Evaluation of Feasibility of Utilization of Blast Furnace Waste Flue Dust-Part I:In Sinter Making

摘要

JSW Steel Limited (JSWSL), Salem Works, is an integrated steel plant, which operates 2 sinter plants with a combined production capacity of 1.2 Mtpa (million tonne per annum) of sinter. JSWSL also operates 2 blast furnaces with a combined capacity of 1.0 Mtpa of hot metal and blast furnaces generate approximately 45,000 tpa (tonne per annum) of flue dust. The sinter produced alongwith other raw material is directly charged into the blast furnace for iron making. The flue dust generated essentially contains unburnt coke and iron rich grains as the value added products. In order to recover these value added products, recycling of flue dust is considered. But the direct recycling of flue dust is not possible as it also contains some undesirable elements, such as zinc and alkali metals (sodium and potassium), which causes operational difficulties in the blast furnace. Laboratory scale leaching experiments were carried out to remove zinc and alkali metals from blast furnace flue dust. The influence of particle size, reaction temperature and sulphuric acid concentration on the removal of zinc were studied. The aim of the present study is to investigate the feasibility of utilization of JSWSL blast furnace waste flue dust by leaching with sulphuric acid to bring down zinc level to below 0.2% with minimal iron loss and recycling it in sinter making facility available in-house. The sinter so produced, if found suitable, is proposed to be used in JSWSL blast furnaces for iron making.