Characterization of dolochar wastes generated by the sponge iron industry

Solid wastes generated by the metallurgical industry contribute significantly towards the enhancement of environmental pollution. The handling, utilization, and safe disposal of these solid wastes are major concerns for the world. Dolochar is such a solid waste generated by the sponge iron industry. Investigations were carried out on the physical, mineralogical, and chemical characteristics for the efficient utilization of dolochar. The detailed studies on physico-chemical properties and petrography were carried out by optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Characterization studies revealed that the dolochar consists of quartz (free as well as locked), free lime, Fe particles, and Ca or Mg and/or Ca+Mg+Fe oxide phases. The washability data of -300 μm dolochar samples indicated that clean coal with 41wt% ash at 18% yield can be produced from dolochar with 78wt% ash. The studies further suggested that the liberation of the dolochar is hard to achieve for clear separation. The dolochar is observed to have high ash fusion temperature and the unburned carbon can be best utilized for power generation.