GB442895A - Process and apparatus for the production of pig-iron - Google Patents

Abstract

442,895. Producing pig iron. BARON, H., 231, Strand, London.-(Siemens & Halske Akt.-Ges.; Siemensstadt, Berlin) Aug. 20, 1934, No. 24023. [Class 72] [See also Group XII] Pig iron containing 2À4 to 3À2 per cent of carbon is produced by introducing amixture of iron ore and a sufficient quantity of carbon to reduce the ore and raise the carbon content of the iron so produced to the desired amount into a fused iron bath having a carbon content substantially equal to the amount referred to above, and which is heated during the addition of ore &c. The iron bath may be contained in an open hearth furnace heated by a flame produced by the combustion of coal dust or oil with air enriched with oxygen or in a tightly sealed electric furnace and the ore used may be fine grained ore such as slick and the carbon finely divided inferior coal. The phosphorus sulphur and silicon contents of the iron produced are reduced to the desired extent by renewing the slag during the reduction and, if necessary, varying the composition of the slag. The waste gases removed from the electric furnace may be used to supply additional heat to the furnace, the supply of electrical energy being varied as each fresh charge of ore and carbon is introduced into the furnace so that the iron bath is not subjected to any increase in temperature. The iron bath used may be produced by the fusion of any form of iron mixed with reducing agents in an open hearth or melting furnace and the fused iron transferred to the electric furnace. The waste gases from the electric or open hearth furnace may be used for preheating and partial reduction of the iron ore charge preferably in a rotary furnace. The ore charge is fed from a hopper 3 through a double valve 4 and a tube 5 into a rotary drum 6 the preheated and partly reduced charge passing by a tube 7 into the furnace 1 containing the iron bath. The gases from the furnace 1 pass upwards through the charge in the drum 6 and are removed by a fan 8. When an open hearth furnace 1 is used the parts 1<a> and 1<b> are lined with carbon bricks and the part 1<c>, at the level of the iron bath 2, is lined with magnesite or similar material. Part of the waste gases from the furnace 1 may be combusted with air or oxygen to provide additional heating for the interior or exterior of the drum 6 and another part of the said gases may be used for heating the furnace 1. A shutter 9 may be provided to close the end of the tube 7 when the furnace 1 is tilted to discharge part or the whole of the charge therein.