[Emission characteristics of PM2.5 from blast furnace iron making]

Electrical low pressure impactor (ELPI) was used to online analyze the PM2.5 particle size and mass concentration distribution in the trapping field and ore tank of blast furnace iron-making plant. Results showed that the grain number concentration of PM2.5 in trapping field after dust removal was in the range of 10(5)-10(6)cm-3 , and the particle size was mainly below 0. 1 μm. While the grain number concentration of the PM2.5 in ore tank after dust removal was in the range of 10(4)-10(5) cm-3, the particle size was mainly below 1.0 μm, and the mass concentration distribution showed a single peak. The micro-morphology of PM2.5 monomer was mainly divided into two categories, spherical particles and irregular aggregates. Chemical composition analysis indicated that the concentrations of water soluble SO(2-)(4) , K+ , Ca2+ were higher than other ions in PM2.5, with the percentage of 10. 32% -28.55% , 10. 36% -12. 15% , 3.97% -15. 4% , respectively. The major elements was Fe, Si, Al, with 16. 8% -31. 62% , 2. 24% -8.76% , 1.24% -5. 89% of total mass, respectively; organic carbon and elementary carbon were 2. 7% -4. 6% and 0. 8% -1. 3% , respectively. The emission factors of PM2.5 in trapping field and in ore tank after dust removal were ranged from 0.045 to 0.085 kg t(-1) and 0.042 to 0.071 kg t-1, respectively.