Sintering heating rate dependence

Depending on the processing conditions such as particle size, temperature, heating rate, and applied pressure, reaction and densification can occur in sequence or concurrently or in some combination of the two. Qualitatively, it is convenient to consider the reaction and the densification as two separate processes and to develop principles that allow predictions of the influence of key process variables which are useful for the design of reaction sintering processes (89,90). 

The capacity of the blast fnmace may be simply determined by the ability to bum carbon, which in turn relates to the oxygen snpply or blast rate. The latter is controlled by the permeability of the shaft charge and hence depends critically on the nature and stmcture of the sinter and coke feed as well as the presence of accretions, which can reduce the cross-sectional area of the shaft. Comparative capacity can be defined by the carbon burning rate per unit of shaft cross-section. The carbon is consumed to supply heat and CO, which in turn is consumed to reduce PbO, as weU as Fc203, CuO, ZnO and other minor metal oxides. Since most sinters have a reasonably consistent composition of around 40 to 45 per cent Pb, it follows that the sinter treatment rate and bullion production rate per unit of shaft cross-section also give meaningful comparative measures. 

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