. What makes it awkward is damp: a jar with a caked or wet base needs describing as such, and should travel upright with its cap secure. Do not put it into a sink, a drain, a general waste bin or a skip, and do not try to dry, dilute or neutralise it. Record the form, which is normally the tetrahydrate, and roughly how much remains.

Usually held as: tetrahydrate.

Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.