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标题：Feldspar flotation as a quartz-purification method in cosmogenic nuclide dating: A case study of fluvial sediments from the Pamir
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作者：Vasila A. Sulaymonova ; Margret C. Fuchs ; Richard Gloaguen 等
期刊名称：MethodsX
印刷版ISSN：2215-0161
电子版ISSN：2215-0161
出版年度：2018
卷号：5
页码：717-726
DOI：10.1016/j.mex.2018.06.014
语种：English
出版社：Elsevier
摘要：Graphical abstractDisplay OmittedHighlights•Our flotation cell is built of borosilicate glass, holds up to 90 g of sample, and achieves quartz and feldspar separation in ≤2 h.•The procedure uses air bubbles to which the feldspars attach, 0.2% HF to reduce the surface energy of quartz, dodecylamine solution as a feldspar collector, and operates at a pH range of 2.4–2.7 at room temperature.•We trace the stepwise enrichment of quartz by X-ray diffraction analysis, which shows that froth flotation is the decisive step to reach 95–100% purity from the initial 23–46%.AbstractCosmogenic nuclide (CN) dating relies on specific target minerals such as quartz as markers to identify geologic events, including the timing of landscape evolution. The presence of feldspar in sediment samples poses a challenge to the separation of quartz and affects the chemical procedures for extracting the radioactive CNs10Be and26Al. Additionally, feldspar contamination reduces the26Al/27Al ratio, thus hinders the accurate determination of26Al by accelerator mass spectrometry (AMS). Using fluvial sediment samples from Central Asia, which contain 16–50 weight percent (wt.%) of feldspar, we show that the standard physical separation and chemical cleaning-up procedures for quartz-enrichment reduces the feldspar content to only 9–47 wt.%. We present a new froth flotation mineral-separation device and procedure that allows for very effective quartz enrichment before CN chemistry. Our flotation cell, which has a volume of 600 cm3, is built of borosilicate glass, holds up to 90 g of sample, and achieves quartz and feldspar separation in ≤2 h for very feldspar-rich samples. We trace the stepwise enrichment of quartz to 95–100% purity with our procedure by X-ray diffraction analysis.
关键词：Mineral separation;Quartz;Feldspar;Accelerator mass spectrometry;Cosmogenic nuclide dating