Determination of thallium by a dithizone mixed-color method
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Trace Elements Investigations↗
Geology topics
Roy S. Clarke
Publications and source records attributed to Roy S. Clarke.
The geochemistry of uranium in apatite and phosphorite
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Trace Elements Investigations↗
The determination of uranium (IV) in apatite
Geologic and mineralogic evidence indicate that the uranium present in apatite may proxy for calcium in the mineral structure as U(IV). An experimental investigation was conducted and chemical evidence was obtained that establishes the presence of U(IV) in apatite. The following analytical procedure was developed for the determination of U(IV). Carbonate-fluorapatite is dissolved in cold 1.5M orthophosphoric acid and fluorapatite is dissolved in cold 1.2M hydrochloric acid containing 1.5 g of hydroxylamine hydrochloride per 100 ml. Uranium (IV) is precipitated by cupferron using titanium as a carrier. The uranium in the precipitate is separated by use of the ethyl acetate extraction procedure and determined fluorimetrically. The validity and the limitations of the method have been established by spike experiments.
Trace Elements Investigations↗