Construction of the headflow and powerflow plots
Examples on how to use these graphs
 Example 1
 Example 2
 Example 3

Example 4
Hydraulic Efficiency

Equation 4

Equation 5
 Equation 6
 Figure 6
Operating Ranges

Equation 7

Equation 8
Pilot Plants Look Different
 Example 6

Equation 9
 Equation 10
Designing the Pumper Stage with Multiple Impellers
 Figure 7
Scaleup of the Auxiliary Tanks
 Example 7
 Example 8
Comparison With Other Impeller Designs
Conclusions
References
Abstract
The methodology of determining the optimum SX
pumpermixer system based on bench top, pilot, or smallscale solvent extraction
systems, is demonstrated. The design of smallscale SXplants is different
than a fullscale plant. The difference is explained here. The use of
dimensionless parameters Nh, Nq, and Np that describe the head, flow and power
of the pumper is shown and how to use them for the scaleup. Additional
data is required to determine the optimum operating range. Applications of this methodology were used to design well known currently
operating SX plants. The emphasis on the optimization of hydraulic
efficiency will be shown on examples, including how the hydraulic efficiency is
affected when the throughput of the system goes beyond the design. Designs
of all sizes of equipment will be shown which optimize the hydraulic efficiency.
Introduction
Solvent extraction (SX) has been used to extract metals for a long time. In the late 1960’s, the popular and accepted Holmes & Narver design was introduced to recover copper [1]. Design data was scarce and new plants were often designed based on past experience. In the early days of largescale solvent extraction, it was not uncommon to find plants based on similar throughputs. The design of solvent extraction plants was an art, understood by a few. With time, four other solvent extraction designs surfaced: Davy, Bateman, Outokumpo, and Krebs. None of these companies publish enough details for engineers to design their own plants. The former all have the same mixersettler concept: one impeller in the first chamber or tank creates the flow and initial dispersion, other impellers maintain the dispersion long enough for the mass transfer to take place, and a settling zone separates the aqueous from the organic phases (Figure 1). Krebs has reversed the order with mixing first and pumping second. 