Abstract

The aim of this study is to put forward a prediction scheme for the expandability of clays by use of inexpensive and rapid chemical analysis. Seventy clay ores from fourteen locations throughout central and west Turkey were characterized mineralogically, chemically, and for expansion testing. Using the ternary plotting scheme of SiO2-Al2O3-fl uxing samples exceeding 50% expansion plotted within and slightly beyond the region proposed by Riley (1951). This study newly extends the region in ternary space for samples suitable for expansion and use in light weight aggregate. Non-expanding samples are associated with mineral assemblages dominated by quartz. In this study, it was determined that the samples without the expandability property were lacking the required chemical aspect of SiO2- Al2O3-fl uxing ratios, mineralogical clay structures, proportions and gas agents. In addition, the effect of having a too low or high position on the triangle diagram was found to have a negative impact on the expandability. When mineralogical analyses, mineral associations, chemical compositions and expandability results were evaluated together, it was observed that Mica GM-Chloride GM; Montmorillonite-Zeolite-Amorphous matter and Clay GM-Amorh Silica-Cristobalite are the samples showing expandability properties for the extent of this study. Also, it was noted that almost all samples with graphite content did expand. The extension of the suitability fi eld on the ternary diagram for prediction of expansion properties, combined with low cost and rapid chemical analysis demonstrate benefi ts for the clay production industry in Turkey, particularly for saving energy and fi nancial resources needed during exploration and early stages of production clay ores.

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