Effect of Ultrasonic Treatment on the Floatability of Coal and Galena

The effect of ultrasonic pretreatment on the floatability of coal and galena is examined. Sonication of coal treated with oxidizing and reducing agents prior to flotation is found to completely restore its hydrophobicity. Flotation of galena by xanthate under incipient collector conditions is improved by using different treatment modes. Sonication in the absence of collector followed by slime removal and conditioning with collector resulted in recoveries several times higher than those in the absence of sonication. A mechanism involving the formation of clean surfaces followed by the occurrence of microbubbles on the hydrophobic solid and the resultant enhancement in bubble-particle attachment is proposed to be responsible for improved recoveries. The results further demonstrate that ultrasonic treatment under appropriate conditions can achieve at least a 50% reduction in collector consumption in the galena/xanthate system.