Increasing the throughput of rotary drum redn. furnace - by controlling vol of air injected into furnace, esp. when mfg. sponge iron by reducing iron ore with coal

摘要

Combustible gases (I) in the furnace charge are burnt by the direction injection, through the furnace wall, of air of combustion or other gases (II) contg. oxygen. Gases (I) are formed by the evapn. or decompsn. of cpds. in the charge, and are burnt inside the latter by gases (II). The position of the injectors for gases (II) and the amt. of such gas (II), are chosen to suit the compsn. of the charge, and esp. to suit the amt. of fine-grained material in the charge. When fine ore is used with a grain size of ca. 80% below 0.5mm, as the furnace charge, the amt. of air or gas (II) is pref. reduced to ca.50% of the stoichiometric amt. required for the combustion of gases (I). When fine iron ore is reduced in a rotary drum furnace, the sponge iron obtd. tends to sinter together to form agglomerates reducing the throughput of the furnace. This undesirable tendency is assessed by a sticking factor(SF), which is the ratio of the average dia. (A) of the sponge agglomerates to the average dia. (E) of the ore grains. The invention produces a marked redn. in this ratio(SF).