Abstract: A direct current arc furnace is described with a cathodic electrode held in the center of the melting vessel and an anodic bottom electrode arrangement in the vicinity of an electrically conductive lower vessel from the vessel wall to the melt. The current supply and removal takes place on one side via leads to a rectifier power supply set up in spaced manner alongside the furnace. The lower vessel is connected in several quadrants with leads and in the vicinity of each quadrant a connecting plate is provided on the furnace wall. Close below the arc the power supplies are led in a horizontal plane to the furnace wall. The current intensity for the quadrants of the lower vessel adjacent to the rectifier power supplies is lower than that of the power supplies to the remaining quadrants. The spacings of the connecting plates for the quadrant areas can be unequal.

Abstract: A process for producing pig iron is described, which contains a reducing shaft furnace 1 and a melting gasifier 2. The sponge iron produced from iron ores in the reducing shaft furnace is supplied to the melting gasifier and converted there into a pig iron melt. The gas produced in the melting gasifier is supplied directly via a line 4 as reducing gas to the reducing shaft furnace. The blast furnace gas passing out of the reducing shaft furnace, after traversing a CO.sub.2 scrubber 6, is at least partly heated in a heat exchanger to 200.degree. to 500.degree. C. and passed to a partial combustion plant 13 where, accompanied by the addition of oxygen, the gas is heated to the necessary reducing temperature.

Abstract: A lining for a direct-current electric-arc furnace, in which at least part of that regions of said furnace which receives the melt is provided on the inside with an electrically conductive, refractory brick lining and a ring-shaped current conductor, on its outside, constitutes the opposite pole to the upper electrode centrally extending into said surface. The entire bottom area is covered with a refractory, insulating brick lining and a brick lining of graphite bricks is applied onto that brick lining in the radially outer wall region of the furnace. Located adjacent thereto in radially inward manner is an annular zone, comprising an electrically conductive, refractory brick lining. The central bottom area above said insulating brick lining is consittuted by a monolithic ramming mass. Furthermore, the material of the wall of said furnace above said brick lining of graphite bricks largely corresponds to that of said insulating brick lining at the hearth bottom.

Abstract: A process for producing pig-iron is described involving the use of a reduction shaft furnace 1 and a melt-down gasifier 2. The sponge iron produced from iron ore in the reduction shaft furnace is fed into the melt-down gasifier and converted into a pig-iron melt. The gas produced in the melt-down gasifier is passed as reducing gas into the reduction shaft furnace both via a cyclone separator 11 and a line 12 and directly via a line 13. The top gas leaving the reduction shaft furnace, after passing through a scrubber 4, is largely returned via a CO.sub.2 scrubber 6, in which CO.sub.2 and H.sub.2 O are removed from the top gas, in such a way that it can be used for forming the reducing gas in the melt-down gasifier and also as a cooling gas for the reducing gas produced in said gasifier.

Abstract: A device is described for straightening a curved steel strand cast continuously by means of a casting wheel machine or a curved mold continuously casting machine. The strand is passed between straightening points with rolls, such as straightening, bending, guide, counter rolls and/or corresponding roll pairs, in accordance with a certain physical law, whereby at least two roll pairs applying bending moments to the strand are provided. The first roll pair is at the same time the roll pair located in the direction of travel of the strand directly downstream of the point of emergence of the strand from the casting machine or is formed by the casting wheel (of the curved mold) itself and a corresponding straightening roll. The second roll pair determines transition of the strand from a finite radius or curvature to a straight line (infinite radius of curvature) at the end of the bending zone. Between these two roll pairs other rolls can be located exclusively along the outside of the strand.

Abstract: A method is disclosed for pretreatment of a lumpy carbon carrier suitable for forming a fluidized bed and a solid bed used in the production of pig iron from iron ore. The ore is pre-reduced in at least one reduction plant and the thus produced iron sponge is subsequently final reduced and fused in a melt-down gasifier with the help of the lumpy carbon carrier and an oxygen-containing gas and is the carbon carrier is fed into the upper part and the oxygen-containing gas is fed into the lower part of the melt-down gasifier. These materials form, together with the iron sponge, a fluidized bed in the melt-down gasifier. Below the fluidized bed, a solid bed is formed consisting of said lumpy carbon carrier. A suitable carbon carrier may be formed by pretreating available coal by one of two methods. Lumpy coal tending to burst upon subjection to a shock-like thermal load is preheated for a minimum of one hour at a temperature of at least 300.degree. C.

Abstract: A process for producing sponge iron from iron ore is described, which is reduced to sponge iron in a reduction shaft furnace by means of a hot reduction gas. For this purpose reduction gas at a temperature in the range 750.degree. to 900.degree. is introduced into shaft furnace (1) level with bustle plane (5) having been produced in a gasifier (2) then cooled and purified in a cyclone separator (12). Reduction gas is introduced below the bustle plane (5) at a temperature below that of the reduction gas introduced in the bustle plane and is preferably introduced into the shaft furnace (1) between 650.degree. and 750.degree.. Increased carburization of the sponge iron is obtained. Increased carbon separation also results through a volume increase, particularly by increasing the cross-section through the lower part of the shaft furnace.

