Daniel Fornasiero - Academia.edu (original) (raw)

Papers by Daniel Fornasiero

Research paper thumbnail of Interaction of Fine and Ultrafine Particles with Gas Bubbles

The interaction of particles with bubbles as a function of particle size (0.1-7 micrometers) and ... more The interaction of particles with bubbles as a function of particle size (0.1-7 micrometers) and surface hydrophobicity was investigated using single bubble flotation experiments. A minimum in collection efficiency was observed at particle diameters of 1-2 micrometers. ...

Research paper thumbnail of Structure of oil-in-water emulsions stabilised by silica and hydrophobised titania particles

Journal of Colloid and Interface Science, Feb 1, 2010

We have studied the stability and structure of emulsions formed in the presence of colloidal mixt... more We have studied the stability and structure of emulsions formed in the presence of colloidal mixtures of partially hydrophobic titania particles and hydrophilic silica particles. On their own, the titania particles attached strongly to the oil-water interface and stabilised emulsions, while the silica particles did not attach to the interface. Adding silica particles to the titania dispersions enhanced coalescence processes during emulsion formation, except under mixing conditions that favoured particle heteroaggregation. The destabilisation of the emulsions was linked to the presence of silica particles in the particle layers at the interface.

Research paper thumbnail of Effect of Water Quality on Chalcopyrite and Molybdenite Flotation

ABSTRACT The objective of this study is to investigate the effects of water quality on mineral fl... more ABSTRACT The objective of this study is to investigate the effects of water quality on mineral floatability. For this, the species commonly found in process water, such as metal and sulphate ions, were investigated for their potential impact on the flotation performance of two valuable sulphide minerals, chalcopyrite and molybdenite. Zeta potential and X-ray photoelectron spectroscopy (XPS) measurements were used to identify the surface species responsible for the flotation of these minerals. Results showed that the flotation of both chalcopyrite and molybdenite was mostly depressed by aluminium and iron ions. Manganese and sulphate ions also depressed the flotation of molybdenite but not that of chalcopyrite. These results and interpretation of the zeta potential of these minerals in the presence of these salts in solution were able to explain the depression of the mineral flotation by metal hydroxide precipitated on the mineral surface. XPS analysis revealed that sulphate ions promoted the oxidation of molybdenite, which had a negative impact the flotation of this mineral.

Research paper thumbnail of The preparation of 99mTc-tertiarybutylisonitrile (99mTc-TBI) by a method suitable for routine clinical use

International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology, 1986

The myocardial imaging agent technetium-99m-hexakis (tertiarybutylisonitrile) (99mTc-TBI) was pre... more The myocardial imaging agent technetium-99m-hexakis (tertiarybutylisonitrile) (99mTc-TBI) was prepared by the reaction of [99mTc]pertechnetate with TBI in 50% ethanol/0.9% saline at 100 degrees C, using stannous chloride as the reducing agent. A study of the reaction parameters enabled the yield to be optimized to better than 90%, although this was reduced to approximately 60% if a purification step was carried out. Chromatographic analysis on ITLC-SG medium showed the final product to be of high radiochemical purity. Biological studies comprising biodistribution in mice over a 2-h period, imaging studies in animals and sub-acute toxicity testing in mice indicated that 99mTc-TBI prepared as here described is a suitable agent for routine clinical use in humans.

Research paper thumbnail of Correlation between copper-activated pyrite flotation and surface species: Effect of pulp oxidation potential

Research paper thumbnail of Boehmite suspension behaviour upon adsorption of methacrylate–phosphonate copolymers

Research paper thumbnail of The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

Minerals Engineering, 2014

ABSTRACT In the flotation of copper ores, several processing plants report that copper recovery i... more ABSTRACT In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS2) and pyrite (FeS2) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.

Research paper thumbnail of Effect of regrinding and pulp aeration on the flotation of chalcopyrite in chalcopyrite/pyrite mixtures

Research paper thumbnail of Influence of pulp aeration on the flotation of chalcopyrite with xanthate in chalcopyrite/pyrite mixtures

International Journal of Mineral Processing, 2015

Research paper thumbnail of Role of polymeric dispersant functional groups in the dispersion behaviour of titania pigment particles

Surface and Colloid Science, 2004

Research paper thumbnail of The interfacial conformation of polypropylene glycols and their foam properties

Minerals Engineering, 2006

Research paper thumbnail of Effect of iron content in sphalerite on flotation

Minerals Engineering, 2005

Research paper thumbnail of Bubble?particle attachment

Journal of the Chemical Society, Faraday Transactions, 1995

... 3, ch. 5. 7 R. Crawford and J. Ralston, Znt. J . Miner. Process., 1988,23, 1. 8 L. R. Fisher,... more ... 3, ch. 5. 7 R. Crawford and J. Ralston, Znt. J . Miner. Process., 1988,23, 1. 8 L. R. Fisher, D. Hewitt, EE Mitchell, J. Ralston and J. Wolfe, Adv. Colloid Interface Sci., 1992,39,397. 9 D. Hewitt, D. Fornasiero, J. Ralston and L. R. Fisher, J. Chem. SOC., Faraday Trans., 1993,89,817. ...

