Annual Meeting Preliminary Program - Full Brochure (PDF) - SME

TECHNICAL PROGRAM
Mineral & Metallurgical Processing:
Flotation III
2:00 PM • Wednesday, February 27
chairs: T. Olson, FLSmidth Minerals, Salt Lake City, UT
S. Miskovic, University of Utah, Salt Lake City, UT
2:00 PM
Introductions
2:05 PM
Effect of Regrinding Chemistry and Particle Breakage Mechanisms
on Fine Particle Flotation
X. Chen 2 , Y. Peng 1 and D. Bradshaw 2 ; 1 School of Chemical Engineering,
The University of Queensland, Brisbane, QLD, Australia and
2
JKMRC, The University of Queensland, Brisbane, QLD, Australia
In this study, the effect of regrinding on the flotation of fine chalcopyrite and its
selectivity against pyrite has been studied. Different grinding media, including
mild steel, stainless steel and ceramic beads, are used, which produced different
regrinding chemistry, such as, pH, Eh, and iron hydroxide contamination. Their
effect on chalcopyrite and pyrite flotation behaviour is studied by using surface
analysis techniques. In addition, different mills are being used for regrinding to
provide different particle breakage mechanisms. So the role of different particle
breakage mechanisms on the flotation of chalcopyrite and its separation from
pyrite is investigated as well.
2:25 PM
XPS Studies of Surface Chemistry on Chalcopyrite-molybdenite
Separation by Flotation
E. Blanco 1 and X. Zhang 2 ; 1 Research-Labs, FLSmidth, West Jordan,
UT and 2 Metallurgy, University of Utah, Salt Lake City, UT
FLSmidth are currently developing studies of surface chemistry on Cu-Mo separation
by Flotation. Flotation recovery was studied as a function of electrochemical
potential, pH, percentage of solids, as main parameters. Then, an improvement
in devising flotation strategies has been achieved through the XPS surface
analysis to understand layers formation in the effective chalcopyrite depression.
A recovery of > 96% of the Molybdenum in the bulk Cu/Mo concentrate was obtained
in the bench scale laboratory. Preliminary XPS results indicate that adsorption
of collector at chalcopyrite surface may happen with addition of depressants.
In the presence of depressants, an oxidation layer might form. The
mechanism of this process may be that bivalent sulfur is transformed into hexavalent
sulfur which will hydrolyze the primary Cu reagents with evolution of H2S
at low pH values. Hydrolysis of SH- ions from collectors permits adsorption and
in changing the surface chemistry using sulf-hydrates depressants the collector
kept off the mineral surface. Effectiveness of conditioning parameters allows save
the numbers of cleaning step on the Cu/Mo separation metallurgical process.
2:45 PM
Investigations on Recovery of Hematite From Two Different
Banded Iron Ores by Flotation
B. Das and B. Mishra; Mineral Processing, CSIR-Institute of Minerals
and Materials Technology, Bhubaneswar, India
Hematite floatability from banded hematite quartzite (BHQ) and banded
hematite jasper (BHJ) using fatty acids and amine as the collectors is investigated
under identical physico-chemical conditions. While the hematite present in BHQ
ore is easy to float using both the collectors, jasper present in BHJ poses different
problems. It forms a fine coating over the hematite surface during the process of
grinding, hence collector ions do not adsorb specifically on hematite surfaces.
This is substantiated by scanning electron microscopy of the two ores indicating
the inclusions of dusty particles over hematite in BHJ ore. The other difference
between the two ores is that quartz grains are coarser and liberated below 100 micron
in case of BHQ compared to BHJ ore. The FTIR study indicated that oleatehematite
or amine-quartz affinity in the BHQ ore is stronger than that of the BHJ
ore. Under the circumstances, it was possible to achieve a concentrate containing
~64% Fe with ~67% recovery from a BHQ ore using both the collectors from a
feed containing around 38% Fe. On the other hand, the hematite concentration in
BHJ ore was poor.
