Tatsuro Ariyama

Influence of Profile of Blast Furnace on Motion and Stress of Burden by 3D-DEM

The objective of the present investigation is to analyze the influence of profile of blast furnace on the burden motion and stress field through 3D-DEM (three-dimensional discrete element method). It is clarified that the decrease of shaft angle speeds up the velocity of burden descending and decreases normal stress between particles or particle and wall. This change is good for the smooth operation of blast furnace. However,-ore and coke would be mixed for the too small shaft angle (75°), which would influence the permeability in blast furnace. Thus, the appropriate shaft angle is around 80°. Decrease of bosh angle prevents the burden descending motion and increases normal stress between particles and bosh wall. Meanwhile, maximum normal stress acting on the wall moves from belly wall to bosh wall in the case of 68° bosh angle, which accelerates abrasion of refractory in bosh by friction force between particles and wall. Although burden descends smoothly in the case of 88° bosh angle, room is not enough for the ascending heated gas flow. Thus, the appropriate bosh angle is about 78°.

Removal of Mn, Nb, V and Ρ from Iron Ore using Iron and Steelmaking Processes

Some rare metal elements such as Mn, Nb and V are contained along with Ρ in iron ore. As a resource strategy in Japan, the possibility of efficient recovery of these elements as byproducts of steel in conventional iron and steelmaking processes has been discussed. It was clarified that rare metals can be easily transferred to molten pig iron in a blast furnace, and to steelmaking slag in a hot metal pretreatment and an oxygen blowing furnace. Rare metals were concentrated in specific mineral phases during the cooling and solidification of the steelmaking slag. The separation of the phases containing higher contents of rare metals from other phases is considered to be a key-point in order to obtain a higher quality ore substitute.

Catalytic Decomposition of Chlorofluorocarbons with Directly Induced Heating System

Decomposition of Chlorofluorocarbons by a honeycomb packing with Pt/WO3/TiO2 catalyst heated directly with an electromagnetic induced heating system was investigated at temperature of 400°C. The decomposition of CFCs in the heating system was found to give higher conversion than in a conventional heating method, which can be attributed to a higher controllability of reaction temperature in the system. The characterization of catalysts showed that the amount of coke formed on the catalyst after the reaction in the system was lower than in the conventional heating system.