Thermal and mineralogical characterization of loess heavy clays for potential use in brick industry

• First analysis on loess heavy clays thermal behavior and possible reactions.
• Loess clays are used as a material in brick industry.
• Chemical content showed significant correlations to minerals.
• Quartz and carbonates contents correlation showed effect of lowering the plasticity.

This paper describes a study of 11 selected samples of loess soil from Serbia, by using differential scanning calorimetry, simultaneously with thermogravimetry and its differential calculation, known as simultaneous thermal analysis (STA). This survey is supplemented by chemical and mineralogical analysis, particle size distribution, and plasticity and drying susceptibility tests. Correlation analysis of major oxides content and certain technological test results were used for better understanding of the raw material composition and product physical properties. The results indicate that the samples were rich in carbonates, with the highest content of alevrite fraction and variable content of clay-sized particles. Mineralogical analysis confirms significant correlations between major oxides content and reveals that the most common non-clay mineral present is quartz, followed by calcite, dolomite and sodium feldspar. Major clay minerals include illite, chlorite, smectite and, in some cases, low quantities of kaolinite. Although STA method is well-known, this is the first time that it was used for discussion about its practical aspect, for characterization of the loess deposits, in terms of exploitation in brick industry.