Last week saw one of the worst environmental disasters in Europe of the last few decades when a toxic slurry was released into the river Danube in Hungary after the collapse of a dam wall at an alumina plant. The red sludge contained a highly toxic mix of poisonous heavy metals and corrosive alkali.
Alumina is pure aluminium oxide, a compound which can then be electrolysed to produce aluminium, the most abundant metal in the earth crust and therefore one of the most widely used worldwide. However, the production of this pure white compound from aluminium ore or bauxite requires the removal of the impurities from the ore using strong alkali. As the dam wall broke, the impurities and the alkali were both released in a toxic red torrent, distinctively coloured by iron oxide removed from the ore, that resulted in the death of 5 people with many more suffering chemical burns, and the relocation of hundreds who lost their homes. The eventual clean up operation could take 18 months.
Hungarian alumina plant disaster
the disaster in 50 pictures