The modification of industrial grade metatitanic and application in SCR DeNOX catalyst preparation



In this paper, industrial grade metatitanic (H2TiO3) from sulphate process was used as the raw material to prepare TiO2 through a series of modification. Granular and honeycomb SCR DeNOX catalysts were made by granulation and molding processes respectively with those TiO2 as the carrier material. The characterisation, mechanical strength and denitration performance of the carrier/catalyst samples were tested and compared with those of commercial anatase nano-TiO2 products. The results showed that the TiO2 sample after the modified operation was remarkably improved in particle diameter, dispersion characteristic (average particle size from 15.79 to 1.746 µm) and the degree of crystallinity (from 93.7% to 98.1%), also the impurity content of K, Na, Ca, Mg, Al, S, etc. was significantly reduced; however, the grain size was increased (from 7.0 to 9.9 nm), and the specific surface area was decreased slightly (from 148.1 to 112.6 m2/g). As a whole, the characterisation was extremely close to commercial anatase nano-TiO2. Catalyst samples prepared with TiO2 after the modified operation had an upgrade on catalytic activity (the maximum denitration rate of granular catalyst from 95.0% to 97.1%; honeycomb catalyst from 92.2% to 93.3%), and the mechanical properties of honeycomb catalysts have been enhanced significantly (compressive strength of axial direction changed from 0.1063 to 0.5965 Mpa). The work indicated that TiO2 prepared with the industrial grade metatitanic from sulphate process was suitable as a carrier material for SCR DeNOX catalyst production. Also the modification was necessary.