PROCESS FOR TREATING PHYSICAL ENRICHMENT RESIDUES OF BAUXITE

摘要

A method of manufacturing alumina or alumina trihydrate from a physical enrichment residue of bauxite, said physical enrichment residue having been pretreated by a process comprising calcination (2020) and leaching (2030), to obtain a so-called pretreated residue, said process comprising the steps of: Digestion (2120) of said pretreated residue with an aqueous sodium hydroxide solution at a temperature of at least 100 ° C, said aqueous sodium hydroxide solution having a concentration of between 100 g Na2O / L and 220 g Na2O / L; Separation (2130) of the solid residue from the liquid phase; Crystallization of aluminum trihydrate (2160) by adding seeds (2170); Separation (2180) of crystallized aluminum trihydrate from the liquid phase, Optionally, calcination (2194) of said aluminum trihydrate to obtain alumina (2196).