Study Of Desulfurization And Denitrification From Grade Natural Manganese Ore

Selective Catalytic Reduction by NH₃ and Limestone/lime-gypsum wet process are widely used to remove NO_x and SO₂ from flue gas respectively.In this study,natural rhodochrosite was taken as precursor,and five groups of catalysts were prepared via thermal treatment under 500-700^oC.The structure and surface activity after calcination were characterized by TG?MS?XRD?XRF?SEM?TEM?XPS?BET?NH₃-TPD and H₂-TPR;The ratio of NO conversion were analysised by simulated flue gas system and flue gas analyzer.Besides,a new process of simultaneous absorption of SO₂ and NO with pyrolusite slurry was studied.Organic surfactant was chosen as the cosolvent to increase the removal efficiency of NO.The conclusions of this work are summarized as follows:?1?The mineral constituents of the rhodochrosite ore are rhodochrosite,quartz,pyrite.After thermal treatment,the rhodochrosite decomposed gradually,forming hausmannite and other species of MnO_x.When the temperature increased to 550^oC,the rhodochrosite calcine gradually and the porous structure?massive accumulation?occurs,which exhibited the maximum specific surface area,largest amount of acid sites and suitable reduction behavior.?2?In the temperature window of 172-261^oC,the NO conversion of sample R550could remain above 90%.Besides,an increse of mass space velocity led to the decrease of NO conversion,and the increase of NH₃/NO ratio resulted in the increase of NH₃conversion.SO₂ and H₂O restrained the de-NO reactivity of R300 obviously.?3?Pyrolusite slurry simultaneous absorption results indicated that The NO conversion efficiency could reach approximately 80.1%,the desulfurization efficiencies were constant in the range of 95.0%to 95.9%.PEG-200 exhibited obvious enhancement for NO absorption removal,and the best mass concentration was 3.0%.Total absorption capability of NO increased with the increase of O₂ concentration and reaction temperature,but the optimal conditions were 9%and 60^oC respectively.The pH of slurry should be controlled at 3-5.MnO₂ and O₂ were both involved in the oxidation reaction of NO and SO₂,the main reaction products were Mn²⁺,SO₄^2-and NO₃^-.