حساب المحتوى المعدني في أطيان الكاؤولين

The association of iron phases in kaolinitic clays caused a difficulty to semi-quantitative determination of the mineralogical composition depending upon XRD analysis, using Cuk1 radiation. The high intensity of background ‘which was produced due to high concentration of iron’ distorted the area under curve and the intensity of peaks for each phase. The high intensity of some high quantity mineral peaks masking the low intensity peaks of other minerals. So it will be difficult to measure the above parameters until sample is treated with heating or chemical reaction. The XRD analysis gives a good qualitative identification of the mineral association in the samples, while the chemical analysis gives almost a correct measurement of mineralogical composition. It is possible to use the x-ray parameters depending on the chemical analysis to determine the mineralogical composition of kaolin tic clays. Most of kaolin deposits have the same mineral association like iron oxides and hydroxides (hematite and goethite), illite, mixed layer, anatase, rutile and quartz. These mineral associations are due to the same geochemical behavior through weathering, leaching intensity, transportation and sedimentation processes on the parent igneous and metamorphic rocks. The differences in their quantities may be due to the diagenetic process, which redistribute mineral phases in their sedimentary environments under different climatic conditions. The mineralogical composition reflects the field of kaolin industrial usage.