Abstract: The invention relates to a process for the desulphurization treatment of a pig iron melt in a container. The characterizing feature of the invention is that the treatment is performed in three phases:In the initial phase such solids are injected that deoxidize the initial slag and increase its basicity and also produce a circulatory movement of the melt and form a basic deoxidized cover slag. In the middle phase the desulphurizing agent is injected for the main desulphurization and in the final phase such solids are injected that purify the melt and produce a final desulphurization and also so influence the desulphurization slag formed that its content of iron granules is low.

Abstract: A zinc- and lead-containing residue from a metallurgical plant is reprocessed by a thermal treatment in a circulating fluidized bed system. A major part of the heat demand is satisfied by a combustion of solid carbonaceous material in the fluidized bed reactor of the circulating fluidized bed system. A reducing fluidizing gas, which is virtually free of free oxygen, is fed to the lower part of the fluidized bed reactor. A solid carbon content of from 5 to 30% is adjusted in the fluidized bed in the lower portion of the fluidized bed reactor, which is supplied in its upper portion with oxygen-containing gases and in which CO.sub.2 is formed only at such a rate that zinc metal is not reoxidized. Substantially all solids are removed in a recycling cyclone from the suspension discharged from the reactor and the removed solids are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dust-like zinc compounds and lead compounds are removed from the gas.

Abstract: A process for desulfurizing molten iron using a fine-grain agent consisting essentially of industrial calcium carbide, a dried coal, the coal containing at least 15% by weight of volatile components, and fine-grained magnesium and which agent is injected in fluidized form into an iron melt by means of a gas, comprising separately storing fine-grained magnesium and a calcium carbide/coal mixture, separately fluidizing the fine-grained magnesium and calcium carbide/coal mixture, combining the fluidized fine-grained magnesium and calcium carbide/coal mixture in a conveying line or lance and injecting the resultant combined fluidized mixture into an iron melt.

Abstract: A fine-grained agent for desulfurizing molten iron comprising industrial calcium carbide, dried coal which contains at least 15% by weight of volatile constituents and which, immediately after being passed into the molten iron, releases at least 80 standard liters of gas per kg of coal, and optionally contains fine-grained magnesium. The coals used are lignites, flame coal, gas-flame coal, gas coal or coking coal. The agent is prepared by addition of the dried coal to the calcium carbide, if appropriate, pre-crushed, and common comminuted to a grain size of 90% <200 .mu.m. The fine-grained magnesium is present in the agent either in uniform distribution, or it is stored and fluidized separately from the carbide/coal mixture and added to the carbide/coal mixture in the transport line or in the lance, if appropriate, with variation during injection.

Abstract: A method and composition for desulfurization of hot metal is disclosed. To the hot metal there is added a composition comprising calcium carbide, a hydrogen releasing compound and magnesium.

Abstract: The invention relates to a process for desulphurizing hot metal in a ladle, in particular in a torpedo ladle, wherein first aluminum and then, by means of a carrier gas, lime (CaO) are blown into the hot metal. The characterizing feature of the invention is that at a rate of 2-20 liters (S.T.P.) of carrier gas/kg of desulphurizing agent, a solid which evolves a gas in the hot metal is blown in together with the lime.

Abstract: A process is described and claimed for reducing the iron content of a CaO-rich slag which is formed during the desulphurization of molten crude iron which comprises adding finely-ground fluorspar to the melt, in the ladle, or adding it to the lade prior to adding the crude iron thereto, in an amount such that the slag is not rendered fluid.

Abstract: The present invention provides a desulphurizing agent, especially for iron melts, based upon calcium carbide and diamide lime, wherein it contains a diamide lime which has been post-treated by flotation or air sifting. The diamide lime used preferably contains 18 to 40% of free carbon.

Abstract: A ladle covered by a lid suitable for carrying out metallurgical reactions, particularly desulphurization, characterized by the fact that the lid is spaced above the ladle so that the edge of the lid overlaps the edge of the ladle, thereby forming an annular slot. A collar open at the top and bottom is inserted in the ladle and is attached to the lid to form outlets for ambient air.

Abstract: Molten metals, especially molten pig iron, are desulfurized by contacting them with a composition comprising calcium carbide or calcium cyanamide and an additive agent yielding water or hydrogen at the temperature of the molten metal; preferred as the additive agents are the alkali metal hydrides, polyethylene or polyamide for yielding hydrogen and hydrate of lime and alkaline earth borates for yielding water.

Abstract: Finely granular desulfurizing agents for iron melts, consisting of at least one alkaline earth metal carbonate and at least one reducing metal carbide and optionally a reducing metal or an alloy thereof, are outstandingly effective in desulfurizing action and, based on the high degree of utilization of said agent, increase the amount of slag formed only to a negligible degree.

Abstract: Molten metals, especially molten pig iron, are desulfurized by contacting them with a composition comprising calcium carbide or calcium cyanamide and an additive agent yielding water or hydrogen at the temperature of the molten metal; preferred as the additive agents are the alkali metal hydrides, polyethylene or polyamide for yielding hydrogen and hydrate of lime and alkaline earth borates for yielding water.

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