Physicochemical processes in the linings of pellet-roasting machines

Abstract

The authors have investigated processes taking place in the lining of pellet-roasting machines at the NMBC. To ensure steady operation of the linings of the forward flow manifold, cooling zone I, and the gas-air chambers, they must be made of materials resistant to iron silicate melts at elevated (1200–1500°C) temperatures. Exceeding of the working temperatures in the manifold and branch connections (above 800°C) is due to “inverting” of the cone and its entry into the branch connections of the hearth. Taking account of experience gained in the use of OK-306 roasting machines at the NMBC, and on the basis of the results of our investigations, we can recommend refractories with an elevated A12O3 content for lining the hearth and manifold. However, the progress of roasting and the operation of the refractories must be constantly monitored; the principal criteria for the latter must be the flow rate of the gas and the temperature at the boundaries between the refractory and the heat insulation, and between the refractory and the gaseous working medium.