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Novel operational method of continuous foam separation of gold –
Injection of metal and/or surfactant solutions into rising foam bed
T. Kinoshita a,∗, Y. Ishigaki a, K. Yamaguchi a, S. Akita a, Y. Yamadab,
S. Nii b, K. Takahashi b, F. Kawaizumi b
a Nagoya Municipal Industrial Research Institute, 3-4-41, Rokuban, Atsuta, Nagoya 456-0058, Japan
b Department of Chemical Engineering, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 4648603, Japan
Received 6 March 2006; received in revised form 8 May 2006; accepted 9 May 2006
報告學生：周暐祥
報告日期：2009/12/07
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Introduction (1/3)
 Total open-pit and underground mineral
resources were 960Mt at 0.7% copper, 0.3g/t
gold, 0.03% molybdenum and 3.1g/t silver.
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Introduction (2/3)
 LME CU Officials $/KG CASH 7.026 $
 LONDON FIX $/KG CASH 38,271 $
 Foam separation, the advantages of the
technique are low energy input and a simple
structure of equipment to obtain required
separation.
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Introduction (3/3)
 A nonionic surfactant, polyoxyethylene nonyl phenyl ether
(PONPE) (聚氧乙烯壬酚醚), showed a strong affinity for
Au(III) and could work as both foam-producer and metal
collector.
 Gold(III) in hydrochloric acid solutions is in the form of
tetrachloro auric acid (HAuCl4).
 In this study, a novel method of continuous foam separation
using PONPE has been proposed with the view of selective
recovery of Au(III) from binary metal solutions with Cu(II).
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Schematic drawing of persent technique
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Schematic diagram of foam separation apparatus
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Experimental procedure
 Experiments were carried out in three different
modes depending on the solution injected into the
rising foam bed in the column.
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Injection of metal solution to foam bed (mode A)
A further increase in the
injection rate, however,
results in a reduction in the
recovery because of the lack
of free surfactant for
capturing the metals supplied.
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Recovery of four metals in mode A
 The present mode was applied to a multi-metal solution
containing Au (III), Cu (II), Ga (III) and Fe (III).
 The selectivity for heavy metals relies mainly on the
affinity between the metals and the surfactant.
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Injection of surfactant solution to foam bed (mode B)
Increased air supply
not only enhances the
upward flow of the
foam bed, but also
suppresses the drainage
of the interstitial water.
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Injection of both metal and surfactant solutions
to foam bed (mode C)
In this manner, the
incompatible objective
of gaining both high
yield and high purity
can be attained in the
present foam
separation without
sacrificing either of
them.
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Conclusion
 In mode A, the separation behavior of metals coincides
with those observed in the solvent extraction using
PONPE.
 In mode B, a decrease in the recovery, however, was
observed with increasing the injection rate.
 In mode C, the trade-off relationship between the
recovery and separation, which are seen in modes A
and B, is successfully compensated in this mode.
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Thanks For Your Attention
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