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General comment High-sulfur coal is used in circulating fluidized bed technology to reduce phosphogypsum and produce SO2 and cement clinker. The phosphogypsum comes from a certain chemical plant under Yuntianhua Group, with a mass fraction of 70.68% for CaSO4. The high-sulfur coal is selected from a coal mine in Zhenxiong County, Yunnan, with a mass fraction of sulfur of 2.87%.In the pilot study on fluidized bed equipment, the influence of reaction temperature, primary air volume, secondary air volume and phosphogypsum treatment volume on flue gas SO2 concentration was investigated, and the optimal conditions for phosphogypsum decomposition were determined: decomposition furnace reaction temperature (1000 ±10)°C, primary air volume 220m3/h, no secondary air, m (phosphogypsum): m (high sulfur coal) = 10:1. Under these test conditions, the volume fraction of SO2 in the flue gas reaches 8.18%, which can be used for sulfuric acid production, the conversion rate of phosphogypsum reaches 90.39%, the mass fraction of CaO in clinker reaches 65%, and the decomposition rate is 95%. |
