Successive Multipl-e-Contact E-xtraction Nomograp
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N THE theory of liquid-liquid extraction, where the idcai dis-
I n this type of extraction the total quantity of solvent used is divided into several equal portions. The feed is treated with one of these portions;: the raffinate from this extraction is then treated with a second batch of the fresh solvent, etc. This is the type of axtraction commonly encouiitcred in thc~laboratory. A ready graphical solution of Equation 1 is obtained from the nomograph. For examplc, the dotted line indicates that if S D I H ,= 2.0, S = 2, and zo = 0.50, then x r / x o = 0.111, and 5.v = 0.056.
tribution law applies, the equation for successive multiplecontact extraction is
(1) where
5- =
weight of solute per Ib. of inert component i n feed
zv = weight of solute per lb. of inerts in final rafrinate H = Tveight 01 iiierts (constant)
S
D
,1IELT.-1N NORD Xord and Company, Znc., Kqport, N. J.
= TTeight of extracting solvent per stage (constant) = number of contacts = distribution coefficient‘
1
Perry, J. H., Chemical Engineer’s Handbook, 2nd od., p. 1245 (1941)
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