Agglomeration of iron-bearing fines: Selection of the binder for optimal briquette strength under various environments

In the production of hot briquetted iron some fine by-product is generated. This material consists mainly of metallic iron and iron oxides. Before utilization of these fines in the steel mill and/or direct reduction plant, agglomeration is required. To get briquettes with sufficient strength a binder has to be added to the fines. In this study, the various binders, ranging from bentonite, molasses plus hydrated lime and starch were used in the preparation of the briquetting feed. For evaluation of the different binders, the compressive strength of the briquettes was measured. Before testing, the briquettes were stored under different ambient conditions (temperature, humidity). The results showed large differences in briquette strength depending on the used binder. Additionally, the performance of the binders was strongly dependent on the storage conditions. Thus, before the selection of an optimal binder, the relevant ambient conditions for the briquettes have to be defined.