Contacting arrangement

1. A liquid-liquid contacting arrangement, adapted to be installed within a liquid-liquid extraction column, the contacting arrangement comprising:

(a) a plurality of pairs of disk and doughnut plates, said pairs stacked in a generally longitudinal stack, said stack being generally perpendicular to broad faces of said disk and doughnut plates,

each pair of said disk and doughnut pairs including:

(i) a disk plate; and

(ii) a doughnut plate, disposed beneath said disk plate;

said disk plate having a first liquid-liquid contacting surface along an external perimeter of said disk plate;

said doughnut plate having a second liquid-liquid contacting surface along an internal perimeter of said doughnut plate; and

(b) a securing arrangement adapted to

(i) affix said disk plate and said doughnut plate of said each pair in a first spaced-apart relationship; and

(ii) affix, in a second spaced-apart relationship, said disk and doughnut pairs with respect to one another;

at least a portion of at least one of said first and second contacting surfaces having teeth disposed in a proximate position to said first and second contacting surfaces,

said proximate position defined by:

L cs-doughnut =K ·( D ext −D int ), for said doughnut plates; and

L cs-disk =K ·( D disk ), for said disk plates,

wherein:

L cs-doughnut is a maximum distance of said teeth on each particular doughnut plate, from said contacting surface of said particular doughnut plate;

L cs-disk is a maximum distance of said teeth on each particular disk plate, from said contacting surface of said particular disk plate;

D ext is an outer diameter of said doughnut plate, excluding any protrusions of said teeth;

D int is an inner diameter of said doughnut plate, excluding any protrusions of said teeth;

D disk is a diameter of said disk plate, excluding any protrusions of said teeth;

said teeth having an average length of at least 2 mm;

K is a coefficient, K being at most 0.05;

and wherein a length ratio of said external perimeter, including said teeth, to a base perimeter of said disk, excluding said teeth, or of said internal perimeter, including said teeth, to a base perimeter of said doughnut, excluding said teeth, is at least 2.0.

2. The contacting arrangement of claim 1 , said length ratio being at least 2.6.

3. The contacting arrangement of claim 1 , said teeth being disposed on at least one of said disk plates.

4. The contacting arrangement of claim 1 , said teeth including teeth disposed on both said contacting surface of said doughnut plate and said contacting surface of said disk plate.

5. The contacting arrangement of claim 1 , said teeth including teeth disposed on at least one of a top surface of said doughnut plate and a top surface of said disk plate, and pointing upwards.

6. The contacting arrangement of claim 1 , said teeth including teeth disposed on at least one of a bottom surface of said doughnut plate and a bottom surface of said disk plate, and pointing downwards.

7. The contacting arrangement of claim 1 , a first disk plate and a first doughnut plate of a particular pair of said being longitudinally separated by a distance L pair , at least a portion of said teeth having a length of at least 0.03·L pair .

8. The contacting arrangement of claim 7 , said average length of said teeth being at least 0.03·L pair .

9. The contacting arrangement of claim 1 , said average length being at least 3 mm.

10. The contacting arrangement of claim 1 , said average length being at least 0.025·D ext .

11. The contacting arrangement of claim 10 , said average length being at most 0.08·D ext .

12. The contacting arrangement of claim 1 , a spacing between said teeth being at least 3 mm.

13. The contacting arrangement of claim 1 , further comprising said column.

14. The contacting arrangement of claim 13 , further comprising a pulsation mechanism, said pulsation mechanism fluidly communicating with an internal volume of said column.

15. The contacting arrangement of claim 13 , at least a particular doughnut plate of said doughnut plates further comprising teeth disposed radially outward with respect to D ext , between said particular doughnut plate and an internal surface of said column.

16. The contacting arrangement of claim 13 , an outer spacing between a particular doughnut plate of said doughnut plates and an inner surface of said column having an area A spacing , an inner contacting area of said particular doughnut plate being defined by π·(D ext ) 2 /4, and an area ratio of said A spacing to said inner contacting area being within a range of 1-5%.

