Aluminium hydroxide (CAS 21645-51-2): storage and disposal

A school or university store keeps this on the general shelf with other metal hydroxides and oxides, labelled by full name because it looks like many other white powders. In a pharmacy the sensible check is whether the bottle is a laboratory reagent or a medicinal ingredient, and the two should not be mixed on one shelf. Keep the container closed and dry, since fine solids that have stood open pick up dust and damp. It needs no special cabinet, but it should be kept away from acid and alkali stock, because it dissolves in both and a spill beside them is a mess to untangle. Date it on arrival.

Few visible signs show with age. A technician is most likely to see a powder that has gone lumpy or caked after standing in a humid store, a crust at the neck of the jar and a label that has darkened or lifted. A gel-like or pasty look in something that should be a dry powder points to a wet container. Because the solid is plain white, the real risk is a bottle that has lost its identity, so a jar with a worn name, no date or no record in the stock list is the case to flag before anyone tries to guess what it is.

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.

Because it is not classified as hazardous on the sources we checked, the waste transfer note route applies, but it is still a chemical waste and the description has to be accurate. The usual code for a laboratory chemical is 16 05 09. In a human healthcare setting, 18 01 07 applies to non-hazardous chemical waste, while discarded medicines are classified separately, normally under 18 01 09. Confirm whether the item is a reagent or a medicinal product. Record whether it is a laboratory reagent or a pharmaceutical item, the quantity and the state of the container. It does not belong in a sink, a drain or the ordinary bin, and nobody should try to dissolve it first. Keep it in a closed, labelled container and request a specialist collection.

Usually held as: solid.

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.