A PRECISE PROCEDURE OF THE PROPORTION OF SMECTITE LAYER CALCULATION SUITABLE FOR INTERSTRATIFIED ILLITE/SMECTITES ANALYSIS OF NATURAL CLAY SAMPLES

The 17Åreflection of the XRD pattern of oriented preparation ethy-lene glycol-solvated sample is an effective indicator to distinguish the disorderly from orderly (IS-ordered and ISII-ordered) illite/smectite interstrata.The experiments in this paper shows that the 17Åreflection intensity of disorderly interstratified illite/smectite varied mainly with the proportion of smectite layers (S%) for the pure sample rather than with the proportion of smectite layers (S%),but also with the disorderly interstratified illite/smectite content (I/S(%)) and other types of mineral contents,especially the content of discrete illite (I(%)) for the mixtures.From the XRD data of mixture samples composed of disorderly interstratified illite/smectite with two different proportions of smectite layers (S%) and different contents of discrete illites (I/S(%)),a precise procedure on the proportion of smectite layers (S%) calculation suitable for disorderly interstratified illite/smectite analysis of natural clay samples has been deduced.In the paper,a precise procedure on the proportion of smectite layer calculation suitable for orderly interstratified illite/smectite analysis of natural clay samples also has been deduced based on the data of Srodons publication (1984) and author's practical XRD analyses.