IMPROVEMENT TO THE BAYER PROCESS AND TO THE ATTACK CHAIN OF BAUXITE ORE

摘要

The invention concerns a method for simultaneously bringing to optimal temperature and concentration an aqueous medium for attacking bauxite ore in an alumina producing installation using the Bayer process, comprising the following steps (a) to (f) which consist in: a) cooling and evaporating, in a multistage evaporation zone an aqueous medium coming from the attack containing the pregnant liquor; b) separating the tailings, precipitating the aluminium trihydroxide and recuperating the aqueous attacking medium, consisting of the decomposed liquor; c) optionally, eliminating by evaporation, in a specific evaporation section, the amount of water required and complementary to that already evaporated in phase (a); d) heating in several stages the aqueous attacking medium; e) using in each of the stages of the heating phase (d) the flash steam generated at each of the stages in the evaporation phase (a); f) heating with the live steam the aqueous attacking medium derived from the heating phase (d). the invention is characterised in that in addition to all said phases, is carried out a phase which consists in simultaneously heating and evaporating the aqueous attacking medium.