Chemical Extraction of Potassium from Soils and Micaceous Minerals With Solutions Containing Sodium Tetraphenylboron: II. Biotite1
- A. D. Scott and
- M. G. Reed2
Biotite samples were treated with NaCl-NaBPh4 solutions and various methods of separating the precipitated K from the resulting mixture were evaluated. As a result, a boiling NH4Cl solution method was adopted for K extraction experiments with small samples and a foaming method was used in the preparation of a large sample of degraded biotite for mineral property studies.
Most of the K in biotite was easily extracted by placing the biotite in 1N NaCl-0.067N NaBPh4 solutions that also contained EDTA. The rate of K removal, however, varied with the size of the particles. In the case of < 50µ biotite, K was removed at an average rate of 1.6 mg. per 100 g. per minute for 3 days. The K in vermiculite particles of the same size was removed even faster.
Na-degraded biotite that contained only 3.9 me. K per 100 g. had an expanding structure. With water and glycerol treatment, however, expansion was limited to about 5 Å. Air-dry, water-treated samples had a basal spacing of 12.3 Å. corresponding to 1 layer of water. The loss of this interlayer water resulted in an endothermic peak at 135° C. in the differential thermal curve of this sample.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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