| 1. |
- Abramov, A.A., et al.
(författare)
-
Chemistry and optimal conditions for copper minerals flotation : theory and practice
- 2005
-
Ingår i: Mineral Processing and Extractive Metallurgy Review. - : Informa UK Limited. - 0882-7508 .- 1547-7401. ; 26:2, s. 77-143
-
Tidskriftsartikel (refereegranskat)abstract
- Reliable information on the surface state of sulphide copper minerals and regularities of sulphidization and flotation of oxidized copper minerals, the composition of sorption layer on the mineral surface forming during its interaction with xanthate or dixanthogen, and the influence of collector forms sorption on the copper minerals floatability and on the optimal conditions for these minerals flotation and depression has been obtained at present. The determined physicochemical models in the form of quantitative equations have been derived for the optimal conditions of flotation and depression of copper minerals under changing pH value and of sodium sulphide, lime, cyanide, zinc–cyanide complexes additions. The equations derived were proven in the laboratory and industrial scale and can be used both in automatic control systems at plants and for improvement of technological processes of selective flotation of copper containing ores.
|
|
| 2. |
- Ahlberg, E., et al.
(författare)
-
The surface oxidation of pyrite in alkaline solution
- 1990
-
Ingår i: Journal of Applied Electrochemistry. - 0021-891X .- 1572-8838. ; 20:6, s. 1033-1039
-
Tidskriftsartikel (refereegranskat)abstract
- The collector-less flotation of pyrite has been studied by conventional techniques and is correlated to the electrochemical behaviour of pyrite in alkaline solution (1m NaClO4, pH 11). It was concluded that the initial oxidation of pyrite produces a hydrophobic sulphur rich surface together with hydrophilic iron hydroxide species. Also upon grinding, the surface is covered by hydrophilic species and therefore no significant flotation was obtained in the absence of a collector. However, collectorless flotation was readily obtained in an iron complexing solution like EDTA. This indicates that the remaining sulphur-rich layer is responsible for the floatability of pyrite under these conditions.
|
|
| 3. |
- Alexandrova, L, et al.
(författare)
-
The influence of mixed cationic-anionic surfactants on the three-phase contact parameters in silica-solution systems
- 2011
-
Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 373, s. 145-151
-
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.
|
|
| 4. |
- Alexandrova, L., et al.
(författare)
-
Thin film studies in mixed cationic-anionic surfactant system
- 2003
-
Ingår i: Proceedings of the XXII International Mineral Processing Congress. - Marshalltown, South Africa : South African Institute of Mining and Metallurgy. - 0958460922 ; , s. 838-846
-
Konferensbidrag (refereegranskat)
|
|
| 5. |
- Alexandrova, L, et al.
(författare)
-
Three-phase contact parameters measurements for silica-mixed cationic-anionic surfactant systems
- 2009
-
Ingår i: Colloids and Surfaces A. - : Elsevier BV. - 0927-7757 .- 1873-4359. ; 348:1-3, s. 228-233
-
Tidskriftsartikel (refereegranskat)abstract
- The stability and interactions in thin wetting films between the silica surface and air bubble containing (a) straight chain C10 amine and (b) cationic/anionic surfactant mixture of a straight chain C10 amine with sodium C8, C10 and (straight chain) C12 sulfonates, were studied using the microscopic thin wetting film method developed by Platikanov [D. Platikanov, J. Phys. Chem. 68 (1964) 3619]. Film lifetimes, three-phase contact (TPC) expansion rate, receding contact angles and surface tension were measured. The presence of the mixed cationic/anionic surfactants was found to lessen contact angles and suppresses the thin aqueous film rupture, thus inducing longer film lifetime, as compared to the pure amine system. In the case of mixed surfactants heterocoagulation could arise through the formation of positively charged interfacial complexes. Mixed solution of cationic and anionic surfactants shows synergistic lowering in surface tension. The formation of the interfacial complex at the air/solution interface was confirmed by surface tension data. It was also shown, that the chain length compatibility between the anionic and cationic surfactants system controls the strength of the interfacial complex. The observed phenomena were discussed in terms of the electrostatic heterocoagulation theory, where the interactions can be attractive or repulsive depending on the different surface activity and charge of the respective surfactants at the two interfaces.
|
|
| 6. |
- Antti, Britt-Marie, et al.