3:05 PM
Applying an AFM in the Study of the Adsorption of Xanthate
on Arsenopyrite
J. Zhang and W. Zhang; University of Arizona, Tucson, AZ
The adsorption of xanthate on arsenopyrite surface in solutions has been studied
by applying an atomic force microscopy (AFM). AFM images show that the collectors
adsorb on arsenopyrite surface in patches at pH 6. The adsorption density
of the patches on mineral surface increases with the chemical dosage increasing.
The increased probe-arsenopyrite adhesion measured in PAX solutions at pH 6 is
attributed to the adsorption of the patches, suggesting the hydrophobic nature of
the patches, which is likely the oily dixanthogen. At a high pH with the addition
of Ca(OH)2, the adsorption of xanthate on arsenopyrite is greatly depressed because
the mineral surface is coated by a lot of precipitates, which is hydrophilic in
nature as shown by the measured strong repulsive probe-arsenopyrite detachment
force. The findings obtained with the AFM study show that the flotation behavior
of arsenopyrite in xanthate solutions is similar to that of pyrite.
3:25 PM
Characterising the Reducing Power of a Sulphide Ore With X-ray
Photoelectron Spectroscopy Technique: A Case Study
G. Montes Atenas; Dept. of Mining Engineering, University of Chile,
Santiago, Chile
Throughout the years, froth flotation research studies carried out at laboratory
scale have acknowledged the significance of surface chemistry phenomena on
the performance of the selective separation. Many techniques, and notably, scanning
electron microscope (SEM)-based technologies have revolutionised the entire
mineral processing industry. Nevertheless, the comprehensive understanding
on how surface chemistry affects the flotation performance is still a matter of
controversy. The aim of this research work is to apply the X-ray photoelectron
spectroscopy (XPS) technique to a sulphide ore at cleaning stages. Special attention
was made to design a protocol for sample preparation preserving the particles
surface as much as possible enabling to extract relevant data from the XPS
analysis. The XPS analysis of the in-situ-fully oxidised ore particles and that of
the original mineral species in the ore were used as the references to analyse spectra
obtained with the ore at cleaning stage. The XPS results showed good reproducibility
with regards to the reducing power of the ore computed using the O1s
line. The activation of pyrite mineral present in the ore is also discussed.
3:45 PM
Modification of Froth Properties in Iron Ore Flotation
J. Gustafsson; Akzo Nobel Surface Chemistry AB,
Stenungsund, Sweden
Flotation is used for beneficiation of iron ore. The gangue minerals are removed
by reverse flotation. The common practice is to use cationic collectors, such as
etherdiamines, for removal of silicates, especially from magnetite ores. The froth
phase which contains the gangue is often voluminous and stable. This creates
problem in the process, especially when the froth phase should be further
processed to improve the iron recovery. The froth properties are affected by the
chemistry of the collector, the water quality and also by particle size and shape of
floated minerals. To evaluate froth properties in laboratory scale Akzo Nobel
Surface Chemistry measures froth formation and stability in addition to performing
traditional flotation tests. The result of these combined measurements gives
improved knowledge about froth properties for different cases of magnetite flotation
and collector chemistries. Furthermore, the aim is to also reduce problems
with froth properties upon scaling up of laboratory procedures. This improves our
ability of taking froth characteristics into account when tailor-making collectors.
4:05 PM
New Methodology Enables Improved Evaluation
of Flotation Collectors
B. Cousins 1 , J. Phillips 2 and D. Salpeter 3 ; 1 Ashland Water Technologies,
Calgary, AB, Canada; 2 Ashland Water Technologies, Bridgeport,
WV and 3 State University of New York, Syracuse, NY
Flotation reagents are critical to the optimum performance of flotation circuits.
How a flotation reagent performs in the first few cells is a key indicator of how
well it will perform throughout the circuit. A method to compare reagent performance
has recently been developed by Ashland Water Technologies. This simple
procedure includes the collection of a timed sample of concentrate from each
cell and measuring the volume of the settled solids. An estimate of the percent-
This is the Technical Program as of September 1, 2012. IT IS SUBJECT TO CHANGE.
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Please see the Onsite Program for final details.