Method of manufacturing a catalyst

1. A method of manufacturing a catalyst, a catalyst precursor, or a catalyst support comprising:

(a) mixing a refractory metal oxide or precursor thereof with a liquid and optionally a catalytically active component or a precursor thereof to form a paste;

(b) adding said paste to an extruder, the extruder having a die plate comprising one or more dies, each die having a plurality of apertures, each aperture having an inlet and an outlet, the outlet of each aperture having a cross sectional area of 6 mm 2 or less; and

(c) extruding the paste through said apertures to form catalyst support extrudates;

wherein the inlet of the apertures has a greater cross sectional area than the outlet of said apertures; and

wherein for at least one die the combined cross sectional area of all apertures at the inlet of the apertures relative to the total cross sectional area of the die at the inlet is higher than 50%.

2. A method as claimed in claim 1 , wherein one or more of the dies comprise rims between the inlet of apertures with an edge pointing in the opposite direction of the extrusion flow, said rim edge having a rounding with a radius of 0.3 mm or less.

3. A method as claimed in claim 2 , wherein said rim edge has a rounding with a radius of 0.1 mm or less.

4. A method as claimed in claim 1 , wherein each aperture has an inwardly tapered opening.

5. A method as claimed in claim 1 , wherein the apertures further comprise a channel having a channel inlet and a channel outlet, the channel inlet and outlet having a substantially equal cross sectional area.

6. A method as claimed in claim 1 , wherein the outlet of each aperture has a cross sectional area of 2.2 mm 2 or less.

7. A method as claimed in claim 1 , wherein for at least one die the combined cross sectional area of all apertures at the inlet of the apertures relative to the total cross sectional area of the die at the inlet is higher than 80%.

8. A die for an extruder comprising a plurality of apertures, each aperture having an inlet and an outlet wherein the inlet of the apertures has a greater cross sectional area than the outlet of said apertures; the outlet of each aperture having a cross sectional area of 6 mm 2 or less; and wherein the combined cross sectional area of all apertures at the inlet of the apertures relative to the total cross sectional area of the die at the inlet is higher than 50%.

9. A die as claimed in claim 8 , wherein the die comprises rims between the inlet of apertures with an edge pointing in the opposite direction of the extrusion flow, said rim edge having a rounding with a radius of 0.3 mm or less.

10. A die as claimed in claim 8 , wherein each aperture has an inwardly tapered opening.

11. A die as claimed in claim 8 , wherein the apertures also comprise a channel having a channel inlet and a channel outlet, the channel inlet and outlet having a substantially equal cross sectional area.

12. A die as claimed in claim 8 , wherein the ratio between the length of the apertures and the perimeter of the apertures is in the range of 0.2-10.

13. A die as claimed in claim 8 , wherein the outlet of each aperture has a cross sectional area of 2.2 mm 2 or less.

14. A die as claimed in claim 8 , wherein for at least one die the combined cross sectional area of all apertures at the inlet of the apertures relative to the total cross sectional area of the die at the inlet is higher than 80%.

15. A die as claimed in claim 8 , wherein said rim edge has a rounding with a radius of 0.1 mm or less.

16. A die plate comprising one or more dies as claimed in claim 8 .