Abstract
In manganese ferroalloys production, gases generated in the lower part of the submerged arc furnace must rise through the solid charge materials. Poor charge permeability may be detrimental to furnace operation by causing clogging and eruptions which, in addition to being a safety hazard, reduce productivity. Sufficient gas permeability in the furnace is also important to achieve proper preheating and prereduction of the charge material; this is also true if the material is pre-treated in a separate unit. The permeability of manganese ores was investigated by measuring the pressure drop while passing air through a manganese ore particle bed at different velocities. Several particle size distributions and particle size fractions were investigated, and measurements were done on both raw and pre-treated ores. It was seen that ores with larger fractions of smaller particle sizes gave a higher pressure drop and fluidized at lower gas velocities. Coefficients in established correlations for pressure drop were calibrated for the tested manganese ores. These calibrated correlations were then applied in numerical flow simulations of typical furnace and pre-treatment scenarios to study the sensitivity of pressure drop and furnace operation to the permeability of the ore material used.