Patent ID: 6048463
Filing Date: 2000-04-11
Classification: B01D,C01F,C02F

Abstract:
A method for treating Bayer process red mud-containing liquor comprising the steps of:a) adding first to said red mud-containing liquor an effective clarifying amount of a lower molecular weight emulsion copolymer formed from monomers methyl acrylate and acrylic acid having a mole ratio of methyl acrylate to acrylic acid of from about 85:15 to about 99.9:0.1 and wherein the lower molecular weight emulsion copolymer has an intrinsic viscosity in 2N NaNO.sub.3 at 30.degree. C. of from about 5 to about 18 dL/g; andb) adding second to said red mud-containing liquor an effective clarifying amount of a high molecular weight emulsion copolymer formed from monomers methyl acrylate and acrylic acid having a mole ratio of methyl acrylate to acrylic acid of from about 85:15 to about 99.9:0.1 wherein the high molecular weight emulsion copolymer has an intrinsic viscosity in 2N NaNO.sub.3 at 30.degree. C. of at least 20 dL/g to form a red mud phase and a clarified liquor phase andc) separating the clarified liquor phase and the red mud phase.