Countermeasures to Improve Sinter Productivity

Abstract

The addition of ultrafine ore to the sinter blend is known to impact green bed permeability and sinter productivity negatively. This study investigates several countermeasures for commercial ore blends containing up to an additional 20 mass% ultrafine ore. The countermeasures explored include the use of organic binders, the incorporation of pulverised ore particles as a binder, and the application of increased suction pressure. The results of this study were categorised into the addition of ultrafine ore to the blend (Blends A, B, and C) and the effect of binders (sodium polyacrylate, ammonium polyacrylate, and pulverised ore particles) on Blend C, that is Blends C(I), C(II), and C(III). It was found that the addition of sodium polyacrylate (Blend C(I)), ammonium polyacrylate (Blend C(II)) and pulverised ore particles (Blend C(III)) increased granule size, compared to Blend C. Although the granules increase in size with the addition of binders, it is noteworthy that adhering layer to nuclei mass ratio, R, remained unaffected at comparable moisture levels. The maximum green bed permeability increased with organic binders while the pulverised ore particles had no obvious effect. The binders improved sinter pot productivity from 32.7 t/m²/day for Blend C to 36.3 t/m²/day for Blend C(I), 36.2 t/m²/day for Blend C(II) and 36.6 t/m²/day for Blend C(III). This increase was due to an enhanced gas flow rate, higher flame front speed and a reduction in the degradation of the granules indicated by a lower <1 mm index.