Institute for Mineral and Energy Resources (IMER)

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The Institute for Mineral and Energy Resources (IMER) is specifically designed to address the challenge of continuing to grow the critical mineral and energy resources industries in a technically, economically, socially and environmentally sustainable manner through interdisciplinary research. IMER will address these complex research challenges faced by providing integrated research, education, professional development and consulting services across all aspects of the mineral and energy resources industries.

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Rheology as a diagnostic tool in the study of particle interactions relevant to mineral flotation
(Australasian Chemical Engineers, 2005) Duarte, A.; Grano, S.; CHEMECA (33rd : 2005 : Brisbane, Australia); Matt Hardin,; Institute for Mineral and Energy Resources
The rheological behaviour of colloidal silica and fine sphalerite particles has been studied to improve our understanding of particle interactions within mixtures of particles having different size and surface properties. The objective of the present study was to develop a tool that can be used to explain particle interactions, especially those that are detrimental to flotation performance, such as interactions between hydrophilic gangue (e.g., silica) and hydrophobic valuable mineral (e.g., sphalerite). The influence of solids volume fraction, pH and reagent additions was investigated for both silica and sphalerite, individually as single minerals and in mixtures of these minerals. For the single minerals studies, it was observed that the maximum aggregation was achieved at a pH value close to the pHiep of each mineral, as predicted by DLVO theory. Copper (II) is extensively used as an activator to enhance surface hydrophobicity of sulphide minerals, hence improving flotation performance. It was observed that copper (II) addition steadily increased sphalerite yield value, but that it had no effect on silica slurries. The addition of 2400 g/t of copper sulphate increased fine sphalerite yield value by approximately 69% from its value in the absence of copper (II). The same trend was observed for collector addition, on which sphalerite yield value increased by 21% when 1000 g/t of sodium isopropyl xanthate was added.
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Flotation Rate Constant Prediction for Metal Sulfide Particles
(AusIMM, 2005) Ralston, J.; Fornasiero, D.; Grano, S.; Duan, F.; Akroyd, T.; Centenary of Flotation Symposium (2005 : Brisbane, Queensland); Johnson, G.; Institute for Mineral and Energy Resources
We have determined the experimental rate constants for chalcopyrite particles floated from a complex sulfide ore and compared them with those calculated using a recently developed flotation model. The model incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using a surface spectroscopic approach. The calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell. We have extended this approach through the application of a property based model to an operating plant, with a satisfactory outcome.
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Surface cleaning action of dithiophosphate collector in pyrite flotation
(2006) Grano, S.; International Mineral Processing Congress (23rd : 2006 : Istanbul, Turkey); Onal, G.; Acarkan, N.; Celik, M.; Atesok, A.; Guney, A.; Sirkecl, A.; Yuce, A.; Perek, K.; Institute for Mineral and Energy Resources
The surface cleaning action of collector was studied by comparing surface changes affected by collector adsorption to those induced by ultrasonic cleaning. The effect of dicresyl dithiophosphate (DCDTP) adsorption on the flotation and electrokinetic properties of pyrite was studied, whilst surface alterations were identified by infrared and X-ray Photoelectron Spectroscopic (XPS) analysis. The mechanism of DCDTP interaction with pyrite is intimately linked to the state of pyrite oxidation prior to adsorption. Evidence for the formation of iron hydroxy complexes with DCDTP is presented. DCDTP interaction with pyrite, which surface regions contains significant oxidation products, results in the removal of surface hydrocarbon and sulphate species. Surface cleaning using ultrasonics substantially improves pyrite flotation recovery and rate. This effect is linked to enhanced DCDTP adsorption after ultrasonic cleaning.
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Selecting Frothers for the Flotation of Specific Ores by Means of Batch Scale Foaming Tests
(AusIMM, 2006) Zanin, M.; Grano, S.; Metallurgical Plant Design and Operating Strategies Conference (5th : 2006 : Perth, Western Australia); Institute for Mineral and Energy Resources
The selection of the proper frother, specifically for a given ore, is essential in flotation. Traditionally, strong and stable froths are required in the scavengers, where metal recovery needs to be maximised, while selectivity must be achieved in the roughers and cleaners, where grade of concentrates is the main issue. The physical properties of a froth are determined both by frother type, by process water composition and by the amount and nature of the suspended particles. The evaluation of different frothers, in terms of metallurgical performance, is complicated at plant scale, since it may lead to periods of malfunctioning of the process and unacceptable decreases in recovery. On the other hand, evaluation based on frother chemistry only, is often unsatisfactory, because the frothing response is strongly ore dependent. A procedure, and proper tools, was developed at the Wark in order to perform the screening of candidate frothers at batch scale on real pulp samples. The main parameters related to froth stability (half-life time, froth height) are measured after introducing the pulp samples into a foaming column, where different conditions in terms of frother addition, agitation and aeration can be maintained. The approach has been applied to the selection of frothers for the flotation of an Australian sulfide ore. Procedure and results are discussed.
