The Use of Salted Pastes of Soil Colloids for X-Ray Analysis

Isaac Barshad
University of California, Berkeley

Abstract: A new technique for the x-ray analysis of soil colloids is proposed based on the finding that the interlayer swelling of montmorillonite persists in the presence of salt solutions and that the x-ray reflection representing the d(001) spacings becomes intensified in salted gels. The technique consists in flocculating the colloid from a suspension with sodium chloride, removing the “free” Fe2O3, Al2O3, and SiO2 by means of a solution of sodium citrate and sodium hydrosulfite, separating the cleaned colloid from the solution as a salted paste, and as such subjecting it to x-ray analysis. The method is not only more rapid than other recommended methods for x-ray analysis of soil colloids, but also—and which is of the utmost importance—yields a much more accurate picture of the mineralogical composition, particularly with respect to the content of the mica and the montmorillonite-type clays.

Clays and Clay Minerals; 1953 v. 2; no. 1; p. 209-217; DOI: 10.1346/CCMN.1953.0020118
© 1953, The Clay Minerals Society
Clay Minerals Society (www.clays.org)