Bauxite residue recycling

A method for recovering scandium from red mud waste resulting from bauxite mining, comprising:

• sulphating the red mud by adding sulfuric acid for converting oxides to sulfates;
• roasting the sulphated red mud until less than 5 ppm iron sulfate and titanium sulfate remain;
• agitating a leach mixture including the roasted red mud by sonication or ball milling to leach scandium from the red mud into a leach liquor;
• and
• precipitating rare earths other than scandium from the leach liquor to generate a solution including scandium sulfate.

In an aluminum/bauxite mining operation having a stream of red mud as a discarded byproduct, a method of processing and recovering scandium from the discarded red mud, comprising:

• gathering a quantity of red mud from a waste stream of byproducts resulting from bauxite mining;
• sulphating the quantity of red mud by adding sulfuric acid to convert oxides in the red mud to sulfates, the oxides including iron oxide and titanium oxide;
• roasting the sulphated red mud 700° C. for 1 hour in a tube furnace, the tube furnace providing ventilation for evacuating sulfates;
• leaching scandium by adding water to the roasted red mud to form a leach mixture;
• agitating the leach mixture by ball milling to expose crystalline structures of scandium to the water for leaching and resulting in a leach liquor including dissolved scandium and rare earths;
• adjusting the pH of the leach liquor to 8.0 from addition of sodium hydroxide to precipitate rare earths and leave scandium in solution in the leach liquor;
• filtering the precipitated rare earths to a filtrate including the dissolved scandium;
• reducing the pH to 1.0 by addition of sulfuric acid;
• and
• adding oxalic acid to precipitate scandium oxalate.