Research paper thumbnail of Influence of dissolved gas on bubble–particle heterocoagulation

Journal of the Chemical Society, Faraday Transactions, 1998

Research paper thumbnail of Electrostatics and Metal Oxide Wettability

The Journal of Physical Chemistry C, 2011

The wettability of a titania surface, whose surface was partially covered with a strongly based o... more The wettability of a titania surface, whose surface was partially covered with a strongly based octadecyltrihydrosilane, was studied above and below the isoelectric point (or pHiep). The advancing water contact angle is at a maximum at the pH iep, decreasing ...

Research paper thumbnail of Ultrathin Wetting Films on Hydrophilic Titania Surfaces: Equilibrium and Dynamic Behavior

The Journal of Physical Chemistry C, 2011

Colloid probe atomic force microscopy experiments were carried out between a titania particle and... more Colloid probe atomic force microscopy experiments were carried out between a titania particle and an air bubble in KCl solutions. The surface charges of both the bubble and the particle were controlled by varying the electrolyte concentration and pH of the solution. In ...

Research paper thumbnail of Properties of Fatty Amine–Silica Nanoparticle Interfacial Layers at the Hexane–Water Interface

The Journal of Physical Chemistry C, 2012

... 6. Ata, S.; Davis, ES; Dupin, D.; Armes, SP; Wanless, EJ Langmuir 2010, 26, 7865 [.

Research paper thumbnail of Colloid Stability and the Influence of Dissolved Gas

The Journal of Physical Chemistry B, 2003

Research paper thumbnail of Very Small Bubble Formation at the Solid−Water Interface

The Journal of Physical Chemistry B, 2003

... Conclusion. The formation of very small gas bubbles (so-called “nanobubbles”) at structured s... more ... Conclusion. The formation of very small gas bubbles (so-called “nanobubbles”) at structured solid−water interfaces has been studied using the tapping mode atomic force microscopy (TMAFM) imaging technique. ... (1) Dai, Z.; Fornasiero, D.; Ralston, J. J. Chem. ...

Research paper thumbnail of Stabilisation of titania pigment particles with anionic polymeric dispersants

Research paper thumbnail of Interaction of Fine and Ultrafine Particles with Gas Bubbles

The interaction of particles with bubbles as a function of particle size (0.1-7 micrometers) and ... more The interaction of particles with bubbles as a function of particle size (0.1-7 micrometers) and surface hydrophobicity was investigated using single bubble flotation experiments. A minimum in collection efficiency was observed at particle diameters of 1-2 micrometers. ...

Research paper thumbnail of Structure of oil-in-water emulsions stabilised by silica and hydrophobised titania particles

Journal of Colloid and Interface Science, Feb 1, 2010

We have studied the stability and structure of emulsions formed in the presence of colloidal mixt... more We have studied the stability and structure of emulsions formed in the presence of colloidal mixtures of partially hydrophobic titania particles and hydrophilic silica particles. On their own, the titania particles attached strongly to the oil-water interface and stabilised emulsions, while the silica particles did not attach to the interface. Adding silica particles to the titania dispersions enhanced coalescence processes during emulsion formation, except under mixing conditions that favoured particle heteroaggregation. The destabilisation of the emulsions was linked to the presence of silica particles in the particle layers at the interface.

Research paper thumbnail of Effect of Water Quality on Chalcopyrite and Molybdenite Flotation

ABSTRACT The objective of this study is to investigate the effects of water quality on mineral fl... more ABSTRACT The objective of this study is to investigate the effects of water quality on mineral floatability. For this, the species commonly found in process water, such as metal and sulphate ions, were investigated for their potential impact on the flotation performance of two valuable sulphide minerals, chalcopyrite and molybdenite. Zeta potential and X-ray photoelectron spectroscopy (XPS) measurements were used to identify the surface species responsible for the flotation of these minerals. Results showed that the flotation of both chalcopyrite and molybdenite was mostly depressed by aluminium and iron ions. Manganese and sulphate ions also depressed the flotation of molybdenite but not that of chalcopyrite. These results and interpretation of the zeta potential of these minerals in the presence of these salts in solution were able to explain the depression of the mineral flotation by metal hydroxide precipitated on the mineral surface. XPS analysis revealed that sulphate ions promoted the oxidation of molybdenite, which had a negative impact the flotation of this mineral.

