Effect of Charge Fractional Composition and the Coke Amount on the Parameters of Manganese Ore Agglomeration

Under laboratory conditions, the method of mathematical planning of experiments was used to study the effect of charge fractional composition (in the range of 2 to 8 mm) and the amount of coke in the charge (in the range of 7 to 13 wt.%) on the agglomeration process characteristics of the “Mamatwan” manganese ore (South Africa). It was found that the main agglomeration parameters vary within the following limits: the initial vacuum under grate – 54...140 mm WC for the charge layer of 350 mm; the maximum temperature – 1365...1440 °С; linear burning speed – 13,4...26,2 mm/min; the charge length of stay at temperatures over 1300 °С (the width of the melting zone) – 2,4...4,8 minutes. Mathematical equations of the combined effect of charge fractional composition and the amount of coke on agglomeration temperature, linear burning speed, width of melting zone (in time), initial vacuum in reactor were calculated. It was found that a major factor in providing the optimum mode of agglomeration is not the amount of coke, but the charge piece size distribution. For example, increasing the charge piece size has an 3,5 times more effective influence on the agglomeration temperature than the amount of coke. For the dust-containing charges the moistening up to 4...6 wt.% H2O is only partially solves the problem of the aerodynamic resistance. Pre-granulation of the dust fraction is needed to improve the gas permeability of the charge.