EFFECTS OF LATTICE DISORDER ON THE QUANTITATIVE DETERMINATION OF KAOLINITE BY X-RAY DIFFRACTION.

A series of approximately sixty X-ray diffraction tests were conducted in order to evaluate quantitatively the crystallinity of six American Petroleum Institute standard kaolinites and to determine the effect of particle orientation on the reflected basal intensities. Three mixtures, consisting of varying percentages of kaolinite, boehmite, and talc, were tested, and the results obtained from two different sample mounting techniques were compared. In addition, a cement-treated technique was utilized to investigate the influence of particle orientation. Lattice disorder effects are shown to become more important as the amount of kaolinite in the soil mixture increases, and it is advantageous to select standards with peak width values which are similar to the minerals being investigated.