Reports

Gadolinium: Distribution between Aqueous and Silicate Phases

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Science  07 Aug 1970:
Vol. 169, Issue 3945, pp. 580-583
DOI: 10.1126/science.169.3945.580

Abstract

Studies of the partition of trivalent gadolinium between aqueous and silicate phases have been made at temperatures from 800° to 900°C and at pressures from 500 to 1000 bars. Constant values for the distribution coefficients for forsterite, enstatite, and diopside were obtained over a concentration range from 0.6 part per billion to 4 parts per thousand in the solid phases. Ratios of silicate crystal-aqueous phase distribution coefficients to silicate melt-aqueous phase distribution coefficients are close to the values for silicate crystal-silicate melt distribution coefficients estimated from natural systems. The free ion activity of trivalent gadolinium in the silicate melts appears to be less than one-hundredth of its value for aqueous phases of the same concentration.