The circulation and accumulation of harmful elements in blast furnace were investigated. The results show that the maximum concentration of K and Na in the belly is about 50 times of that in the charge. The zinc increased by 80 times and the Pb is insignificant. The impact of the circulation and accumulation of K, Na, Pb and Zn on the fuel consumption was quantitatively analyzed using Rist diagram. The results show that the gas utilization decreased and the coke rate increased linearly with the increase of load and accumulation times of each harmful element. Given the accumulation times of each element, the loading of Na, K, Zn and Pb into BF leads to the increase of coke rate by 13.99 kg/tHM, 6.25 kg/ tHM, 3.63 kg/tHM and 0.02 kg/tHM, respectively. The increased coke rate and the decreased gas utilization under various loads and accumulation times of each element was estimated.

The effect of TiO 2 content on the phase compositions of sinter was conducted under reaction equilibrium at oxygen partial pressure of 5610 23 atm. The results showed that TiO 2 mainly existed in the phase of perovskite. With the increase in TiO 2 content, the content of secondary hematite phase increased and the ratio of hematite and magnetite in the sinter phase decreased. Meanwhile, the ratio of perovskite and Ca 2 SiO 4 increased and the increased level of perovskite was larger than that of the Ca 2 SiO 4 phase. The volume fraction of the phase silico-ferrite of calcia and alumina decreased from 44?9 to 41?5%, and the chemical formula of silico-ferrite of calcia and alumina changed from 4?7CaO.9?2Fe 2 O 3 .Al 2 O 3 .2?3SiO 2 to 1?6CaO.4?9Fe 2 O 3 .Al 2 O 3 .1?8SiO 2 when the percentage of TiO 2 was from 0 to 12 mass-% in the sinter.

The reduction of FeO from iron-saturated FeO-CaO-SiO 2 -MgO-Al 2 O 3 -TiO 2 slags by graphite has been studied under static conditions between 1473 and 1623 K. The results show that the Fe/Ti mole ratio in the sample matrix decreases with increasing time and temperature. Most of the FeO was reduced within the first 10 min at 1573 K. The degree of reduction was found to increase rapidly with increasing temperature below 1573 K and was controlled not only by the effective diffusivity of CO and FeO concentration, but also the formation of iron-titanium oxide in the sample. At the same time and temperature, the degree of reduction of FeO in Ti-bearing slag was higher than that of Ti-free slag, because TiO 2 can decrease the liquidus temperature and prompt reduction of the slag.

he structurally related viscosity model proposed in our previous studies has been extended to TÍO2 bearing melts. Experimental data on different systems containing CaO, MgO, AI2O3, TÍO2 and SÍO2 were assessed, and good agreement was achieved between the calculated and measured viscosities. It can be concluded that the addition of TÍO2 results in a decrease in viscosity, which is consistent with the experimental findings.

The optimized blast furnace design is the prerequisite for low-carbon smelting. The salamander depth and bosh angle are the key parameters, which determine the blast furnace longevity. In this paper, the physical and mathematical force model of deadman and cooling stave was established. The relationship between operating parameters and the salamander depth, as well as bosh angle, was analysed, and the gas flow scouring curve was proposed. The following results were obtained: first, the reasonable salamander depth/hearth diameter ratio and bosh angle should be 23∼25% and 73°∼75°in China, respectively. Second, the key factors that influence the floatation of deadman and wear of the cooling stave are the deadman voidage and the slag crust thickness, respectively. Lastly, it is necessary to adjust some measures such as coke ratio, blow velocity and tuyere length. This paper is meant for optimizing the design of blast furnace.