Claims
- 1. 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; and
- b) 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 and
- c) separating the clarified liquor phase and the red mud phase.
- 2. The method of claim 1 wherein said high molecular weight copolymer is from about 75 to about 80 percent hydrolyzed in said red mud-containing liquor.
- 3. The method of claim 1 wherein said high molecular weight copolymer has a mole ratio of methyl acrylate to acrylic acid of from about 90:10 to about 99.5:0.5.
- 4. The method of claim 1 wherein said high molecular weight copolymer has a mole ratio of methyl acrylate to acrylic acid of 97.5:2.5.
- 5. The method of claim 1 wherein the total alkalinity of the red mud containing liquor is from about 10 to about 300 grams per liter expressed as sodium carbonate.
- 6. The method of claim 1 wherein the solids content of the red mud containing liquor is from about 10 grams per liter to about 350 grams per liter.
- 7. The method of claim 6 wherein the treatment of the red mud containing liquor is conducted at a temperature of from about 30.degree. C. to about 115.degree. C.
- 8. The method of claim 1 wherein the treatment of the red mud containing liquor is conducted at a temperature of from about 5.degree. C. to about 250.degree. C.
- 9. The method of claim 1 wherein the high and low molecular weight copolymers are from about 60 to about 90 percent hydrolyzed in the red mud-containing liquor.
- 10. The method of claim 1 wherein the high molecular weight copolymer has an intrinsic viscosity in 2N NaNO.sub.3 of from about 20 to about 40 dl/g.
- 11. The method of claim 1 wherein the lower molecular weight copolymer has an intrinsic viscosity in 2N NaNO.sub.3 of from about 10 to about 18 dl/g.
Parent Case Info
This application is a continuation-in-part of copending application Ser. No. 08/991,103 entitled "Water Continuous Methyl Acrylate Emulsion Polymers For Improved Flocculation Of Red Mud In The Bayer Process" filed on Dec. 12, 1997, by inventors Radhakrishnan Selvarajan and Everett C. Phillips.
US Referenced Citations (26)
Foreign Referenced Citations (4)
Number |
Date |
Country |
3033 |
Oct 1996 |
AUX |
54-4986 |
Jan 1979 |
JPX |
2 080 272 |
Jul 1980 |
GBX |
WO 9605146 |
Feb 1996 |
WOX |
Non-Patent Literature Citations (3)
Entry |
"Flocculation and Sedimentation of Red Mud", 1980 pp. 39-50, TMS Light Metals Committee @109th AIME Annual Meeting Feb. 24-28, 1980. |
"Expansion Coefficients and Conformational Properties of Heterodisperse Poly(acrylamide-co-sodium acrylate)", K.J. McCarthy, et al. (Journal of Applied Polymer Science, vol. 33, 1683-1698 (1987). |
"Viscosity-Molecular Weight Relationships and Unperturbed Dimensions of Linear Chain Molecules" M. Kurata et al., Polymer Handbook 3.sup.rd Edition, 1989, Wiley-Interscience Publication. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
991103 |
Dec 1997 |
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