1995 年 35 巻 4 号 p. 372-379
The permeability of the combustion-melting zone in the sintering bed of the Dwight-Lloyd process, which affects process efficiency in terms of productivity and product yield as well as quality control, was found to be dependent largely on the sinter cake load upon the combustion-melting zone during sintering. In order to control and reduce the sinter cake load, the magnetically-levitated sintering method was devised. As a result of sintering pot tests, the sintering time was shortened by a maximum of 30% without a decrease in product yield and coke combustion efficiency was improved despite an acceleration of sintering speed. In addition, the reduction degradation index, RDI, and reducibility, JIS-RI, were improved. The size distribution of product sinter tends to be sharp. Improvement in permeability were proportional to the degree of load reduction. CT analyses of sinter cake samples showed that the load on the combustion-melting zone during sintering accelerates ordinarily the plugging of stem pores with melt and disturbs gas flow through the sintering bed in the middle and bottom layer. The permeability improvements resulting from applying the magnetic levitation are attributed to the formation of a homogeneous network with a pore size appropriate for gas flow as well as increase in porosity of stem pores by about 8%.
