They’ll recycle and remediate hard-to-treat bi-product of alumina production.
February 4, 2013
by PLANT STAFF
MONTREAL—Orbite Aluminae Inc. and Veolia Environmental Services have signed an agreement to treat and recycle red mud generated by alumina production using the Bayer process.
Financial details of the agreement have not been released.
The terms of the partnership between Montreal-based Orbite, a developer of green alumina extraction technology, and Paris-based Veolia, a global waste management specialist, include the construction of the first plant to treat red mud using Orbite’s patented process.
The companies intend to treat and recycle the difficult to process red mud, a caustic waste that is often stored in situ and stockpiled around the world, which increases the risk of accidental spills.
In the Bayer process, bauxite is washed with a hot solution of sodium hydroxide at 175 degrees C, which converts the aluminium oxide in the ore to sodium aluminate. The other components do not dissolve. The solid impurities, or red mud, are filtered off. The remaining alkaline solution is cooled, and aluminium hydroxide precipitates as a white, fluffy solid, which when heated decomposes to aluminium oxide.
Orbite describes its patented process as crushing, then acid leaching aluminous claystone. By using various temperatures and pH levels, the process selectively isolates the aluminum component and removes iron and other impurities, without producing red mud. The process also has the potential to extract high-value elements and rare earths,
The company is currently commissioning a high-purity alumina production plant in Cap-Chat, Que.