Electrochemical investigation of contact angle and of flotation in the presence of alkylxanthates. II. Galena and pyrite surfaces

1977 ◽  
Vol 30 (5) ◽  
pp. 981 ◽  
Author(s):  
JR Gardner ◽  
R Woods
Keyword(s):  
Contact Angle ◽  
Electrode Potential ◽  
Electrochemical Investigation ◽  
Pyrite Surface ◽  
Mineral Surface ◽  
Hydrated Iron Oxide ◽  
Mineral Particles ◽  
Lead Electrode ◽  
Nitrogen Bubble ◽  
Metal Xanthate

The contact angle between a nitrogen bubble and galena and pyrite surfaces immersed in methyl-, ethyl- or butyl-xanthates has been determined as a function of the electrode potential and of the quantity of xanthate species formed by interaction with the mineral surface. For galena, the initial chemisorbed xanthate layer was found to be hydrophobic when ethyl- or butyl-xanthates were employed, but hydrophilic for the methyl homologue. The presence of dixanthogen enhanced the contact angle but the metal xanthate diminished it. This conclusion was supported by contact angle studies at a lead electrode. For pyrite the surface was hydrophilic except when dixanthogen was formed, but a significant quantity was required on the mineral surface before a finite contact angle was observed. This behaviour is interpreted in terms of the presence of hydrated iron oxide on the pyrite surface. ��� The potentials at which particulate bed electrodes of galena and pyrite begin to float were determined for ethyl- and butyl- xanthates. The potentials correspond to the regions where chemisorption of xanthate takes place on galena and where significant quantities of dixanthogen are formed on pyrite. ��� With butylxanthate, flotation was inhibited when excessive quantities of xanthate species were present on galena or pyrite. The inhibition arose from flocculation of the mineral particles.

Electrochemical investigation of contact angle and of flotation in the presence of alkylxanthates. I. Platinum and gold surfaces

1974 ◽  
Vol 27 (10) ◽  
pp. 2139 ◽  
Author(s):  
JR Gardner ◽  
R Woods
Keyword(s):  
Contact Angle ◽  
Gold Electrode ◽  
Electrochemical Investigation ◽  
Gold Surfaces ◽  
Gold Particles ◽  
Electrode Surfaces ◽  
Maximum Angle ◽  
Static Contact ◽  
Nitrogen Bubble ◽  
Concentration Levels

The contact angle between a nitrogen bubble and platinum or gold electrode surfaces immersed in xanthate solutions has been determined as a function of the quantity of dixanthogen on the metal surface for the methyl, ethyl and butyl compounds. Significant angles result from fractional coverages, but multilayers are required before the maximum angle, characteristic of the particular alkyldixanthogen, is reached. The quantity of dixanthogen required to float a particulate bed electrode of gold spheres was determined for a number of alkylxanthates. The required quantity varied from multilayers for methyl to low fractional coverages for the longer chain compounds. Nevertheless the static contact angle corresponding to these coverages was in each case found to be close to 55� for the three alkyldixanthogens studied. When butyl- or pentyl-xanthates were used at typical concentration levels applicable to practical situations (10 p.p.m.), flotation was inhibited when the quantity of dixanthogen formed was more than two to four times greater than the minimum amount necessary for flotation to occur. This inhibition arose from flocculation of the gold particles.

Pyrite Surface Alteration of Synthetic Single Crystals as Effect of Microbial Activity and Crystallographic Orientation

2007 ◽  
Vol 20-21 ◽  
pp. 350-353 ◽  
Author(s):  
Katja Etzel ◽  
Harald Huber ◽  
Reinhard Rachel ◽  
Gottfried Schmalz ◽  
Michael Thomm ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Crystallographic Orientation ◽  
Cell Attachment ◽  
Epifluorescence Microscopy ◽  
Pyrite Surface ◽  
Mineral Surface ◽  
Metallosphaera Sedula ◽  
Surface Alteration ◽  
Thermophilic Archaea ◽  
Scanning Electron

To enhance our understanding of effects of microbially mediated pyrite dissolution and the influence parameters such as varied metabolism and crystallographic orientation of pyrite surfaces some dissolution experiments were performed. Microbial etching experiments on pyrite surfaces of different orientation, including {111} and {210} were devised. The experiments were performed using two strains of thermophilic Archaea (Sulfolobus metallicus, Metallosphaera sedula). Epifluorescence microscopy observations showed that the strains attach to the mineral surface. Studies with Scanning Electron Microscopy (SEM) showed cell attachment and etching effects after one week of incubation. Surface alteration produced structures following crystallographic orientation up to several 10 μm in size. For all incubated pyrite samples it became apparent that surface alteration was more pronounced with M. sedula than with S. metallicus.

