Determination of allophane and amorphous inorganic matter in clay fraction of soils 1 allophane and allophane-halloysite:mixturc

Abstract

The quantitative determination of allophane and amorphous inorganic matter by means of an alternate dissolution with 8 NHCl and 0.5 n NaOH, a dissolution with boiled 0.5 n NaOH, an extraction with acid ammonium oxalate solution, the cation-exchange capacity delta value of allophane, and a new method proposed in this study was discussed using allophane-halloysite mixture sample*. The new method proposed here Is based on the difference of weight loss with heating between 105 and 200°C, In the mixture samples, it was made clear that the method using the alternate dissolution with HCl and NaOH solution was the best suited for the purpose, and the method based on the weight loss with heating gave similar results. The contents of allophane and amorphous matter obtained by means of measuring the weight loss with heating were only approximate but the procedure is very simple and easy. © 1976 Taylor & Francis Group, LLC.