Abstract: A heating bath including molten metal is situated at an entry into a hot roll mill such that the metal stock entering the hot roll mill passes through the heating bath to acquire heat therefrom. A cooling bath including molten metal is situated at an exit from the hot roll mill such that the metal stock exiting from the hot roll mill passes through the cooling bath delivering heat thereto. The molten metal in each of the baths is caused to flow counter to the direction of passing of the metal stock therethrough to form within each bath a hotter fraction and a cooler fraction of the molten metal. The molten metal is circulated between the heating bath and the cooling bath so that a hottest fraction of the molten metal in the cooling bath is transferred to the heating bath and a coolest fraction of the molten metal in the heating bath is transferred to the cooling bath.

Abstract: A process for producing pig iron is described involving the use of a reduction shaft furnace 1 and a melt-down gasifier 2. The sponge iron produced from iron ore in the reduction shaft furnace is fed into the melt-down gasifier and converted into a pig iron melt. The gas produced in the melt-down gasifier is passed as reducing gas into the reduction shaft furnace both via a cyclone separator 11 and a line 12 and directly via a line 13. The top gas leaving the reduction shaft furnace, after passing through a scrubber 4, is largely returned via a CO.sub.2 scrubber 6, in which CO.sub.2 and H.sub.2 O are removed from the gas, in such a way that it can be used for forming the reducing gas in the melt-down gasifier and also as a cooling gas for the reducing gas produced in said gasifier.

Abstract: An apparatus for charging a melting gasifier (2) with gasification media and with sponge iron discharged from a direct reduction shaft furnace (1) arranged above the melting gasifier is described. This comprises inlets and outlets in the lower part of the shaft furnace, connecting lines (4) in the form of downcomers between the shaft furnace and the gasifier in the upper region of the latter, symmetrically to the longitudinal axis of the shaft furnace and/or the gasifier and discharge means (7) for the sponge iron, such as screw conveyors or the like aligned radially to said longitudinal axis. The connecting lines at least approximately vertically issue into the lowermost, substantially horizontal base region of the shaft furnace. The discharge means are arranged at the melting gasifier inlets (9) in the discharge direction behind the connecting lines and the gasification medium inlet (3) is located in the longitudinal axis of the melting gasifier immediately adjacent to the sponge iron inlets.

Abstract: A process for melting metal scrap, particularly steel scrap or such high-melting charge material in a shaft furnace operated in cokeless manner by means of fluid fuels is described. The furnace shaft used for carrying out the process is separated from the furnace hearth connected to the bottom thereof by means of a cooled grate arrangement. The burners issue substantially vertically to the longitudinal axis of the shaft into the furnace and the combustion air is recuperatively preheated by means of the shaft furnace waste gases. The amount of heat introduced into the melting unit by means of the burners is subdivided in dosable manner into a component drawn off from the furnace shaft and a component remaining in the furnace hearth. For this purpose the radiating surface of the wall lining in the furnace hearth is between 1.5 and 3.5 m.sup.2, particularly 2 and 2.8 m.sup.2 ton of molten metal produced. The radiation-active, average layer thickness of the gas in the furnace hearth is between 1.5 and 3.

Abstract: Described is a method for operating a melt-down gasifier(4) in which iron-ore-containing charge materials or iron sponge obtained from same by direct reduction are smelted due to the addition of carbon carriers and blowing an oxygen-containing gas through oxygen nozzles (6) into a fluidized bed created by same, and are (further) reduced to make liquid pig iron or steel starting material. On failure or reduction of the oxygen supply below a predetermined quantity and on failure of the water cooling system of the oxygen nozzles, the still present oxygen supply is cut-off and an inert gas is fed into the melt-down gasifier through the said oxygen nozzles instead, for protecting said oxygen nozzles. Thus, liquid fluidized bed matter is prevented from penetrating into the oxygen nozzles and to solidify in same. In the case of failure of the water cooling system of the oxygen nozzles, the inert gas serves also at the same time as cooling medium.

Abstract: There is disclosed a process of dezincifying the flow of material at the operation of a plant for the production of pig iron including a direct reduction shaft furnace and a meltdown gasifier.The crude reducing gas drawn off the meltdown gasifier is dedusted in two steps. In the first step zinc-poor coal dust is separated in a cyclone operated at a higher temperature, which is recycled into the meltdown gasifier. In the second step, upon cooling of the gas leaving the first cyclone, solid particles enriched with zinc are separated at a lower temperature. The dezincified reducing gas is fed to the direct reduction shaft furnace and the zinc-rich substances separated off the second cyclones are processed to a zinc concentrate.