Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 24 for “"Xanthates"”.
-
Copper and zinc xanthates
Includes bibliographical references.
-
The separation of ionic and organic mercury from water using milk proteins, xanthates and keratin
… mercury from water solutions with milk proteins, xanthates, and structural proteins have been investigated. Milk proteins, including lactalbumin, casein, whey and whole milk were tested in concentrations of one part protein per 500 parts water. Once filtered, these proteins removed up to 90% of …
-
Thermodynamic studies of xanthate adsorption on pyrite
… enthalpy (ΔH°) changes, for the adsorption of xanthates on pyrite. The electrochemical technique is based on the measurement of the open-circuit potentials of a pyrite electrode immersed in xanthate solutions at various temperatures. The thermochemical technique involves the determination of …
-
The role of collectors in the flotation of partially oxidised copper ores
The effects of xanthates, dithiophosphates, dithiocarbamates and mixtures of these collectors on the froth flotation performance of partially oxidised and oxidised copper sulphide ores were investigated in this study. More specifically, the role of the functional groups of the collectors, their …
-
Thermolysis Route for Accessing Amorphous Metal Sulfide Thin-Film Catalysts for the Hydrogen Evolution Reaction
… work, low temperature thermolysis of metal ethyl xanthates (M = Mo, Co, Fe, Ni) was used to prepare amorphous metal and mixed metal sulfide films on fluorine-doped tin oxide for the hydrogen evolution reaction (HER). Films prepared by dip-coating showed optimal coverage, as monitored by scanning …
-
An investigation into the floatability of platinum group arsenides and tellurides under varying collector and solution chemistries
… be its weaker electrochemical interaction with xanthates due to its poor electron-conducting properties. Operating under acidic conditions significantly improved the interaction of sperrylite with xanthates, hence its floatability. In the presence of PAX at pH 3, the microflotation recoveries of …
-
An investigation into the relationship between electrochemical properties and flotation of sulphide minerals
… between the flotation of sulphide minerals using xanthates as collectors and the electrochemical properties of the flotation system. It is well known that electrochemical mechanisms in flotation systems have a major influence on flotation since the reactions occurring at the mineral/solution …
-
Flotation of sulfide minerals with alkyl pyridinium salts
… and recovery in comparison to conventional xanthates. The best flotation results, in terms of both grade and recovery, were achieved with cetyl pyridinium chloride (CpCl). A distinct advantage of using CpCl instead of a conventional xanthate, such as sodium isopropyl xanthate (NaIpX), is …
-
AFM surface force measurements between hydrophobized gold surfaces
… by self-assembly of alkanethiols and xanthates of different chain lengths. The results showed long-range attractions despite the fact that the hydrophobizing agents chemisorb on gold and, hence, the adsorption layer is immobile. When the gold surfaces were hydrophobized in a 1 Ã 10-3 M …
-
Towards Water-Soluble Peroxyl Radial Clocks
… investigation of the use of alkyl and acyl xanthates as precursors to peroxyl radical clocks. These radical precursors offer the advantage that they have a pronounced ultraviolet absorption that tails into the visible, permitting efficient photochemical generation of the same alkyl radicals, …
-
The use of mixed thiol collectors in the flotation of Nkomati sulphide ore
… scope of this work was confined to the use of xanthates, DTC’s and DTP’s since they are in common use in industry, are supplied over a relatively low price range and have shown potential performance enhancements when used as mixtures. The standard University of Cape Town (UCT) batch flotation …
-
Nonstoichiometry of chalcocite in water-xanthate systems
… without xanthate. Stability regions for copper xanthates were also shown to be dependent on the sulfur oxidation state. As oxidation proceeded from elemental sulfur to sulfate, the copper xanthate stability region extended to lower potentials, directly dependent on the sulfide ion concentration. …
-
Surface Modification of Nanoparticles Using Controlled Radical Polymerization For Designed Interfaces
… on Marcomolecular Design via Interchange of Xanthates (MADIX) polymerization was demonstrated to graft polymer brushes on silica nanoparticles. For this work, a xanthate was anchored on the surface of silica nanoparticles using click chemistry. Polymerizations of styrene and vinyl acetate …
-
The thermochemical behaviour of thiol collectors and collector mixtures with sulphide minerals
… and galena. Thiol collectors investigated were xanthates of varying chain length (SEX, SIBX, PNBX and PAX) as well as dithiocarbamates (diethyl-DTC and n-butyl DTC) and diethyl-DTP. The current study seeks to gain knowledge of which collector interacts best with which mineral and an …
-
Fundamental studies of thionocarbamate interactions with sulfide minerals
… improved selectivity of IPETC and IBECTC over xanthates. Infrared reflection-absorption spectroscopic studies show that KEX is preferentially adsorbed on Cu° over IPETC and IBECTC. Between IPETC and IBECTC, the latter is more favorably adsorbed than the former. Kinetic studies using UV …
-
Radical Approaches to Alangium and Mitragyna Alkaloids
… unsaturated alpha-haloamides (d and e), xanthates (f), vinyl bromides (g and h). For this, a robust and efficient synthesis of an allyl tetrahydroisoquinoline core (i and j) was developed, following conversion into the desired radical precursors these compounds were treated with …
-
Synthesis of binary, ternary, and alloyed metal sulfides by a solvent-less route
… protocol, the work demonstrates the utility of xanthates as a single source precursor in the fabrication of semiconductor materials due to their low decomposition temperature and high possibility of forming pure crystalline products. The synthesis part of this study was divided into two …
-
On the selective flotation of pentlandite from pyrrhotite in Sheba's Ridge ores
… showed that using the different chain length xanthates or polysaccharide depressants on their own did not produce any pentlandite selectivity over pyrrhotite, but, when these reagents were used in conjunction with one another, some pentlandite selectivity was obtained. The best combination was …
-
A determination of the effect of changing collector chain length under varying Water Quality
… determined the concentration of residual xanthates present after flotation. i The study found that the longer chained collector, SIBX, behaved atypically to what has been observed in other studies. It obtained lower solids and recoveries than SEX in water with low ionic strengths. …
Page 1 of 2