process for lock co - rich off gas in metal smelting

摘要

PURPOSE:To contain a large amount of CO in the exhaust gas produced by blowing powdery and granular limestone into the steel bath of a converter provided with an exhaust gas recovery device in particular thereby causing the CO2 produced by the thermal decomposition thereof to react with the C in molten steel. CONSTITUTION:Powdery limestone is blown together with a carrier gas through the bottom tuyeres of a converter toward the molten steel bath surface in a converter, and the CO2 produced by decomposition reaction is caused to react with the C in the molten steel, whereby CO is formed. The greater part of the CO produced is recovered by a converter exhaust gas recovering device and as a result, the content of C in the molten steel is decreased and the O2 source necessary for decarbonization is saved. As a carrier gas, an inert gas such as CO2 is used, besides O2 gas. The maximum grain size Dmax of the limestone used is in the relation of the formula; for example, the suitable grain sizes of the limestone are =2mm. when the distance from the tuyeres up to the bath surface is 1.5m.