Nickel activity in silicate liquids; some preliminary results
1979; Mineralogical Association of Canada; Volume: 17; Issue: 2 Linguagem: Inglês
ISSN
1499-1276
AutoresI. H. Campbell, A. J. Naldrett, P. L. Roeder,
Tópico(s)Concrete and Cement Materials Research
ResumoThe activity coefficient of nickel oxide (?Nro) in a number of silicate liquids has been determined by equilibrating the liquid with a Ni-Fe alloy at a known l(Og). Two series of experiments were carried out. .terr:es .l: Eighteen silicate liquids, ranging in composition from high-Mg basalt to dacite, were run at constant temp€rature (1300C) and l(Oz) (log l(Or) = -8.20) to assess the influence of composition on ?Nro. The activity coefficient varies from 7.8 in the high-Mg basalt to 30 in the dacite. The increase in ?Nro with the acidity of the liquid is ascribed to the decreasing number of octahedral sites in the liquid. Series 2: Four of the liquids used in Series I were run at a constant CO2/H2 ratio at temperature intervals of 50 between 1200 and 1400oC. Within the accuracy and temperature range of the experiments, ?,.rro ie proportional to the absolute temperature, provided the melt composition remains constant. As the activity of NiO is a measure of the solubitity of Ni in a silicate liquid, it can be used as an aid to predicting the Ni content of phases that crystallize from that liquid. Both the partitionine (D) of Ni between olivine and silicate liquids and the distribution coefficient (Ko) for Ni between immiscible sulfide and silicate liquids are considered as examples. Both parameters are strongly dependent on temperature and, to a lesser extent, on the composition of the silicate liquid.
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