| 1. |
- Ayyala, S, et al.
(författare)
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Effect of corrosion inhibitors on grinding and flotation of a lead-zinc ore
- 1993
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Ingår i: Minerals Engineering. - 0892-6875 .- 1872-9444. ; 6, s. 929-935
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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.
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| 2. |
- Wang, Yanmin, et al.
(författare)
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Hydrophobic magnetite seeding of hematite ultrafines in high gradient magnetic separation
- 1993
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Ingår i: Minerals Engineering. - 0892-6875 .- 1872-9444. ; 6, s. 537-546
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Tidskriftsartikel (refereegranskat)abstract
- The application of hydrophobic magnetite seeding to concentrate hematite ultrafines (<10 µm) in slimes using a high gradient magnetic separator (HGMS) with coarse expanded metal matrices was investigated. It was shown that the selective aggregation at high shear rate of the seeded hematite particles (produced by surface treatment with sodium oleate and colloidal magnetite) could significantly enhance the HGMS capture of hematite ultrafines. The mechanism of selective aggregation was discussed in terms of the combination of hydrophobic and magnetic interactions.
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| 3. |
- Ahlberg, E., et al.
(författare)
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The surface oxidation of pyrite in alkaline solution
- 1990
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Ingår i: Journal of Applied Electrochemistry. - 0021-891X .- 1572-8838. ; 20:6, s. 1033-1039
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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.
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| 4. |
- Ayyala, Sekhar, et al.
(författare)
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Aggregate Characteristics in Coagulation and Flocculation
- 1993
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Ingår i: Mineral Processing and Extractive Metallurgy Review. - : Informa UK Limited. - 0882-7508 .- 1547-7401. ; 12:2-4, s. 165-184
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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.
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| 5. |
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| 6. |
- Forssberg, Eric, et al.
(författare)
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Influence of grinding method on complex sulphide ore flotation: a pilot plant study
- 1993
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Ingår i: International Journal of Mineral Processing. - 0301-7516 .- 1879-3525. ; 38:3, s. 157-175
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Tidskriftsartikel (refereegranskat)abstract
- The present work deals with plant investigations on the influence of conventional and autogenous grinding methods in the floatation of a complex sulphide ore. The study includes the investigation of the particle size and shape analysis and the pulp chemical measurements-Eh, pH, O2 concentration of cations and anions, at several stages of the grinding and flotation circuits. The rougher floatation concentrates of the Cu-Pb and Zn circuits were analysed to evaluate the floatation behaviour of chalcopyrite, galena and sphalerite. The results indicate better liberation of minerals in coarse size fractions for the pulp ground by autogenous mill while conventional grinding shows higher degree of liberation in the fine size range. Metallurgical analyses of the final floatation concentrates shows higher recoveries of Cu, Pb and Zn for the pulp ground by autogenous milling. The grades of Cu and Pb were better with conventional grinding but the recoveries were less than those obtained by autogenous grinding. Several interesting observations concerning pulp chemistry (e. g. the concentrations of Fe ions is lower in pulps ground by conventional method than by autogenous means!) are discussed.
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| 7. |
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| 8. |
- Forssberg, Eric, et al.
(författare)
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Stabilization of mineral processing wastes
- 1992
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Ingår i: Emerging process technologies for a cleaner environment. - Littleton, Colo : Society for Mining, Metalurgy and Exploration. - 873351061 ; , s. 223-227
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Konferensbidrag (refereegranskat)
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| 9. |
- Forssberg, Eric
(författare)
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Strukturförändringar i Luleå
- 1993
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Ingår i: Bergsmannen med Jernkontorets Annaler. - 0284-0448. ; :2, s. 22-23, 25
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Bergsingenjörsutbildningen vid Tekniska högskolan omformas till linjen för industriell kemi.
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| 10. |
- Forssberg, Eric, et al.
(författare)
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Vibrationssignalanalyse bei der Eisenerzmahlung
- 1994
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Ingår i: Aufbereitungstechnik - Mineral processing. - 0004-783X. ; 35:10, s. 505-
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Tidskriftsartikel (refereegranskat)abstract
- Vibration signal measurements were performed on a commercial scale grinding process operated at LKAB. Three channels of mechanical vibration signals from the axial, horizontal and vertical directions, and one channel of acoustic signal at the centre of the abrasion zone outside the ball mill shell, were picked up, digitised and processed using a personal computer. The feed rate, power draw, pulp temperature were recorded automatically by the process control system while material samples of mill feed and product were taken for determination of particle size distribution and pulp density during signal acquisition. The particle size distributions, time-domain waveforms and power spectra were illustrated and discussed. By multivariate data analysis, close relationships were established between grinding parameters and the pattern of vibration signals. The results show that vibration signal analysis could be used to monitor grinding parameters for industrial scale ball mills.
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