Synthesis of Mn, Fe, Ni, Co oxide-hydroxide phases on manganese oxides on a model for transition metal ore formation in recent basins /
Experimental data are presented on the sorption dynamics of the dissolved forms of Ni, Co, Mn, Fe from seawater by manganese oxides (Mn304). The study of the initial sorbent and final products by scanning microscopy, X-ray photoelectron spectroscopy, X-ray analysis has revealed that these components...
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| Dokumentumtípus: | Cikk |
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University of Szeged, Department of Mineralogy, Geochemistry and Petrology
Szeged
1979
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| Sorozat: | Acta mineralogica-petrographica
24 No. 1 |
| Kulcsszavak: | Kőzettan, Ásványtan, Földtan |
| Tárgyszavak: | |
| Online Access: | http://acta.bibl.u-szeged.hu/24644 |
| Tartalmi kivonat: | Experimental data are presented on the sorption dynamics of the dissolved forms of Ni, Co, Mn, Fe from seawater by manganese oxides (Mn304). The study of the initial sorbent and final products by scanning microscopy, X-ray photoelectron spectroscopy, X-ray analysis has revealed that these components accumulate in the form of a newly-formed sorbed layer. The process is of a multistage nature. The initial stages are characterized by the development of ion-exchange and hydrolytic reactions, and the later ones by the interface autocatalytic oxidation of the components accumulated. The composition of the newly-formed compounds is controlled by the kinetics of the two basic stages, viz.: a) sorption proper; b) interface catalytic oxidation. The highest oxidized forms of the metals accumulated are observed at the relatively lower sorption rates, when the blocking effect of the first stage does not inhibit the development of the second stage. For instance, during the final experimental runs, at the relatively lower sorption rates, the external parts of the newly-formed layer show fairly large amounts of oxidized forms (%): Mn4+ =60, Ni3+ =30, Co3+ =30. Iron, as evidenced by MOSSBAUER spectroscopy, is present within the sorbed layer as FeOOH-HaO. The specific feature of the sorption of metals by hydrous manganese oxides is a partial interaction of Ni and Co with structural Mn2+ and Mn3 + . As a results of this interaction, Mn is displaced from the substrate into the solution in an amount equivalent to 16.14% of the sorbed Co or 17.96% of the sorbed Ni. The results presented together with a survey of the existing situation in the experimental field relating to the problem under study support the validity of an earlier model describing formation of the transition metal ore accumulations in recent basins. According to this model, the process is a multistage chemisorption interaction in which the main role is the interface autocatalytic oxidation of the sorbed metals. |
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| Terjedelem/Fizikai jellemzők: | 63-90 |
| ISSN: | 0365-8066 |