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Improving the flotation behavior of a sulfide ore by controlling electrochemical interactions during grinding
(Electrochemical Society, Inc., 2006) Grano, S.; Huang, G.; International Symposium on Electrochemistry in Mineral and Metal Processing (7th : 2006 : Denver, Colorado)
The effect of grinding media and purging gas during grinding, on the flotation behaviour of a complex copper-lead-zinc sulphide ore was investigated. The optimum recoveries and grades of chalcopyrite were obtained with 21 % chromium medium combined with nitrogen purging. Mild steel medium may depress chalcopyrite flotation due to a high amount of oxidized iron species in the mill discharge. Grinding media displayed an influence on the Eh and galvanic current between media and mineral electrodes. The more electrochemically active the grinding media and the more oxidizing the environment, the greater the amount of oxidised iron in the slurry. Mild steel and high chromium media are more electrochemically active than the examined sulphide minerals. A generic approach to optimizing grinding conditions to improve the flotation separation of sulphide minerals is suggested by the study.
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Use of the foam drainage equation to model water flow in flotation froth
(Engineers Australia, 2007) Randriamanjatosoa, L.; Zanin, M.; Grano, S.; CHEMECA (35th : 2007 : Melbourne, Australia)
The standard foam drainage equation (Leonard and Lemlich, 1965; Goldfarb et al., 1988) was taken to model froth water flow in laboratory flotation column, using polypropylene glycols (PPG 425 and PPG 725) as frothers. Simulations were run to investigate the sensitivity of the model with respect to operating parameters. In the absence of particles, the model is in agreement with the experiments within a certain range of frother concentration; below and above which, it failed. Experimentally measured water flow rate was overestimated by the model at low and high frother concentration. Such discrepancies may be attributed to the assumptions accompanying the standard foam drainage equation. For instance, the model was modified to accommodate the effect of surface shear viscosity, which was measured using a deep channel surface shear viscometer. When plotted against frother concentration, surface shear viscosity follows the same trend as that of net water flow rate. It showed a maximum value within an intermediate range of frother concentration. The modified foam drainage equation that takes into account the interfacial properties of the gas-liquid interface significantly reduced the discrepancies between the model and experiment. However, a further improvement of the model is necessary to be applicable to three phase flowing froths in mineral processing industry.
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Froth stability as a performance indicator in sulphide minerals flotation plants
(Engineers Australia, 2007) Zanin, M.; Wightman, E.; Grano, S.; CHEMECA (35th : 2007 : Melbourne, Australia)
The implications of froth stability for recovery in mineral flotation are often underestimated. In the last years, technology and automation have been widely implemented in flotation plants, so that automatic level control and in-line visual analysis of the froth are now a standard feature in modern concentrators. However, most of the decision making process still relies on the operator's experience. The best flotation strategy is generally determined empirically, and froth stability, in particular, is rarely quantified. In this work, froth stability has been assessed, down the bank, in two different concentrators treating copper sulphide minerals. Froth stability was measured, in situ of the flotation cells, by the use of a transportable device (modified froth stability column), and other froth descriptors, like froth velocity and froth depth, were also measured. Differences in froth stability have been correlated to the different plant operating conditions, and implications on the recovery of minerals across the froth phase are discussed. It is shown that different flotation strategies may lead to similar metallurgical performance, and that froth stability can be a useful indicator to optimise operating conditions in the flotation cells.
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A model study of copper rougher recovery optimisation at PT Freeport Indonesia
(Australasian Institute of Mining and Metallurgy, 2007) Grano, S.; Akroyd, T.; Mular, M.; Nelson, M.; Mill Operators' Conference (9th : 2007 : Fremantle, Western Australia); Institute for Mineral and Energy Resources
A fundamental model, which considers the subprocesses of particle collection by bubbles in flotation, is applied to two comprehensive flotation surveys in the rougher stages of C3 concentrator, PT Freeport Indonesia. The flotation surveys focused on the collection of: • cell-by-cell and size-by-size metallurgical, • cell hydrodynamic, and • pulp and surface chemistry information. The two surveys were conducted at significantly different feed tonnages, giving rise to significantly different feed particle size distributions, pulp densities and mean pulp residence times. A series of model simulations are performed with the aim of quantifying changes in copper recovery, on both a size-by-size and unsized basis, with changes in values of the hydrodynamic parameters and hydrophobicity of the copper sulfide mineral. This was carried out in an effort to identify the most promising route to increase overall copper recovery in roughing. It was found that by increasing the hydrophobicity of the copper sulfide mineral surfaces it became possible to optimise cell hydrodynamics, which targeted increased fine (-12 μm) copper sulfide mineral recovery but without adversely affecting coarse (+150 μm) copper sulfide mineral recovery.
