Alternative aluminium extraction beside the Bayer process:
Today the process that is used almost exclusively for the production of aluminum is the so-called Bayer process. In this process, bauxite is exposed to caustic soda at a temperature of 180°C. Through this the Aluminum is selectively dissolved as Na[Al(OH)4], while iron is separated as an oxide-hydrate (red mud) via filtration. Because of the fine distribution of the precipitate, the filtration process is often fraught with technical problems. At about 1200°C the aluminum fraction begins to crystallize and is finally converted to Aluminum oxide. The wet digestion of the bauxite results in a majority of the silicic acid crystallizing as sodium aluminum silicate which precipitates together with the red mud. The formation of these silicates is therefore connected with aluminum losses, which naturally increase with higher SiO2 concentrations of bauxite.
KON Chemical Solutions has the know-how for alternative routes for the production of aluminum from bauxite containing high concentrations of silicates. This process is especially useful in raw materials containing lower concentrations of aluminum. The simultaneous separation of iron and aluminum is one of the core points of this process. This process rout could also handle the red mud residuals of the Bayer process. That approach wound generate two benefits.
- On one hand, valuable raw materials are obtained
- On the other hand, waste is disposed