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| 2. |
- Ullakko, Kari, et al.
(författare)
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Isothermal Martensite Transformation of Fe-Ni-C Alloys as a Function of Hydrostatic Pressure
- 1990
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Ingår i: Materials Science Forum volumes 56-58. - Zürich : Trans Tech Publiations. ; , s. 197-200
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Konferensbidrag (refereegranskat)abstract
- Isothermal martensite transformation as a function of hydrostatic pressure was studied in Fe-Ni-C alloys. It was observed that the transformation was much the same as it happens as a function of time. Any noticeable differences in the morphology between isothermal and athermal martensite were not seen.
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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. |
- 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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| 6. |
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| 7. |
- Berglund, Gun
(författare)
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Pulp Chemistry in Sulphide Mineral Flotation
- 1991
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Ingår i: International Journal of Mineral Processing. - 0301-7516 .- 1879-3525. ; 33:1-4, s. 21-31
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Tidskriftsartikel (refereegranskat)abstract
- Variations in the oxidizing conditions of the pulp and their subsequent effects on flotation were examined for three types of natural sulphide ore, a complex pyrite ore, a sphalerite-galena ore and a chalcopyrite ore. Different gas mixtures ranging from pure nitrogen to pure oxygen were used to control the oxidizing conditions. The use of an oxygen rich flotation gas was found to be a suitable method for changing the oxidizing conditions and improving flotation under controlled conditions. The flotation results were correlated to the oxygen content and the redox potential, parameters which describe the pulp chemistry conditions.
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| 8. |
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| 9. |
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| 10. |
- Björkman, Bo, et al.
(författare)
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Kinetics of Impurity Elimination During Roasting
- 1994
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Ingår i: Extraction and processing for the treatment and minimization of wastes, 1994. - Warrendale, Pa : Minerals, Metals & Materials Society. - 0873392612 ; , s. 825-842
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Konferensbidrag (refereegranskat)abstract
- Four different arsenic containing dusts from the Boliden plant, Boliden Mineral AB, Sweden have been examined. A kinetic study of the arsenic elimination was performed in a laboratory scale roasting furnace for roasting furnace ESP dust and smelting furnace ESP dust. Characterisation and thermodynamic calculations were carried out to determine the mineralogy, and the stability of compounds in the dusts studied. The characterisation methods used were chemical analysis, X-ray diffraction analysis and microprobe analysis. It was found in the experiments that a high degree of As elimination was obtained for roasting furnace ESP dust and a low degree for smelting furnace ESP dust. Derived kinetic models are given. A prediction of the As-elimination for settling furnace dust and converter ventilation dust is presented
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