1-23. (canceled)
24. A process for activating a batch of polymerisation catalyst which comprises fluidising the batch of polymerisation catalyst in a fluidisation zone of an activator vessel, wherein the activator vessel comprises a fluidisation zone and a disengagement zone above the fluidisation zone, the diameter of the fluidisation zone of the activator vessel being at least 1 m, the height of the fluidised bed of catalyst being at least twice the diameter of the fluidisation zone and the height of the disengagement zone being between 1 to 3 m.
25. A process according to claim 24 wherein the height of the fluidised bed of catalyst is at least three times the diameter, for example at least four times the diameter.
26. A process according to claim 24 wherein the height of the fluidised bed of catalyst is between 2 and 8 m, and preferably between 4 and 8 m.
27. A process according to claim 24 wherein the expansion on fluidisation is above 100%, such as at least 120%.
28. A process according to claim 24 wherein the diameter of the fluidisation zone of the activator vessel is at least 1.2 m, and preferably at least 1.5 m.
29. A process according to claim 24 wherein the settled bed has a depth between 1.8 and 3 m.
30. A process according to claim 24 wherein the settled bed has a bulk volume of greater than 1.5 m3.
31. A process according to claim 24 wherein the height of the disengagement zone is between 1 to 2 bed diameters.
32. A process according to claim 24 wherein the height of the disengagement zone is between 0.25 to 0.75 times the height of the fluidisation zone.
33. A process according to claim 24 wherein the disengagement zone has the same cross-sectional area as the fluidisation zone such that the fluidisation zone and disengagement zone form a single cylindrical activator vessel having a total height between 3 and 11 m.
34. A process for activating a batch of polymerisation catalyst which comprises fluidising the batch of polymerisation catalyst in a fluidisation zone of an activator vessel, the diameter of the fluidisation zone of the activator vessel being at least 1.2 m and the height of the fluidised bed of catalyst being at least twice the diameter of the fluidisation zone.
35. A process according to claim 34 wherein the height of the fluidised bed of catalyst is at least three times the diameter, for example at least four times the diameter.
36. A process according to claim 34 wherein the height of the fluidised bed of catalyst is between 2 and 8 m, and preferably between 4 and 8 m.
37. A process according to claim 34 wherein the expansion on fluidisation is above 100%, such as at least 120%.
38. A process according to claim 34 wherein the diameter of the fluidisation zone of the activator vessel is at least 1.5 m.
39. A process according to claim 34 wherein the settled bed has a depth between 1.8 and 3 m.
40. A process according to claim 34 wherein the settled bed has a bulk volume of greater than 1.5 m3.
41. A process according to claim 34 wherein the activator vessel comprises a fluidisation zone and a disengagement zone above the fluidisation zone, the height of the disengagement zone being between 1 to 3 m.
42. A process according to claim 34 wherein the activator vessel comprises a fluidisation zone and a disengagement zone above the fluidisation zone, the height of the disengagement zone being between 1 to 2 bed diameters.
43. A process according to claim 34 wherein the activator vessel comprises a fluidisation zone and a disengagement zone above the fluidisation zone, the disengagement zone having the same cross-sectional area as the fluidisation zone such that the fluidisation zone and disengagement zone form a single cylindrical activator vessel having a total height between 3 and 11 m.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for the preparation of nanomaterials of metal oxides doped with metal ions in low valence state and the said process comprising the steps of:
a) mixing the precursor containing the salt of metal belonging to IIA, IIIA or IIIB group with one or more dopant precursor containing the salt of lanthanide,
b) homogenizing the above said precursors of metal salts and dopant, herein described as oxidizer, in water along with activated charcoal and combustible organic fuel to obtain a paste like mass,
c) heating the above said homogenized mass obtained in step (b) in a especially designed container, as herein described, uniformly at a temperature in the range of 200\xb0-1000\xb0 C., for a period till a bright yellow flame is produced and volatile gases are removed from the top of the said container,
d) cooling the above said container and removing the fluffy mass of nanomaterial in the form of nanowires of the desired metal oxides with dopant of lanthanide in low valence state.
2. A process according to claim 1, wherein the salt of metal used is selected from the group consisting of nitrate, acetate, oxalate, carbonate and hydroxide, preferably nitrate.
3. A process according to claim 1, wherein the metal in metal salts used is selected from the group consistent of calcium, strontium, yttrium, aluminum and any mixture thereof.
4. A process according to claim 1, wherein the precursor of dopant used is salt of lanthanide selected from the group consisting of europium, cerium, neodymium, dysprosium or any mixture thereof.
5. A process according to claim 1 wherein the combustible organic fuel used is selected from the group consisting of urea, hydrazine, citric acid and glycine, preferably urea.
6. A process according to claim 1 wherein the temperature used for combustion of fuel is preferably in the range of 200\xb0-600\xb0 C.
7. A process according to claim 1 wherein the activated charcoal used is in the range of 0.1-5.0 mole % of total metal salts used in the precursors.
8. A process according to claim 1, wherein the fluffy and voluminous mass obtained in step(c) is reduced to powder to obtain nanowires of the desired metal oxides materials.
9. A process according to claim 1 wherein the size of nanowires of desired metal oxide material is controlled by the ratio of fuel to oxidizer.
10. A process according to claim 1 wherein the molar ratio of fuel to oxidizer used is in the range of 0.5-7.0, preferably 2.0.
11. A process according to claim 1 wherein the size of the nanowires of desired metal oxide material obtained is in the range of 3-15 nm.
12. A process according to claim 1 wherein the container used is made of alumina, quartz, ceramic, or stainless steel, preferably quartz.
13. A process according to claim 1 wherein the container used is capable of withstanding at high temperature of 200\xb0-1200\xb0 C.
14. A process according to claim 1, wherein the nanomaterial of metal oxides obtained has dopant metal ion in low valence state of +2 or +3 instead of +3 or +4.
15. A process according to claim 1, wherein the dopant in low valence state present in the nanomaterial of metal oxides is any of Eu+2, Ce+3, Nd+2, Dy+2 or any mixture thereof.
16. A process according to claim 1, wherein the nanomaterial of metal oxides obtained is useful for magnetic, luminescent and semi conducting applications.
17. A process according to claim 8 wherein the size of nanowires of desired metal oxide material is controlled by the ratio of fuel to oxidizer.
18. A process according to claims 9 wherein the molar ratio of fuel to oxidizer used is in the range of 0.5-7.0, preferably 2.0.
19. A process according to claim 10 wherein the size of the nanowires of desired metal oxide material obtained is in the range of 3-15 nm.
20. A process according to claim 14, wherein the dopant in low valence state present in the nanomaterial of metal oxides is any of Eu+2, Ce+3, Nd+2, Dy+2 or any mixture thereof.