Ore–Carbon Briquets Derived from Power Plant Ash and Slag

Abstract

The material composition of magnetic fractions in fly ash and slag from lignite-based thermal power plants is studied. The production of high-quality iron concentrate by magnetic separation is hindered by the high content of Ca, Mg, and Mn oxides in spinels of magnetite type (up to 13% altogether). The magnetic fraction includes a considerable proportion of glassy phase (up to 15%), containing 15–45% Fe₂O₃. The probable limiting iron content in the final product is 59–60% (84.4–85.8% Fe₂O₃). The magnetic fraction of the fly ash and slag may be recommended as the iron-bearing component of ore–carbon briquets. Coal based on incompletely burned lignite concentrate without additional treatment is not sufficiently reactive for use as the carbon component of such briquets. It is shown here for the first time that, with appropriate treatment, both components may be used together in ore–carbon briquets suitable for the blast furnace.