| 1. |
- Abdel-Khalek, N.A., et al.
(författare)
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Effect of starch type on selectivity of cationic flotation of iron ore
- 2012
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Ingår i: Mineral Processing and Extractive Metallurgy. - 0371-9553 .- 1743-2855. ; 121:2, s. 98-102
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Tidskriftsartikel (refereegranskat)abstract
- Cationic flotation is one of the most widely accepted technologies for upgrading siliceous iron ore using polysaccharides (mainly starches) as depressing agents for iron bearing minerals while floating silica with amines. In this paper, a group of starches are investigated as depressants for haematite. These starches are wheat, corn, rice, potato and dextrin. The role of starch type on the selectivity of the separation process has been studied through zeta potential, adsorption measurements as well as flotation tests. The effects of type of starch and pH of the medium have been studied. The results indicate that the selectivity of the separation process is strongly affected by the type of starch used, where better results are obtained with corn starch or wheat starch in comparison to the other types. Fourier transform infrared spectroscopy measurements indicated that the interaction between starches and haematite surface is intermolecular interaction.
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| 2. |
- Alexandrova, L, et al.
(författare)
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The influence of mixed cationic-anionic surfactants on the three-phase contact parameters in silica-solution systems
- 2011
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Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 373, s. 145-151
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Tidskriftsartikel (refereegranskat)abstract
- The formation of thin wetting films on silica surface from aqueous solution of (a) tetradecyltrimetilammonium bromide (C14TAB) and (b) surfactant mixture of the cationic C14TAB with the anionic sodium alkyl- (straight chain C12-, C14- and C16-) sulfonates, was studied using the microscopic thin wetting film method developed by Platikanov. Film lifetimes, three-phase contact (TPC) expansion rates, receding contact angles and surface tension were measured. It was found that the mixed surfactants caused lower contact angles, lower rates of the thin aqueous film rupture and longer film lifetimes, as compared to the pure C14TAB. This behavior was explained by the strong initial adsorption of interfacial complexes from the mixed surfactant system at the air/solution interface, followed by adsorption at the silica interface. The formation of the interfacial complexes at the air/solution interface was proved by means of the surface tension data. It was also shown, that the chain length compatibility between the anionic and cationic surfactants controls the strength of the interfacial complex and causes synergistic lowering in the surface tension. The film rupture mechanism was explained by the heterocoagulation mechanism between the positively charged air/solution interface and the solution/silica interface, which remained negatively charged.
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| 3. |
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| 4. |
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| 5. |
- Ikumapayi, Fatai, et al.
(författare)
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Recycling of process water : effect of calcium and sulphate ions in sulphides flotation
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 51-61
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The effects of major components of calcium and sulphate ions in process water on sulphide mineral flotation has been investigated through Hallimond flotation of pure sulphide minerals using tapwater and water containing sulphate and calcium ions as well as through bench scale flotation of complex sulphide ores using tapwater and process water and with tapwater in the presence of calcium and sulphate ions. Hallimond flotation indicated activation of pyrite and slight depression of galena and chalcopyrite in the presence of high concentration of major species of calcium and sulphate ions using potassium amyl xanthate as collector. Bench scale flotation indicated activation of zinc when processwater was used and flotation in tapwater containing calcium and sulphate ions presented similar but not identical results.
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| 6. |
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| 7. |
- Ikumapayi, Fatai, et al.
(författare)
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Recycling of process water in sulphide flotation : Effect of calcium and sulphate ions on flotation of galena
- 2011
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Ingår i: 5th International Flotation Conference 2011. - Red Hook : Curran Associates, Inc.. - 9781618393951 ; , s. 222-249
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Konferensbidrag (refereegranskat)abstract
- The effects of major components of calcium and sulphate species present in recycled process water on galena flotation has been investigated through Hallimond flotation, zeta-potential, diffuse reflectance FTIR spectroscopy and XPS measurements using pure galena mineral as well as bench scale flotation tests using complex sulphide ore. The significance of process water species in flotation has been assessed using deionised water, process water and simulated water containing calcium and sulphate ions in experiments. In addition, the effect of temperature in bench scale flotation tests has also been examined.Hallimond flotation indicated lower recoveries of galena in the presence of calcium and sulphate ions using potassium amyl xanthate as collector. Calcium ions increase zeta-potential of galena while sulphate ions have no effect. FTIR and XPS studies revealed the presence of surface oxidised sulfoxy, hydroxyl and carbonate species on galena at pH 10.5 in deionised and process water, which surface species affected xanthate adsorption. Bench scale flotation using two different complex sulphide ores showed that galena recovery is better in process water than tap water at room temperature. Flotation results also indicated decrease of galenarecovery at temperatures lower than 22oC in either tap water or process water.