The anodic oxidation of ethylxanthate on metal and galena electrodes

1972 ◽  
Vol 25 (11) ◽  
pp. 2329 ◽  
Author(s):  
R Woods
Keyword(s):  
Current Efficiency ◽  
Electrode Potential ◽  
Surface Characteristics ◽  
Infrared Analysis ◽  
Metal Xanthate ◽  
Lead Electrodes ◽  
Initial Layers ◽  
C 50 ◽  
Constituent Elements ◽  
Galena Electrode

The products of the electrochemical oxidation of potassium ethylxanthate have been identified by infrared analysis and microanalysis for the constituent elements. The current efficiency for the formation of diethyl dixanthogen depends on the nature of the electrode, and at 0.5 V was found to be 100, 98, 90, c. 50, and 0% for platinum, gold, copper, galena, and lead respectively. The remainder of the current passed at this potential resulted in the formation of the metal xanthate.� Dixanthogen is formed on lead electrodes only at potentials of > 1.0 V, where lead xanthate is unstable with respect to oxides of the metal. The lead xanthate produced on a galena electrode at pH 9.1 involves the release of thiosulphate ions. The formation of lead xanthate by this reaction, followed by its reduction to lead, is shown to change the surface characteristics of a galena electrode to those of lead. However, the formation and reduction of the initial layers which takes place on cycling the electrode potential does not change a galena surface and cannot involve loss of sulphur from the surface to the solution. This supports the conclusion that the chemisorbed xanthate monolayer is first covered by dixanthogen and that lead xanthate forms only when bulk layers are produced.

scholarly journals Incorporation of hydrophobized mineral particles in activated sludge flocs: a way to assess ballasting efficiency

2005 ◽  
Vol 52 (10-11) ◽  
pp. 177-184 ◽  
Author(s):  
G. Defontaine ◽  
J. Thormann ◽  
B.S. Lartiges ◽  
A.G. El Samrani ◽  
O. Barrès
Keyword(s):  
Activated Sludge ◽  
Optical Microscopy ◽  
Sodium Oleate ◽  
Surface Hydrophobicity ◽  
Mineral Surface ◽  
Coated Particles ◽  
Sludge Flocs ◽  
Mineral Particles ◽  
Microbial Flocs

The role of mineral surface hydrophobicity in attachment to activated sludge flocs was investigated. Fluorite and quartz particles of similar granulometry were hydrophobized by adsorbing sodium oleate and dodecylamine chloride, respectively. Mineral hydrophobicity was assessed by flotation expriments. The attachment of particles to microbial flocs was determined by optical microscopy. The results indicate that hydrophobized particles are always better incorporated within activated sludge flocs than non-coated particles. A comparison with Aquatal particles used as sludge ballast reveals that hydrophobized minerals are associated with microbial flocs to the same extent.

scholarly journals Ultraviolet Irradiation on a Pyrite Surface Improves Triglycine Adsorption

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 50 ◽  
Author(s):  
Santos Galvez-Martinez ◽  
Eva Mateo-Marti
Keyword(s):  
Functional Group ◽  
Chemical Species ◽  
Photoemission Spectroscopy ◽  
Molecular Adsorption ◽  
Surface Chemical ◽  
Pyrite Surface ◽  
Mineral Surface ◽  
Chemical Changes ◽  
X Ray ◽  
Highly Sensitive

We characterized the adsorption of triglycine molecules on a pyrite surface under several simulated environmental conditions by X-ray photoemission spectroscopy. The triglycine molecular adsorption on a pyrite surface under vacuum conditions (absence of oxygen) shows the presence of two different states for the amine functional group (NH2 and NH3+), therefore two chemical species (anionic and zwitterionic). On the other hand, molecular adsorption from a solution discriminates the NH2 as a unique molecular adsorption form, however, the amount adsorbed in this case is higher than under vacuum conditions. Furthermore, molecular adsorption on the mineral surface is even favored if the pyrite surface has been irradiated before the molecular adsorption occurs. Pyrite surface chemistry is highly sensitive to the chemical changes induced by UV irradiation, as XPS analysis shows the presence of Fe2O3 and Fe2SO4—like environments on the surface. Surface chemical changes induced by UV help to increase the probability of adsorption of molecular species and their subsequent concentration on the pyrite surface.

