Abstract
Mixtures of fine powders with the basicities from 0.6 to 5.0 consisting of hematite (80%), slaked lime, and quartz were heated rapidly to 900-1400°C and cooled in air. The process of mineral formation of them during the rapid heating was examined.
At about 950-1000°C, calcium ferrite was formed and caustic lime originated from slaked lime was consumed completely. At the temperature lower than 1 150°C, quartz hardly reacted with other minerals such as hematite, caustic lime, and calcium ferrite. Thus, their microstructures changed, independently of their basicities, into those consisting of primary hematite, calcium ferrite, and quartz.
At the temperature higher than about 1 160-1180°C, calcium ferrite melted and reacted with quartz. By this reaction, characteristic microstructures were formed according to their basicity. The microstructure of mixtures with the basicity lower than 1.6 consisted of glassy silicate and secondary hematite originated from calcium ferrite. The microstructure of mixtures with the basicity higher than 2.0 consisted of calcium ferrite and dicalcium silicate.
On the basis of the above results, the microstructures and their formation processes of iron are sinters with various basicities were discussed.
