Abstract: There is disclosed a process for recovering valuable metals from a dust containing zinc comprising mixing the dust containing zinc with a reductant and a flux for regulating the basicity of slag, forming the mixture into pellets with a pelletizer, charging the pellets into a shaft type preheating-prereducing furnace provided with a preheating zone at the upper part and with a reducing zone at the lower part and removing, in the preheating zone, moisture and ignition loss components in the pellets, while prereducing in the reducing zone, the pellets under such conditions that a reduction of iron oxide is made to proceed selectively while the reduction of zinc oxide is suppressed to the possible minimum, charging the prereduced pellets into a melting furnace to melt and reduce them in the furnace, separating zinc, or zinc and lead, by evaporation followed by condensation to recover them, and separating iron and lead, or iron, according to the difference in their specific gravities to recover the iron as a molte

Abstract: A furnace system including a main furnace for melting and reducing material to form molten metal and slag which are to be continuously discharged therefrom and provided with an outlet port formed in an upper portion of the side wall thereof, and an auxiliary furnace connected to the main furnace and communicating with the interior of the main furnace through the outlet port. The molten metal and the slag are allowed to continuously flow from the main furnace into the auxiliary furnace while maintaining the melt level in the main furnace above the level of the outlet port so as to seal the outlet port. The molten metal and the slag are discharged from the auxiliary furnace at the same rate as the increase in the amount of the molten metal and the slag in the main furnace. The auxiliary furnace may be provided with temperature control device for independently controlling the temperatures of the molten metal and the slag in the auxiliary furnace.

Abstract: In a method for producing a reactivity promoted carbonaceous solid reductant used for direct reduction of iron ore by means of an additional alkaline earth metal compound, and improved method wherein the improvement comprises grinding and mixing the carbonaceous solid reductant with the alkaline earth metal compound and agglomerating the resulting mixture to produce the reactivity promoted carbonaceous solid reductant of a definite grain size.

Abstract: A method for recovering zinc from substances containing a zinc compound which comprises supplying a carbonaceous substance and a zinc compound-containing substance onto the hearth layer in a sintering apparatus, vaporizing the zinc compound in said substance as metal to separate the compound therefrom by forming a locally strong reducing atmosphere at the combustion temperature of sintering material, oxidizing the resultant vapor-form zinc into zinc oxide under a strong oxidizing atmosphere, and then discharging the resultant zinc oxide as such from said sintering apparatus.

Abstract: A method of discharging material from a rotary furnace is disclosed, which method comprises the steps of feeding the material from a preheater into the rotary furnace under gastight conditions, subjecting the material to heat treatment within the rotary furnace, connecting the inlet port of a container to the discharge opening of the rotary furnace, discharging the material from the rotary furnace while maintaining gastight conditions, and thereafter detaching the container from the rotary furnace.

Abstract: A method of treating, in a vertical grate furnace, raw materials in an iron reduction process is disclosed. The raw materials are fed onto a grate-containing section which is separated from at least one other section of the grate furnace. Subsequently, the grate-containing section is attached to the other section or sections by moving the other section or sections upwardly or downwardly so as to achieve and maintain gastight conditions between the grate-containing section and the other section(s). The raw materials then undergo preliminary heat treatment in the grate furnace. Finally, the grate is tilted to discharge the treated materials from the grate furnace through an outlet provided on the side wall of the furnace.