Tree analysis, widely used to evaluate the grade-recovery-boundary by gener
ating a grade-recovery-curve, is used in evaluating froth flotation circuit
separation efficiency. This paper analyses the tree analysis experimental
procedure and then models it. It is suggested that since many output stream
s in a tree analysis are identical, a fact hitherto unreported, there may b
e large errors in the experimental procedures. Modeling suggests that there
is no such thing as a unique grade-recovery-curve; rather, each such curve
is dependent on the operator, the equipment used, how the experiment was r
un, and, more important, the level of the tree analysis, e.g., 4, 20 or 100
. Clearly, the experimental tree analysis procedure is arbitrary: the surfa
ce chemistry varies during any one float and differs among floats in the sa
me analysis, is sensitive to the decisions an operator makes, requires an e
xperienced operator, depends on the discretion of the operator, has an arbi
trary end-of-float point, is dependent on when and the amount of collector
added, depends on the type of cell used, how that cell is operated and whet
her and how much froth cleaning spray is added. Regrettably, tree analysis
is neither well defined nor readily repeated by independent operators. Two
instrument designs for doing tree analysis are presented. The first automat
es tree analysis enabling 20, 50 or 100 level trees to be run. Unfortunatel
y, this tree analysis instrument is difficult to stabilize. A second, more
accurate instrument is also discussed, which is easier to operate. (C) 1998
Elsevier Science B.V. All rights reserved.