Amine-aldehyde resins and uses thereof in separation processes
View Patent ↗Amine-aldehyde resins are disclosed for removing a wide variety of solids and/or ionic species from the liquids in which they are suspended and/or dissolved. These resins are especially useful as froth flotation depressants in the separation of bitumen from sand and/or clay or in the beneficiation of clay (e.g., kaolin clay) from an impure clay-containing ore. The resins are also useful for treating aqueous liquid suspensions to remove solid particulates, as well as for removing metallic ions in the purification of water.
1. A method for purifying an aqueous liquid suspension, comprising:
treating a liquid suspension comprising clay with a urea-formaldehyde resin having a formaldehyde to urea molar ratio of about 1.5:1 to about 4:1, wherein an alkaline reaction condition is maintained throughout the synthesis of the urea-formaldehyde resin; and
removing, either after or during the treating step, a purified liquid or at least a portion of the clay by sedimentation or floatation.
2. The method of claim 1 , wherein treating the liquid suspension comprises flocculating the clay.
3. The method of claim 1 , wherein at least a portion of the clay is removed by sedimentation.
4. The method of claim 1 , wherein the liquid suspension is from a phosphate production facility.
5. The method of claim 4 , wherein the purified water is removed for reuse in phosphate production.
6. The method of claim 1 , wherein the urea-formaldehyde resin is modified with one or more anionic functional groups.
7. The method of claim 1 , wherein the urea-formaldehyde resin is stabilized by reacting with an alcohol comprising ethanol, n-propanol, isopropanol, n-butanol, or isobutanol.
8. The method of claim 1 , wherein the urea-formaldehyde resin has a concentration of free formaldehyde of less than 1%, based on the total weight of the urea-formaldehyde resin.
9. The method of claim 1 , wherein the urea-formaldehyde resin is formed by reacting a monomer mixture consisting essentially of urea and formaldehyde.
10. The method of claim 1 , wherein the urea-formaldehyde resin has a number average molecular weight (Mn) of about 400 grams per mole to about 1,200 grams per mole.
11. The method of claim 1 , wherein the urea-formaldehyde resin has a concentration of free formaldehyde of less than 1%, based on the total weight of the urea-formaldehyde resin, the urea-formaldehyde resin has a number average molecular weight (Mn) of about 400 grams per mole to about 1,200 grams per mole, and the urea-formaldehyde resin is stabilized by reacting with an alcohol comprising ethanol, n-propanol, isopropanol, n-butanol, or isobutanol.
12. A method for purifying an aqueous liquid suspension, comprising:
treating a liquid suspension comprising a solid contaminant with a generally cationic urea-formaldehyde resin having a formaldehyde to urea molar ratio of about 1.5:1 to about 4:1, wherein an alkaline reaction condition is maintained throughout the synthesis of the urea-formaldehyde resin; and
removing, either after or during the treating step, a purified liquid or at least a portion of the solid contaminant by sedimentation or floatation.
13. The method of claim 12 , wherein treating the liquid suspension comprises flocculating the solid contaminant.
14. The method of claim 12 , wherein at least a portion of the solid contaminant is removed by sedimentation.
15. The method of claim 12 , wherein the liquid suspension is from a phosphate production facility.
16. The method of claim 15 , wherein the purified water is removed for reuse in phosphate production.
17. The method of claim 12 , wherein the solid contaminant comprises sand, clay, or a combination thereof.
18. The method of claim 17 , wherein the liquid suspension is a clay-containing effluent slurry from a phosphate production facility.
19. The method of claim 12 , wherein the urea-formaldehyde resin is etherified with an alcohol selected from the group consisting of: ethanol, n-propanol, isopropanol, n-butanol, and isobutanol.
20. The method of claim 12 , wherein the at least a portion of the solid contaminant is removed by floatation.
21. The method of claim 20 , wherein the floatation comprises froth floatation.
22. The method of claim 12 , wherein the urea-formaldehyde resin has a number average molecular weight ranging from about 400 grams per mole to about 1,200 grams per mole.
23. The method of claim 12 , wherein the urea-formaldehyde resin is formed by reacting a monomer mixture consisting essentially of urea and formaldehyde.
24. The method of claim 12 , wherein the urea-formaldehyde resin has a concentration of free formaldehyde of less than 1%, based on the total weight of the urea-formaldehyde resin.
25. The method of claim 12 , wherein the urea-formaldehyde resin has a concentration of free formaldehyde of less than 1%, based on the total weight of the urea-formaldehyde resin, the urea-formaldehyde resin has a number average molecular weight (Mn) of about 400 grams per mole to about 1,200 grams per mole, and the urea-formaldehyde resin is stabilized by reacting with an alcohol comprising ethanol, n-propanol, isopropanol, n-butanol, or isobutanol.
26. The method of claim 12 , wherein the urea-formaldehyde resin has a formaldehyde to urea molar ratio of about 2:1 to about 3:1, the urea-formaldehyde resin has a concentration of free formaldehyde of less than 1%, based on the total weight of the urea-formaldehyde resin, the urea-formaldehyde resin is stabilized by reacting with an alcohol comprising ethanol, n-propanol, isopropanol, n-butanol, or isobutanol, and the urea-formaldehyde resin is formed by reacting a monomer mixture consisting essentially of urea and formaldehyde or a monomer mixture consisting essentially of urea, formaldehyde, and ammonia.