13 History
Seaweed in the chemical industry: glass and iodine
Ar bezhin hag an industriezh kimiek : ar gwer hag an iod
Finistère is not particularly known for its chemical industry. And yet, since the 17th century, Breton seaweed has supplied factories.
The soda (sodium carbonate) industry developed first. This product was extracted from the ashes of dried seaweed. It is essential to the making of glass, to lower its melting temperature. This activity ceased at the end of the 18th century, when new processes were discovered.
Activity resumed in 1829, in the wake of a major discovery: in 1812, the chemist Bernard Courtois identified a new product in seaweed ashes, iodine. Quickly adopted in photography and medicine, it became the driving force of a new Breton industry. This died out in 1952, in the face of competition from iodine extracted from Chilean nitrates.
Today, the baton has been taken up by the extraction of the alginates contained in the large kelp.