A reciprocating-plate extraction column for hydrometallurgical applications
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Some other designs of r e c i p r o c a t i n g - p l a t e columns a r e shown in Figs. 1 and 2. 3,4 In the column shown in Fig. 1 the sieve p l a t e s do not extend over the e n t i r e c r o s s s e c t i o n a l a r e a of the column shell; the s e g m e n t a l f r e e a r e a of the plate s e r v e s as a p a s s a g e for the continuous phase around the p l a t e s , and if a r r a n g e d so as to be on opposite sides on a l t e r n a t e p l a t e s , a c r o s s flow a r r a n g e m e n t of the two p h a s e s will be approximated. The p l a t e s a r e provided with s k i r t s on t h e i r p e r i p h e r y , extending downwards when the lighter phase is to be
RECP IROCATN IG
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MECHANISM
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SIEVE PLATE/
I. RECIPROCATING-PLATE COLUMNS RO0
The idea of using a set of r e c i p r o c a t i n g sieve p l a t e s was suggested by van Dtjck in his patent for pulsed columns. 1 An e x t r a c t i o n column utilizing this p r i n c i ple was developed by K a r r . 2 The sieve p l a t e s in this column differ in two r e s p e c t s f r o m those g e n e r a l l y used in pulsed columns: the holes a r e of a s u b s t a n t i a l l y l a r g e r d i a m e t e r , and the open a r e a of the p l a t e s is also c o n s i d e r a b l y l a r g e r than that r e c o m m e n d e d for pulsed columns. However, the e s s e n t i a l m e c h a n i s m for p r o ducing and maintaining a d i s p e r s i o n of one liquid in the other is the same in the two types of column: both liquids have to p a s s through the s a m e openings in the p l a t e s and it is mainly the s h e a r in and near the holes that p r o d u c e s d r o p l e t s of a s i z e g e n e r a l l y s m a l l e r than the hole d i a m e t e r . J. LANDAU is Professor and A. DIM and R. HOULIHAN are Graduate Students, Department of Chemical Engineering, University of New Brunswick, Fredericton, N.B., Canada. Manuscript submitted March 20, 1973 METALLURGICAL TRANSACTIONS
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EO RC NA AT TN REACLP ITR IEG MECHANISM
Fig. 1--Reciprocating plate column. VOLUME 4, DECEMBER 1973-2827
ROD
2
ROD
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pulsed and r e c i p r o c a t i n g - p l a t e c o l u m n s . 1) I n s t a n t a n e o u s P r e s s u r e at Base of P u l s e d C o l u m n Pbp = Ps + Pip + n A P f
[1]
where Ps 9
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Pip
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/ n PLATE
--static pressure contribution, --inertial contribution due to pulsing of entire content of liquid in the column, --frictional and inertial contribution due to unsteady flow through a plate, --number of plates
F o r Pip we have
2 -'---
Pip = pL gc
dUl dt
[21
where f
PLATE
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u l - - i n s t a n t a n e o u s bulk v e l o c i t y of liquid in c o l u m n L --height of liquid in c o l u m n . 2) I n s t a n t a n e o u s P r e s s u r e at Base of R e c i p r o c a t i n g Plate Column
[3]
Pbr = Ps + n A P j PLATE
2 -"-
F i g . 2--Reciprocating plate column with adjacent plates out of phase.
d i s p e r s e d , and upwards when it is d e s i r e d to d i s p e r s e the h e a v i e r phase. Since the two p h a s e s need not p a s
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