Research paper thumbnail of The preparation of 99mTc-tertiarybutylisonitrile (99mTc-TBI) by a method suitable for routine clinical use

International journal of radiation applications and instrumentation. Part B, Nuclear medicine and biology, 1986

The myocardial imaging agent technetium-99m-hexakis (tertiarybutylisonitrile) (99mTc-TBI) was pre... more The myocardial imaging agent technetium-99m-hexakis (tertiarybutylisonitrile) (99mTc-TBI) was prepared by the reaction of [99mTc]pertechnetate with TBI in 50% ethanol/0.9% saline at 100 degrees C, using stannous chloride as the reducing agent. A study of the reaction parameters enabled the yield to be optimized to better than 90%, although this was reduced to approximately 60% if a purification step was carried out. Chromatographic analysis on ITLC-SG medium showed the final product to be of high radiochemical purity. Biological studies comprising biodistribution in mice over a 2-h period, imaging studies in animals and sub-acute toxicity testing in mice indicated that 99mTc-TBI prepared as here described is a suitable agent for routine clinical use in humans.

Research paper thumbnail of Correlation between copper-activated pyrite flotation and surface species: Effect of pulp oxidation potential

Research paper thumbnail of Boehmite suspension behaviour upon adsorption of methacrylate–phosphonate copolymers

Research paper thumbnail of The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

Minerals Engineering, 2014

ABSTRACT In the flotation of copper ores, several processing plants report that copper recovery i... more ABSTRACT In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS2) and pyrite (FeS2) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.

Research paper thumbnail of Effect of regrinding and pulp aeration on the flotation of chalcopyrite in chalcopyrite/pyrite mixtures

Research paper thumbnail of Influence of pulp aeration on the flotation of chalcopyrite with xanthate in chalcopyrite/pyrite mixtures

International Journal of Mineral Processing, 2015

Research paper thumbnail of Role of polymeric dispersant functional groups in the dispersion behaviour of titania pigment particles

Surface and Colloid Science, 2004

Research paper thumbnail of The interfacial conformation of polypropylene glycols and their foam properties

Minerals Engineering, 2006

Research paper thumbnail of Effect of iron content in sphalerite on flotation

Minerals Engineering, 2005

Research paper thumbnail of Bubble?particle attachment

Journal of the Chemical Society, Faraday Transactions, 1995

... 3, ch. 5. 7 R. Crawford and J. Ralston, Znt. J . Miner. Process., 1988,23, 1. 8 L. R. Fisher,... more ... 3, ch. 5. 7 R. Crawford and J. Ralston, Znt. J . Miner. Process., 1988,23, 1. 8 L. R. Fisher, D. Hewitt, EE Mitchell, J. Ralston and J. Wolfe, Adv. Colloid Interface Sci., 1992,39,397. 9 D. Hewitt, D. Fornasiero, J. Ralston and L. R. Fisher, J. Chem. SOC., Faraday Trans., 1993,89,817. ...

Research paper thumbnail of Influence of dissolved gas on bubble–particle heterocoagulation

Journal of the Chemical Society, Faraday Transactions, 1998

Research paper thumbnail of Electrostatics and Metal Oxide Wettability

The Journal of Physical Chemistry C, 2011

The wettability of a titania surface, whose surface was partially covered with a strongly based o... more The wettability of a titania surface, whose surface was partially covered with a strongly based octadecyltrihydrosilane, was studied above and below the isoelectric point (or pHiep). The advancing water contact angle is at a maximum at the pH iep, decreasing ...

Research paper thumbnail of Ultrathin Wetting Films on Hydrophilic Titania Surfaces: Equilibrium and Dynamic Behavior

The Journal of Physical Chemistry C, 2011

Colloid probe atomic force microscopy experiments were carried out between a titania particle and... more Colloid probe atomic force microscopy experiments were carried out between a titania particle and an air bubble in KCl solutions. The surface charges of both the bubble and the particle were controlled by varying the electrolyte concentration and pH of the solution. In ...

Research paper thumbnail of Properties of Fatty Amine–Silica Nanoparticle Interfacial Layers at the Hexane–Water Interface

The Journal of Physical Chemistry C, 2012

... 6. Ata, S.; Davis, ES; Dupin, D.; Armes, SP; Wanless, EJ Langmuir 2010, 26, 7865 [.

Research paper thumbnail of Colloid Stability and the Influence of Dissolved Gas

The Journal of Physical Chemistry B, 2003

Research paper thumbnail of Very Small Bubble Formation at the Solid−Water Interface

The Journal of Physical Chemistry B, 2003

... Conclusion. The formation of very small gas bubbles (so-called “nanobubbles”) at structured s... more ... Conclusion. The formation of very small gas bubbles (so-called “nanobubbles”) at structured solid−water interfaces has been studied using the tapping mode atomic force microscopy (TMAFM) imaging technique. ... (1) Dai, Z.; Fornasiero, D.; Ralston, J. J. Chem. ...

Research paper thumbnail of Stabilisation of titania pigment particles with anionic polymeric dispersants