Abstract: A process of producing molten iron involves: a) introducing iron oxide, flux, oxygen, nitrogen, carbon, and hydrogen to a smelter reactor; b) maintaining conditions to cause (i) the iron oxide to be reduced, (ii) molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of foaming, FeO-containing slag, and (iii) carbon monoxide gas to rise through the slag; c) causing at least some of the carbon monoxide to react with the oxygen; d) releasing an offgas containing CO, CO2, H2, and H2O; and e) removing at least some of the molten iron and slag from the reactor. Good process stability is achieved by: f) repeatedly measuring, during the process, the conditions of the slag height, the temperature of the molten iron, the levels of CO, CO2, H2, and H2O in the offgas, the carbon level in the molten iron, and the FeO level in the slag, and g) subsequently adjusting one or more process variables (e.g.

Abstract: In order to lower the sulfuric content of the offgas from a smelter reactor in which iron oxide is reduced to molten iron, in the presence of sulfur contaminants, a sufficient amount of a source of zinc is included in the charge to the reactor that the combined weight of the zinc source and the iron oxide source contains at least about 0.6% Zn (calculated as elemental zinc), on a dry weight basis. The temperature of the offgas is maintained at or above approximately 700.degree. C. Vaporized zinc, present in the offgas, binds with sulfur in the offgas to precipitate solid ZnS. After removal of the ZnS, the offgas may have a sulfuric content below 50 ppm by volume of H.sub.2 S equivalent. Suitable sources of zinc include blast furnace dust, electric arc dust, basic oxygen furnace dust, zinc calcine, and zinc sinter.

Abstract: A process of smelting iron that comprises the steps of:a) introducing a source of iron oxide, oxygen, nitrogen, and a source of carbonaceous fuel to a smelting reactor, at least some of said oxygen being continuously introduced through an overhead lance;b) maintaining conditions in said reactor to cause (i) at least some of the iron oxide to be chemically reduced, (ii) a bath of molten iron to be created and stirred in the bottom of the reactor, surmounted by a layer of slag, and (iii) carbon monoxide gas to rise through the slag;c) causing at least some of said carbon monoxide to react in the reactor with the incoming oxygen, thereby generating heat for reactions taking place in the reactor; andd) releasing from the reactor an offgas effluent,is run in a way that keeps iron losses in the offgas relatively low. After start-up of the process is complete, steps (a) and (b) are controlled so as to:e) keep the temperature of the molten iron at or below about 1550.degree. C.