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Copper and molybdenite recovery in plant and batch laboratory cells in porphyry copper rougher flotation
(Science Press, 2008) Ametov, I.; Grano, S.; Zanin, M.; Gredelj, S.; Magnuson, R.; Bolles, T.; Triffett, B.; International Mineral Processing Congress (IMPC) (24th : 2008 : Beijing, China)
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Factors affecting froth stability in mineral flotation and implications on minerals recovery: A case of study
(GECAMIN Ltd, 2008) Zanin, M.; Gredelj, S.; Grano, S.; International Mineral Processing Seminar (5th : 2008 : Santiago, Chile); Casali, A.; Gomez, C.; Kuyvenhoven, R.; Institute for Mineral and Energy Resources
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The Detrimental Impact of High Pulp Temperature on Sphalerite Flotation After Zinc Regrinding in the Zinc Plant of Somincor, Lundin Mining Corporation, Neves Corvo, Portugal
(AusImm, 2008) He, S.; Grano, S.; Manouchehri, H.; Fordham, M.; Curral, J.; MetPlant 2008 (18-AUG-08 : Western Australia)
This paper focuses on the impact of high pulp temperature on sphalerite flotation after the zinc regrind circuit in the Zinc Plant of Somincor, owned and operated by Lundin Mining Corporation. In the zinc circuit, the zinc rougher concentrate is reground with forged steel media before flotation with one stage of roughing and scavenging, and three stages of cleaning to obtain a zinc final concentrate (zinc grade >50%). After regrinding, sphalerite flotation has been found to be seriously affected by high pulp temperature which may occur during the summer months. Mineral recoveries were found to be seriously reduced at pulp temperatures above 60°C. At this high pulp temperature, neither elevated copper sulfate concentration nor a decreased pH alone appreciably increased Zn recovery. However, a combination of these two (e.g. a decrease in pH from 11.5 to 10.8, and an increase in copper sulfate dosage from 400 g/t to 800 g/t) was found to reduce Zn depression at high pulp temperature. At pulp temperatures below 45°C, the negative influence of pulp temperature on mineral recoveries was minimal. A systematic series of flotation tests and solution/surface analyses were performed to reveal causes for poor sphalerite flotation at high pulp temperature after regrinding. The decrease in mineral recovery was shown to be associated with variations in the surface species on mineral particles in response to the increased pulp temperature. These variations in the surface species include collector desorption and superficial oxidation to form lead/zinc oxide/hydroxides on mineral particles. The influence of the type of regrinding media on sphalerite flotation at high pulp temperature was also addressed in this work.
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Optimising regrinding chemistry for pyrrhotite flotation
(Engineers Australia, 2008) Ye, X.; Gredelj, S.; Grano, S.; CHEMECA (36th : 2008 : Newcastle, Australia); Institute for Mineral and Energy Resources
Changes in the surface properties of minerals with grinding and regrinding play a key role in mineral flotation performance, being recognised in industry through the development of the IsaMill and Stirred Mill Detritor. This paper describes some initial results in a larger study which attempts to quantify changes in the flotation properties of sulphide minerals with regrinding using different mills. Pyrrhotite has been chosen in the current study due its importance in the recovery of Platinum Group Minerals and in its separation from pentlandite in Sudbury basin nickel ores. This current paper focuses on the results obtained using a Magotteaux Mill only. Factors which affected pyrrhotite flotation were particle size, grinding media contamination, and exposure of new mineral surface. Pyrrhotite recovery decreased with size reduction from 90%, achieved before regrinding, to 77%, 64%, 30% and 7% after regrinding with stainless steel medium to d{80} values of 60, 40, 20 and 10 m, respectively. Contact angle measurements were applied to quantify surface hydrophobicity as a function of particle size and the B.E.T. method was used to obtain the surface area. Increased collector addition only partially restored pyrrhotite recovery. The surface of the pyrrhotite mineral was changed by regrinding in a way that hindered collector adsorption onto the new mineral surface. A further dramatic depression of pyrrhotite recovery when using mild steel regrinding medium demonstrated that there was an additional contribution to pyrrhotite depression from media contamination in this case.
