METHOD FOR PRODUCING MOLTEN IRON,申请号JP20050377694-传众专利搜索

METHOD FOR PRODUCING MOLTEN IRON

申请公布号：JP2007177295(A)

申请号：JP20050377694

申请日期：2005.12.28

申请公布日期：2007.07.12

申请人：

NIPPON STEEL CORP

发明人：YAMAZAKI TSUTOMU;HIRATA HIROSHI;MIFUKU HIROKI;KUWAUCHI YUKI;NAGAI WATARU;NOBEMOTO AKIRA

分类号：C21C5/36;C21B11/00;C21B13/14;C21C5/28;C21C5/30;C21C5/40

主分类号：C21C5/36

摘要：PROBLEM TO BE SOLVED: To improve heat conductive efficiency while maintaining a secondary combustion rate at a high level, in a process of producing molten iron by supplying reduced iron together with a carbonaceous material and oxygen into a melting furnace containing seed molten iron. SOLUTION: This production method comprises the steps of: making a powder including iron oxides contain the carbonaceous material to form an agglomerate; preliminarily reducing the iron oxides by heating the agglomerate at a high temperature in a pre-reduction furnace 8 while using the contained carbonaceous material as a reducing material; supplying the produced reduced iron together with the carbonaceous material and oxygen to the melting furnace 1 containing the seed molten iron to control a composition of the slag produced on the molten iron into, by mass%, 12-18% Al<SB>2</SB>O<SB>3</SB>and 12-18% MgO, while controlling the value (A) to less than 5, which is obtained by the following expression on a relationship between a basicity (B) of the produced slag and a temperature T(K) of the molten iron after having been melted: A=7×10<SP>-7</SP>×exp(-6.2143×B)×exp((20,663×B+7,655.1)/T). The method also includes controlling a carbon content in the reduced iron to 2 to 10 mass%, and a ratio (total carbon (kg)/total oxygen (Nm<SP>3</SP>)) of total carbon to total oxygen supplied to the melting furnace 1 to 0.9 to 1.5. COPYRIGHT: (C)2007,JPO&INPIT