Compounds and compositions for use as foaming or frothing agents in ore and coal flotation
View Patent ↗Compounds of formula (I) wherein R 1 and R 2 are each independently C 1 -C 2 alkyl, and m is 1, 2, 3, 4, or 5 and compositions of formula (II) wherein R 1 and R 2 are each independently C 1 -C 4 alkyl, and n is an integer >_0 and wherein the average molar value of n for the total of the compounds of formula (II) in said composition is in the range of (1) to (3) and methods for production thereof.
1. A composition comprising at least two compounds of formula (II):
wherein R 1 and R 2 are each independently C 1 -C 4 alkyl, and n is an integer ≧0 and wherein the average molar value of n for the total of the compounds of formula (II) in said composition is in the range of 1 to 2.
2. A composition according to claim 1 wherein the average molar value of n is about 1.7.
3. A composition according to claim 1 wherein R 1 R 2 CH— is 4-methyl-pent-2-yl.
4. A composition according to claim 1 , wherein the compound of formula (II) where n=0 comprises less than 15% by weight of the total composition.
5. A composition according to claim 1 , wherein the compound of formula (II) where n=0 comprises less than 10% by weight of the total composition.
6. A composition according to claim 1 , wherein the compound of formula (II) where n=0 comprises less than or equal to 6.5% by weight of the total composition.
7. A composition according to claim 1 , wherein the total combined weight of compounds where n=0 and n=1 is such that the closed-cup flash point of said composition is greater than 65° C.
8. A composition according to claim 1 , wherein the total weight of compounds of formula (II) where n is greater than 4 is less than 20% of the combined total of compounds of formula (II).
9. A composition according to claim 1 which further comprises other additives.
10. A method of preparing a composition comprising at least two compounds of formula (II):
wherein R 1 and R 2 are each independently C 1 -C 4 alkyl, and n is an integer ≧0, and
wherein the average molar value of n for the total of the compounds of formula (II) in said composition is in the range of 1 to 2, said method comprising:
reacting an excess of C 3 C 9 secondary alcohol with ethylene oxide in the presence of a catalyst in an ethoxylation vessel to form a mixture of two or more compounds of formula (II), separating at least a portion of unreacted secondary alcohol from the mixture, and recycling the unreacted secondary alcohol back to the ethoxylation vessel.
11. A method according to claim 10 , wherein the C 3 -C 9 secondary alcohol is 4-methyl-2-pentanol.
12. A method according to claim 10 wherein the unreacted secondary alcohol is removed by distillation to provide a composition comprising unreacted secondary alcohol in an amount of less than 15% by weight of the total composition.
13. A method according to claim 12 , wherein unreacted secondary alcohol comprises less than 10% by weight of the total composition.
14. A method according to claim 12 , wherein the unreacted secondary alcohol comprises less than or equal to 8% by weight of the total composition.
15. A method according to claim 10 comprising a distillation step to remove from the composition compounds of formula (II) wherein n=0 and n1 such that the closed-cup flash point of said composition is greater than 65° C.
16. A method according to claim 11 wherein total weight of compounds of formula (II) where n is greater than 4 in said composition is less than 20% of the combined total of the compounds of formula (II) in the composition.
17. A method according to claim 10 , wherein the ethylene oxide to C 3 -C 9 secondary alcohol ratio is kept below 70 wt % in said ethoxylation vessel.
18. A method according to claim 17 , wherein the ratio is kept below 10 wt %.
19. A method according to claim 10 , wherein the catalyst is an alkali metal or alkaline earth metal base catalyst or a Lewis or Bronsted acid catalyst.
20. A method according to claim 10 , wherein the catalyst is a Narrow Range Ethoxylation catalyst.
21. A method according to claim 19 , wherein the alkali metal catalyst is potassium hydroxide.
22. A froth flotation process for the recovery of clean coal from a slurry, the process comprising adding a composition according to claim 1 to the slurry.
23. A froth flotation process according to claim 22 , wherein the froth flotation process is performed in a Microcel®.
24. A froth flotation process according to claim 22 , wherein the froth flotation process is performed in a Jameson® cell.
25. A froth flotation process according to claim 22 wherein the froth flotation process is performed in an EKOF® cell.
26. A method for improving the performance of a dissolved air flotation process, the method comprising adding a composition according to claim 1 to lower the liquid surface tension of a slurry used in the process.
27. A flotation process for the recovery and concentration of desirable minerals or selective removal of undesirable minerals from a slurry, the process comprising adding a composition according to claim 1 to the slurry.
28. A flotation process for the recovery of sulphide minerals from a slurry, the process comprising adding a composition according to claim 1 to the slurry.
29. A froth flotation process for refining mineral or coal, the process comprising adding a composition according to claim 1 to a slurry of mineral or coal.