| 摘要 |
<p>PURPOSE:To produce molten iron at good thermal efficiency in a low cost by respectively adjusting the quantity and the composition of the molten iron, the quantity of carbonaceous material and secondary combustion ratio of gas in a furnace, etc., and also, partially remaining the molten iron and molten slag in the furnace when tapping, at the time of producing the molten iron by using scrap as raw material in the top-bottom blowing converter. CONSTITUTION:The cheap steel scrap 7 and coal 6 are charged into top-bottom blowing converter 1 having the molten iron 5 and the molten slag 4 and pure oxygen, etc., is blown from a top-blowing lance 3 and N2 or the other inert gas are blown from the furnace bottom to stir the molten iron and the molten slag. In this case, the molten slag quantity Sw in the furnace is regulated with the rated molten iron quantity Mmax and the bottom blowing gas quantity Bgas shown in the inequality I, and all of 1.0-1.7 CaO/SiO2 value, 0.6-2.3% Fe concn. in the molten slag, 5-40% of the carbonaceous material quantity in the furnace per the molten slag quantity, and 2.5-4.7% concn. in the molten iron are adjusted, and the top blowing oxygen quantity and the fixed carbon content FC in the carbonaceous material are adjusted so that the secondary combustion ratio PC of the gas in the furnace satisfies the inequality II, and also, 5-50% of the molten iron and >=80% of the molten slag in the furnace is left at the time of tapping, and then, the production of the molten iron in the next is started.</p> |