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Hydrocarbon prospectivity of Al-Sirhan Basin, southeast Jordan
(University of Jordan, 2008) Abul Khair, H.; Abed, A.; Amireh, B.; Institute for Mineral and Energy Resources
Al-Sirhan area in southeast Jordan is studied for its hydrocarbon potentiality.Petrophysical studies including porosity,permeability,water saturation,and hydrocarbon saturation are done using wire line logs for candidate reservoirs.Total organic carbon analysis is done for two candidate source intervals.Seismic investigation is also done using seventeen seismic sections that cover almost the central and eastern part of the area.Finally,closures, reserves,and proposed migration pathways of hydrocarbons are studied in order to assess the hydrocarbon potentiality of the study area. Within the Cambrian sequence,Salib Formation is found to contain good porosity due to partial dissolution of feldspars,very low permeability,and high water saturation.This formation is capped by the shales of the overlying Burj Formation.Possible source rock is the carbonates of the Burj Formation.Several types of closures with good capacities exist within the Salib Formation.The major risks,when considering Salib Formation as a target for petroleum exploration,are low TOC content of the source rock,low permeability and high water content of the reservoir rock. Within the Ordovician and Silurian sequence,the glacially deposited Trebeel Formation is found to contain good porosity,low permeability,and low water saturation.This formation is caped by the shales of the overlying Batra Formation.Several intervals contain good source rocks within this system.These are the shales of Sahl as Suwwan Formation,the shale layers at the upper part of Umm Tarifa Formation,and the shales of the overlying Batra Formation.TOC analysis in the present study proved that Hiswa Formation might be considered good source rock.Organic carbon analysis carried by several petroleum companies indicated the high TOC content of the lower part of Batra Formation and the upper shale layers of Umm Tarifa Formation (Paleoservices,1989). Several types of closures are found within Trebeel Formation.All the main closures were tested by wells and found to be almost dry.Thus,the major risks when considering Trebeel Formation as a target for petroleum explorations,are the low permeability of the reservoir rock, and the lack of potential untested closures. The only way that might cause filling the closures of the study area with hydrocarbons is from the source rocks within the Al-Sirhan Graben in Saudi Arabia.As the graben formed deeper depositional environment during the Paleozoic Era,better source conditions exist within the graben.Thus,hydrocarbons might be generated in the graben and migrated through the Jordanian borders to reach Al-Sirhan closures which exist at higher elevations. This scenario forms high risk as the pathway is interrupted by several growth faults that provide possible paths for hydrocarbons to escape to the surface.Accordingly,the study area is classified as high risk area for petroleum exploration.
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The critical influence of pulp oxygen content on the separation of pentlandite from pyrrhotite in two process streams of the Clarabelle Mill of Vale Inco, Sudbury, Canada
(Science Press, 2008) He, S.; Grano, S.; Manouchehri, H.; Taylor, A.; Lawson, V.; Duo, W.; International Mineral Processing Congress (IMPC) (24th : 2008 : Beijing, China)
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Flotation behaviour of sulphide mineral size fractions with controlled contact angle
(Engineers Australia, 2008) Muganda, S.; Zanin, M.; Grano, S.; CHEMECA (36th : 2008 : Newcastle, Australia); Institute for Minerals and Energy Resources (IMER)
The flotation response of chalcopyrite has been characterized as a function of particle size and advancing contact angle. The advancing contact angle of individual size fractions was manipulated to different values, measured using the Washburn technique. A flotation feed sample was constituted from the individual size fractions. Parameters such as frother concentration, impeller rotational speed, and superficial gas velocity were the same in each flotation test. The chalcopyrite sample, in the absence of any steps to intentionally manipulate the contact angle, displayed advancing contact angles which varied with particle size fraction. In the presence of a standard thiol collector, the advancing contact angle was also particle size dependent, with the -20 micron fraction displaying the lowest contact angle. Flotation tests showed that the chalcopyrite size fractions above 20 microns floated independently of each other, and that the flotation response was the same for the same particle contact angle and size fraction across different flotation tests. The flotation response was characterized by the maximum recovery at infinite flotation time and the distributed rate constant, assuming a single floatable fraction existed within each size fraction. When the distributed and undistributed rate constants were compared, the latter gave a greater dependency on contact angle as it took into account the non-floating fraction. The two rate constants converged at high advancing contact angles as the non-floating fraction approached zero. Further work on mineral floatability characterization will lead to the development of calibration curves of rate constant against particle size and contact angle, a tool that could be used to benchmark flotation response.
