Adhesive behaviour of ultrafine particulate matters from iron ore sintering flue gas on grate bar and control technique

Abstract

Controlling the adhesion of potentially corrosive substances from flue gas on grate bar is crucial for extending the operational lifespan of the equipment. The adhesive behaviour and mechanism of ultrafine particulate matters (UPM) throughout the sintering process were elucidated, and measures to control adhesion on grate bars were developed. Research findings indicated that a small quantity of UPM were found on grate bar during the initial sintering stages (ignition stage and middle stage I and II). The main compositions of UPM were Fe_xO_y-rich, CaO-rich, and aluminium silicate-rich particles. In contrast, corrosive substances like alkali metal compounds were almost absent. These UPM adhered onto grate bar primarily through inertial impaction. When moving to the final sintering stages (middle stage III and temperature rising stage), many UPM rich in corrosive substances like NaCl and KCl adhered to the grate bar. These UPM adhered to grate bar through thermal diffusion and vortex deposition. Solid waste water washing technology can greatly decrease the quantity of UPM (rich in NaCl and KCl) on the grate bar due to vortex deposition and thermal diffusion, and it represents a potentially promising way to control adhesion and corrosion on grate bars.