Abstract: In the operation of a furnace for the production of iron or steel, the air preheater and the pipe communicating the preheater with the furnace are constructed of steel shells lined with an acid-resisting cement, with refractory lining overlying the cement. The acid-resisting cement is composed of quartz sand and refractory material in the form of hollow spheres, silicate binder, and hardener. The spheres are 10 - 40 vol.% of the total volume of quartz sand and spheres.

Abstract: An improvement in the process for regulating the operation of a blast furnace in response to analysis of the effluent blast furnace gas residing in continuously admixing the blast furnace gas with a carrier gas, removing from said admixture CO, CO.sub.2 and H.sub.2 thereafter feeding the remaining gas admixture comprising carrier gas and N.sub.2 into a nitrogen measuring means. Also disclosed is an apparatus therefore, especially one which permits said removal by oxidation of CO and H.sub.2 and adsorption of the CO.sub.2 and H.sub.2 O.

Abstract: A process for hot topping by electro-slag-remelting in which before or before and during hot-topping a portion of the liquid remelting slag in the mold is removed in order to achieve a hot topping of the ingot under a reduced amount of slag.

Abstract: An improvement in the method of desulfurizing molten pig iron by forming a fluidized stream of a solid desulfurizing agent consisting of finely divided calcium carbide which is contained in a pressure vessel which comprises a discharge connected to an immersion lance by a conveying pipe, by injecting a fluidized gas at a pressure upwardly into the desulfurization agent, withdrawing the resultant fluidized desulfurizing agent from the pressure vessel, introducing a separate stream of gas into the conveying pipe and conveying said fluidized desulfurizing agent together with the fluidizing and feeding gases into the pig iron through said immersion lance, determining the amount of the solid desulfurizing agent, and the through-flow quantity of gas flow, being the sum of amount of fluidizing gas and the amount of feeding gas, and maintaining a predetermined gas/solid ratio which improvement comprises using as the desulfurizing agent finely divided calcium carbide mixed with a solid material which decomposes or eva

Abstract: Residual slag incrustations containing calcium oxide are removed from a surface in the presence of which molten iron has been desulfurized by contacting said incrustations with a source of an oxide of boron.

Abstract: An improvement in a process for dispensing a fluidizable solid from the lower portion of a pressure vessel equipped with a weighing device, a closable supply, a discharge, and a source of three gas flows, a first of which is applied within the vessel at a level above the solid to be fluidized, a second of which is applied within said vessel in a lower portion thereof, and a third of which is applied within the discharge orifice of the vessel, which discharge orifice terminates in a chamber, which improvement involves determining the amount of solid dispensed and determining the throughflow of gas in relationship to the amount of solid dispensed to maintain a constant gas/solid ratio while maintaining the pressures such that the pressure applied to the lower portion of the vessel is greater than the pressure applied at a level above of the solids which, in turn, is greater than the pressure applied to the discharge orifice, all of which are greater than the pressure maintained within the chamber, and an appara