Abstract: A powdery or fine granular ore containing metal oxides is melted and refined by charging the ore and a part of a reducing gas discharged from a vertical type of melting and reducing furnace into a fluidized bed type of preliminary reducing furnace to preliminary reduce the ore therein, charging the preliminary reduced ore heated at a high temperature into the above described melting and reducing furnace and melting and reducing the ore by using a carbonaceous solid reducing agent and air or oxygen rich air heated at a high temperature and discharging the molten metal and the molten slag from the melting and reducing furnace. By using the preliminary reduction step, the pretreatment of the powdery or fine granular ore containing metal oxides, such as formation into pellets, sintered ores, briquets and the like can be omitted.

Abstract: A process for operating blast furnaces is disclosed, which comprises assuming a plurality of reference spaces, each of which serves as a stacking space for burden material and is defined by a plurality of line segments having inclination angles .theta..sub.1 and .theta..sub.2 with respect to a horizontal line on a surface of a previously stacked burden, before a predetermined volume of the burden material is charged from a charging equipment; settling a newly stacked surface of the burden in one of the standard spaces in such a manner that the newly stacked surface consists of two line segments having inclination angle .theta..sub.1 and .theta..sub.

Abstract: Fe-B molten metal for producing amorphous alloys are produced in a low cost by using a vertical furnace wherein beds packed with a carbonaceous solid reducing agent are formed and two or three stages of tuyeres are provided in the lower portion of said furnace, feeding a preliminarily reduced powdery iron ore into the furnace through the upper stage of tuyeres together with hot air and feeding boron oxide or boric acid into the furnace through the lower stage of tuyeres together with hot air and, if necessary blowing hot air into the furnace through the lowest stage of tuyeres. In stead of the above described vertical furnace, a usual blast furnace provided with one or two stages of tuyeres at the lower portion of said furnace is used. In this case, sintered iron ore, pellet-formed iron ore or lump iron ore is fed from the top of the furnace and powdery boron oxide or boric acid is fed through the tuyeres.

Abstract: A method of operating a blast furnace comprising the steps of selecting sight factors mathematically and statistically as effective in determining the operating condition of a blast furnace, sensing the eight factors as sample data, converting the sample data into variable factors, comparing the sample data and the variable factors with predetermined limiting factors, generating numerical non-dimension values corresponding to the level of satisfaction between the sample date or variable factors and the corresponding limiting values, multiplying the numerical non-dimensional values by predetermined corresponding weight allocation indices, summing separately the results of the multiplication for the sample data and the variable factors to form a numerical factor grand addition output and a variable factors grand addition output, summing the numerical factors grand addition output and the variable factors grand addition output to form an overall grand addition output and taking appropriate action to control the