Abstract
A series of tests on the nature of self-fluxing sinter was carried out using a small sintering pan. In one case limestone was added to Larap ore (rich in magnetite) to make a basisity, CaO/SiO2 having a planned value at a constant coke ratio (ordinary basisity: 0·5, 0·9, 1·3; high basisity: 2, 3, 4). In another case coke rates in raw mixture were changed from 1·2 to 8·7 per cent by different limestone additions. Subsidiary tests, dealing with small firedcompacts of the same materials, were performed successfully to explain some of the effects of sintering temperature and atmosphere.
The addition of limestone had a good effect on permeability in sintering, and decreased the time required considerably. A brief survey of the expected degree of remaining freelime, which was involved in hydration, was given. A considerable increase was found in the microstrength of sinter by the addition of limestone. The reducibility of sinter was decreased gradually as the lime was increased. The principal factor involved was an increase in the quantity of slag. Evidence was obtained which indicated some of the conditions necessary for sulphur evolution to occur in sintering. The results suggested that it should be possible to increase the desulphurization ratio to some extent. Also the microscopic study of sinter structure was widely carried out.
