Improvement of the gas-dynamic and thermal modes of external heating of a sintering mixture layer

Improving the gas-dynamic and thermal modes of external heating of a sintering charge layer, including preheating the layer, igniting the charge, and subsequent heat treatment of the layer, is important for increasing the productivity of sintering machines, improving the sinter quality, and saving fuel. AF‑5 design solutions can fully achieve all these operations. When setting up the operation of the sintering machines, layer preheating is eliminated and the ignition hearth is moved onto the vacuum chamber no. 1. The hot air supply to the hearth, which prevents thermal shock when the layer emerges from under the hearth, is also eliminated.

In this study, because of charge heating with lime, deep throttling of the first vacuum chambers of the sintering machine, and the operation of the sintering machines at a charge layer height of 560 mm, the layer shrinkage was minimal. This finding confirmed the efficiency of the decision to eliminate charge layer preheating. The influence of the charge layer height on the operating mode of the ignition hearth is discussed. The ineffectiveness of sintering machine equipment used worldwide with two parallel prefabricated collectors, instead of one, and a sectional design is experimentally established. Technical solutions to eliminate the negative consequences of dismantling the waste gas recirculation system are clarified. Moreover, recommendations for modernizing prefabricated collectors for stage 1 gas purification from dust are detailed. The advantages of using exhaust guide vanes instead of throttling vacuum chambers after the ignition hearth have been experimentally demonstrated. The features of the operation of sintering machine exhausts in a single scheme with a desulfurization unit are considered.