17. The contacting arrangement of claim 1 , said disk and doughnut pair having at least one of: at least one disk aperture passing through said disk plate, and at least one doughnut aperture passing through said doughnut plate, an aperture area of said disk aperture being of a non-uniform radial distribution along said disk plate, such that an innermost area of said disk plate contains at least 60 area % of said at least one disk aperture, said innermost area being at most 50 area % of said disk plate.

18. A liquid-liquid contacting arrangement comprising:

(a) a plurality of pairs of disk and doughnut plates, said pairs stacked in a generally longitudinal stack, said stack being generally perpendicular to broad faces of said disk and doughnut plates,

each pair of said disk and doughnut pairs including:

(i) a disk plate; and

(ii) a doughnut plate, disposed beneath said disk plate;

said doughnut plate having a second liquid-liquid contacting surface along an internal perimeter of said doughnut plate; and

(b) a securing arrangement adapted to

(i) affix said disk plate and said doughnut plate of said each pair in a first spaced-apart relationship; and

(ii) affix, in a second spaced-apart relationship, said disk and doughnut pairs with respect to one another;

at least a portion of said second contacting surface having teeth disposed in a proximate position to said second contacting surface,

said proximate position defined by:

L cs-doughnut =K ·( D ext −D int ), for said doughnut plates; and

wherein:

L cs-doughnut is a maximum distance of said teeth on each particular doughnut plate, from said contacting surface of said particular doughnut plate;

D ext is an outer diameter of said doughnut plate, excluding any protrusions of said teeth;

D int is an inner diameter of said doughnut plate, excluding any protrusions of said teeth;

said teeth having an average length of at least 2 mm;

K is a coefficient, K being at most 0.05;

and wherein a length ratio of said internal perimeter including said teeth to a base perimeter of said doughnut, excluding said teeth, is at least 2.0.

19. The contacting arrangement of claim 18 , further comprising said column and a pulsation mechanism, said pulsation mechanism fluidly communicating with an internal volume of said column.

20. A liquid-liquid contacting arrangement comprising:

(a) a plurality of pairs of disk and doughnut plates, said pairs stacked in a generally longitudinal stack, said stack being generally perpendicular to top and bottom broad faces of said disk and doughnut plates,

each pair of said disk and doughnut pairs including:

(i) a disk plate; and

(ii) a doughnut plate, disposed beneath said disk plate;

said disk plate having a first liquid-liquid contacting surface along an external perimeter of said disk plate;

said doughnut plate having a second liquid-liquid contacting surface along an internal perimeter of said doughnut plate;

(b) a securing arrangement adapted to

(i) affix said disk plate and said doughnut plate of said each pair in a first spaced-apart relationship; and

(ii) affix, in a second spaced-apart relationship, said disk and doughnut pairs with respect to one another;

(c) a column housing said longitudinal stack and said securing arrangement; and

(d) a pulsation mechanism, fluidly communicating with an internal volume of said column;

wherein at least a portion of at least one of said first and second contacting surfaces have teeth disposed in a proximate position to said first and second contacting surfaces,

said proximate position defined by:

L cs-doughnut =K ·( D ext −D int ), for said doughnut plates; and

L cs-disk =K ·( D disk ), for said disk plates,

wherein:

L cs-doughnut is a maximum distance of said teeth on each particular doughnut plate, from said contacting surface of said particular doughnut plate;

L cs-disk is a maximum distance of said teeth on each particular disk plate, from said contacting surface of said particular disk plate;

D ext is an outer diameter of said doughnut plate, excluding any protrusions of said teeth;

D int is an inner diameter of said doughnut plate, excluding any protrusions of said teeth;

D disk is a diameter of said disk plate, excluding any protrusions of said teeth;

said teeth having an average length of at least 2 mm;

K is a coefficient, K being at most 0.05;

wherein a length ratio of said external perimeter including said teeth to a base perimeter of said disk, excluding said teeth, or of said internal perimeter including said teeth to a base perimeter of said doughnut, excluding said teeth, is at least 2.0;

said teeth including teeth disposed on at least one of:

said top broad face of said doughnut plate and said top broad face of said disk plate, and pointing upwards; and

said bottom broad face of said doughnut plate and said bottom broad face of said disk plate, and pointing downwards.