GB453423A - Improvements in or relating to the production of cast-iron - Google Patents

Abstract

453,423. Extracting iron. TENNANT, W. J., 111, Hatton Garden, London- (Fondrilux Soc. Anon.; 5, Rue Philippe, Luxembourg) Feb. 5, 1935, No. 3742. [Class 72] [See also Group XII] In the production of cast-iron from ores in which sponge iron is produced in a shaft furnace and then melted in another furnace working independently of the first furnace, the ore is so treated with heating gases in the first furnace as to pass first through a zone at a temperature of about 700‹ C. where it is reduced and then through a zone at a temperature close to the sintering point e.g. at about 1000‹ C. to produce a vitreous coating on the reduced ore which prevents reoxidation when it is being transferred to the second furnace where it is melted. Carbon in any desired form such as coke, ashes, or charcoal is supplied to the melting furnace in such quantities as are necessary for the residual reduction of the iron sponge and for the carbonization of the cast-iron produced. If the silicon content of the cast-iron is not high enough silicon or ferro-silicon may be added. The heating value of the gases in the furnace may be increased by the addition of other gases e.g. exhaust gases. The shaft furnace 1, is provided with a conical or tapered bottom, the heating gas being supplied from a generator 3 and may be heated in a heat-exchanger 4 before it pssses into the gas supply pipe d. Air which is also heated in the exchange 4 is fed to the furnace 1 by a pipe e and the mixture of air and gas ignited by an igniting device f. The furnace 1 is provided with a discharge device c for the reduced ore which is then transferred to the melting furnace 2 which is an ordinary cupola furnace in which the blast nozzles are substituted by gas burners g fed with preheated gas from the generator 3 and air preheated in the exchanger 4. The exchanger 4 is heated by gases passing from the furnace 1 through a pipe b.