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| 8. |
- Ikumapayi, Fatai, et al.
(författare)
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Recycling of process water in sulphide flotation : effect of calcium and sulphate ions on flotation of galena
- 2012
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 39, s. 77-88
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Tidskriftsartikel (refereegranskat)abstract
- The effects of major components of calcium and sulphate species present in recycled process water on galena flotation has been investigated through Hallimond flotation, zeta-potential, diffuse reflectance FTIR spectroscopy and XPS measurements using pure galena mineral. The significance of process water species in flotation has been understood using deionised water, process water and simulated tap water containing equivalent calcium and sulphate ions concentration as in process water.Hallimond flotation indicated marginally lower recoveries of galena in the presence of calcium and sulphate ions using potassium amyl xanthate as collector. Zeta-potential shows the adsorption of calcium ions whereby the potential are seen to increase while sulphate ions have no significant effect. FTIR and XPS studies revealed surface calcium carbonate and/or calcium sulphate species in process water which affected xanthate adsorption. Presence of surface oxidised species such as sulfoxy, hydroxyl species on galena at pH 10.5 in deionised and process water was also revealed.
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| 9. |
- Ikumapayi, Fatai, et al.
(författare)
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Recycling process water in complex sulphide ore flotation
- 2012
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Ingår i: XXVI International Mineral Processing Congress (IMPC) 2012. - New Dehli : The Indian Institute of Metals. - 9788190171434 ; , s. 4411-4425
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Konferensbidrag (refereegranskat)abstract
- An approach to environmental sustainability and improved process economy, in sulphide minerals production is recycling of process water in flotation of complex sulphide ores, although the chemistry of process water may be a critical issue to flotation efficiency. The influence of major components of calcium and sulphate ions in process water on xanthate collector adsorption and flotation response using pure chalcopyrite, galena and sphalerite minerals were investigated by Hallimond flotation, zeta-potential measurement, FTIR and XPS spectroscopy studies, while bench scale flotation tests were also carried out using complex sulphide ores. The impact of the species in flotation was comprehended using deionised water, tap water, process water and simulated water containing equivalent amount of calcium and sulphate species in process water. Hallimond flotation results showed a decrease of chalcopyrite and galena recovery in process water and also in the presence of calcium and sulphate ions in both deionised and process waters, whereas sphalerite does not respond to flotation. The adsorption of calcium and metal ions but not sulphate ions on the minerals is evidenced by zeta-potential data. FTIR and XPS studies revealed the presence of surface oxidized sulfoxy species and surface calcium carbonates on chalcopyrite in the presence of process water and water containing calcium ions, surface oxidized sulfoxy and carbonate species on galena in the presence of deionised water, process water and water containing calcium and sulphate ions, all at flotation pH 10.5, and these surface species influenced xanthate adsorption. The presence of surface oxidized sulfoxy and carbonate species at the sphalerite flotation pH 11.5 were seen in the presence of deionised water, process water and water containing calcium and sulphate ions, but the surface species does not influence xanthate adsorption. Bench scale flotation using two different complex sulphide ores showed that chalcopyrite, galena and sphalerite recoveries are better in process water than tap water. The studies showed that the process water can be recycled in flotation with no detrimental effect on grade and recovery of sulphide minerals.
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| 10. |
- Ikumapayi, Fatai, et al.
(författare)
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Recycling process water in sulfide flotation, Part A: Effect of calcium and sulfate on sphalerite recovery
- 2012
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Ingår i: Minerals & metallurgical processing. - : Springer Science and Business Media LLC. - 0747-9182. ; 29:4, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- In order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the influence of major species, calcium and sulfate in process water on sphalerite flotation was investigated through Hallimond tube flotation, zeta potential, diffuse reflectance Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements using sphalerite mineral sample. Assessment of process water species in flotation was done using deionized water, process water and simulated water containing calcium and sulfate ions in experiments. Hallimond flotation shows increased sphalerite floatability in process water compared to deionized water, but no significant effect on the presence of calcium and sulfate ions in deionized water using isobutyl xanthate as a collector. The presence of calcium ions reduced the sphalerite's negative zeta potential, while at higher concentrations, a charge reversal occurred, at about pH 11. FTIR and XPS studies revealed the presence of surface-oxidized sulfoxy and carbonate species on sphalerite at pH 11.5 in deionized water, process water and water containing calcium and sulfate ions. These surface species do not influence xanthate adsorption.
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