Segregation of binary mixtures of particles during the filling of a two-dimensional representation of a hopper

Abstract

This paper contains a summary of results obtained from experiments carried out at The Wolfson Centre for Bulk Solids Handling Technology at the University of Greenwich on the segregation of dry binary particle mixtures of the same material when they fill a hopper. A test facility has been built which represents a two-dimensional segment of a hopper. Binary mixtures were fed into this container using amplitude feedback-controlled vibratory feeders via a static in-line mixer and one of two different feed chute designs; one curved and the other straight. ‘Thieving’ probes were used to sample the segregated heap of material from the hopper. The contents of each probe then underwent size analysis to ascertain the change in the size distribution from that of the original mixture. It is shown that a mechanism, termed embedment, caused by the vertical component of the feed velocity on impact with the forming heap, has a dramatic effect on the segregation process. A detailed discussion of the relationship between the possible mechanisms occurring in the heap formation process in the light of the segregation patterns observed is given.

Keywords

segregation particulate materials heap mechanisms experimental results

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References

Carson

J. W.

Royal

T. A.

Goodwill

D. J.

Understanding and eliminating particle segregation problems. Bulk Solids Handling, 1986, 5 (1), 139–144.

Drahun

J. A.

Bridgwater

The mechanisms of free surface segregation. Powder Technology, 1983, 36, 39–53.

Tanaka

Segregation models of solid mixtures composed of different densities and particle sizes. Ind. Eng. Chem., Process Des. Dev., 1971, 10 (3), 332–340.

Bridgwater

Foo

W. S.

Stephens

D. J.

Particle mixing and segregation in failure zones: Theory and experiment. Powder Technol, 1985, 41, 147–158.

Lawrence

L. R.

Beddow

J. K.

Powder segregation during die filling. Powder Technol, 1968–9, 2, 253–259.

Brown

R. L.

The fundamental principles of segregation. J. Inst. Fuel, 1939, 13 (5), 15–23.

Brown

G. J.

Creasey

D. S.

Miles

N. J.

Coal handleability—a good or a bad coal?

Particle Particle System Characterisation, 1996, 13, 260–263.

Cowgill

Wong

Standish

Stockpiling behaviour as observed in a model experiment. In Proceedings of the Fifth IEAust International Conference on

Bulk Materials Storage, Handling and Transportation, Newcastle, New South Wales, Australia, 10–12 July 1995, pp. 451–455 (Institution of Engineers, Australia, Barton, Australian Capital Territory).

Jaeger

H. M.

Nagel

S. R.

Physics of the granular state. Science, 1992, 255, 1523–1531.

10.

Mattheé

Segregation phenomena relating to bunkering of bulk materials: Theoretical consideration and experimental investigation. Powder Technol., 1967–8, 1, 265–271.

11.

Williams

J. C.

The segregation of particulate materials; a review. Powder Technol., 1976, 15, 245–251.

12.

Makse

Havlin

King

Stanley

Spontaneous stratification in granular mixtures. Nature, 1997, 386, 379–382.

13.

Bagster

D. F.

Studies on the effect of moisture content and coarse and fine particle concentration on segregation in bins. Kona, 1996, 14, 138–143.

14.

Bagster

D. F.

The influence of cohesion on the segregation pattern in bins. In Proceedings of the First IEAust International Conference on

Bulk Materials Storage, Handling and Transportation, Newcastle, New South Wales, Australia, 22–24 August 1983, pp. 203–206 (Institution of Engineers, Australia, Barton, Australian Capital Territory).

15.

Baxter

Tuzun

Heyes

D. M.

Hayati

Fredlund

The micro-mechanics of segregation and stratification in granular heaps. In Proceedings of the World Congress on

Particle Technology, Brighton, 1997, paper 326 (Institute of Chemical Engineers, London).

16.

Salter

G. F.

Pittman

A. N.

Reed

A. R.

Barnes

R. N.

Mixing of particulate solids using static mixers. In Proceedings of the Fifth IEAust International Conference on

Bulk Materials Storage, Handling and Transportation, Newcastle, New South Wales, Australia, 10–12 July 1995, pp. 395–401 (Institution of Engineers, Australia, Barton, Australian Capital Territory).

17.

Salter

G. F.

Investigation into the segregation of heaps of particulate material with particular reference to the effects of particle size. PhD thesis, University of Greenwich, Woolwich, London, March 1999.

18.

Barnes

R. N.

Resonant vibratory feeders. In Proceedings of the Fourth IEAust International Conference on

Bulk Materials Storage, Handling and Transportation and the Seventh IFPS International Symposium on Freight Pipelines, Wollongong, New South Wales, Australia, 6–8 July 1992, pp. 321–326 (Institution of Engineers, Australia, Barton, Australian Capital Territory).

19.

Williams

J. C.

Kahn

M. I.

The mixing and segregation of particulate solids of different particle size. Chem. Engr, 1973, 19–25.

20.

BS 1796: Part 1, 1989 Methods Using Test Sieves of Woven Wire Cloth and Perforated Metal Plate (British Standards Institution, London), equivalent to ISO 2591–1:1988(E) (International Standardization Organization, Geneva).

21.

O'Dea

Waters

Quantifying segregation in a bulk solids handling system. In Proceedings of the Fourth IEAust International Conference on

Bulk Materials Storage, Handling and Transportation and the Seventh IFPS International Symposium on Freight Pipelines, Wollongong, New South Wales, Australia, 6–8 July 1992, pp. 413–417 (Institution of Engineers, Australia, Barton, Australian Capital Territory).