Environmental Engineering FOURTH EDITION

Reuse, Recycling, and Resource Recovery 28 1

output

I

Input

%+YO -

Binary XI +Yl

separator ir: WY2

Figure 14-6. Definition sketch of a binary separator.

been no separation. Accordingly, the purity of the extract stream as a percent may be
defined as

P(xl) = (L) 100.

x1 +YI

(14.7)

A separator might extract only a small amount of pure x, so that the recovery &,)
would also be very small. The performance of a materials separator is assessed by both
recovery and purity, and may thus be characterized by an additional parameter, the
separator eflciency E(x,y), as (Worrell 1979)

112

E(x,y) = (2 x E) x 100. (14.8)

EXAMPLE 14.2. Abinary separator, a magnet, is to separate aproduct, ferrous materials,
from a feed stream of shredded refuse. The feed rate to the magnet is 1000 kgh, and
contains 50 kg of ferrous materials. The product stream weighs 40 kg, of which 35 kg
are ferrous materials. What is the percent recovery of ferrous materials, their purity,
and the overall efficiency?
The variables in Eqs. (14.6), (14.7), and (14.8) are

R(xl) = (g) 100 = 70%

P(xl) = (m) 100 = 88%.

35

Then

Eg,,) = (g) (g) 100 = 70%.