| 1. |
- Yuan, Xuemin, et al.
(författare)
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Flotation of a complex sulphide ore I. Cu/Zn selectivity control by adjusting pulp potential with different gases
- 1996
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Ingår i: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 46:3-4, s. 155-179
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the possibility of using gases with varying oxygen activity and their influence on copper-zinc selectivity, flotation tests were done in a mechanical laboratory cell on a fine-grained complex sulphide ore with high pyrite and pyrrhotite content. The pulp environment was modified by changing the grinding media and by using different gases in the pre-conditioning a flotation steps. A statistical design with two levels of grinding media, four levels of pre-conditioning, and three levels of flotation gas type, was used. It is found that the grinding environment is the most dominant variable influencing the flotation results. Strong interactions exist between the pre-conditioning type and the flotation gas for mild steel grinding. Such interactions, and even the direct influence of pre-conditioning and flotation gas type, are statistically insignificant for stainless steel grinding, which often gave good copper flotation. The Cu/Zn selectivity shows a strong dependence on the pre-conditioning type and flotation gases for mild steel grinding, but not for stainless steel grinding. The best Cu/Zn selectivity happens for the combination of 5% oxygen pre-conditioning and air flotation after mild steel grinding. It seems that galvanic reactions after or during the mild steel grinding facilitate surface oxidation of sulphides. A mechanism similar to ferric leaching is proposed. As expected, it was observed that the oxidising or reducing environment in the pulp, as measured by the pulp potential, has a strong influence on the flotation results.
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| 2. |
- Yuan, Xuemin, et al.
(författare)
-
Flotation of a complex sulphide ore II. Influence of grinding environments on Cu/Fe sulphide selectivity and pulp chemistry
- 1996
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Ingår i: International Journal of Mineral Processing. - 0301-7516 .- 1879-3525. ; 46:3-4, s. 181-204
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Tidskriftsartikel (refereegranskat)abstract
- To investigate the possibility of using gases with varying oxygen activity and their influence on copper-zinc selectivity, flotation tests were done in a mechanical laboratory cell on a fine-grained complex sulphide ore with high pyrite and pyrrhotite content. The pulp environment was modified by changing the grinding media and by using different gases in the pre-conditioning a flotation steps. A statistical design with two levels of grinding media, four levels of pre-conditioning, and three levels of flotation gas type, was used. It is found that the grinding environment is the most dominant variable influencing the flotation results. Strong interactions exist between the pre-conditioning type and the flotation gas for mild steel grinding. Such interactions, and even the direct influence of pre-conditioning and flotation gas type, are statistically insignificant for stainless steel grinding, which often gave good copper flotation. The Cu/Zn selectivity shows a strong dependence on the pre-conditioning type and flotation gases for mild steel grinding, but not for stainless steel grinding. The best Cu/Zn selectivity happens for the combination of 5% oxygen pre-conditioning and air flotation after mild steel grinding. It seems that galvanic reactions after or during the mild steel grinding facilitate surface oxidation of sulphides. A mechanism similar to ferric leaching is proposed. As expected, it was observed that the oxidising or reducing environment in the pulp, as measured by the pulp potential, has a strong influence on the flotation results.
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| 3. |
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| 4. |
- Yuan, Xuemin, et al.
(författare)
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Statistical interpretation of flotation kinetics for a complex sulphide ore
- 1996
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 9:4, s. 429-442
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Tidskriftsartikel (refereegranskat)abstract
- Kinetic flotation models were applied to data from tests with reactive gases (hydrogen and sulphur dioxide) on a complex sulphide ore. The models were evaluated by statistical techniques, after non-linear regression on the model parameters. It is found that a first order model with rectangular distribution of floatability fits the test data very well. Statistical tests on copper, silver and lead kinetic data show that reactive gases have a greater influence on silver mineral flotation compared to copper-lead minerals. Sulphur dioxide generally gives higher ultimate silver recoveries than sodium bisulphite, and the magnitudes depend on the interactions between the modifiers and theflotation gases (5% H2 N2 and air). Correlation analysis suggests that silver flotation is probably determined by the floatability of a separate mineral such as tetrahedrite. Multivariate analysis on pulp chemistry data reveals that the pulp pH is the most significant variable among the pulp chemistry data, provided the grinding is iron free. The pH effect is attributed to the addition of sulphur dioxide. After autogenous or non-reducing grinding, the naturally-occurring variations in redox levels are too small to influence the flotation results, despite the tests being made with a complex sulphide ore.
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