STEL Controls has developed a concentrated solar thermal (CST) drying system capable of rapidly reducing moisture content in mined clays—such as bentonite, kaolin, and ball clays—before transportation or processing.

The technology harnesses high-intensity solar flux, focused directly onto the material bed, to accelerate evaporation without degrading the clay’s physical or chemical properties. Using precision-engineered concentrating optics, the system can achieve drying rates up to 6 lb of water per hour per one square meter of concentrator and reach temperatures of 2500°F in seconds.

Tests on bentonite clay demonstrated immediate temperature rise, fast evaporation, and consistent moisture removal, even with variable particle size, bulk density, and uneven moisture content.

The modular design allows scaling to match production requirements, making it suitable for on-site pre-drying at mining locations—reducing hauling costs, lowering fuel consumption at processing plants, cutting CO₂/NOx emissions, and improving material handling. Unlike conventional fossil-fueled dryers, CST drying eliminates combustion emissions, operates with minimal operational costs, and leverages abundant renewable energy in remote mining areas. This solution can be integrated into batch or continuous drying systems and adapted for a range of industrial minerals requiring moisture reduction prior to shipment or processing.