METHOD FOR REMOVING NOX USING THE NATURAL MANGANESE ORES

PURPOSE: Disclosed is a treatment method of nitric oxides (NOx) from flue gas using natural manganese ore as catalyst, which makes use of ammonia as reductant and is operated at low reaction temperature of 130-250 deg.C. CONSTITUTION: Selective catalytic reduction (SCR) method using natural manganese ore as catalyst, composed of pyrolusite (about 80 wt% of MnO2) and Fe, Ca, Mg, Al, and Si as oxide form, uses ammonia as reductant to remove nitric oxides in the reaction conditions of temperature of 130-250 deg.C and NOx to NH3 feed ratio of 0.7-1.2. Along to its particle size, the ore may be used in the packed-bed or the honeycomb reactor system for SCR catalyst. For honeycomb system, natural manganese ore is crushed up to particle size of below 1 μm using a mill and then ore solution of 20-50 wt% is prepared at pH of 6.5-8.5 to coat on the surface of honeycomb substrate. At this time, methylcellulose (MC), polyvinylalcohol (PVA), carboxymethylcellulose (CMC), polyethyleneglycol (PEG), silica sol, and alumina sol are added in the solution with 1-5 wt%. The honeycomb catalyst is prepared by dipping the substrate in the mixed solution and dry at 103 deg.C for 4-6 h and calcining at 350-500 deg. for 4-8 h.