Pre-reduction sintering process with flue gas recirculation for reduction alkalis harm and flue gas emission

Abstract

A pre-reduction sintering process with flue gas recirculation (PSP_fsg-FGR) was developed to mitigate alkalis harm to the blast furnace and reduce the flue gas emission in the whole ironmaking process. The results indicated that the pre-reduction sintering process (PSP) can effectively remove 58.02% of K and 30.68% of Na from raw mixtures and improve yield and tumbler index to 74.40% and 68.69%, respectively. Moreover, PSP was conducive to reducing NO _x and SO₂ emissions and simultaneously increasing CO content in flue gas. Circulating CO-containing flue gas to sintering bed effectively recycled CO and further improved K and Na removal ratio to 74.11% and 32.92%, respectively. Microstructural analysis revealed that the pre-reduced sinter mainly consisted of magnetite, wustite and a small quantity of metallic iron, and very few silicate glass phase was also formed. This process can simultaneously realize alkali metal elements removal as well as flue gas emission reduction from the integrated ironmaking process.

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