Zinc carbonate (CAS 3486-35-9): storage and disposal

Because it is a carbonate, acids are the obvious partner to keep it from. Any acid in the prep room will make it fizz and give off gas, so the jar should sit on a general shelf well away from the acid store, and a leaking bottle above it is the sort of accident worth planning around. Otherwise the storage is ordinary: a dry, labelled, tightly closed container, kept off the floor and away from the washing-up area, where a spill must never be allowed to reach a drain. Powder from a school science cupboard often sits in a plastic jar that has been refilled or topped up, so make sure the label still names the contents and carries a date of receipt.

Start with the container and its label, since that is where most of the evidence is. A powder jar that has been opened many times can show a dusty residue on the thread, a cap that no longer turns freely and a label that has been rubbed or stained until the name is hard to read. Inside, look for hard lumps or a crust where damp air has reached the powder. Zinc carbonate itself gives few striking visible signs with age, so do not expect colour changes or fumes. If the label has gone, or the jar has been refilled from something else, treat the contents as unidentified until that is cleared up.

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a non-regulated or low hazard laboratory pack with compatible chemicals.

Before asking for a collection, write down what is actually in the container, its size and whether the label is still readable, because an unlabelled white powder is harder to place than a clear one. Zinc carbonate is classified under aquatic hazard statements, so it must never be washed to a drain or put out with ordinary waste, and nobody should try to react it with acid to make it disappear. A laboratory pack uses 16 05 06* and discarded inorganic stock outside a laboratory pack uses 16 05 07*. The powder is grouped away from acids in a compatible pack and goes for specialist collection.

Usually held as: powder.

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.