Effect of electrode membrane surface ratio and thickness on lead electrode potential

1981 ◽  
Vol 75 (3-4) ◽  
pp. 185-190 ◽  
Author(s):  
K. L. Cheng ◽  
Sunetra N. Kar Chaudhari
Keyword(s):  
Electrode Potential ◽  
Membrane Surface ◽  
Lead Electrode ◽  
Electrode Membrane

scholarly journals Size-Dependent Affinity of Glycine and Its Short Oligomers to Pyrite Surface: A Model for Prebiotic Accumulation of Amino Acid Oligomers on a Mineral Surface

2018 ◽  
Vol 19 (2) ◽  
pp. 365 ◽  
Author(s):  
Rehana Afrin ◽  
Narangerel Ganbaatar ◽  
Masashi Aono ◽  
H. Cleaves II ◽  
Taka-aki Yano ◽  
...  
Keyword(s):  
Amino Acid ◽  
Pyrite Surface ◽  
Mineral Surface ◽  
Size Dependent ◽  
Amino Acid Oligomers

Bubble–surface interactions with graphite in the presence of adsorbed carboxymethylcellulose

Soft Matter ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 587-599 ◽  
Author(s):  
Jueying Wu ◽  
Iliana Delcheva ◽  
Yung Ngothai ◽  
Marta Krasowska ◽  
David A. Beattie
Keyword(s):  
Contact Angle ◽  
Polymer Concentration ◽  
Adsorbed Layer ◽  
Surface Interactions ◽  
Bubble Surface ◽  
Graphite Surface ◽  
Mineral Surface ◽  
Film Rupture ◽  
Bubble Rise ◽  
Wetting Film

Bubble rise and collision against a graphite surface pre-treated with an adsorbed layer of carboxymethylcellulose. The adsorbed layer can prolong wetting film rupture, dramatically slow the dewetting of the mineral surface, and reduce the final contact angle of the bubble. Adsorption of CMC from a solution of higher polymer concentration amplifies the effect of the polymer.

Impact of Heavy Oil Sewage Components on the Performance of Coagulated Particles

2019 ◽  
Vol 394 ◽  
pp. 69-72
Author(s):  
Bo Yang ◽  
Jian Zhang ◽  
Xue Fei Huang ◽  
Tao Yu ◽  
Cheng Tun Qu
Keyword(s):  
Contact Angle ◽  
Heavy Oil ◽  
Electrode Potential ◽  
Oil Content ◽  
Ph Value ◽  
Surface Wettability ◽  
Standard Electrode Potential ◽  
The Relationship ◽  
Oil Wastewater

In this paper, the relationship between the components of heavy oil wastewater and thesurface wettability of coagulation particles were studied. The effects of cations (Ca2+, Mg2+, Fe2+,Fe3+), oil content and pH on wettability of coagulated particles surface in heavy oil wastewater werestudied by measuring the contact Angle, and the possible mechanism was discussed. It was foundthat the contact Angle decreased with the increase of pH value. The change of oil content isnegatively correlated with the contact Angle. Surface wettability of coagulated particles arecorrelated with cationic concentration in sewage and standard electrode potential. When cationicconcentration is less than 500 mg/L, surface wettability is positively correlated with standardelectrode potential. When cationic concentration is more than 1000 mg/L, surface wettability ismainly related to the total amount of cationic ions in sewage.

scholarly journals A Study of Temperature Effect on the Xanthate’s Performance during Chalcopyrite Flotation

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 426 ◽  
Author(s):  
Dongbo An ◽  
Jinhong Zhang
Keyword(s):  
Contact Angle ◽  
Temperature Effect ◽  
Elevated Temperatures ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Mineral Surface ◽  
Copper Ore ◽  
Weight Percentage ◽  
Macro Scale ◽  
Reflectance Ftir

A multi-scale investigation was conducted to study the surface properties of xanthate-absorbed chalcopyrite at elevated temperature to understand the temperature effect on the xanthate’s performance during chalcopyrite flotation. Firstly, a macro-scale study was initiated to investigate the temperature effect on the hydrophobicity of mineral surface by means of contact angle measurement, Hallimond tube microflotation and lab flotation tests; secondly, a micro–scale study was conducted to clarify the temperature effect on the adsorption of chemicals on mineral surface employing an atomic force microscope (AFM) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). In the experiments, pure chalcopyrite samples were used for contact angle measurement, Hallimond tube microflotation, AFM and FTIR; and copper ore samples (1.51% Cu, 5.88% Fe 0.029% Mo, 5.23% S in weight percentage) were used for lab flotation tests. FTIR spectra and AFM images showed that, when potassium amyl xanthate (PAX) was used as the collector in this study, oily dixanthogen was the main hydrophobic species on the chalcopyrite surface. The morphological change of dixanthogen patches at elevated temperatures has a more significant impact than changes in the amount of adsorption species. Increasing temperature within a certain range is beneficial for the collector’s performance by increasing flotation recovery.

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