On the occasion of the 4th blast furnace repairing in September 1960, our company conducted the modernization of the entire installation for pig iron smelting for the purpose of the 100 percent operation of self-fluxing sinter, the chief materials of which come from domestic iron resources.
This installation consists of a DL type sintering machine with grate area 13.1m2, a blast furnace with hearth diameter 10 ft-6 in and inner volume 129m3, two units of hot stoves with heating surface 5, 000m2, a blower with maximum power 540kW, a Theisen disintegrator with maximum capacity 20, 000Nm3/hr and so on.
This blast furnace, since started on December 3, 1960, has been smelting the foundry pig iron with the following features for operation:
1.100 percent operation of self-fluxing sinter.
2. Perfect control of sizing of burden materials.
Before being charged into the furnace, the sinter was sized to the mean size of 17mm, 50-5mm: 92 percent upwards, and the cokes to the mean size of 45mm, 70-12mm: 98 percent upwards.
3. The hot blast of 900°C was used with the adoption of high temperature blast.
4. By the operation of low basicity: Slag CaO/Si02=1.00±0.05, the decrease of slag volume and the reduction of Si were accelerated.
Thanks to the methods shown above, the operation of foundry pig iron has shown remarkably excellent records: pig products, 208t/day, productivity, 1.6t/m3; and coke rate 550kg/t despite the fact that no injection of fuel or oxygen was done.