Potassium oxalate (CAS 583-52-8): storage and disposal

On a school prep room shelf the tub of potassium oxalate tends to sit with the other oxalates and white salts bought for qualitative tests, and the risk is mistaking one for another. Name it in full on the label and date it on arrival. A dry, well organised store suits a general class chemical. Harm by swallowing and skin contact means gloves are sensible, and serious eye irritation means eye protection when scooping. Pathology and university stores that hold it as an additive keep it with their own stock records, away from food and drink areas and from acid stock.

What a technician sees first is a tub with white crystals that move freely. The monohydrate can take up damp and cake into lumps, and a lid left loose lets dust into the crystals. The salt gives few distinctive signs of its own, so judge the container: a faded or lifted label, a crusted neck, a cracked tub or a missing date of receipt. A tub that has been decanted into a smaller unmarked pot is recorded as it is found. If the contents have changed colour or smell, close the lid, describe what you can see and report it.

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.

Waste code 16 05 06* is the usual entry for a school or university holder. Where it is a discarded organic chemical outside a laboratory pack, 16 05 08* applies, and a human healthcare setting such as a pathology lab would use 18 01 06*. Say which fits. It never goes into a sink, a drain, a general waste bin or a skip, and staff should not try to treat it first. The record should say whether it is loose crystal or additive stock, the container size and how much is left. Blood tubes are a different matter and are not covered by a chemical collection.

Usually held as: monohydrate, blood tube additive.

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.