Experimental Research Of Red Mud Slurry For Industrial Flue Gas Desulfurization

The wet Flue Gas Desulferization(FGD) technology is one of the most effective measures to reduce SO2emissions from power plant. But the high operation cost is the main obstacles of its promotion. In the alumina plant, large number of red mud discharged not only brings huge economic burden to the enterprise, but also do harm to the environment.This study is based on increasingly serious SO2emissions and solid waste pollution caused by red mud. Red mud from Bayle-sintering mixed process was°used as raw material provided by aluminum company.With the X-ray Diffraction (XRD), Grading Analyzer, Scanning Electron Microscopy (SEM) and other analysis technologies, chemical and mineral composition particle size and other properties of red mud were analyzed. Firstly, the desulphurization absorption tower was designed and manufactured. Gas and liquid transportation equipment such as air blower and the slurry pump were selected according to desulfurization process. Secondly, an experimental platform was installed in the Zhengzhou Xinli Power Litd. Co. Thirdly, the influential factors of red mud desulfurization were examined by orthogonal tests and single factor experiments. At the same time, the comparing experiments were done between this process and limestone method.The following results were obtained:(1) The desulfurization efficiency of red mud slurry over93%for more than4hours, which is more better than that of limestone method (only82.2%) under the same conditions;(2) The desulfurization efficiency was first increased then decreased with liquid-solid ratio increasing and the effect of flow velocity to the desulfurization efficiency is the same to the liquid-solid ratio; along with the increase of the liquid-gas ratio increases. The desulfurization efficiency influence followed by liquid gas ratio、gas velocity、and liquid-solid ratio.(3) when the liquid-solid ratio is7/1, the gas velocity is3.6m3/h, liquid gas ratio is12L/m3,the desulfurization efficiency can attain98.8%,it is the best desulfurization condition.(4) When the red mud slurry pH value is less than5,the systerm shoud add fresh red mud slurry to keep high desulfurization efficiency. Becouse red mud absorption efficiency began to drop when he red mud slurry pH value is less than5.(5)Silica and perovskite is inert substance,they can not react with SO2,but react with calcite、Hydration garnet、calcium silicoaluminate hydrate silicon and hematite、 aluminium acid calcium and hematite. The desulfurizatio products mainly contian gypsum and the calcium sulfate.The research above results, not only provide good theory research for red mud which is used in wet desulfurization, but also open up a new way for red mud comprehensive utilization.