(författare)
-
Pulp chemistry in calcite flotation. : Modelling of oleate adsorption using theoretical equilibrium calculations
- 1989
-
Ingår i: Mining engineering. - 0026-5187. ; 2:1, s. 93-109
-
Tidskriftsartikel (refereegranskat)abstract
- This paper considers the conditions required for direct flotation of calcite. Flotation experiments have been performed with oleate as the collector reagent and water glass as the dispersant and modifier. To be able to explain what happens in the flotation, solubility and adsorption experiments have been conducted parallel to, and under the same conditions as, the flotation experiments. Theoretical equilibrium calculations have been made with the help of data from the practical experiments for the purpose of modelling the adsorption experiments. With theoretical equilibrium calculations it is possible to predict that silicate ions will form complexes with calcium ions at the mineral surface.
|
|
| 7. |
- Antti, Britt-Marie, et al.
(författare)
-
Pulp chemistry in industrial mineral flotation. Studies of surface complex on calcite and apatite surfaces using FTIR spectroscopy
- 1989
-
Ingår i: Mining engineering. - : Elsevier BV. - 0026-5187. ; 2:2, s. 217-227
-
Tidskriftsartikel (refereegranskat)abstract
- Flotation experiments in a Hallimond tube have been performed on calcite and apatite at pH levels and oleate concentrations judged to be interesting from the point of view of adsorption isotherms. For the calcite system, adsorption isotherms indicate precipitation of calcium oleate after monolayer formation at pH 9, 10 and 11. In the apatite system, a double layer of oleate is formed. This means that apatite, unlike calcite, is sensitive to collector reagent overdosage. With the aid of FTIR techniques it is possible to demonstrate the existence of a surface complex in the apatite system with a calcium-oleate ratio of 1:1 at monolayer coverage of the surface. In conditions corresponding to bulk precipitation of calcium oleate, this compound can be detected by FTIR analysis of unfloated material.
|
|
| 8. |
|
|
| 9. |
- Ayyala, Sekhar, et al.
(författare)
-
Aggregate Characteristics in Coagulation and Flocculation
- 1993
-
Ingår i: Mineral Processing and Extractive Metallurgy Review. - : Informa UK Limited. - 0882-7508 .- 1547-7401. ; 12:2-4, s. 165-184
-
Tidskriftsartikel (refereegranskat)abstract
- Physical characteristics of mineral aggregates (such as density, size, shape, structure and strength) formed by either electrolytic coagulation or polymeric flocculation, need to be critically controlled by optimum conditioning in mineral processing. The present paper discusses the various experimental techniques used to determine these properties. In addition, physical and chemical factors that determine the rates of floe growth and which subsequently influence the floe morphology are summarised. This review also elucidates the hydrodynamic aspects of creeping flow and summarises the various settling velocity equations pertaining to the calcuation of floe density.
|
|
| 10. |
- Ayyala, S, et al.
(författare)
-
Effect of corrosion inhibitors on grinding and flotation of a lead-zinc ore
- 1993
-
Ingår i: Minerals Engineering. - 0892-6875 .- 1872-9444. ; 6, s. 929-935
-
Tidskriftsartikel (refereegranskat)abstract
- Grinding and flotation experiments on a Pb-Zn ore were carried out to evaluate : 1) wear of the grinding media both in the presence and absence of an inhibitor and 2) effect of the inhibitor on the flotation of Pb-Zn minerals. The percentage reduction in the wear of the grinding media was observed to be between 25-36%, depending on the type of the inhibitor and its critical concentration. The inhibitors used in the investigation were sodium sulphite, sodium nitrite, sodium chromate and sodium silicate. The results indicate that a specific corrosion inhibitor, for example sodium sulphite, may give better recoveries and grades in flotation but is not as efficient as sodium chromate in inhibiting the wear of the grinding media. Pulp solutions (after grinding) analysed for metal ion concentrations showed low Fe. Iron released into the solution as a result of corrosion reactions subsequently forms insoluble hydroxy complexes and may coat the mineral surfaces. Such hydrophilic coatings may adversely affect the floatabilities of minerals. The particle size analysis of the ground product has been carried out and the results are discussed.
|
|
