Desulfurization of Coal by Flotation of Coal in a Single-Stage Process

A single-stage flotation process was developed in which coal was floated out and pyrite was depressed. Up to 90% of the pyritic sulfur content of bituminous coal could be removed at 75% coal recovery. The process was applied to three Canadian and two United States coals. Higher coal recoveries were obtained for low sulfur coals; up to 94.4% coal recovery was possible with 18.2% pyritic sulfur removal. Sulfate sulfur, trace elements, and ash were also removed. The effects of particle size, temperature, slurry density, and flotation time were studied. From a simplified rate equation a nonintegral order was obtained for the flotation process.