Thermal-alkaline synthesis of phosphorus salts from low-grade Central Kyzylkum phosphorites

This study investigates the thermal-alkaline processing of low-grade phosphorites from the Central Kyzylkum deposits to obtain phosphorus-containing products suitable for further chemical and agricultural applications. The mineralogical and physicochemical characteristics of the raw phosphorite were examined using infrared spectroscopy, thermal analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The phosphorite concentrate was found to contain mainly fluorocarbonate apatite and quartz, together with calcite, dolomite, glauconite, feldspars, and other minor phases. Experimental treatment with alkaline salts promoted the transformation of the phosphate component and the formation of calcium-containing phosphorus compounds. Infrared spectra confirmed the presence of phosphate, sulfate, and silicate groups in the obtained products. Thermal analysis revealed stepwise endothermic transformations accompanied by a total mass loss of approximately 15% over the temperature range investigated. SEM-EDS observations showed the formation of calcium sulfate crystals near phosphorite particles and confirmed the presence of calcium, sulfur, phosphorus, and oxygen in the solid products. The results demonstrate the technical feasibility of processing low-grade Central Kyzylkum phosphorites by a thermal-alkaline route. This approach may reduce demand for acid reagents and support the development of resource-efficient technologies to produce phosphorus-containing materials from local mineral resources.

Hali tarjima qilinmagan