Abstract
Two periods of operation of a 1,370 m³ blast furnace, lasting 31 and 30 nominal days, were studied. The first period was characterized by the predominant use of pellets produced at the Sokolovsko-Sarbay Mining and Production Association from skarn concentrate, while the second period utilized pellets produced at the Mikhailovsky Mining and Processing Plant from ferruginous quartzites. Calculated indicators were used to assess the impact of this on various aspects of blast furnace processes. In particular, the following was revealed: the development of direct reduction of Fe from FeO decreased by 1.7% abs; the degree of hydrogen reduction increased by 2.4% abs; the average degree of equilibration of materials by the lifting force of the gas flow from the tuyeres horizon to the charge surface decreased by 1.92% rel; the increase in the dynamic pressure of the gases rising from the hearth to the furnace top, reduced to the empty cross-section under operating conditions in temperature and pressure, was: 2.58% at the charge layer surface, 3.03% at the bottom of the shoulders; the duration of coke movement to the combustion zone decreased by 0.59%; the kinetic energy of blast outflow from the tuyeres increased by 3.35%; the length of the loose part of the tuyere hearth to the axial part of the furnace increased by 0.64%. In the blast furnace under consideration, with an increase in the proportion of pellets from iron silicate concentrate from 7.02 to 25.45%, the exclusion of pellets from magnetite concentrate from 12.23%, without changing the specific consumption of skip coke, the furnace productivity was increased by 0.68%, the consumption of total coke by 1.6 kg/t, and the total reducing fuel by 4.84 kg/t of pig iron.
Keywords:
metallurgical process, pig iron, coke, pellets, magnetite, concentrate, ferruginous quartzite, reduction, heat transfer, gas movement, movement of materials to the furnace.