Continuous Phosphorus Removal in Electric-Arc Steelmaking.

摘要

1,190,487. Electric steelmaking. METALLGESELLSCRAFT A.G., STEEL CO. OF CANADA Ltd. and PICKANDS MATHER & CO. May 10, 1968 [May 15, 1967], No.22416/68. Heading C7D. Phosphorus-containing iron-bearing material, particularly iron sponge, is continuously charged to an arc furnace to which slagging materials are also charged, the feeding rate of lime being increased during the charging so that the CaO/SiO 2 ratio of the slag rises whereby phosphorus is removed from the bath at a rate which is substantially constant and higher than the rate at which it is being added by the charge. The feedrates may be controlled or an oxygen lance employed so that the FeO concentration in the slag is between 6% and 24% and the bath temperature is between 2550‹ F. and 2850‹ F., the feedrate of the ferrous material preferably being so controlled that that temperature is maintained while power to the electrodes is maintained at or near the maximum. To produce a vigorous boil in the bath the sponge iron should contain a residual combined oxygen content of 0À1% to 1À75%. Slagforming materials are preferably added to the arc regions where turbulence is high; the slag may be tapped intermittently or continuously at a location remote therefrom.