Investigation of the mineralogical composition of Altintau kaolins using x-ray diffraction analysis

This article presents the findings of an in-depth study into the mineralogical makeup of kaolin samples sourced from the Altintau deposit, focusing on the phase changes that occur during thermal processing. It details how microbiological and chemical treatments alter the mineral structure of kaolin, supported by electron microscopy images that illustrate the distribution of iron particles, quartz, micas, and chamotte powders after high-temperature firing, and secondary kaolin from the Altintau deposit. The research reveals that the kaolin from this deposit is a polymineral raw material, with iron mainly present as finely dispersed hematite particles, which can aid in its processing. What's more, the kaolin exhibits a high content of kaolinite, increasing its desirability due to the abundance of chromogenic minerals. A highly effective microbiological enrichment method is proposed, involving the reduction of iron oxides to lower oxidation states in an acidic environment, followed by microbial-assisted precipitation and removal. The mineralogical analysis of kaolin treated with this method shows a important enhancement in the diffraction intensity of kaolinite lines, indicating improved purity.