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Analysis of uncertainties in manometric gas-adsorption measurements II: Uncertainty in alpha S-analyses and pore volumes
(Academic Press Inc Elsevier Science, 2008) Badalyan, A.; Pendleton, P.; Institute for Mineral and Energy Resources
We describe procedures to propagate the uncertainty in adsorption data and alpha(S)-values to generate uncertainty in apparent primary, secondary, and total micropore volumes for porous activated carbons exhibiting Type I and IV character. The alpha(S)-data are interpolated from selected non-porous reference material (NPRM) adsorption isotherm data with some adsorbents exhibiting surface chemistry quite different from and some similar to that of the porous adsorbents (PA). We show that a statistically constant apparent total micropore volume can be determined independent of the NPRM surface chemistry. In contrast, NPRM surface chemistry appears to influence our ability to identify unequivocally the filling and condensation ranges of micropore filling, leading to statistically different apparent primary and secondary micropore volumes.
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Dependence of MILD combustion on fuel-air injection pattern within a recuperative furnace
(University of Queensland, 2009) Craig, R.; Dally, B.; Mi, J.; Australian Combustion Symposium (2009 : Brisbane, Qld.); Institute for Mineral and Energy Resources
A MILD combustion furnace was used to examine the feasibility of both counterflow and co-flow firing of reactants: natural gas (91.4% CH4) and air. It was found that the stability of MILD combustion under the counterflow conditions is highly sensitive to the momentum ratio of fuel to air ejecting into the furnace and that the present furnace geometry does not lend itself to this flow configuration. For most of the counterflow conditions studied, the exhaust gasses contained unburned hydrocarbons as well as high levels of CO and H2, implying that fuel short circuiting was occurring inside the furnace. In contrast, the co-flow firing configurations, especially with premixing of the reactants, have proven to work extremely well. Very low emissions of CO, H2 and NOx were recorded for a variety of equivalence ratios and firing rates.
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Free chlorine analysers: a user's selection guide
(Australian Water Association Inc, 2009) Badalyan, A.; Holmes, M.; Chow, C.; Vitanage, D.
Selecting new instrumentation for integration into water quality monitoring programs is fraught with uncertainties and potential pitfalls. An evaluation methodology for assisting water managers and operators to make the correct choice of an online free chlorine (FC) analyser based on key performance parameters is presented. Eight amperometric and one colorimetric online FC monitors were evaluated against 15 metrological parameters (response, delay, rise and fall times, linearity, limit of quantification, day-to-day repeatability, the effect of interferences, etc.) according to the procedure outlined in the two standards: ISO Standards 8466-1 (1990) and 15839 (2003). The test results were compared with the analysers' technical characteristics supplied by their manufacturers. In general, colorimetric systems performed better than amperometric systems, with the latter experiencing significant interference from the pH of water which was not adjusted during tests. All analysers performed within manufacturers' claimed limits for some metrological parameters, whereas for other parameters their performance was not adequate. It is strongly encouraged to perform evaluation tests under conditions similar to those in the field before purchasing a monitor.
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A Study of Detachment of Model Coarse Particles from Bubbles Using a Novel Electro-Acoustic Technique
(Engineers Australia, 2009) Xu, D.; Ametov, I.; Grano, S.; CHEMECA (37th : 2009 : Perth, Australia); Institute for Mineral and Energy Resources
In this paper, a detachment of particles from bubbles was investigated using a novel electro-acoustic technique. The experimental setup consisted of a loudspeaker connected to a computer through an amplifier. A teflon capillary tube was attached to the membrane of a loudspeaker. A bubble-particle aggregate on the other end of the capillary tube was subjected to vibration when the sinusoidal signal of fixed frequency and amplitude generated by the computer was transmitted to the loudspeaker. The critical amplitude of particle detachment was determined at a fixed frequency (50 Hz). The detachment experiments were conducted using model quartz particles of various size and hydrophobicity. Results showed that particles (600-850 m) with high contact angle (90 degree) required high amplitudes for detachment from bubbles. In contrast, quartz particles with low contact angle (49 degree) exhibited the considerably lower critical detachment amplitude. The critical detachment amplitude was related to the stability of bubble-particle aggregates. The results of electro-acoustic experiments correlated well with the outcomes of corresponding bench flotation tests.
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Diagenetic and epigenetic alteration of Cretaceous to Paleogene organic rich sedimentary successions in northwestern Jordan, typical of the western margin of the Arabian Plate
(Gulf Petrolink, 2009) Dill, H.; Kus, J.; Abed, A.; Sachsenhofer, R.; Abul Khair, H.; Institute for Mineral and Energy Resources

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