Chromium(III) sulfate (CAS 10101-53-8): storage and disposal

Identification is the main job. Chromium stock on a prep-room shelf often includes sulfates, chlorides, oxides and compounds in other oxidation states, and several are classified differently from this one. Put it on a general shelf with its full name, the word hydrate and the date on the label, and keep it physically separate from other chromium jars so a technician reaching for one does not take the other. A tray and a tight lid guard against damp, and a dry cupboard suits it better than a damp bench. It needs no corrosive or fire store. Check the stock record against the label when the term starts.

This substance gives few visible signs of age. The colour can differ between jars without meaning much, so do not use it as a marker, though a jar that has turned patchy or developed a hard crust has probably taken in moisture. Look at the container: clumping, caked powder round the neck, a cap that has stuck and a label that no longer names the exact compound. A jar of green or violet powder with a worn label and no date should be treated as an unidentified chromium salt until its identity is confirmed, since neighbouring chromium compounds are classified differently.

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 We do not publish a drain or general waste route for any chemical.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

It leaves the site as a chemical waste under a waste transfer note, even though it is not normally classified as hazardous. The usual code is 16 05 09, though the producer classifies the waste. Describe it precisely as chromium(III) sulfate hydrate and note the colour and condition, because a vague entry such as chromium salt could be read as something else entirely. Leftover solution from a practical goes into a labelled bottle, not a sink or drain. Keep the original jar if the seal is sound. Nobody should try to precipitate or treat the stock first. Request a specialist collection and say how many jars there are.

Usually held as: hydrate.

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.