HYPERBARIC BAUXITE FILTRATION: NEW WAYS IN BAUXITE TRANSPORTATION

Sant´ Ana M, Morales J, Prader R, Kappel J, Heinzle M

At Barcarena in northern Brasil, Alunorte has commenced processing of bauxite from the newly developed Paragominas mine.

The challenge was to transport the bauxite over a distance of 260km to the existing alumina refinery in Barcarena.

Several options for transportation were studied. This resulted in Alunorte’s decision as the first company in the world to grind the bauxite, mix it with water and transport the suspension containing approx. 50% bauxite in a pipeline to the refinery. The next problem to be solved was to dewater the very fine bauxite to the low residual moisture content required by the existing refinery using the Bayer Process. Several options were investigated, the most promising being filter presses and hyperbaric disc filters. The decision was made in favour of the hyperbaric disc filter due to the continuous operation and lower investment costs.

This resulted in the largest installation of hyperbaric filters in the world with a total filtration area of 840m². This paper gives an overview of the whole investment project starting from the equipment selection process, the basic design of the plant, installation and start-up at the beginning of 2007.