Improvement of Productivity by Stand-support Sintering in Commercial Sintering Machines

The sinter cake load on the combustion-melting zone has a great effect on structure formation of sinter cake especially at the lower layer. It increases the permeability resistance of sintering bed due to gas channel plugging and also affects the qualities of the sinter products indirectly. A new sintering technique, called "Stand-support sintering", for supporting the sinter cake with bars or plates attached to pallets has been developed. As a result of a pot test, it was found that the stand-support sintering sharply shortened the sintering time. Further, productivity was improved by nearly 20%. This technique was applied to the sintering machines at Kimitsu works. Nearly homogenous sinter cake support was obtained when the stands were properly arranged in pallets to make shrinkage and gas flow rate of sintering bed constant in the width and strand directions at the commercial plant. As a result of an operation test with the low stands and the high stands, it was found that the improvement of productivity of the high stands was larger than that of the low stands. Product yield and SI did not decrease even though FFS increased. Stands started to support the sinter cake load just after the melt near the top of the stands solidified. Shrinkage stopped and gas flow rate increased when the stands started to support the sinter cake load. Porosity above 5mm in sinter cake with stands was larger than that in sinter cake without stands in the lower part of the bed. An increase in the unsintered portion was not seen near the stands. Sinter products with stands were porous and had good reducibility.