To recover aluminum values in the maximal yield by adding an oxalic acid stabilizer solution to a solution according to the Bayer's process after separating red mud and suppressing the precipitation of sodium oxalate crystals.

Red mud is separated from a solution according to the Bayer's process obtained by treating a bauxite ore and at least one oxalic acid stabilizer solution in two compounds represented by formulae I and II (R1 is a straight- chain or a side chain, a saturated or an unsaturated hydrocarbon group having ≥5 carbon atoms; R2 and R3 are each selected from a halogen, an alkyl, a cylcoalkyl, a hydroxyalkyl or the like; R4 is a bivalent cross-linking group selected from alkyls, cycloalkylenes, arylenes or the like optionally hetero- interrupted with a heteroatom selected from oxygen, sulfur or nitrogen) in an amount of about 1-50 ppm is added to the solution according to the Bayer's process. Lauryl-N,N-dimethylamine oxide is cited as an example of the oxalic acid stabilizer solution.