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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Bayer process | 2/2 | https://en.wikipedia.org/wiki/Bayer_process | reference | science, encyclopedia | 2026-05-05T10:46:05.458075+00:00 | kb-cron |
On October 4, 2010, the Ajka alumina plant in Hungary had an incident where the western dam of its red mud reservoir collapsed. The reservoir was filled with 700,000 cubic metres (25 million cubic feet) of a mixture of red mud and water with a pH of 12. The mixture was released into the valley of Torna river and flooded parts of the city of Devecser and the villages of Kolontár and Somlóvásárhely. The incident resulted in 10 deaths, more than a hundred injuries, and contamination in lakes and rivers.
== History == In 1859, Henri Étienne Sainte-Claire Deville in France developed a method for making alumina by heating bauxite in sodium carbonate, Na2CO3, at 1,200 °C (2,190 °F), leaching the sodium aluminate formed with water, then precipitating aluminium hydroxide by carbon dioxide, CO2, which was then filtered and dried. This process is known as the Deville–Pechiney process. In 1886, the Hall–Héroult electrolytic aluminium process was invented, and the cyanidation process was invented in 1887. The Bayer process was invented in 1888 by Carl Josef Bayer. Working in Saint Petersburg, Russia to develop a method for supplying alumina to the textile industry (it was used as a mordant in dyeing cotton), Bayer discovered in 1887 that the aluminium hydroxide that precipitated from alkaline solution was crystalline and could be easily filtered and washed, while that precipitated from acid medium by neutralization was gelatinous and difficult to wash. The industrial success of this process caused it to replace the Deville–Pechiney process, marking the birth of the modern field of hydrometallurgy. The engineering aspects of the process were improved upon to decrease the cost starting in 1967 in Germany and Czechoslovakia. This was done by increasing the heat recovery and using large autoclaves and precipitation tanks. To more effectively use energy, heat exchangers and flash tanks were used and larger reactors decreased the amount of heat lost. Efficiency was increased by connecting the autoclaves to make operation more efficient. Today, the process produces nearly all the world's alumina supply as an intermediate step in aluminium production.
== See also == Ajka alumina plant accident Deville process Hall–Héroult process History of aluminium
== References ==
Habashi, F. (2005). "A short history of hydrometallurgy". Hydrometallurgy. 79 (1–2): 15–22. Bibcode:2005HydMe..79...15H. doi:10.1016/j.hydromet.2004.01.008.