Metal oxides dispersant composition
View Patent ↗This invention relates to metal oxides dispersant compositions comprising (a) certain a metal oxides dispersant, and (b) an oxime. The invention also relates to a process for dispersing metal oxides in an aqueous system that involves adding the dispersant composition to the aqueous system.
1. A process for improving the dispersability of metal oxides in an aqueous system which comprises:
adding to an aqueous system a composition comprising:
a) a phosphonated nonionic alkyl polymer, and
b) an oxime,
wherein the aqueous system comprises at least one metal oxide and wherein the weight ratio of (a) to (b) is from 0.5:1 to 20:1, and whereby (a) and (b) can be added separately at the same location, or independent locations, or as a mixture.
2. The process of claim 1 wherein the oxime is methyl ethyl ketoxime.
3. The process of claim 2 wherein the aqueous system is in contact with the metal surface of a heat exchanger of a steam generating system and wherein the steam generating system comprises a residual dispersant and the weight ratio of (a) to (b) is from 0.5:1 to 5:1.
4. The process of claim 3 wherein the steam generator residual dispersant is from 1 to 100 ppm.
5. The process of claim 4 wherein the steam generator residual dispersant is from 2 to 50 ppm.
6. The process of claim 5 wherein the steam generator residual dispersant is from 5 to 25 ppm.
7. The process of claim 6 wherein the oxime is added to a feedpoint which will expose the said methyl ethyl ketoxime to a temperature of at least 65° C.
8. A process for improving the dispersability of metal oxides in an aqueous system which comprises:
adding to an aqueous system a composition comprising:
a) a phosphino carboxylate, and
b) an oxime,
wherein the aqueous system comprises at least one metal oxide and wherein the weight ratio of (a) to (b) is from 0.5:1 to 20:1, and whereby (a) and (b) can be added separately at the same location, or independent locations, or as a mixture.
9. The process of claim 8 wherein the oxime is methyl ethyl ketoxime.
10. The process of claim 9 wherein the aqueous system is in contact with the metal surface of a heat exchanger of a steam generating system and wherein the steam generating system comprises a residual dispersant and the weight ratio of (a) to (b) is from 0.5:1 to 5:1.
11. The process of claim 10 wherein the steam generator residual dispersant is from 1 to 100 ppm.
12. The process of claim 10 wherein the steam generator residual dispersant is from 2 to 50 ppm.
13. The process of claim 12 wherein the steam generator residual dispersant is from 5 to 25 ppm.
14. The process of claim 13 wherein the oxime is added to a feedpoint which will expose the said methyl ethyl ketoxime to a temperature of at least 65° C.
15. The process of claims 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , or 14 wherein the dispersant composition also contains a phosphonate.
16. The process of claims 1 or 8 wherein the at least one metal oxide is a metal oxide selected from the group of metals consisting of iron, copper, and nickel.