| 1. |
- Forssberg, Eric, et al.
(författare)
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Aufbereitung von hochphosphorhaltigen Hämatiterzen in Nordschweden
- 1977
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Ingår i: Erzmetall. - 0044-2658. ; 30:11, s. 505-510
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Until now, the iron ores mined in Sweden were mostly of the magnetite type and, therefore, easy to concentrate. But in addition to these ores, there exist considerable reserves of hematite iron ores. Deposits located north of the city of Kiruna contain certain apatite-rich hematite ores which are extremely fine-grained. The authors explain how the selectivity problems that are due to this fine-grained structure of the ores and that arise during the flotation are handled.
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| 2. |
- Forssberg, Eric, et al.
(författare)
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Phosphate bonded fused alumina abrasive resistant material
- 1980
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 9:5, s. 211-215
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Tidskriftsartikel (refereegranskat)abstract
- Suitable particle size distribution and proportion of binder phase have been determined by measurements of mechanical strength and abrasion tests. A pump impeller was made. Comparative abrasion tests have shown that the abrasion resistance is better than that of a cast iron impeller and comparable to that of a rubber impeller.
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| 3. |
- Wang, Xianghuai, et al.
(författare)
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Activation of arsenopyrites by copper(II) ions
- 1989
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 18:6, s. 288-294
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Tidskriftsartikel (refereegranskat)abstract
- Copper adsorption on arsenopyrite minerals has been investigated. The effect of solution pH, Cu(II) concentration, oxygen, and oxidation on Cu(II) adsorption were examined. The results indicate that activation of arsenopyrite by Cu(II) in acidic media proceeds according to an ion exchange mechanism. Quantities describing the adsorption processes and reaction time are related either parabolically or logarithmically, depending on the initial copper (II) concentration and solution pH. Oxygen inhibits the adsorption of Cu(II) on arsenopyrite in acidic media, but copper initially adsorbed on an arsenopyrite surface does not undergo desorption upon prolonged oxidation. Increasing the solution pH can reduce the effect of oxygen on copper adsorption. The principles underlying the processes are discussed.
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| 4. |
- Wang, Xianghuai, et al.
(författare)
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Adsorption of copper(II) by pyrite in acidic to neutral pH media
- 1989
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 18:6, s. 262-270
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that no iron is liberated from the pyrite during the adsorption of Cu(II) by pyrite. The mass of Cu(II) removed by pyrite in an acidic neutral proceeds at an exceedingly slow rate. In the presence of iron-complexing agents, the removal of Cu(II) by pyrite in the initial step is very rapid, but then follows the same relationship exhibited in the absence of such complexing agents. The rate of Cu(II) adsorption depends on the solution pH and the Cu(II) concentration in solution. The adsorption rate increases with an increase in the solution pH. The influence of oxygen on the adsorption of Cu(II) by the pyrite is critical. In solutions with lower pH, copper initially adsorbed on pyrite surface undergoes desorption from the surface upon prolonged reaction with oxygen. The possible mechanism involved in the processes and the practical implications of the findings are discussed.
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| 5. |
- Wang, Xianghuai, et al.
(författare)
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Effect of oxygen on Cu(II) adsorption by sphalerite in acidic to neutral pH media
- 1989
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 18:5, s. 243-250
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Tidskriftsartikel (refereegranskat)abstract
- Sphalerite activation with Cu(II) ions in acidic and neutral pH media was investigated. Special attention was paid to the short-time adsorption characteristics and the effect of oxygen on the activation. In acidic media, the adsorption of Cu(II) ions on sphalerite in the initial stage is controlled by a surface dissolution + surface nucleation process. Oxygen inhibits the adsorption of Cu(II) on sphalerite. In neutral pH media, the process of sphalerite activation by Cu(II) ions can be described by a three-step model, and the effect of oxygen on Cu(II) adsorption is negligible.
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| 6. |
- Wang, Xianghuai, et al.
(författare)
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Pyrrhotite activation by Cu(II) in acidic to neutral pH media
- 1989
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Ingår i: Scandinavian journal of metallurgy. - 0371-0459 .- 1600-0692. ; 18:6, s. 271-279
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Tidskriftsartikel (refereegranskat)abstract
- An investigation of the activation of two natural pyrrhotite minerals by Cu(II) is described. The activation of pyrrhotite by Cu(II) ions involves a stoichiometric replacement of iron in the lattice by Cu(II) from the solution. The solubility of pyrrhotite, defined as the liberation of iron, decreases in the presence of Cu(II), presumably due to the formation of copper sulphides on the pyrrhotite surface. Copper adsorption increases with an increase in the solution pH. Oxygen inhibits the adsorption of copper on pyrrhotite, but the effect of oxygen decreases with an increase in solution pH. study shows that contrary to prevailing opinions, oxygen together with a high pulp pH cannot prevent copper adsorption on pyrrhotite.
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| 7. |
- Wang, Xianghuai, et al.
(författare)
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Thermodynamic calculations on iron-containing sulphide mineral flotation systems, I. The stability of iron-xanthates
- 1989
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Ingår i: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 27:1-2, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Thermodynamic calculations have been carried out for the Fe-EX-H2O system to study the stability of iron-xanthates. It has been shown that the formation and stability of insoluble iron-xanthate compounds depend critically on the xanthate concentration, the pH, and the redox potential of the solutions. Ferric xanthate is stable in acidic solutions, which may cause and improve the flotation of iron-sulphides under the corresponding conditions. Insoluble hydroxyl ferric xanthates, FeOH (EX)2 (s) and Fe(OH)2EX(s), are obtained in the weakly acidic to alkaline pH range. The formation of liquid dixanthogen is favoured at high xanthate concentrations and redox potentials. It has been found that under conditions where insoluble ferric-xanthate compounds are stable, the quantity of aqueous dixanthogen is relatively small and no liquid dixanthogen can be obtained. The "intermediate pH depression" phenomenon is then observed during the flotation of pyrite with xanthates.
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