In the Bayer process, alumina is extracted from bauxite using a series of steps including (i) grinding, (ii) absorption, (iii) leaching, (iv) filtering, (v) cooling, (vi) precipitation, and (vii) drying and calcining ![[Pasted image 20210717213636.png]] The Bayer process is carried out in four steps: 1. After the bauxite is crushed, washed and dried, it is dissolved with caustic soda at high temperatures. 2. The mixture is filtered to remove the impurities, called “red mud,” which is properly discarded. The remaining alumina solution is transferred to tall tanks called precipitators. 3. In the precipitator tank, the hot solution starts to cool and aluminum hydroxide seeds, very small particles, are added. The aluminum hydroxide seeds stimulate the precipitation of solid aluminum hydroxide crystals. The aluminum hydroxide settles at the bottom of the tank and is removed. 4. Finally, the aluminum hydroxide is washed of any remaining caustic soda and heated to remove excess water. After this process, alumina (aluminum oxide) emerges as a fine white powder. It looks much like sugar used in baking, but is hard enough to scratch a pane of glass. [[Sustainabilty of Industrial Production]] [[Refining Assets]]