Enhanced desulfurizing flotation of coal using sonoelectrochemical method

• Enhanced desulfurizing flotation of low sulfur coal by sonoelectrochemistry.
• The electrolyte was sodium chloride and the additive was anhydrous ethanol.
• The combination of high sulfur reduction, high yield, as well as low moisture.
• Ultrasound irradiation promotes electron transfer efficiency.
• Ultrasound irradiation increases clean coal yield.

Enhanced desulfurizing flotation of low sulfur coal was investigated using sonoelectrochemical method. The supporting electrolyte used in this process was sodium chloride and the additive was anhydrous ethanol. The effects of treatment conditions on desulfurization were studied by a single-factor method. The conditions include anhydrous ethanol concentration, sodium chloride concentration, sonoelectrolytic voltage, sonoelectrolytic temperature, sonoelectrolytic time and coal sample granulometry. The optimal experimental conditions achieved for anhydrous ethanol concentration, sodium chloride concentration, sonoelectrolytic voltage, sonoelectrolytic temperature and sonoelectrolytic time are 1.7 mol L−1, 5.1 × 10−3 mol L−1, 10 V, 70 °C, 50 min achieved for a −0.18 mm coal sample. Optimal conditions cause a sulfur reduction of up to 69.4%. The raw and treated coals were analyzed by infrared spectroscopy and a chemical method. Pyritic sulfur, organic sulfur, ash as well as moisture are partially removed. The combination of high sulfur reduction, high yield, as well as high ash reduction was obtained in the newly developed method of enhanced flotation by sonoelectrochemistry. Ultrasound irradiation promotes electron transfer efficiency and increases clean coal yield.