Study On The Decrepitation Behavior,Mechanism And Abatement Of Natural Lump Ore

Under the background of carbon peak and carbon neutralization,the energy saving and emission reduction of steel industry is increasingly urgent.Increasing the proportion of lump ore into the furnace,optimizing the blast furnace charge structure,and replacing the high-cost acid pellets can relieve the pressure of iron and steel enterprises on environmental protection and raw material costs.However,the natural iron lump ore will decrepitation in the furnace to produce fragments and powders,which will block the pores of the material layer and affect smooth running of the blast furnace.In this paper,the lump ore commonly used in blast furnaces is taken as the research object.The decrepitation behavior and mechanism of lump ore are systematically studied,and the decrepitation prevention methods of PB and Newman lump ore are explored.The main conclusions are as follows:Lump thermal decrepitation behavior.The higher the temperature,the more serious the thermal decrepitation of lump ore.The decrepitation index of PB,Newman and South Africa lump ore at 700℃ are 17.52%,13.62% and 0.88% respectively.Thermal decrepitation mainly occurs within the first 10 minutes of the lump ore being heated.The decrepitation index of PB and Newman lump ore increases with the increase of particle size,and the index of South African lump ore does not change much under different particle sizes.Physical water content has a slight effect on decrepitation of PB and Newman lumps,but has no effect on South African lumps.Mechanism of lump decrepitation.The crystal water in PB and Newman lump ore will decompose to produce water vapor at high temperature,which will form steam high pressure in the pore channel,resulting in excessive pore pressure.When the water vapor pressure of the pore size exceeds the strength of the lump ore,it will decrepitation at the weak interface containing Si and Al in the lump ore.Method for abatement thermal decrepitation of lump ore.Muffle furnace preheating and microwave oven radiation treatment were adopted to abatement the thermal decrepitation of PB and Newman lump ore.Preheating in a muffle furnace at 400 °C for 60 min can reduce the decrepitation index to 0.38% and 2.21%,respectively.The decrepitation index can be reduced to 0.26% and 3%,respectively,under 900 W microwave power radiation treatment for 20 min.84Figures,12 Tables,89 References...